NLS2009061, Response to Request for Additional Information for the Review of the License Renewal Application

Response to Request for Additional Information for the Review of the License Renewal Application

ML092400412
Person / Time
Site:	Cooper
Issue date:	08/13/2009
From:	Minahan S Nebraska Public Power District (NPPD)
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
NLS2009061
Download: ML092400412 (421)

Text

H Nebraska Public Power District

'Always there

Always there when when you you need us" us" 54.17 54.17 NLS2009061 13, 2009 August 13, R~gulatory Commission U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555-0001

Subject:

Response to Request for Additional Information Information for the Review of the Cooper Cooper Nuclear Station Station License License Renewal Application Renewal Application Cooper Cooper Nuclear Station, Docket No. 50-298, DPR-46

References:

1.

1. Letter from Tam Tran, U.S. Nuclear Regulatory Regulatory Commission, to Stewart B. Minahan, Nebraska Public Public Power District, dated July 14, 14, 2009, "Request "Request for Additional Information for the Review of the Cooper Nuclear Station License License Renewal Renewal Application Application (TAC No. MD9763 and MD9737)." MD9737)."

(ADAMS (ADAMS Accession Accession Number ML091880478)

Number ML091880478)

2. Letter from Tam Tran, U.S. Nuclear Regulatory Regulatory Commission, to Stewart B. Minahan, Nebraska Public Power District, dated July 14, 14, 2009, "Request "Request for Additional Information for the Review of the Cooper Nuclear Nuclear Station License Renewal Application (TAC No. MD9763 and MD9737)." MD9737)."

(ADAMS Accession Number ML091900645) ML091900645)

3. Letter from Stewart B. Minahan, Nebraska Public Power District, to U.S.

Nuclear Nuclear Regulatory Regulatory Commission, dated September "License September 24, 2008, "License Renewal Application."

Application."

Dear Sir or Madam:

The purpose of this letter is for the Nebraska Nebraska Public Power District to respond to the Nuclear Regulatory Commission Commission Requests Requests for Additional Information (RAI) (References (References 1 and 2) regarding regarding the Cooper Cooper Nuclear Nuclear Station License Renewal Renewal Application (LRA). These responses are provided provided in Attachments 1 and 2, respectively. Certain Certain changes to the LRA (Reference(Reference 3) have been made to reflect reflect these RAI responses and other clarifications.

clarifications. These changes are provided in . 3.

Should you have any questions regarding this submittal, please contact contact David Bremer, License License Renewal Project Manager, at (402) 825-5673.

825-5673.

COOPER NUCLEAR NUCLEAR STATION STATION P.O.

P.G. Box 98! Browni/Oe, NE 98 / Brownville, 68321-0098 NE 68321-0098 Telephone: (402) 825-3811 Telephone: (402) 825-3811 !/ Fax:

Fax: (402)

(402) 825-5211 825-5211 www.nppd.com www.nppd.com

NLS2009061 Page 2 of2 of 2 I declare declare under penalty penalty of perjury that the foregoing is true and correct.

Executed on 'J Av (Date)

(Date) 1

,*/*te *2.) 0 2., IJ (J l1

~tf4~L Sincerely, Stewart B. Minahan Stewart Minahan Vice President President - Nuclear and Chief Nuclear Officer Officer

/wV Iwv Attachments cc: Administrator wi Regional Administrator w/ attachments USNRC - Region IV IV Cooper Project Manager Manager wi w/ attachments attachments USNRC - NRR Project Directorate IV-1 IV- 1 Senior Senior Resident Inspector wi w/ attachments attachments USNRC -- CNS Nebraska Health Health and Human ServicesServices w/

wi attachments Department of Regulation Department Regulation and Licensure Licensure NPG Distribution wi w/ attachments attachments CNS Records Records wi w/ attachments attachments

4 ATTACHMENT 3 ATTACHMENT LIST OF REGULATORY COMMITMENTS© OF REGULATORY COMMITMENTS©4 4

ATTACHMENT 33 ATTACHMENT LIST REGULATORY COMMITMENTS0 OF REGULATORY LIST OF COMMITMENTS©4 Correspondence Number: NLS2009061 Correspondence The following table identifies those actions committed to by Nebraska Nebraska Public Power District (NPPD) in this document. Any other other actions discussed discussed in the submittal represent intended or planned planned actions by NPPD. They are described described for information only and are not regulatory commitments. Please Please notify the Licensing Manager at Cooper Nuclear Licensing Manager Nuclear Station of any questions questions regarding this document or any associated regulatory commitments.

COMMITMENT COMMITMENT COMMITTED DATE COMMITTED DATE COMMITMENT COMMITMENT NUMBER NUMBER OUTAGE OR OUTAGE None None J

PROCEDURE PROCEDURE 0.42 REVISION 24 PAGE 25 18 OF 25

NLS2009061 Attachment Page 1 of 19 Attachment Attachment 1 Response to Request Request for Additional Information Information License Renewal for License Renewal Application Application Cooper Nuclear 50-298, DPR-46 Nuclear Station, Docket No. 50-298, DPR-46 The Nuclear Regulatory Regulatory Commission (NRC) Request Request for Additional Information Information (RAI) regarding the License regarding License Renewal Renewal Application Application is shown in italics. The Nebraska Nebraska Public Power District's (NPPD) response to each RAI is shown in block block font.

RAI B.I.37-3 NRC Request: RAIB.1.37-3

Background

License Renewal Application (LRA) aging Application (LRA) aging management program (AMP) managementprogram (AMP) B.I.37, B. 1.3 7, "Thermal Aging "Thermal Aging and Neutron and Embrittlement of Cast Neutron Embrittlement Cast Austenitic Austenitic Stainless Steel, " manages Stainless Steel, manages the reduction reduction of of fracture toughness due to thermal fracture toughness aging and thermal aging and reduction reduction ofoffracture toughness due to radiation fracture toughness radiation embrittlement on the intended embrittlement intendedfunction cast austenitic function of cast austeniticstainless stainless steel (CASS) components.

components. The AMP includes includes screening screeningcriteria criteria to identifY identify susceptible susceptible components and andfor for each potentially potentially susceptible component aging susceptible management is accomplished aging management accomplished by either either a supplemental supplemental examination examination component-specific evaluation or component-specific evaluation of susceptibility.

susceptibility. The applicant claims that applicant claims that AMP B.I.37 B. 1.3 7 is consistent consistent with Generic GenericAging Lessons LearnedLearned (GALL)

(GALL) report report aging aging management program (AMP) program (AMP) XI.M13.

XI.MI3.

Issue The "Scope of Program Program""program program element of the GALL report report states: "Forpotentially states: "For potentially susceptible components, the program susceptible components, program provides provides for the consideration consideration of the synergistic synergistic loss ofof fracture toughness due to neutron fracture toughness embrittlement and neutron embrittlement and thermal aging embrittlement." Also, thermal aging StandardReview Standard Planfor Review Plan for Review ofLicense Renewal Application Applicationfor NuclearPower for Nuclear Plants Power Plants (SRP-LR), Table Table 3.1-2, 3.1-2, Rev. 1, states: The programconsists states: Theprogram consists of(1) of(1) determination determination of the susceptibility susceptibility of cast cast austenitic austeniticstainless stainless steel components to thermal thermal aging aging embrittlement, embrittlement, (2)(2) accountingfor the synergistic accountingfor synergistic effects of thermal thermal aging and neutron aging and neutron irradiation, irradiation, and (3) implementing implementing a supplemental supplemental examination examination program, program, asas necessary.

necessary. However, However, item (2) regarding regarding the synergistic synergistic effects of thermal thermal aging aging and neutron embrittlement is omitted in the updated neutron embrittlement safety analysis analysis report (USAR) supplement described report (USAR) described in Section A.I.I.37.

A.1.].3 7. This omission omission implies implies that that this program consistent with the GALL Report AMP XI.MI3.

program may not be consistent XL.M13.

Request Clarify if ClarifY if the program programaccounts accounts for for the synergistic synergistic effects of thermal thermal aging aging and and neutron neutron embrittlement, and if embrittlement, if does, does, explain how the synergistic synergistic effects of thermal aging and thermal aging and neutron neutron embrittlement embrittlement areare considered considered in the program program or provide provide a reference reference where this information information is available. explain the inconsistency available. Also, explain light-water reactor inconsistency between light-water reactor Section A. .1.3 7 and A.I.I.3 Table 3.1-2.

SRP-LR, Table 3.1-2.

NLS2009061 Attachment Page 2 of 19 NPPD Response:

As stated in LRA Appendix B, Section B.1.37, B. 1.37, the Thennal Thermal Aging and NeutronNeutron Irradiation Irradiation Embrittlement Embrittlement of CASS Program will be consistent with the program described described in NUREG-NUREG-1801,Section XI.M13, 1801, XI.M13 , Thermal Thennal Aging and Neutron Irradiation Irradiation Embrittlement Embrittlement of Cast Austenitic Austenitic Stainless Stainless Steel (CASS) Program. The synergistic effects ofthennal synergistic effects of thermal aging neutron and neutron embrittlement embrittlement will be addressed in the Cooper Nuclear Station (CNS) program Station (CNS) program as they are in the NUREG- 1801 program. The CNS operating NUREG-1801 experience review operating experience review process evaluates evaluates industry technical developments technical developments and incorporates relevant guidance into appropriate site programs and procedures.

procedures. This process ensures ensures that new industry developments developments regarding the synergistic synergistic effects effects of thermal aging and neutron embrittlement will be evaluated and relevant guidance ofthennal guidance incorporated into the appropriate incorporated appropriate site programs.

LRA Section A.I.l.3 A. 1. 1.377 addresses addresses and is consistent consistent with the three program elements described in in NUREG-1800, NUREG-1800, Table 3.1-2. However, to further clarify program consistency, subsection (a) of (a) of the third paragraph paragraph ofLRAof LRA Section A. 1. 1.1.37 1.37 is revised as shown in Attachment Attachment 3, Change 11. 11.

NRC Request: RAI3.6-1RAI 3.6-1

Background

LRA Section In LRA Section 3.6.2.2.2, 3.6.2.2.2, the applicant applicantstates states the surface surface contamination buildup of contamination buildup high-voltage ofhigh-voltage insulators is gradual insulators gradual and and in most areas areas washed away by rain and rain and the glazed glazed surface aids this aids contamination removal. The surface contamination removal. surface contamination contamination of insulators insulators can be a problem in areas areas where there there are greaterconcentrations are greater concentrationsof airborne airborne particles particles such as nearnearfacilities facilities that dischargesoot or near discharge near the seacoast seacoastwhere salt spray spray is prevalent.

prevalent. The applicant applicantclaims that Cooper Nuclear Cooper Nuclear Station (CNS) is not located Station (CNS) near the seacoast located near seacoastor nearnear other sources sources of airborne airborne particles; therefore, surface particles; therefore, contaminationis not an aging surface contamination aging effect requiring management. During requiring management. During the license renewal renewal audit at CNS in April 2009, audit at 2009, the staff reviewed significant significant condition condition report report (SCR) 2003-1844 (SCR) 2003-1844 and and noted thatthat on October October 28, 2003, a pole fire on a cross arm arm between the 345 kVsub yard and kV sub yard and main main unit transformer transformeroccurred.

occurred. As a resultresult of the fire, fire, the southern southern end of of the beam or crosscross member burned burned through through allowing allowing the C phasephase to drop, drop, but remained remained suspended suspended above the ground. southern insulator ground. The southern insulator on the disconnect disconnect switch was damaged.

damaged.

also stated The SCR also stated that that dustfibers fibers and particles particles from the harvesting harvesting ofsoybeans soybeans and disc operationof the adjacent operation adjacent farm farm field field near near the switchyard, switchyard, settled on the exterior exterior surface surface of the insulatorbells and insulator and became wetted during during highfog or light light rain/mist rain/mistconditions.

conditions. This contaminationwith light contamination light moisture moisture caused leakage current caused leakage across the insulators, current across insulators, which resulted resulted in aafire.

fire. The staff also noted that that the identicalfire also occurred identical fire also occurredin the CNS switchyard switchyard on the 345 kVkVBooneville Booneville wooden structure structure in 1997 due to the insulator insulatorcontamination.

contamination.

Issue Issue Contaminant(e.g., dust)

Contaminant dust) collection on high-voltage high-voltage insulators, and when with light insulators, and light rain rain or moisture, can moisture, can form afilm a film on the insulators and creates insulators and creates path a path for electricity electricity to flow across. A across.

NLS2009061 Attachment Page 33 of 19 small amount amount of electricity electricity can leak through through this path path and create create phase phase to phase phase or phase phase to ground fault.

ground fault.

Request Explain Explain why degradation degradationof of insulator insulator quality due due to surface surface contamination contaminationof farm dust is not an offarm an aging effect aging effect requiring management since plant requiring management plant operations operations have experiencedinsulator failures at experienced.insulatorfailures eNs.

CNS.

NPPD Response:

The 2003 condition was event driven and its root cause was addressed addressed through a design modification. The identified condition did not involve a degradation of insulator quality. The light surface contamination identified in this event did not cause arcing across the insulator or flashover, as has been been observed in other industry industryoperating operating experience, such as in coastal plants.

It is common to have small amounts ofleakage of leakage current across a high voltage voltage insulator, which allows a charge to build up on the cold end of the insulatorinsulator if the insulator is not properly properly grounded. On a steel structure this ground ground path is intrinsic to the structure. On a wooden structure, the ground path has to be added by design.

During the integrated plant assessment, NPPD identified where CNS experienced experienced a cross-arm fire on a wood transmission structure between between the 345 kV sub yard and main unit transformer.

This transmission transmission line is not in the scope oflicense of license renewal, but the condition was evaluated evaluated and documented documented in the site operating experience experience and aging management management review (AMR) reports, because of similarities in-scope transmissions lines. The following problem statement was similarities to in-scope documented documented in the root causecause report:

"On October "On October 28, 2003 at 01 01:30

30 a.m.,

a.m., Security notified the Control Room of a pole fire on the cross arm between between the 345 kV sub-yard sub-yard and main unit transformer. The Control Room performed a manual reactor scram scram at 02:00 a.m. to stabilize conditions. As a result of the fire, the south end of the beambeam or cross member member burned through allowing the C phase to drop, but suspended above ground. The south insulator remained suspended insulator on the disconnect switch was damaged damaged by the impact caused by this conductor and later fell to the ground when the switch was opened.

No automatic actuations actuations were experienced experienced or required."

required."

The damage identified in this event was a result of the fire, not a result of an electrical fault or or arcing. There was no automatic actuation resulting from a failure of the 345 kV line that would would indicate indicate an electrical fault. Operations manually manually shut down the reactor, as a conservative measure in case the 345 kV line failed.

According According to the root causecause report, surface contaminant contaminant buildup on the 345 kV high-voltage insulators caused insulators caused by high humidity coupled with airborne corn/soybean particles particles during harvest, allowed allowed a charge to build-up build-up on the cold end of the high-voltage high-voltage insulator string due to corona.

NLS2009061 Attachment Page 4 of 19 The combination combination of these conditions is a rare event that can occur occur independent independent of the age of the itself, corona does not typically cause sufficient heat to generate affected insulators. By itself, generate a fire.

The root cause evaluation evaluation determined determined that cracks cracks in the cross arm were filled with moisture and dust/fiber particles. The natural resistance resistance in the cross arm material generated generated enough heat to cause a fire. A similar event has occurred occurred on other NPPD 345 kV poles with cross arms, such as in the NPPD switchyard at CNS on the 345 kV Booneville Booneyille wooden structure structure in 1997. Cross arm fires on 345 kV wooden wooden structures in the NPPD system were eliminated by bonding a grounding conductor to the cold end of each insulator conductor insulator string, across the top of the cross arms, and down the provides a safe path to ground for the stray currents created pole. This provides conditions.

created by these conditions.

The 2003 event event was limited to the 345 kV high-voltage high-voltage insulators insulators and wooden wooden structures.

Similar 345 kV wooden structures at CNS were were removed or grounded to prevent similar events.

This design deficiency deficiency is not applicable to the 161 kV wooden structures.

In summary, the 2003 event was due to the fact that the pole structure was not properly properly grounded, thus allowing stray voltages voltages to build up on the high voltage insulator insulator cold end end resulting in enough heat to ignite the wooden cross arm. By properly grounding grounding the cold end, the voltage potential that could be caused caused by corona from a similar event event would be harmlessly harmlessly drained to ground. The incident incident was event driven as a design deficiency, not an aging issue. It is therefore concluded therefore concluded that the surface contamination of farm dust on high-voltage insulators surface contamination insulators is not an aging effect requiring management management for the period of extended operation.

NRC Request: RAI RAI 3.6-2

Background

The most prevalent mechanism contributing prevalent mechanism contributingto loss of conductor conductorstrength strength of an aluminum aluminum core core steel reinforced reinforced (ACSR)

(A CSR) transmission conductor is corrosion, transmission conductor corrosion, which includes includes corrosion corrosion of the core and steel core and aluminum aluminum stand standpitting.

pitting. For conductors, degradation For ACSR conductors, begins as a loss of degradation begins of zinc from the galvanized galvanized steel core wires.

wires. In LRA LRA Section 3.6.2.3, the applicant applicant states that the 4/0 ACSR transmissionconductor ACSR transmission conductor as as tested in the Ontario OntarioHydro Hydro test bounds bounds the CNS CNS transmission transmission conductors.

conductors. The applicant applicantfurther states that further states that transmission transmissionconductors conductors at CNS will have ample strength through the period strength through period of extended operation.

operation.

Issue Loss of conductor conductor strength corrosioncould strength due to corrosion could occur in transmission transmissionconductors.

conductors. The applicant did applicant did not demonstrate demonstrate how plant-specific transmissionconductors plant-specific transmission conductors at at CNS would have adequate design adequate design margin margin to perform their their intendedfunction during the period function during period ofof extended operation.

operation.

Request Explain Explain in detail detail how plant-specific transmissionconductors plant-specific transmission conductors at CNS would have adequate adequate design margin design margin to withstand withstand the heavy load requirementsafter load requirements after a degradation degradation of conductor

NLS2009061 Attachment Page 5 5 of 19 strength due to corrosion to perform their intendedfunction during the period of extended strength due to corrosion to perform their intended function during the period of extended operation.

operation.

NPPD Response:

As stated in the CNS LRA, corrosion in ACSR conductors conductors is a very slow acting mechanism, and the corrosion corrosion rates depend largely on air quality, which includes suspended suspended particle chemistry, SO 2 concentration S02 concentration in air, precipitation, precipitation, fog chemistry chemistry and meteorological meteorological conditions. Air in rural areas generally contains contains low concentrations concentrations of corrosive corrosive suspended particles particles and SO S02,2 , which keeps keeps the corrosion rate to a minimum. In the immediate immediate rural area surrounding CNS there are no industries that emit corrosive corrosive suspended particles particles or S02.

The following three type of ACSR conductors conductors are used for in-scope in-scope transmission lines at CNS:

336.4 MCM 26/7 ACSR: [Ultimate Strength 14050 lbs. / Heavy Load 4327 lbs.] Initial 69.2% 1 Design Margin 69.2%'

397.5 MCM 26/7 ACSR: [Ultimate [Ultimate Strength 16190 lbs. / Heavy Load 4810 lbs.] Initial Design Margin 70.3%70.3%

4/0 AWG (212 MCM) 6/1 ACSR: [Ultimate [Ultimate Strength 8350 lbs. / HeavyHeavy Load 2761 2761lbs.]

lbs.]

Initial Design Design Margin Margin 66.9%

The size of the transmission conductor is indicated by the first number. The two numbers ofthe "MCM" are the number of conducting strands and the number following "MCM" number of supporting strands.

License renewal applicants applicants use the 4/0 ACSR example because it has the lowest strength margin initially, which means it also has the lowest strength margin after aging.

A 4/0 ACSR (212 MCM) with a 6/1 stranding transmission conductor conductor type has the lowest initial design margin in the National Electrical Safety Code (NESC). Also, the 6/1 stranding stranding (6 galvanized steel strand) is the most susceptible aluminum strands, and 1 galvanized susceptible to corrosion. Evaluation Evaluation of the 4/0 ACSR conductor ofthe conductor type shows the conservative conservative nature of the design of transmission transmission conductors. The following illustration using the 4/0 ACSR transmission conductor conductor demonstrates reasonable reasonable assurance assurance that the CNS transmission conductors will have ample strength through through the period period of extended operation.

The NESC requires that tension on installed conductors conductors be a maximum maximum of 60% 60% of the ultimate conductor strength. So by NESC design, the minimum initial ultimate strength strength margin including including heavy loading requirements requirements is 40%.

I During During the preparation preparation of this response, a typographical typographical error error was noted in LRA Section 3.6.2.2.3 on Page LRA Section Page 3.6-5.

3.6-5.

This section section has been revised to provide a correction correction (see Attachment Attachment 3, Change Change 9).

NLS2009061 Attachment Page 6 of 19 Page The NESC also provides provides a method to calculate the maximum tension tension on a conductor under assumed heavy load conditions, which includes consideration temperature consideration of ice, wind and temperature extremes. The NESC method was used for calculatingcalculating the heavy load tension (the maximum tension load) for the NPPD transmission conductors.

conductors. The ultimate strength and the maximum maximum tension load of 4/0 ACSR are 8350 lbs. and 2761 lbs. respectively. The margin between between the maximum tension load and the ultimate strength is (8350 - 2761 == 5589) 5589Ibs., 5589 lbs., which isis (5589 / 8350 = 0.669) 67%

(5589/8350 67% of ultimate strength, which exceeds exceeds the NESC NESC initial design Hydroelectric study showed a requirement of 40% of ultimate strength margin. The Ontario Hydroelectric 30%

30% loss of composite composite conductor conductor strength strength in an 80-year old conductor. In the case of the 4/0 4/0 ACSR transmission conductors, conductors, a 30%

30% loss of ultimate strength would createcreate an ultimate strength strength for an 80-year 80-year old 4/0 ACSR cable of [8350 - (0.30 X 8350) = = 5845] 5845 lbs. With the maximum maximum tension load of2761lbs.,

of 2761 lbs., there would still be [5845 - 2761 == 3084; 3084 / 5845 =

3084/5845 0.5276] 52.8% of ultimate strength margin, which exceeds 0.5276] 52.8% exceeds the NESC initial design design requirement of 40% of ultimate strength margin.

Since Since the 4/0 ACSR conductor has the lowest initial design margin of transmission conductors in in the scope of license renewal renewal for CNS, CNS, all other conductors conductors are bounded by this example.

Because Because the 4/0 ACSR 6/1 conductor conductor was included included in the Ontario Hydroelectric Hydroelectric study, the bounding value of a 30% loss of composite conductor strength in an 80-year old conductor conductor is conservative conservative for other conductors, sincesince the single single steel strand is more susceptible susceptible to corrosion.

This illustrates with reasonable assurance that transmission transmission conductors will have ample strength through the period of extended operation.

For nearly all LRAs since 2001,2001, a similar approach has been accepted accepted for the discussion for aging effects effects for transmission conductors based on the bounding bounding example example of the 4/0 transmission conductor. A review of industry operating experience experience and NRC generic communications communications related to the aging of transmission conductors revealed that no additional aging effects effects exist beyond those identified. A review of plant-specific plant-specific operating experience experience did not identify any aging effects effects for transmission transmission conductors. Accordingly, Accordingly, loss of conductor conductor strength is not an aging aging effect effect requiring requiring management management for transmission conductors.

conductors.

NRC Request: RAI 3. 3.6-3 6-3

Background

LRA Section In LRA Section 3.6.2.2.3, the applicant applicantstates that the design states that design of transmissionconductor of transmission conductor and switchyard switchyard bus bolted connection preclude torque relaxation connection preclude torque relaxation as confirmed by plant-specific plant-specific operating operating experience experience (OE). design of switchyard (DE). The design switchyard bolted connections connections includes Bellville includes Bellville washers.

washers. The type of bolting boltingplate and and the use of Bellville washers industry standard washers is the industry standardto preclude torque relaxation.

preclude torque relaxation.

NLS2009061 Attachment Page 7 of 19 Issue Electric Electric Power Research Institute Power Research (EPRI)document TR-104213, Institute (EPRI) TR-104213, "Bolted Joint Maintenance "BoltedJoint Maintenance& &

Application Application Guide,"

Guide, " identifies specialproblem identifies a special problem with Belleville washers.

washers. It states that hydrogen embrittlement is a recurring embrittlement recurring problem with Belleville washers washers and springs. When springs and other springs. springs are electroplated, are electroplated,the plating plating process processforces hydrogen into into the metal grain boundaries. If grain boundaries. If the hydrogen removed, the spring hydrogen is not removed, spring may spontaneously spontaneously failfail at any time while in service.

service.

Request Identify if if electroplated electroplated Belleville washers are currently washers are currently used at CNS.CNS. IfIf they are, are, explain why hydrogen embrittlement hydrogen embrittlement is not a problem problem atat CNS.

CNS.

NPPD Response:

TR-104213 (December The focus of EPRI TR-I04213 (December 1995) 1995) is on the design design and assembly of pressure boundary, mechanical, and structural bolted joints. Part III of this report addresses mechanical mechanical joints, which includes electrical electrical connections. This report addresses electrical electrical connections for bus bar connections connections and terminal connections.

connections. This report does not address switchyard connections connections for transmission conductors conductors or switchyard bus. EPRI TR-I04213 TR-104213 (December 1995) 1995) Section Section 7.2.2 identifies the problem ofhydrogen'embrittiement of hydrogen, embrittlement for Belleville Section. 15.7.5.3 Belleville washers. Section 15.7.5.3 and the glossary further expand on the issue. Section 15.7.5 15.7.5 is the "Summary "Summary of Changes to Materials Specifications,"

Materials Specifications," and Section 15.7.5.3 is the "Summary Section 15.7.5.3 "Summary of Changes for ANSI B18.21.1." ANSI B18.21.1 BI8.21.1." B18.21.1 has not changed changed since 1972. One of the significant specification specification changes changes made in 1972 was to addressaddress embrittlement.

embrittlement. Prior to 1972, ANSI B B18.21.1 18.21.1 included no provision to prevent possible hydrogen embrittlement if if the washers were plated. The standard used by manufacturers manufacturers of electroplated electroplated steel products including including washers washers has addressed addressed the issue of hydrogen embrittlement embrittlement since 1972.1972.

Based on site documentation, documentation, the Belleville Belleville washers used for the in-scope transmission transmission conductor conductor and switchyard switchyard bus electrical connections electrical connections are either aluminum or stainless steel. Since the aluminum or stainless steel Belleville Belleville washers are not electroplated, there is not a hydrogen embrittlement embrittlement issue for electroplated electroplated Belleville Belleville washers for CNS.

As stated in LRA Section 3.6.2.2.3, 3.6.2.2.3, the switchyard component connections are included in the routine maintenance maintenance of the 161 kV and 69 kV switchyards, switchyards, which verifies verifies the effectiveness effectiveness of of connection design the connection design and installation practices.

practices. These routine tasks verify the condition of the switchyard electrical connections switchyard electrical connections for CNS.

NRC Request: RAI 2.4-1 RAI2.4-1 Section XII-2.3.5.1.8 of the Cooper SectionXII-2.3.5.1.8 Cooper Nuclear Station (CNS)

Nuclear Station (CNS) USAR discusses discusses ajib ajib crane crane located located at the equipment equipment hatch on the reactor building operating reactor building operatingfloor floor atat elevation elevation 958 '-3".

'-3 ". This jib crane jib crane is not included included in Table Table 2.4-1 o/the of the LRA.

LRA. IfIf this component is not included includeddue to an oversight, oversight,

NLS2009061 Attachment 1 Page 88 of 19 please provide please provide a description description of the scoping and aging management review (AMR). If aging management If it is covered somewhere else in the LRA, please please indicate indicate the location.

location. If If it is excludedfrom the scope oflicense renewal, provide the basis renewal,please provide basisfor its exclusion.

exclusion.

NPPD Response:

The supporting base plate and anchors are in the scope of license renewal renewal and addressed in Table Table 2.4-4 under line items "Base "Base plates,"

plates," "Equipment pads/foundation," and "Anchor "Equipment pads/foundation," "Anchor bolts."

bolts." The base plate and anchors are designed to resist seismic seismic loads such that the cranecrane will not fall and potentially impact impact safety-related safety-related structures, systems, or components. The crane itself does not perform a license renewal intended intended function as defined defined in 10 CFR 54.4(a)(1), (2) or (3), (3), and therefore is not within the scope of license renewal.

NRC Request: RAJ RAI 2.4-2 Based on a review of Section 2.4.1, Reactor Based Reactor Building and Primary Building and PrimaryContainment, Containment,ofthe LRA LRA and Table clear if Table 2.4-1, it is not clear if the following components have been included included in the scope of of license renewal and subject to an AMR:

renewal and AMR:

a) seal assembly (including Refueling seal (includingrefueling refueling bellows) b) Drywell emergency airlock airlock c) Drywell coating coating d) shear ring Drywell shear ring e) Drywell to reactor reactorwall bellows J) j) Ring girder designed to transfer girder designed transfer the vertical and horizontal vertical and horizontalloads loads of the reactor reactorpressure pressure vessel skirtflange skirt flange to the top of the reactor reactor pedestal pedestal g) Torus lateral Torus seismic restraints lateral seismic (Table 2.4-1 of restraints (Table of the LRA LRA only lists lists the columns and saddles) saddles) h) Penetrationnozzles welded to the Drywell, Penetration Drywell, guard guard pipes, pipes, flued heads, heads, and limit stops i) Traversingin-core Traversing in-core probe guide tube penetrations probe guide (Ref: CNS USAR Section V-2.3.4.4) penetratiQns (Ref j) j) Stabilizer Stabilizer assembly inspection ports inspection ports (Ref(Ref: CNS USAR Section V-2.3.4.5) k) Dryer-separator Dryer-separator pit pit liner linerplate (Ref: CNS USAR plate (Ref USAR Section XII-2.2.1) 1)

l) Reactor building Reactor building roof metal deck m) Reactor Reactor building building roof roof n) Steam tunnel tunnel concrete concrete roof (Table (Table 2.4-1 of the LRA lists concrete LRA only lists beams,floor slabs, concrete beams, slabs, interior interior walls and exterior walls) exterior walls) o)

0) Sliding supportplates Sliding support plates p) p) Spent fuel pool liner linerplate plate leak chase system If If these components areare not included included due to an oversight, oversight, please provide provide a description description of the scoping and AMR. If scoping and If they are are covered somewhere else in the LRA, LRA, please indicate the location.

please indicate location.

NLS2009061 Attachment Page 9 of 19 If If they are are excludedfrom the scope of license renewal, renewal,please provide provide the basis for their basisfor exclusion.

exclusion.

NPPD Response:

a) The refueling refueling forms a seal between the reactor reactor vessel and the surrounding surrounding primary containment drywell containment drywell to permit permit flooding of the reactor well above the vessel. It is not a containment pressure boundary containment performs no license renewal intended boundary component. It performs intended function. The refueling refueling bellows is not safety-related required to demonstrate safety-related and is not required demonstrate compliance compliance with regulations regulations identified identified in 10 CFR 54.4(a)(3).

54.4(a)(3). Failure Failure of the seal assembly will not prevent satisfactory satisfactory accomplishment accomplishment of a safety function. Leakage, ifif any, through the bellows is directed to the drain system inside inside the drywell.

b) CNS does not have a drywell emergency emergency airlock.

c) Coating is not relied on to maintain function of the drywell. Protective Protective coating coating is not not safety-related and is not required to demonstrate safety-related demonstrate compliance compliance with regulations regulations identified in 10 CFR 54.4(a)(3).

54.4(a)(3). Failure of the protective coating will not prevent prevent satisfactory satisfactory accomplishment accomplishment of a safety safety function. Accordingly, drywell coatingcoating is not within the license renewal.

scope of license d) The drywell shear ring is integral to the reactor concrete concrete pedestal. It is included included in the scope of license license renewal and is included within the LRA Table Table 2.4-1 Concrete Concrete line item "Reactor pedestal."

"Reactor pedestal."

e) Drywell to reactor well bellows provides a seal between the primary containment containment drywell and the liner of the reactor well to permit flooding of the reactor reactor well above the vessel. It is not a containment containment pressure boundary component. It is not safety-related, safety-related, and failure of of the bellows bellows will not prevent prevent satisfactory satisfactory accomplishment of a safety safety function. Leakage, Leakage, if any, through the bellows is directed directed to a drain system to prevent prevent the leakage leakage from from contacting contacting the drywell shell. ItlisIhs not required to demonstrate demonstrate compliance with regulations identified in 10 CFR 54.4(a)(3). Therefore, Therefore, the bellows do not perform a license renewal renewal intended intended function.

f) The ring girder is designed to transfer the vertical and horizontal horizontal loads of the reactor pressure vessel skirt flange to the top of the reactor reactor pedestal. It is a subcomponent subcomponent of the reactor vessel support. It is included included in the scope of license renewal, and is within the LRA Table 2.4-1 Steel and and Other Other Metals Metals line item "Reactor "Reactor Vessel Support Assembly."

Assembly."

g) The torus lateral seismic restraints are subcomponents subcomponents of the torus supports. They are included included in the scope oflicense of license renewal and are within the LRA LRA Table 2.4-1 2.4-1 Steel and OtherMetals line item "Torus Other "Torus external supports (saddles, columns)."

columns)."

NLS2009061 Attachment Page 10 of 19 h) Penetration Penetration nozzles welded to the drywell, guard pipes, and flued heads, are in the scope renewal and are addressed in the Mechanical of license renewal Mechanical section of the LRA, Section Section 2.3.2.7. Where limit stops are used, they are considered part ofthe penetration assembly of the penetration assembly and are included within the LRA Table 2.4-1 Steel and Other Metals line item "Primary Other Metals "Primary containment mechanical mechanical penetrations penetrations (including those with bellows)."

bellows)."

i) The primary containment containment traversing traversing in-core in-core probe guide tube penetrations penetrations are.in the scope of license renewal. They are within the LRA Table 2.4-1 2.4-1 Steel and and Other Other Metals Metals line item "Primary containment containment mechanical mechanical penetrations (including those with bellows)."

penetrations (including bellows)."

j)j) stabilizer assembly inspection ports (hatches) are inspection The stabilizer inspection hatches hatches through the drywell shell similar in design to the drywell equipment hatches. They are in the scope drywell scope of license renewal oflicense renewal and subject subject to AMR. The AMR results for the LRA Table Table 2.4-1 Steel and Other Other Metals Metals line item "Drywell equipment equipment hatches" hatches" also apply to the stabilizer stabilizer assembly inspection hatches.

k) dryer-separator pit liner plate is integral The dryer-separator integral to the reactor reactor cavity liner, and is included with that line item within LRALRA Table 2.4-1 Steel and and Other Metals Metals line item "Reactor "Reactor liner." During refueling, the blocks separating the reactor cavity cavity liner." cavity and the dryer- .

separator area are removed making these two areas one. The liner is continuous continuous across this area, and as such, the reactor cavity cavity component name is applicable to the entire area.

1)

1) The reactor building building roof metal decking is in in scope of license license renewal. Tables Tables 2.4-1 and 3.5.2-1 are revised to add a new line item for roof decking (see Attachment 3, 3, Changes 1 and 7.)

7.)

m) . The reactor building building roof structure structure is in the scope of license license renewal.

renewal. It is included within the LRALRA Table 2.4-1 Steel and OtherOther Metals Metals line item "Structural "Structural steel: beams columns, plates."

plates."

n) The steam tunnel concrete concrete roof is in scope of license license renewal. It is included within the Concrete line item "Steam LRA Table 2.4-1 Concrete "Steam tunnel."

tunnel."

o)

0) Sliding support plates are in scope oflicense of license renewal. They are included within the LRA Table 2.4-1 Steel and Other Other Metals Metals line item "Torus "Torus external external supports (saddles, columns)."

columns)."

p) The spent fuel pool liner plate plate leak chase system is in scope of the license renewal. It is is an integral attachment attachment to the spent fuel pool liner, and is included included within within the LRA Table Table and Other 2.4-1 Steel and OtherMetals "Spent fuel pool liner plate."

Metals line item "Spent

NLS2009061 NLS2009061 Page 1111 of 19 19 RAI 2.4-3 NRC Request: RAI2.4-3 Section 2.4.2, Section 2.4.2, Water Water Control Control Structures, Structures, of the LRA LRA states states that that the the intake intake structure structureis is provided provided with a crane cranefor equipment maintenance.

for equipment maintenance. Table Table 2.4-2 of the LRA the LRA doesdoes not list this crane list this crane to be within the scope of license renewal. If license renewal. If this component component is not included included duedue to anan oversight, oversight,please please provide a description provide descriptionof the scoping scoping andand AMR. If If it is covered covered somewhere somewhere else in in the LRA, please indicate please location. If indicate the location. If it is excluded from the the scope scope of license license renewal, renewal,please pleaseprovide provide the basis the basisforfor its exclusion.

exclusion.

Response

NPPD Response:

The intake structure crane is addressed in LRA Section 2.4.2, "Water "Water Control Structures."

Structures." It is nonsafety-related, and located away from safety-related nonsafety-related, safety-related systems and components components when not in use. Its failure will not prevent satisfactory accomplishment accomplishment of a safety function, and it is not credited for mitigating a regulated regulated event. The crane is not within the scope oflicense of license renewal and is not subject to AMR since it does not perform perform any of the license renewal intended in 10 CFR 54.4(a)(1), (2) or (3). Accordingly, it is not listed in LRA Table functions defined in"tO 2.4-2 (Water Control Structures Components Subject to an Aging Management 2.4-2 (Water Management Review).

NRC Request:

Request: RAI RAI 2.4-4 Section 2.4.2 of the LRA states that LRA states that the traveling traveling screens screens andand trash racks in the intake trash racks intake structure structure prevent debris debrisfrom entering entering the circulating water circulating water pumps and and service service water waterpump bays. bays.

Traveling screen casing Traveling screen and associated casing and associatedframing framing are included in Table are included Table 2.4-2.

2.4-2. However, However, Table Table 2.4-2 does does not list the trash racks trash racks to be within within the scope of license renewal. If trash racks are license renewal. If trash racks are not included included due to an an oversight, oversight,please please provide descriptionof the scoping and provide a description AMR. If and AMR. If they are covered somewhere else in the LRA, are covered LRA, please please indicate location. If indicate the location. If they are are excludedfrom from the scope of license renewal, renewal, please provide the basis basisfor their their exclusion.

exclusion.

NPPD Response:

Response

The The nonsafety-related nonsafety-related traveling traveling screens screens and trash racks are located located at the entrance entrance to the intake intake structure to keep debris debris from entering entering the circulating circulating and service water (SW) (SW) bays. The trash racks racks are intended to protect the traveling traveling screens from large large debris. The The trash racks racks prevent prevent the water water velocity, primarily primarily the higher velocities velocities associated with the circulating circulating water pumps,pumps, from drawing drawing large debris into the traveling traveling screens screens during during normal normal plant plant operation. For normal normal and emergency emergency operations, operations, the SW pumpspumps draw a much lower volume volume of water. The lower lower flow rates of of the the SW system minimize minimize the potential potential for large large debris debris being being drawn drawn into the flow path that could damage damage thethe traveling traveling water screens.

screens. Therefore, trash racks racks do notnot provide a license license renewal renewal intended intended function as defined in in 10 CFR 54.4(a)(1),

54.4(a)(1), (2)(2) or (3).

(3). As such, such, trash trash racks racks are not not listed in LRA LRA Table Table 2.4-2.

2.4-2.

)

NLS2009061 Attachment Page 12 of 19 NRC Request: RAJ RAI 2.4-5 Section XJI-2.2.7.2 SectionXIJ-2.2. 7.2 of the CNS eNS USAR states the following:

thefollowing:

"A three-foot three:foot wide by four-foot four:foot high hole has has been installed installed near near the far north end of the guide far north guide wall.

wall. A gate and and gate frame frame assembly has also has also been provided provided to allow for opening and/or closing for opening and/or ofthe hole depending depending on the forecast river levels.

forecast river levels. The purpose purpose ofthe hole is to provide a flow path path from the Missouri Missouri River to the Service Water Waterpump bay duringduring low river river water level conditions needed to ensure Service Water conditions Water pump operability.

operability." "

The guide wall is included included in Table Table 2.4-2 of the LRA.

LRA. However, However, Table 2.4-2 does not list the gate gate and the associated and associatedframe assembly to be within frame assembly within the scope of license license renewal.

renewal. If If these components are are not included included due to an oversight, oversight,please pleaseprovide provide a description description of the scoping scoping and AMR. If If they are are covered somewhere else in the LRA, please please indicate indicate the location.

location. IfIf they are are excludedfrom the scope scope ofof license license renewal, please provide renewal,please provide the basis basis for for their their exclusion.

exclusion.

NPPD Response:

The gate and gate frame assemblyassembly described above are within the scope scope of license renewal. The gate is an active component component and is therefore not subject subject to AMR. The gate frame assembly is subject subject to AMR AMR as an integral integral part of the guide wall and is included included within the LRA LRA Table 2.4-2 line item "Guide "Guide wall."

wall."

NRC Request: RAJ RAI 2.4-6 Section 2.4.2 of the LRA discusses sluice gates and LRA discusses and their theirfunction function to provide a suction pathfor suction path the service water waterpumps should the inlet to service water bay become clogged. clogged. Table 2.4-2 does Table does not list list the sluice sluice gates to be within the scope of license renewal. If license renewal. If the sluice gates gates are are not included due due to an oversight, oversight, please provide a description provide description of the scoping and and AMR. If If they are are covered somewhere else in the LRA, LRA, please indicate indicate the location.

location. IfIf they are are excludedfrom the scope of license renewal, renewal, please provide basisfor provide the basis for their exclusion.

their exclusion.

NPPD Response:

The sluice gate between circulating water bay and the service water bay provides an alternate between the circulating flow path in case case the nonsafety-related nonsafety-related traveling screens screens become become clogged, if if silt builds up in the normal flow path, or if if needed to support support maintenance. Site calculations calculations and evaluations evaluations have shown that the clogged screens screens would pass adequate adequate flow to meet the flow demands of the service water system, and that sufficient time is available for CNS to take corrective action for silt buildup without reliance reliance on the sluice gate. Therefore, Therefore, the sluice gate does not perform perform a function, and failure to provide this flow path will not prevent the service water system safety function,and

NLS2009061 Attachment Page 13 of 19 from accomplishing accomplishing its safety safety function. Accordingly, the sluice gate is not within the scope scope ofof license license renewal.

NRC Request: RAJ RAI 2.4-7 Section 2.4.2 of the LRA LRA discusses concrete skirt, discusses a concrete skirt, sheet piling along the river piling along face and riverface and rip-rap rip-rap in front of the intake infront intake structure structure providing providing scour scour protection.

protection. Table Table 2.4-2 does does not list these components to be within the scope of licenselicense renewal renewal andand subject to an AMR. Please Please provide provide the basis for the exclusion of these componentsfrom the scope of license renewal.

basis for renewal.

NPPD Response:

Response

The concrete concrete skirt and sheet piling are integral parts of the concrete concrete foundation. The concrete skirt is included in the line item "Foundation" "Foundation" and the sheet piling-is piling~is included with the line item "Structural steel, beams, columns, and plates" "Structural plates" listed in Table Table 2.4-2. The rip-rap is provided as a secondary measure to minimize minimize erosion in the area of the foundation, which which is not a required isnot safety function. Rip-rap failure would not impact the ability to provide water to the service service water water bays. The rip-rap is not credited credited in any regulated event. Accordingly, it does not perform a license renewal intended function as defined in 10 CFR 54.4(a)(1), (2) or (3) and is not subject to an AMR.

anAMR.

NRC Request: RAI 2.4-8 Request: RAJ discussed in Section As discussed Section 2.4.3, "Turbine "Turbine Building, Building,Process ProcessFacilities Facilitiesand Yard Structures, Structures," of the

LRA, LRA, the multi-purpose facility is supported multi-purpose facility supported piles. on piles. Table 2.4-3 of the LRA LRA only lists the concretefoundation concrete and does not list foundation and piles. If list these piles. If the foundation piles are foundation piles are not included due to an oversight, oversight,please please provide descriptionof the scoping provide a description and AMR. If scoping and If they are are excluded fromfrom the scope of license license renewal, pleaseprovide the basis renewal, please basisfor their their exclusion.

exclusion.

NPPD Response:

Response

The foundation piles for the multi-purpose multi-purpose facility are in-scope of license renewal and subject to in-scope oflicense AMR. LRA LRA Table 2.4-3 has been revised to include this line item (see Attachment 3, 3, Change Change 2).2).

However, there are no aging effects requiring management management for steel piles since the oxygen levels levels are low enough a few fet(tfeet below the surface surface to preclude significant significant corrosion. This is consistent with the previously previously approved approved applicant applicant position documented documented in the license renewal Safety Evaluation Report for the Nine Mile Point Nuclear Nuclear Station (NUREG-1900, Section 2.4B. 12.2).

2.4B.12.2).

LRA Table Table 3.5.2-3 has been been revised to reflect reflect this (see Attachment Attachment 3, Change 8). 8).

NLS2009061 Attachment Page 14 of 19 NRC Request: RAJ RAI 2.4-9 Section 2.4.3 ofthe LRA Section LRA discusses discusses turbine generator pedestal turbine generator pedestal structure.

structure. Since Table 2.4-3 of the LRA LRA combines many components under under a single component groupgroup (e.g., concrete concrete beam, beam, columns, columns, floor slab floor interior walls),

slab and interior clear if walls), it is not clear turbine generator if the turbine generator pedestal pedestal is within within the scope oflicense renewal and subject to an AMR.

renewal and AMR. Please Please provide a description description of the scoping scoping and AMR or provide provide the basis basisfor exclusion.

for its exclusion.

NPPD Response:

The turbine generator pedestal of license renewal pedestal is within the scope oflicense renewal and subject to AMR. Since it is part of the turbine building's interior interior concrete, it is included within the LRALRA Table 2.4-3 Concrete Concrete line item "Beams, columns, columns, floor slabs and interior walls."

walls."

NRC Request: RAI RAJ 2.4-10 Table 2.4-3 of the LRA LRA only lists roof decking and and concrete concrete roofslab.

slab. Please that the Please confirm that built-up roofing roofing system was not used in construction constructionof various various buildings buildings covered in Section 2.4.3 of the LRA. Otherwise,provide LRA. Otherwise, provide a description description of the scoping andand AMR AMR or provide provide the basis basis for for the exclusion exclusion of the built-up built-up roofing roofing system from the scope of license license renewal.

renewal.

NPPD Response:

Built-up roofing systems were used in the structures listed in Section 2.4.3 of the LRA.

However, the roofing systems, including roofing membranes, membranes, are not within the scope oflicense of license nonsafety-related and provide protection renewal. They are nonsafety-related external environment protection from external environment to roof roof decking and roof slabs. Shielding and protection protection are provided by roof decking and roof slabs.

The built-up roofing system does not performperform any of the license renewal intended functions defined in 10 CFR 54.4(a)(1), (2) (2) or (3).

NRC Request: RAI RAJ 2.4-11 Table 2.2-3, Structures Table Structures within the Scope ofLicense Renewal, Renewal, of the LRALRA lists cranes, cranes, trolleys, trolleys, monorails and monorails and hoists as components within the scope of licenselicense renewal.

renewal. Table Table 2.4-3 of the LRA only lists lists monorails, monorails, crane crane rails rails and and girders.

girders. Please Please provide provide the basis basis for cranes (e.g.,

for excluding cranes (e.g.,

turbine building crane) turbine building crane) and their associated sub-components (bridge, trolley, hardware, their associated sub-components (bridge, trolley, hardware, etc.),

located located within the in-scope structures structuresdescribed described in Section 2.4.3 of the LRA, from the scope of of license renewal.

renewal.

NLS2009061 1 Page 15 of 19 NPPD Response:

As indicated in LRA Table 2.2-3, cranes, trolleys, monorails and hoists are evaluated as components or commodities of the structure in which they are located. Accordingly, structural components subcomponents (including bridge, rails and girders), which are the turbine building crane and its subcomponents of the LRA and subject to AMR, are evaluated in Section 2.4.3, "Turbine in scope ofthe "Turbine Building, Structures," and are included within the LRA Table 2.4-3 Steel and Process Facilities and Yard Structures,"

Other Metals Other "Crane rails and girders."

Metals line item "Crane girders." The associated bolting is evaluated as a bulk Section 2.4.4, "Bulk Commodities," and is included in LRA Table 2.4-4 Bolted commodity in Section connections line item "Structural connections "Structural bolting."

bolting." Other subcomponents, specifically hoists and associated hardware, are supported by the structural componentscomponents included under crane rails and girders. These subcomponents subcomponents do not supportsupport a license renewal intended function identified in 54.4(a)(1), (a)(2),

10 CFR 54.4(a)(1), (a)(2), or (a)(3).

(a)(3).

NRC Request: RAJ RAI 2.4-12 Section 2.4.3 of the LRA Section LRA describes describes the exhaust stack on top of the diesel diesel generator generatorbuilding buildingroof as nonessential.

as nonessential. Table 2.4-3 does not includeinclude the exhaust stackstack within the scope scope of license license renewal. Please renewal. Please verify that this component does not have an intended intendedfunction function relative relative to potentialspatial potential spatialinteraction interactionbased based on the criterion criterionof 10 CFRCFR 54.4{a)(2).

54.4(a)(2).

NPPD Response:

The diesel exhaust stack does not have an intendedintended function relative relative to potential potential spatial interaction interaction based on the criterion of 10 CFR 54.4(a)(2). Its failure will not prevent satisfactory satisfactory accomplishment accomplishment of a safety function. Each emergency emergency diesel generator generator has a continuously continuously available available exhaust flow path that bypasses bypasses the exhaust stack on top of the diesel generator generator building roof.

roof.

NRC NRC Request: RAI2.4-13 RAJ 2.4-13 Table 2.2-3, Structures Structures within the Scope of License Renewal,Renewal, of the LRA lists the turbine LRA lists turbine building (including (including appendages) appendages) as as structures structures within the scope of license renewal.

of license renewal. Section 2.4.3 of the LRA LRA defines the water treatment area, water treatment area, machine machine shop, shop, exhaust fan fan room, room, and heating heating boiler boiler room turbine building as turbine building appendages, appendages, but no specificjnformation specificinformationrelative relative to these structures are structures are provided provided to verify the completeness oflisted components in Table 2.4-3 and Table 2.4-4.

andTable 2.4-4. Please Please provide provide a more detailed description detailed description of the turbine building turbine building appendages, appendages, and confirm that the entire entire turbine turbine building building and its appendages appendages are are within the scope of of license renewal renewal and that the components applicable applicable to these facilities facilities fall within the listed components in Table 2.4-3 and Table 2.4-4.

NLS2009061 Attachment Page 16 of 19 NPPD Response:

The turbine building appendages appendages are constructed of reinforced reinforced concrete concrete floor slabs, structural steel framing with metal siding at exterior exterior walls, and a composite composite roof structure similar to that of of the turbine building. The west west wall of these structures is the exterior wall of the turbine turbine building which is of reinforced reinforced concrete concrete construction. The turbineturbine building appendages appendages provide support for the power supply for the Z Sump, and are in the scope oflicense of license renewal and subject to AMR. The scoping and AMR of the turbine building appendages is included with the turbine building, since they are of similar construction. Accordingly, the description description of the turbine building appendages appendages is provided in LRA section section 2.4.3, 2.4.3, under turbine building. As it is shown in in the LRA Table 2.2-3, 2.2-3, the turbine building (including appendages) appendages) is in the scope of license oflicense renewal. The structural structural components components in the turbine turbine building appendages are therefore therefore subject to AMR, and are within the components components listed in Tables 2.4-3 and 2.4-4.

NRC Request: RAJ RAI 2.4-14 Section 2.4.3 of the LRA discusses the Z Sump, an LRA discusses an underground undergroundsteel lined concrete concrete tank, tank, located located beneath the early early [sic] release release point tower. Table tower. Table 2.4-3 of the LRA LRA does not list this concrete concrete tank to be within within the scope of license renewal and subject to an AMR. If renewal and If this component is not included due to an oversight, pleaseprovide a description oversight, please description ofthe scoping scoping and AMR. AMR. If If it is covered somewhere else in the LRA, please please indicate location. If indicate the location. If it is excludedfrom the scope of license renewal, of license renewal,please please provide provide the basis basisfor for its exclusion.

exclusion.

NPPD Response:

The underground underground steel lined concrete concrete tank, located beneath the elevatedelevated release point tower, is in the scope of license renewal license renewal and subject to AMR. The steel and concrete concrete portion portion of this tank is identified identified in LRA Table 2.4-3 line items "Sumps "Sumps liner" and "Sumps,"

"Sumps," respectively.

NRC Request: RAJ RAI 2.4-15 Table 2.4-1, Reactor Table Reactor Building Building and PrimaryContainment, and Primary Containment, listslists shield plugs as in-scope components.

components. However, However,for for various structurescovered in Section various structures Section 2.4.3, TableTable 2.4-3 of of the LRA shieldplugs as in-scope components and subject to an AMR. If does not list shield If they are are covered somewhere else in the LRA,LRA, please please indicate indicate the location.

location. IfIf they are are excluded from the scope of of license renewal, renewal,please please provide the basis for their exclusion.

basis for their exclusion.

NPPD Response:

The shield plugs for the turbine building, process facilities, and yard structures covered in in Section 2.4.3 are evaluated as bulk commodities commodities in Section 2.4.4, "Bulk "Bulk Commodities."

Commodities." They

NLS2009061 1 Page 1717 of 19 19 are listed within the LRA Table 2.4-4 Steel and Other Metals line item "Manways, hatches, are listed within the LRA Table 2.4-4 Steel and Other Metals line item "Manways, hatches, manhole covers, and hatch covers."

NRC Request: RAI2.4-16 RAI 2.4-16 describedin the As described the CNS USAR SectionSection XIJ-2.

XII-2.2.15, the optimum water 2.15, the water chemistry gasgas generator generator (0 WCGG) building (OWCGG) buildingis is aa Class Class II structure structurelocated located along along the north north wall of the turbine turbine building.

building.

Table 2.2-4 of the LRA Table LRA indicates indicates that that this this building building hashas been been excludedfrom excludedfrom the scopescope of license license renewal. Please renewal. Pleaseprovide provide the technical technicalbasis basisfor its exclusionfrom for its exclusion from the scope*oflicense scope of license renewal.

renewal.

Specifically, verify that Specifically, that this this structure structure does does not have an an intended intendedfunction function relative relative to potential potential spatial interactionbased spatial interaction based on the criterion criterionof 10 CFR CFR 54.4(a)(2).

54.4(a)(2).

NPPD Response:

The OWCGG building, located along the north wall of the turbine building, is a nonsafety-related structure structure that contains no safety-related safety-related components. Failure of the building will not accomplishment of a safety function (no potential spatial interaction). The prevent satisfactory accomplishment building does not perform any of the license renewal intended functions defined in 10 CFR 54.4(a)(1),

54.4(a)(1), (2)

(2) or (3). Therefore, it is not within the scope oflicense of license renewal.

NRC Request: RAI RAI 2.4-17 2.4-17 Table 2.4-4 oftheLRA Table of the.LRA does not include include the following component types, below. If types, as listed below. If they are covered somewhere else in the LRA, are LRA, please indicate location. If indicate the location. If they are are excludedfrom from the scope of license license renewal, pleaseprovide the basis renewal, please basis for their their exclusion.

exclusion.

1. Shieldingfor Shielding for high energy line break (Table (Table 2.4-4 only lists pipe whip restraints),

restraints),

2. Grout Grout pads pads for for building building structural structural column base plates, plates, and

3. Fire Fire dampers dampers NPPD Response:

1. Shielding Shielding for high energyenergy line break break (HELB),

(HELB), is included included within the LRALRA Table 2.4-4 2.4-4 line line "Missile shields."

item "Missile shields." Specific HELB shielding shielding applicable applicable only to the primary containment containment is included within within the LRA Table 2.4-1 line item "Drywell"Drywell shell protection protection panels panels and jet deflectors."

deflectors."

2. Grout pads pads for building building structural structural column column base plates plates are are sub-parts sub-parts of the the concrete concrete equipment equipment foundations foundations and are not specifically specifically identified identified as a separate separate line item. They They are included within included within the LRA Table 2.4-4 LRA Table 2.4-4 line line item "Equipment pads/foundations."

"Equipment pads/foundations."

NLS2009061 Attachment 1 Attachment Page 18 of 19 3.

3. Fire dampers are addressed addressed in Section 2.3.3.8 "Heating, Ventilation Ventilation and Air Conditioning" Conditioning" of the LRA, and Table 2.3.3-8 line item "Damper Housing." Section 2.4.4 Housing." 2.4.4 addresses the structural portion associated with these dampers and is of the LRA addresses identified in Table 2.4-4 as line item "Damper identified "Damper framing."

NRC Request: RAI RAI B. 1.31-2 B.1.31-2

Background

LRA Section B.1.31 LRA Section B. 1.31 states that the acceptance states that acceptance criteria criteriaare are defined defined in specific inspection inspection or test procedures, procedures, and that that the procedures procedures confirm component integrity integrity by verifying the absence absence ofof aging aging effects or or by comparing applicable parameters comparing applicable parameters to limits based based on applicable applicable intended functions establishedby plant functions established plant design basis. The majority of the acceptance design basis. acceptance criteria criteriagiven in CNS-RPT-0 7-LRDO 7, Revision 2, "Aging CNS-RPT-07-LRD07, "AgingManagement Management Program EvaluationResults - Non-Class Program Evaluation Non-Class 1 Mechanical, Mechanical, ""Attachment "PeriodicSurveillance Attachment 2, "Periodic Surveillance and Preventive Preventive Maintenance Maintenance Activities, were either, either, "No unacceptable unacceptable loss of material, material," or "No unacceptable unacceptable cracking cracking or change change in material properties.

material properties. ""

By contrast, contrast, GALL report report Appendix A, Section A. 1.2.3.6, "Acceptance A.1.2.3.6, "Acceptance Criteria" Criteria"indicates indicates that the bases for for the criteria criteriashould be described describedand and the criteria criteriaagainst againstwhich the need for corrective action corrective action will be evaluated, evaluated,should should ensure ensure that that the structure structureand or component intended function(s) function(s) are maintainedunder are maintained under all current licensing basis current licensing basis design conditions. In addition, design conditions. this addition, this section notes that acceptance acceptancecriteria criteria could be specific numerical numericalvalues, values, or could consist consist of a discussion of the process discussion process forfor calculating calculating specific numerical values. If numericalvalues. If acceptance acceptance criteria criteriado not permit degradation,then there is no need to discuss permit degradation, discuss current licensing basis current licensing basis design design loads, loads, since since the structure structure oror component should continue to function continue function as originally originally designed.

designed.

Issue Issue informationprovided The information provided does not describe describe the basesfor for the acceptance acceptance criteria.

criteria. Although LRA Section B.1.

B. 1.31 states that 31 states that the procedures procedures confirm the absenceabsence of aging aging effects, apparently apparently aging effects may be tolerated, tolerated,but just cannot cannot be unacceptable.

unacceptable. However, However, the term "unacceptable" "unacceptable" is quantified and not quantified and the process process for determining determining "unacceptable" "unacceptable" is not provided.

provided.

Request Provide Provide the basis basisfor for the acceptance acceptance criteria criteria given for for each component or system described described inin LRA Section the LRA Section B. 1.31, "Periodic B.1.31, "PeriodicSurveillance Surveillance andand Preventive Preventive Maintenance, Maintenance, " and specifically specifically describe describe how the term "unacceptable" "unacceptable" will be quantified.

quantified.

NPPD Response:

Any indications indications or relevant conditions of degradation degradation are reported reported and submitted for further evaluation as part of the corrective corrective action program. These further evaluations are performed by by engineers qualified by virtue of training and experience engineers experience to evaluate evidence of potential potential aging aging

NLS2009061 Attachment Page 19 of 19 effects. Evaluation Evaluation is performed performed against criteria Which which ensure that the structure or component component intended function(s) are maintained maintained under all current licensing basis design conditions during the period of extended extended operation. These criteria are no evidence evidence of wear, corrosion, corrosion, cracking, change in material change material properties (for elastomers),

elastomers), or fouling to the extent that the intended function of the structure structure or component component could be compromised. Specific quantitative quantitative or qualitative criteria criteria acceptability are contained in manufacturer for acceptability manufacturer information information or vendor manuals for some individual components.

individual components. The engineering review process is used in situations where engineering review where appropriate judgment of the qualified engineer manufacturer data is unavailable. The judgment manufacturer engineer is applied to make this determination determination based on the design design requirements requirements of the structure structure or component.

NLS2009061 Attachment Page 1 of 41 Attachment 2 Response to Request for Additional Infonnation Information for License License Renewal Renewal Application Application Cooper Nuclear Nuclear Station, Docket Docket No. 50-298, DPR-46 The Nuclear Regulatory Regulatory Commission (NRC) Request for Additional Additional Infonnation Information (RAI) regarding regarding the License License Renewal Renewal Application Application is shown in italics. The Nebraska Nebraska Public Power District's (NPPD) response to eacheach RAI is shown in block font.

NRC NRC Request:

Request: RAI2.3.3-1

Background

License renewal rule Title 10 of the Code renewal rule Code ofFederal Federal Regulations Regulations (10 CFR)

CFR) Section 54.21(a)(1) 54.21 (a)(1) requiresapplicants requires applicants to identify identifY and list all all components components subject to an an aging aging management management review (AMR). The staff confirms inclusion inclusion ofall components subject to AMRAMR by reviewing reviewing the license renewal components within the license renewal boundary.

boundary.

Issue During scoping and screening During the scoping screening review process, process, the continuation continuation from one drawing another drawing to another could not be established.

established.Drawing numbers and/or Drawing numbers and/or locations locations for continuations continuationswere not identified, could not be located identified, identified, or the continuation located where identified, continuationdrawing drawing was not provided.

provided.

License Renewal ContinuationLocation Continuation Location / Issue Issue Application (LRA)

Application Section/DrawingNumber 2.3.3.3 SER VICE WATER LRA-2006-SHO1 LRA-2006-SHOI G/H/J-12: The continuations G/H/J-12: continuationsfor four lines forfour lines in scope for (a)(2) are not identified.

LRA-2006-SH04 LRA -2006-SH04 J-8: Continuationfrom drain valve 121 refers to Note

2. Valve 121 is not included in Note 2.

2.3.3.14 2.3.3.14 REACTOR WATER WATER CLEANUP (R WCU)

LRA-2027-SHO1 LRA-2027-SHOI A-I: two lines continued continued "TO DRAIN" with no continuation continuation drawing identified.

B-1 (2 places):

places): lines "TO DRAIN HEADER" HEADER" with no I continuation continuation drawing identified.

NLS2009061 Page 2 of 41 C-1 and B-2: lines C-I HOODED SINK" with no lines "TO HOODED continuationdrawingidentified TURBINE EQUIPMENT EQUIPMENT COOLING COOLING LRA-2007-0 LRA-2007-0 downstream of valve 612 shown as A-3: Line downstream as in scope scope for (a)(2) continuing to drawing (a)(2) continuing drawing 2091 SH 3.

Draw Drawing 2091 SH 3 was not provided.

A-5 (2 places),

A-5 B-6: Lines identified places), B-5 and B-.6: identified as in (a)(2) are scope for (a)(2) are identified identified as continuing continuingto "TO WASTE" WASTE" without having the continuation location continuation location identified, DEMINERALIZED WA TER WATER LRA -2005 SH 2 LRA-2005 downstream of valve DW-339 as in B-3: shows a line downstream (a)(2) and scope for (a)(2) and subject to an AMR. No continuation continuationwas provided LRA-2013 LRA-20J3 F-7:

F-7: continuation downstream of valve 588 continuationsays line downstream and 590 "TO TCC SYS CHEM TANK. " Confirm SYS CHEMTANK." Confirm this should be "TO SURGE TANK. TANK.""

2.3.4.1 2.3.4.1 LEAKAGE MSIV LEAKAGE PA THWA Y PATHWAY LRA-2004-SHO1 LRA-2004-SH01 D-1: 1/2,4" stainless steel piping

~" stainless (1/2" CH-4) piping (112" CH-4)piping piping continuing on "To SR-1CSR-iC RX BLDG".

RXBLDG".

2.3.4.2 CONDENSA TE MAKEUP C

LRA-2042-SH03 D-1 0: Shows 2" D-10: 2" line continuedto LRA line continued -2038 Zone D-LRA-2038 D-

10. Unable

10. Unable to find the continuation continuation on LRA -2038.

LRA-2038.

LRA-2049-SH03 C/D-2:

CID-2: Lines downstream downstream of valves (187)(187) and and (188)

(188) are are shown as in scope for (a)(2)

(a)(2) with no continuation continuation location location identified 1-CM-189-1"" identified D-3: Line 1-CM-189-1 D-3: identified as continuing "TO as continuing UIP DR" EQUIP DR" with no continuation continuationlocation location identified Request Provide sufficient information Provide information for continuation of boundary for the continuation boundary identification issues identified identification issues portions of the system within the license all portions permit the staff to review all above to permit license renewal renewal boundary.

boundary.

NLS2009061 Attachment Page 33 of 41 NPPD Response:

The table from the RAI is reproduced with the addition of a column column for the response to each each individual item as follows.

individual License Renewal License Continuation Location Location / Issue Response

Response

Application Application (LRA)

(LRA)

Section/Drawing Section/Drawing Number 2.3.3.3 2.3.3.3 SERVICE WATER SERVICE WATER LRA-2006-SHO1 LRA-2006-SH01 G/H/J-12: The continuations G/H/J-12: continuations for These lines stop as they are four lines in scope for (a)(2) are not shown on the drawing. There is is identified. continuation for these four no continuation lines which which were previously the riverwell and fire protection protection backup supplies to the service service water pump glands.

LRA-2006-SH04 LRA-2006-SH04 J-8: Continuation Continuation from drain valve Note 2 refers to the lines 121 refers to Note 2. Valve 121 is downstream downstream of valve 120 (which not included included in Note 2. includes 121) such that the includes valve 121) continuation continuation identified in Note 2 is appropriate appropriate for valve 121 and this line continues to control control building sump 1IL L as noted. This line line is not not shown on another drawing.

Ii

",

2.3.3.14 2.3.3.14 REACTOR WATER WATER CLEANUP CLEANUP (RWCU)

LRA-2027-SHO1 LRA-2027-SH01 A-1: two lines continued "TO A-I: These two lines drain into an DRAIN" DRAIN" with no continuation open drain at the specified specified drawing identified. location location and do not continue to another drawing.

another B-1 B-1 (2 places): lines "TO DRAIN DRAIN These two lines drain into a drain drain HEADER" HEADER" with no continuation continuation header at the specified location drawing identified. and do not continue continue to another drawing.

NLS2009061 Page 4 of 41 C-1 and B-2: lines "TO HOODED C-I These two lines drain into a SINK" with no continuation continuation hooded sink at the specified drawing identified drawing location and do not continue continue to another drawing.

f TURBINE TURBINE EQUIPMENT EQUIPMENT COOLING COOLING LRA-2007-0 LRA-2007-0 A-3: Line downstream downstream of valve A boundary boundary wall should be 612 shown as in scope scope for (a)(2) shown on LRA-2007-0 LRA-2007-0 (A-3)

(A-3) at continuing to drawing 2091 SH 3. valve DW-612 since the line Drawing Drawing 2091 SH 3 was not downstream of valve DW-612 downstream DW-612 provided, provided. continues continues to the optimum water chemistry chemistry building (as shown shown onon drawing 2091 SH03 (B-2>>(B-2)) Which which does not contain safety-related contain safety-related equipment. The line is therefore not highlighted as in scope for 10 CFR 54.4(a)(2).

54.4(a)(2).

A-5 (2 places), B-5 and B-6: Lines These lines drain into an open identified identified as in scope for (a)(2)

(a)(2) are waste drain at the specified identified identified as continuing to "TO location and do not continue continue to WASTE" WASTE" without having the another drawing.

continuation location location identified, identified, DEMINERALIZED DEMINERALIZED WATER WATER LRA-2005 SH 22 B-3: shows a line downstream downstream of This is a local local sample root valve valve DW-339 DW-339 as in scope for (a)(2)

(a)(2) with no continuation.

and subject to an AMR. No continuation was provided.

LRA-2013 LRA-2013 F-7: continuation says line The continuation "TO"TO TCC SYS downstream downstream of valve 588 and 590 CHEM ADD TANK" TANK" (Drawing "TO "TO TCC SYS CHEM TANK."

CHEM TANK." (A-7)) is a drawing error.

2007 (A-7>>

Confirm this should be "TO Per Drawing LRA-2007-0, the SURGE TANK."

TANK." line continues to the turbine equipment cooling cooling surge tank rather rather than the chemical chemical addition addition tank.

NLS2009061 Attachment Page 5 of 41 2.3.4.1 MSIV LEAKAGE PATHWAY PATHWAY LRA-2004-SHO1 LRA-2004-SHOI D-l: W' V2" stainless steel piping (1/2" (1/2" The line continues to sample rackrack CH-4) piping continuing on "To SR-l C which is in scope. The SR-IC SR-IC RX BLDG". line does not continue continue to another

,

drawing. The line and components components associated with the rack are included in Table Table 3.4.2-2-8 for the main condensate condensate system [10 CFR 54.4(a)(2)].

54.4(a)(2)].

2.3.4.2 2.3.4.2 CONDENSATE MAKEUP MAKEUP LRA-2042-SH03 LRA-2042-SH03 D-I0: Shows 2" D-10: 2" line continued to LRA-2042-SH03 LRA-2042-SH03 (D-10)(D-I0) is LRA-2038 Zone D-10. Unable Zone D-I0. Unable to correct. The 2" 2" line is on the find the continuation on LRA-2038.

LRA-2038. reactor water cleanup (R (RWCU)

WCU) precoat pump and LRA-2038, LRA-2038, Sh. 1 (D-I0)

(D- 10) at the RWCU RWCU precoat area directs you to detail detail BB. Note 55 on LRA-2038-SHO1 LRA-2038-SHOI then directs you to details on on LRA-2038-SH02. On LRA-LRA-2038-SH02.

2038-SH02 (E-10),

2038-SH02 (E-l 0), the detail BB BB directs you back back to LRA-2042-LRA-2042-SH03 (D-10)

(D-I0) and all lines are shown shown as being in scope to their end point.

LRA-2049-SH03 LRA-2049-SH03 C/D-2: Lines downstream downstream of These lines stop at the specified specified valves valves (187)

(187) and (188)

(188) are shown as location and do not continue continue to in scope for (a)(2)

(a)(2) with no another drawing.

continuation location identified.

D-3: Line 1-CM-189-1" l-CM-189-1" identified identified This line drains into a funnel onon as continuing "TO EQUIP DR" an equipment equipment drain that does not with no continuation continuation location continue continue to another drawing.

identified.

NLS2009061 Attachment 2 Attachment Page 6 of 41 NRC Request: RAI3.1.2.3-1

Background

Background License Renewal Application Application (LRA) Table Table 3.1.2-3 contains contains items addressing carbon steel valve addressingcarbon bodies less than than 4 inches nominal nominalpipe size exposed to indoor indoor air their external air on their external surfaces.

surfaces. The applicant proposes applicant proposes that that this combination combination of component and and material materialis notfound in the GALLGALL Report (general Report (general note G). The applicant further proposes applicantfurther proposes that that this combination ofenvironment this combination and material material is not subject to aging aging and that no agingaging management program is required.

managementprogram required.

Issue Issue In its review, review, the staff found that stafffound essentially identical that essentially combinations of materials identicalcombinations materialsand environments environments were present present in the GALL GALL Report, Report, albeit albeit not in the reactor reactor coolant coolantsystem. The staff noted that that the applicant's applicant's basis basis for for stating that no aging stating that aging effect was present present was that that the temperature temperatureof the components under consideration was above the dewpoint.

under consideration dewpoint. The GALL Report finds that the aging finds that aging effect of loss of material materialdue to exposure of steel surfaces indoor air, surfaces to indoor air, which can result in condensation result condensation but only rarely, should be considered.

rarely, should considered. The staff also also noted apparentcontradiction some apparent contradictionbetween plant-specific plant-specific notes 102 and and 104 which areare related related to these components.

components.

Request Please clarify the plant-specific Please clarifY and to justify plant-specific notes and aging management justifY why aging management is not required requiredfor these components given that, during normal that, during normal plant plant events such as refueling, refueling, the components components under under consideration considerationwill be at at or near near ambient temperature.

ambient temperature.

NPPD Response:

Response

Plant specific notes 102 and 104 are located on Page 3.1-28, prior to Table 3.1.2-1 (Reactor (Reactor Vessel). Note 102 states:

component surface "High component temperature precludes moisture accumulation surface temperature accumulation that could result in in corrosion."

corrosion."

Note 102 applies to steel components of the reactor vessel and reactor reactor coolant pressure boundary with high operating temperatures operating temperatures (> 212 'F)

OF) that have external surfaces exposed external exposed to indoor air.

components are at temperatures where condensation During normal operation, these components condensation is not possible. Without the presence of moisture, corrosion is not possible. Although Although these components components are at or near (but seldom seldom if ever below) ambient temperatures temperatures during shutdown conditions, such as refueling refueling outages, these conditions are comparatively brief. brief. Any minor minor accumulated during shutdown is quickly evaporated moisture accumulated evaporated during Operating during startup. Operating components are not subject to loss of material due to corrosion.

experience has shown that these components experience

NLS2009061 Attachment Page 7 of 41 Plant-Specific Plant-Specific Note 104 states:

"The loss of material material is a potential aging effect for carbon steel surfacessurfaces in air where the surface temperatures temperatures are below the local local dew point."

point."

Note 104 applies to steel components ofthe of the reactor coolant pressure boundary that have external surfaces surfaces exposed exposed to indoor air but that operate temperatures close to ambient. These operate at temperatures components components are considered susceptible to loss of material and the aging effect effect is managed managed by the Surfaces Monitoring Program. Because some common component External Surfaces operate at component types operate different temperatures temperatures (e.g.,

(e.g., a pipe or valve in one part of the reactor coolantcoolant system (RCS) may operate operate at full system temperature temperature while a pipe or valve in a different part of the RCS may normally be at ambient temperatures), the aging management ambient temperatures), management review (AMR) results tables contain two adjacent adjacent lines for the component type, both with the same same material (carbon (carbon steel) and environment environment (air - indoor). The first component material type may experience experience the aging effect effect of of loss of material and the second with no aging effects effects identified. To eliminate potential potential confusion, Note 104 is applied to the first line and Note 102 is applied to the second. However, Note 104 as written refers to component temperatures below the local dew point which component surface temperatures would correspond correspond to an environment environment condensation rather than air - indoor. Therefore, Note of condensation 104 has been clarified to refer to steel surface temperature temperature that are "near ambient temperature" temperature" versus "below the dew point" (see Attachment Attachment 3, Change 3). 3).

RAI 3.2.2.1-4 NRC Request: RAI3.2.2.1-4

Background

Background LRA and SRP Tables LRA Tables 3.2.1-34 address address the loss of material materialdue to general, general, pitting, and crevice pitting, and crevice corrosion corrosion from the internal surfaces of steel piping, internal surfaces piping, piping piping components, components, andpipingpiping elements exposed to condensation.

condensation. The applicant applicantproposes proposes to manage manage thisthis aging agingprocess process through through the use of of its aging aging management management program, "PeriodicSurveillance program, "Periodic and Preventive Surveillance and Preventive Maintenance" (LRA Maintenance" (LRA B.1.31). The GALL Report recommends that this aging agingprocess process be managed managed through through the use ofof the aging aging management program, "Inspection of Internal Surfaces in management program, "Inspection Internal Surfaces Miscellaneous Piping Miscellaneous Piping and Ducting Components" (GALL Report Volume 2 Chapter Ducting ChapterX.M38).

XI.M38). The proposed aging proposed aging management program management program is not consistent consistent with the aging management program proposed aging management program proposed by the GALL Report.

Report. As a result, result, the applicant applicant proposes that the aging proposes that aging management management review items associated associated with Table 3.2.1-34 are consistent are consistent with the GALL GALL Report in terms of material, of material, environment, environment, andand aging aging effect but a different different aging managementprogram aging management credited(generic program is credited (generic note E).

Issue Issue In its review ofLRA Table 3.2.1-34, LRA Table 3.2.1-34, the staff noted that the agingaging effect being considered considered is loss of material materialfrom internalsurfaces from the internal surfaces ofofpiping piping in the reactor reactor core isolation isolationcooling (RCIC)

(RCIC) also noted that system. The staff also that in the table table included included in the proposed proposed aging aging management program (AMP), the applicant program (AMP), routinely states applicant routinely states whether whether the inspections inspections to be performed are are

NLS2009061 Page 8 of 41 internalor external.

internal external. However, However, for for piping inspection in the RCIC system, the applicant piping inspection applicantis silent concerning inspections to be conducted concerning whether the inspections conducted areare internal, internal, external, external, or both.

or both.

Request Please specify in the proposed Please proposedAMP whether the inspections inspections to be conducted conducted of piping in the ofpiping RCIC system are are internal, internal, external external or both.

or both.

NPPD Response:

The carbon steel piping line item with an internal environment of "condensation" "condensation" in LRA Table Table 3.2.2-5 (Reactor (Reactor Core Isolation Cooling System) refers to line item 34 of LRA LRA Table 3.2.1. The Table 3.2.1.

aging management management program activity for this RCIC system carbon carbon steel piping piping is a visual visual internal inspection.

NRC Request: RAI 3.2.2.1-5 RAI3.2.2.1-5

Background

LRA and SRP Tables LRA Tables 3.3.1-47 address address the loss of material material due to general, general,pitting, pitting,and and crevice crevice corrosion corrosion from the steel piping, piping, piping components,piping piping components, elements, tanks and heat exchanger piping elements, components.

components. The SRP defines the environment environment as "closed "closed cycle cooling water water". ". The LRA LRA defines the environment environment asas "treated "treated water". applicantproposes water". The applicant that "treated proposes that "treatedwater" approximates approximates "closed cycle cooling water" (LRA note 306). The applicant applicant proposes manage proposes to manage this aging agingprocess through process through the use of its aging management program aging management program "Water Chemistry Control Chemistry Control

--Auxiliary Systems" (LRA B.

Auxiliary Systems" 1.38). The GALL Report B.1.38). Report recommends that that this aging aging process process be managed managed through through the use of the aging aging management management program program "Closed Cycle Cooling Cooling Water System" System" (GALL Report Volume 2 Chapter Chapter XI.M21).

XIM21). The proposed aging management proposed aging management program program is not consistent consistent with the aging aging management program proposed management program proposed by the GALL Report.

GALL Report. As As a result, applicantproposes result, the applicant that the aging proposes that aging management associatedwith Table management review items associated Table 3.3.1-47 are are consistent consistent with the GALL Report in terms of material, environment, and material,environment, and aging effect aging effect but a different aging managementprogram different aging program is credited (generic note E).

credited (generic E).

Issue Issue In its review ofLRA Table 3.3.1-47, LRA Table 3.3.1-47, the staff noted that neither neither the target targetvalues for the water chemistry nornor the industry standard industry standard upon which the target water target water chemistry values are are based are are provided.

provided. The staff also notedfrom the operating experience associated operating experience associatedwith the proposed proposed aging management program management program that that water chemistry excursions are excursions are not rare rare events. The stafffurther stafffurther noted that proposed aging that the proposed aging management managementprogram program calls forfor a one time inspection inspection to verify the effectiveness of the water water chemistry program.

program. Lastly, Lastly, the staff questions questions the effectiveness of a one time inspection inspectionprogram program for the components being being considered considered in light of the waterwater chemistry chemistry excursions reportedin the applicant's excursions reported applicant'soperating operatingexperience and and the inclusion inclusion of ofperiodic periodic inspections in the aging inspections aging management managementprogram recommended by the GALL Report.

program recommended Report.

NLS2009061 Attachment Page 9 of 41 Request Please provide Please provide information information concerning concerning the target target water water chemistry values, source of the values, the source industry guidelines used in determining industry guidelines appropriatewater chemistry determining the appropriate chemistryforfor the system (it (it should be noted that that water chemistry chemistry guidance guidanceprovided provided by a manufacturer manufactureror a waterwater treatment treatment company do not constitute constitute an industry industry standard),

standard),the critical critical characteristics characteristicsof the system(s) being considered, considered, e.g., boiler boilerpressures, pressures,and justification regarding andjustification regardingwhy a one time inspection inspection should be considered adequate to manage considered adequate manage aging aging in light light of the stated stated variability variabilityin the water chemistry.

chemistry.

NPPD Response:

As stated in LRA Table 3.3.1, 3.3.1, item 47, loss of material components exposed material for steel components exposed to closed cycle cooling water is managed by the Water cycle Water Chemistry Control - Closed Cooling Water Water Program for components of closed cooling water systems, Program such as the reactor reactor equipment cooling equipment and diesel generator cooling water water systems. The design auxiliary steam system electric design of the auxiliary electric boiler requires a high level of water conductivity conductivity to propagate generated by the electric arc generated propagate the electric the boiler coil. This renders renders the system unsuitable unsuitable for control under the EPRI guidelines for chemistry control of closed cooling chemistry referenced by the GALL programs. Similarly, the cooling water referenced chemistry portion of the heating and ventilation requirements for the chilled water portion chemistry requirements ventilation system reflect the specific design of the components involved such that EPRI requirements ofthe requirements cannot cannot be met. For For these systems, the Water Water Chemistry Contro1- Systems Program manages loss of Control - Auxiliary Systems of material for steel components. This line item is used in LRA Table 3.3.2-14-1, material 3.3.2-14-1, Auxiliary LRA Table 3.3.2-14-2, Auxiliary Steam System 54.4(a)(2)], LRA Condensate Drains System [10 CFR 54.4(a)(2)),

54.4(a)(2)), and LRA Table

[10 CFR 54.4(a)(2)], 3.3.2-14-11, Heating Table 3.3.2-14-11, Ventilation System [10 CFR Heating and Ventilation CFR 54.4(a)(2)),

54.4(a)(2)], for the internal suffaces of piping internal surfaces piping and components.

The chemistry values used in the Water Chemistry Auxiliary Systems Program Control - Auxiliary Chemistry Contro1- Program are listed in LRA Section B.1.38. Information on the industry recommendations recommendations used as the basis program was provided previously in the NPPD response for this program response to RAI B. 1.38-1.22 The use of B.1.38-1. of recommendations as the basis for this existing manufacturer recommendations manufacturer well-established existing program is a well-established practice of industry user groups focused on water chemistry consistent with the practice approach consistent guidelines.

guidelines.

As stated in Section X-10.1.1 Section X-I 0.1.1 of the Cooper Nuclear Station (CNS) (CNS) Updated Updated Safety Safety Analysis Analysis Report auxiliary steam system is 150 psig. Steam Report (USAR), the operating pressure of the auxiliary Steam pressure pressure reducing reducing stations are provided pressure to 50 and 15 psig. This is provided to reduce this initial pressure also discussed in the NPPD response B. 1.38-2 provided in this letter.

response to RAI B.1.38-2 2 NLS2009040, Stewart B. Minahan to USNRC, "Response to Request for Additional Information for License 2 NLS2009040, Stewart B. Minahan to USNRC, "Response to Request for Additional Information for License Application - Aging Management Renewal Application Programs," June Management Programs," 15, 2009 (ADAMS Accession Number June 15,2009 Number ML091690050).

NLS2009061 Attachment Page 10 of 41 To address the variability variability of water water chemistry, corrective corrective actions were taken to improve improve internal communications communications and individual accountability individual accountability of the chemistry department staff chemistry department staffby by completing completing communication techniques and human performance. In addition, the cherpistry training on better communication chemistry department department discusses human performance tools at each chemistry chemistry morning morning meeting. Periodic meetings with system engineering engineering to review chemistry chemistry data, including excursions in the levels of of corrosion corrosion inhibitors, were initiated. This serves to identify maintenance maintenance and testing activities activities which may affect system chemistry, and provides provides opportunities opportunities for the engineers to give management of their assigned systems.

feedback on the aging management feedback Aging effects effects are managed by the Water Chemistry Control Control- - Auxiliary Auxiliary Systems Program through routine confirmation confirmation of water quality in accordance quality accordance with industry recommendations recommendations and appropriate corrective action. The One-Time appropriate timely corrective One-Time Inspection Inspection Program is not relied upon to manage manage aging effects; rather, it provides provides for inspections of components managed managed by the Water Chemistry Chemistry Control Control- - Auxiliary Auxiliary Systems Program Program to verify unacceptable unacceptable loss of material material is not occurring and the chemistry control program is adequate.

occurring RAI 3.2.2.1-8 NRC Request: RAI3.2.2.1-8

Background

Background LRA and LRA and Standard StandardReview Review Plan (SRP) Tables 3.2.1-35 address Plan (SRP) address the loss loss of material materialdue to general,pitting, general, crevice, galvanic, pitting, crevice, galvanic, and microbiologic microbiologiccorrosion corrosionas well as asfouling fouling of steel containment isolationpiping containment isolation and components piping and components exposed to raw water. water. The applicant applicant proposes proposes to manage this aging manage this agingprocess process through through the use of its aging aging management management program "Periodic program "Periodic Surveillance Surveillance and Preventive Preventive Maintenance" Maintenance" (LRA B. 1.31). The GALL Report recommends that B.1.31).

this aging this aging effect be managed through the use of the aging managed through aging management managementprogram program "Open Cycle Cooling Water Cooling Water System" Report Vol.

System" (GALL Report Vol. 2 XIM20). The proposed aging management proposed aging program program is not consistent consistent with the aging management program aging management program proposed by the GALL Report.

proposed Report.

As a result, result, the applicant applicant proposes proposes that the aging management review items associated aging management with associated with Table Table 3.2.1-35 are consistent are consistent with the GALL Report in terms of material, environment, material, environment, and aging aging effect effect but a different different aging managementprogram aging management program is credited credited (generic (generic note E).

Issue Issue In its consideration considerationof these aging aging management management review items, items, the staff notes that inspection inspection of the internal surfaces of all containment isolation internal surfaces all containment isolation piping piping is not specifically specifically mentioned in the proposed proposed program.

program. The staff also also noted that that the aging aging management managementprogram program recommended by the GALL GALL Report addresses inspection, performance testing, and materials of construction Report addresses inspection, performance testing, and materials construction containment of containment isolationpiping isolation piping while the program program proposed proposed by the applicant applicant is only an inspection inspection program program which may mayor or may not inspect the internal internalsurfaces surfaces of the subject piping. questions how piping. The staff questions the proposed aging management proposed aging management program program will address internalcorrosion address internal corrosion using external inspections.

inspections.

NLS2009061 Attachment Page 11 of 41 Request Please clarify how the proposed Please clarify proposed program program will manage manage corrosion internalsurfaces corrosion on the internal surfaces ofof containment isolation piping.

containment isolation piping.

NPPD Response:

The line items items that compare to Table 3.2.1, 3.2.1, Item 35 are not containment containment isolation isolation piping piping or open cycle cooling water system components.

components. They are carbon carbon steel component types of flange, trap, valve body, piping, and filter unit housing shown in Tables Tables 3.2.2-6 (Standby (Standby Gas Treatment System)

System) and 3.2.2-7 (Primary Containment Containment System). The raw water environment environment identified for for these components is untreated untreated water in drains for these systems and not river water.

NPPD does not propose to address external inspections. As discussed in address internal corrosion using external in Appendix B. 1.31 Periodic B.l.31 Periodic Surveillance and Preventive Maintenance Program Preventive Maintenance Program description, for the standby standby gas treatment treatment and primary containment systems, corrosion primary containment corrosion on the internal surfaces surfaces ofof these components will be managed managed by:

1. Performing visual inspection inspection of a representative sample sample of standby gas treatment system carbon steel components exposed to raw water (drain water) to manage loss of material.

carbon

2. Performing Performing visual inspection inspection of the internal surface of a representative representative sample of carbon steel equipment equipment and floor drain components exposed to raw water (drain water) within within the primary containment system to manage loss of material.

primary containment NRC Request: RAI3.2.2.2-1 RAI 3.2.2.2-1

Background

Background LRA and LRA and SRP Sections Sections 3.2.2.2.3.6 refer refer to LRA and SRP Tables LRA and Tables 3.2.1-8. tables address 3.2.1-8. These tables address the loss of material materialdue to pitting pitting and crevice corrosion corrosionon stainless stainless steel, steel, piping, piping piping, piping components, components, and piping piping elements as as well as tanks exposed to internal condensation. These internal condensation.

tables 'further evaluation" tables recommend "further evaluation" on the part part of the staff applicantproposes staff. The applicant proposes to to manage manage this aging aging process process through through the use of its aging aging management managementprogram, "Periodic program, "Periodic Surveillance Surveillance andand Preventive Preventive Maintenance" Maintenance" (LRA B. 1.31). The GALL B.1.31). Report recommends that GALL Report this aging agingprocess process be managed managed through through the use of a plant-specific plant-specific aging managementprogram.

aging management program.

The applicant applicant proposes that the aging proposes that aging management management review items associated associated with Table 3.2.1-8 3.2.1-8 are consistent are consistent with the GALL Report in terms of material, environment, and aging material, environment, and aging effect but a different aging aging management programis credited management program (genericnote E).

credited (generic Issue Issue In its review of LRA Table ofLRA Table 3.2.1-8, 3.2.1-8, the staff noted that that the aging being considered aging effect being consideredis lossloss of of material material from the internal internalsurfaces surfaces of ofpiping piping in the RCIC system. The staff also noted that in the table included included in the proposed proposedAMP, applicantroutinely AMP, the applicant routinely states inspections to be states whether the inspections

NLS2009061 Page 12 of 41 performed areare internal internal oror external. However,for external. However, for piping inspection in the RCIC system, the piping inspection applicantis silent concerning applicant inspections to be conducted concerning whether the inspections conducted are internal, external, are internal, external, or both.

both.

Request Request Please specify in the proposed Please inspections to be conducted of proposed AMP whether the inspections ofpiping piping in the RCIC system are internal,external are internal, or both.

external or both.

NPPD Response:

component type listed in LRA Table 3.2.2-5 (Reactor The only component (Reactor Core Isolation Cooling System) System) that refers to line item 8 ofLRA body" with an internal "valve body" of LRA Table 3.2.1 is "valve internal environment environment of of "condensation." The aging management program activity "condensation." The aging management program activity for this for this component type is a visual inspection inspection of internal surfaces.

NRC Request: RAI3.3-3

Background

LRA Table 3.3.2-4, In LRA tubing and valve bodiesfabricatedfrom 3.3.2-4, tubing stainlesssteel exposed to bodiesfabricatedfrom stainless condensation credit the Periodic (internal)credit condensation (internal) PeriodicSurveillance Surveillance and Preventive Maintenance and Preventive Maintenance program.

program.

In LRA LRA Table 3.3.2-14-25, tubing 3.3.2-14-25, tubing and and valve bodies fabricated from stainless bodiesfabricatedfrom stainless steel exposed to condensation (internal)credit condensation (internal) One-Inspection program.

credit the One-Inspection instances the AMR program. In both instances AMR line refer to GALL AMR items refer AMR Item# VIID-4 VII.D-4 andLRA 3.3.1-54. The GALL Report and LRA Table 3.3.1 Item# 3.3.1-54.

recommends GALLGALL AMP X1M24 "CompressedAir Monitoring" XIM24 "Compressed includes (a)

Monitoring" which includes (a) frequent leak testing of valves, valves, piping, other system components, piping, and other especially those made of carbon components, especially carbon and stainless steel and steel, and stainless steel; monitoringthat and (b) preventive monitoring that checks airair quality at various various locations in the system to ensure locations ensure that that oil, water, rust, oil, water, rust, dirt, dirt, and other other contaminants contaminantsare are kept within the specified limits.

within limits.

Issue It is not clear staff how the inspections clear to the staffhow performed by the Periodic inspectionsperformed Periodic Surveillance Surveillance and Preventive Maintenance program Preventive Maintenance program or or the One-Time Inspection program Inspection program will substitute the substitute recommendations of GALL AMP XI recommendations M24 "Compressed XIM24 "CompressedAir Monitoring".

Monitoring".

Request Request Pleasejustify the use of the Periodic Please PeriodicSurveillance andPreventive Surveillance and Maintenanceprogram Preventive Maintenance program in the GeneratorSystem and Diesel Generator Diesel and the One-Time Inspection program in the Service Air System for Inspection program aging management,which will only perform visual aging management, visual and/or and/or NDE inspections, in lieu NDE inspections, lieu of GALL GALL AMP XIM24, XIM24, which include testing and include leak testing and checksfor airair quality.

quality.

NLS2009061 Attachment 2 Page 13 of 41 41 NPPD Response:

The Compressed Air Monitoring Program recommended in NUREG- NUREG-1801 1801 (GALL) Volume 2 XI.M24 is based on industry response to NRC Generic Letter (GL) 88-14 for Chapter XLM24 maintaining proper instrument air quality and primarily consists of air quality monitoring and compressed air systems identified in LRA Tables 3.3.2-4 leakage monitoring. The areas of the compressed (Diesel Generator System) and 3.3.2-14-25 3.3.2-14-25 (Service (Service Air System) are in the diesel generator generator starting air system and service air system that contain no air dryers. In some cases, componentscomponents are normally isolated from from the rest of the system. Thus, air quality and leakage monitoring will management activities.

not be effective aging management Surveillance and Preventive The CNS Periodic Surveillance Preventive Maintenance Maintenance Program described described in LRA B.1.31 and the One-Time Inspection Inspection Program Program described in LRA B. 1.29 provide for visual inspections or B.1.29 or other NDE techniques, among other elements, to detect loss of material. These are the same techniques included in other programs NUREG-l18011 ((GALL) programs described in NUREG-180 GALL) Volume 2 that are credited to manage loss of material due to pitting and crevice crevice corrosion on the internal surfaces of components. LRA Table 3.3.2-14-25 3.3.2-14-25 addresses the service air system. Stainless steel, tubing, and valve bodies in this system are resistant to corrosion from condensation. Therefore, a one-time inspection inspection is appropriate to manage manage loss of material.

Therefore, the Periodic Surveillance Surveillance and Preventive Preventive Maintenance Maintenance Program and the One-Time One-Time Inspection Inspection Program provide reasonable assurance assurance that the effects of aging are managed such that these components will continue continue to perform perform their intended intended functions consistent with the current current licensing licensing basis through the period of extended extended operation.

NRC Request: RAI 3.3.2.1-5 RAI3.3.2.1-5

Background

LRA LRA and SRP Tables Tables 3.3.1-79 address address the loss of material materialdue to pitting, pitting, crevice corrosion corrosionand fouling of stainless fouling stainless steel piping, piping components, piping, piping components, and piping piping elements exposed to raw water.

water.

The applicant applicant proposes proposes to manage manage this aging aging process process through through the use ofof its aging aging management

program, program, "One Time Inspection" (LRA B.1. 29). The GALL B.1.29). GALL Report recommends that this aging process process be managed managed through through the use of the aging managementprogram, aging management program, "Open Cycle CoolingCooling Water System" System" (GALL Report Vol. Vol. 2 XIM20).

XI.M20). The proposed aging management program proposed aging management program is not consistent consistent with the aging managementplan proposed aging management proposed by by the GALL Report.

Report. As As a result, result, the applicant applicant proposes that the aging proposes that aging management management review items associated associated with Table 3.3.1-79 are are consistent consistent with the GALL GALL Report in terms of material,environment, of material, environment, and aging effect effect but a different aging aging management management program program is credited (genericnote E).

credited (generic Issue In its review ofofLRA LRA Table 3.3.1- 79, the staff noted that the One Time Inspection 3.3.1-79, Inspection Aging Aging Management Management Program Program is designed designed to be used when the environment environment to which a system, structure structure

NLS2009061 Page 14 14 of 41 component is or component is exposed exposed is is invariant invariantwith time,time, for for example treated treatedwater water systems wherewhere the water chemistry is frequently monitored and carefully water chemistry is frequently monitored and carefully controlled. controlled. In In such systems, systems, the lack lack of of priorcorrosion prior corrosionmay be an an indicator indicatorthat thatfuture future corrosion corrosionwill not occur.occur. Raw waterwater systems, systems, includingany including any untreated untreatedand and substantially substantiallyunmonitored unmonitoredwater water system, system, cannot cannot be considered consideredto be invariantwith time in terms of chemistry or invariant or microbiology.

microbiology.

Request Pleasepropose Please propose a program programto manage manage the agingaging of the components components underunder consideration considerationwhichwhich recognizes variabilityof the chemistry recognizes the variability chemistry and and microbiology microbiology of raw raw water, water, andand which acknowledges inability to use past acknowledges the inability corrosionperformance past corrosion performance as as an indicator indicatorof offuture future corrosion corrosion under under such circumstances.

circumstances.

NPPD Response:

The stainless steel component types in a raw water environment environment that credit the One-TimeOne-Time Inspection Program and align with LRA Table 3.3.1, 3.3.1, item 79 are those in the off-gas and radwaste radwaste systems as shown in LRA Tables Tables 3.3.2-14-14 (Off Gas System [10 CFR 54.4(a)(2)]) 54.4(a)(2)])

and 3.3.2-14-23 3.3.2-14-23 (Radwaste System [10 CFR 54.4(a)(2)]). The requirements of the GALL Open Cycle Cooling Cooling Water System (Service(Service Water Water Integrity) program are derived from GL 89-13 for for service water systems, which pertains pertains to systems that transfer heat from safety-related safety-related structures, systems, or components to the ultimate ultimate heat sink. Since Since the off-gas and radwaste systems do not safety-related structures, systems, or components, they are not subject to GL transfer heat from safety-related 89-13 requirements. Accordingly, it would be inappropriateinappropriate to credit credit the Service Service Water Integrity Program (which includes all components components subject subject to GL 89-13) for aging management.

management.

The off-gas off-gas system components components managed managed by the One-Time Inspection Program Program are shown shown on on drawing LRA-2009-0 LRA-2009-0 (Air Removal System) (D-8) and support off-gas support off-gas sampling. The stainless steel component types of tubing and valve body are exposed to condensation condensation from the sampling.

Although Although the water vapor from the condenser condenser sampled by this system is subject subject to the influence influence of the Water Chemistry ofthe Chemistry Control Control- - BWR BWR Program, Program, NPPD conservatively conservatively considered considered this sample water "raw water."

water "raw water." This condensation, condensation, though not directly monitored by a water water chemistry chemistry program, originates program, originates from treated water, is not aggressive, aggressive, and does not contain significant levels contain significant levels of impurities impurities such as those in a traditional raw or river water environment. environment.

The The radwaste system components components managed by the One-Time One-Time Inspection Inspection Program are shown shown primarily primarily on drawing LRA 2042-SH02 drawing LRA 2042-SH02 (Reactor (Reactor Water Cleanup Cleanup System) and consist of of component component types eductor, piping, pump pump casing, tank, tubing, and valve body body used for processing processing reactor reactor water cleanup cleanup system resins. These stainless steel steel components components are not normally in in service. Although the water used in this process service. Although the water used in this process is demineralized demineralized water, NPPD NPPD conservatively conservatively identified it as "raw identified "raw water" since since there are no specific water chemistry chemistry controls once once the the process process begins.

begins. However, the the water originates originates from treated treated water, is not not aggressive, aggressive, and does not not contain contain significant significant levels of impurities such as those those in a traditional traditional raw raw or river river water water environment.

NLS2009061 Attachment Page 15 of 41 Stainless steel has historically Stainless historically proven acceptable acceptable for long-term long-tenn service in non-aggressive environments due to its inherent environments inherent corrosion corrosion resistance. There has been no operating operating experience experience at indicating aging effects requiring management CNS indicating management for stainless steel in these environments.

Therefore, the One-Time One-Time Inspection Inspection Program is acceptable acceptable to confirm confinn that either (a)

(a) the aging effect is indeed indeed not occurring, or (b) the aging effect is occurring occurring very slowly so as not to affect affect the component intended function.

component intended NRC Request: RAI3.3.2.1-7 RAI3.3.2.1-7

Background

LRA LRA and SRP Tables Tables 3.3.1-83 address address the reduction reduction of heat transfer transfer due to fouling fouling of stainless stainless and copper steel and copper alloy heat exchanger exchanger tubes tubes exposed to raw water. The applicant raw water. applicantproposes proposes to to manage this aging manage aging process through the use of its aging process through aging management managementprogram, "Periodic program, "Periodic Surveillance and Surveillance and Preventive Maintenance" (LRA B.

Preventive Maintenance" 1.31). The GALL B.1.31). Report recommends GALL Report recommends that this aging agingprocess managed through process be managed through the use of the aging aging management management program, program, "Open Cycle Cooling Water System" Cooling System" (GALL ReportReport Vol. 2 XIM20).

XI.M20). The proposed proposed aging aging management programis not consistent program consistent with the aging aging management managementprogram program proposed proposed by the GALL Report.

Report.

As a As a result, result, the applicant applicant proposes proposes thatthat the aging aging management management review items associated associatedwith Table 3.2.1-83 are Table consistent with the GALL Report in terms of material, are consistent material, environment, environment, andand aging aging effect but a different aging aging management management program program is credited credited (generic (genericnote E).

Issue In its review ofLRA Table 3.3.1-83, the staff noted that the item under LRA Table under consideration considerationis heating/cooling heatinglcooling coil serving serving the nitrogen nitrogen system. The staff also noted that aging effect under that the aging consideration consideration is loss of heat transfer transfer due due to fouling.

fouling. Based on the information informationpresented presented in the application,the staff application, must assume staffmust assume that that the applicant applicant correctly correctly chose to apply Table 3.3.1-83 to this component.

component. In the absence absence ofadditional information, the staff must also assume that additional information, thatgeneric generic letter letter 89-13 applies applies to the component under under consideration.

consideration.

Request Please propose an Please propose an aging aging management program equivalent management program equivalent to the open cycle cooling cooling water water AMP orjustify or justify why generic generic letter 89-13 does not apply to this system. This justification justification should include include a complete description description of the water system associated associated with the nitrogen including the nitrogen system including water source water source and its typical typical chemical composition.

composition.

NPPD Response:

The GALL Open Cycle Cooling Water System (Service (Service Water Integrity) Program requirements requirements are derived derived from GL 89-13 for service water water systems, defined defined in the generic letter as systems that transfer heat from safety-related structures, systems, or components to the ultimate heat sink.

safety-related structures, Since Since the nitrogen nitrogen system does not transfer heat from safety-related safety-related structures, systems, systems, oror components, GL89-13 requirements. Therefore, components, it is not subject to GL89-13 Therefore, it would be inappropriate to

NLS2009061 Attachment Page 16 of 41 credit the Service Water Integrity Program (which includes all components subject to GL 89-13) 89-13) for aging management.

As stated in item 83 ofLRA of LRA Table 3.3.1, the Service Water Integrity Program manages reduction Table 3.3.1, of heat transfer in heat exchanger tubes exposed exposed to service water. For other components exposed to untreated untreated or unmonitored water evaluated as raw water, the Periodic Surveillance and Periodic Surveillance Preventive Maintenance Program manages Preventive Maintenance manages reduction of heat transfer using periodic visual inspections.

The heat transfer coil listed in LRA Table 3.3.2-13 (Nitrogen System) is submerged submerged in potable potable water inside the vaporizer conservatively evaluated as raw water. Makeup sources vaporizer tank, which is conservatively include include the CNS potable water system and rainfall rainfall which flows into the open top of the vaporizer vaporizer tank. The inspection described described in LRA Section B. 1.31 as part of the Periodic B.1.31 Surveillance and Periodic Surveillance Preventive Maintenance Program provides Preventive Maintenance provides reasonable reasonable assurance that the effects of aging are managed managed such the coil will continue to perform its intended function consistent with the current current licensing basis through the period of extended extended operation operation NRC Request: RAI 3.3.2.2.6-2 Request: RAI3.3.2.2.6-2

Background

The GALL Report identifies identifies aging aging effects for stainless stainless steel spent fuel storage storage racks racks and and neutron neutron absorbing absorbing materials materials (e.g., Boraflex oror boron-steel boron-steel sheets) in boiling water reactor boiling water (B WR) treated reactor (BWR) treated water.

water. Aging effects include loss of material/general corrosion and reduction material/general corrosion and reduction neutron of neutron absorbing absorbing capacity, andfurther capacity, and evaluation of a plant-specific further evaluation plant-specific aging aging management program for managementprogram neutron absorbing those neutron absorbing materials.

materials. The GALL GALL Report, Report, Revision 1, 1, does not address address the specific use ofMetamicTM, MetamicTM, a boronboron carbide carbidealuminum composite, composite, as a neutron neutron absorber materialin absorber material spent fuel pools.

pools.

LRA LRA Section 2.3.3.9, "FuelPool 2.3.3.9, "Fuel Pool Cooling Cooling and and Cleanup, Cleanup,"" identifies identifies that that the spent fuel pool cooling and cleanup cooling and cleanup system includes MetamicTM, to provide criticality includes MetamicTM, provide criticality control. control.

In a license license amendment that thatpermitted permitted the use ofMetamicTM Metamic' in the spent fuel pool at Cooper Nuclear Nuclear Station Station (CNS), the applicant applicant implemented a couponcoupon surveillance programin its license surveillance program amendment commitments to assess amendment assess degradation degradationof thisthis material material in its environment.

environment.

Issue CNS LRA LRA Section 3.3.2.2.6, 3.3.2.2.6, "Reduction "Reduction ofNeutron-Absorbing Neutron-AbsorbingCapacity Capacityand Loss of ofMaterial Material due to General General Corrosion, addresses Boral Corrosion, " addresses Boral spentfuel storage storage racks exposed to a treated treated water environment, environment, but does not address Metamic'.

addressMetamic LRA Table TM. LRA Table 3.3.2-9 states states that management of that management of loss of material materialfor "aluminum/boron "aluminum/boroncarbide carbide panels panels is performed by the Neutron Neutron Absorber Monitoring Monitoring andand Water Water Chemistry Control- B Chemistry Control- WR Programs.

BWR Programs. However, However, the CNS LRA LRA does not present present sufficient specific plant information on how these programs plant information programs will manage reduction of manage reduction of

NLS2009061 Attachment Page 17 of 41 neutron-absorbing capacity or loss of material neutron-absorbing capacity materialfor for MetamicTM Metamic' in the spent fuel pool.pool. Section B. 1.23 of the LRA, B.1.23 entitled "Neutron LRA, entitled "NeutronAbsorber Monitoring, Monitoring, ""specifically specifically indicates indicates that the scope program includes of this program "all Boral includes "all the CNS Boral in the spent fuel CNS spent pool, "" and fuel pool, does not and does include MetamicTM not include Metamic' or aluminum/boron aluminum/boron carbide.

carbide.

Request 1.

1. Regarding aging effects for Regarding aging for MetamicTM Metamic' used in the spent fuel pool: pool:

a.

a. IdentifY Identify the aging aging effects which apply to the MetamicTM Metamic' (e.g., loss of of material/general corrosion material/general corrosionand reduction of neutron-absorbing and reduction capacity).

neutron-absorbingcapacity).

b. If If the aging aging effects requiring requiring management management (AERM)

(AERM)for Metamic' MetamicTM do not include include both of the aging aging effects cited cited in the GALL GALL Report neutron absorbing Reportfor neutron absorbing materials, materials, provide technical basis provide the technical basis (including (includingoperating experience) that operating experience) justifies justifies the exclusion of the aging aging effect(s) cited in the GALL Report.

Report.

2.

2. If If the applicant identifies AERMfor MetamicT, applicant identifies Metamic', describe describe the aging aging management program(s) program(s) that will be used. Specifically:

used. Specifically:

a.

a. If If the applicant applicant proposes proposes the CNS WaterWater Chemistry Control - BWR Chemistry Control B WR Program Program for aging management, describe aging management, describe how this this program program will be used to manage manage AEMR AEMRfor for TM Metamic Metamic'.

b.

b. Provide Provide the 10 elements of the aging aging management programfor management program for MetamicTM Metamic' (i.e.,

(i.e.,

scope of ofprogram, program, preventive actions, actions,parameters monitored or inspected, parameters monitored inspected, detection detection of aging aging effects, monitoring monitoringand and trending, trending, acceptance, acceptance, corrective corrective actions, confirmation actions, process, administrative confirmation process, controls, operating administrative controls, operatingexperience),

experience),

including the coupons that including that will be under surveillance.

surveillance.

c. Indicate whether the MetamicTM Indicate whether Metamic' panels panels and coupons coupons in the CNS spent fuel pool are are vented or or not.

not.

d.

d. Indicate the installation Indicate date of the Metamic' installation date MetamicTMpanels/racks panels/racks in the CNS spent fuel pool.

pool.

e.

e. Describe surveillance approach Describe the surveillance approach that that will be used in the cited AMP, specifically the methods, specifically methods, techniques techniques (e.g., visual, visual, weight, weight, volumetric, volumetric, surface surface inspection),frequency, inspection), frequency, sample size, datadata collection, collection, timing, and acceptance timing, and acceptance criteria.

criteria.

NLS2009061 Page 18 of 41 ff Discuss the correlation Discuss correlation between measurements measurements of the physical physical properties properties ofof MetamicTM Metamic' coupons and the integrity integrity of the Metamic Metamic' panels in the storage mpanels storage racks.

racks.

g.

g. Identify the subcritical margin used in the criticality subcritical margin criticalityanalysis.

analysis. Describe Describe how the program program acceptance acceptance criteria criteria account account for for potential degradationbetween potential degradation surveillance surveillance periods.

periods.

h. For the eNS For CNS Metamic' MetamicTM coupons:

coupons:

i. Identify the quantity quantity and and location location of Metamic' MetamicTM coupons coupons relative relative to the spentfuel racks racks during during the license renewal period.

renewal period.

ii.

ii. Describe Describe how the coupons are are mounted and whether they are arefully fully exposed to the spent fuel pool water.

water.

iii.

iii. Describe Describe the specific testing testing that will be done for for determining determining the MetamicTM Boron-J O areal Metamic' Boron-l 0 areal density,density, verifying surface corrosion (if surface corrosion (if any) any) and examining examiningfor blister blisterformation.

formation.

iv.

iv. removalfrom the pool After removal poolfor inspection will the coupons be inserted for inspection inserted locations in the pool?

back at the same locations pool?

Describe how the resultsfrom the inspections of the MetamicTM coupons will be

i. Describe how the results from the inspections of the Metamic' coupons will be monitoredand monitored and trended, trended, including includingfrequency and and sample size (e.g., the number number of of coupons examined coupons examined at each each surveillance).

surveillance).

j. Describe corrective actions Describe the corrective actions that that would be implemented if coupon test results if coupon results acceptance criteria.

do not meet the acceptance criteria.

k.

k. Discuss Discuss any relevant industry or plant-specific relevant industry operatingexperience plant-specific operating applicableto experience applicable to Metamic Mpanels the Metamic' panels and coupons.

coupons.

NPPD Response:

Response

L.a.

l.a. As indicated indicated in LRA LRA Table 3.3.2-9, the aging effect requiring requiring management management for aluminum I/ boron carbide carbide (Metamic (MetamicTM)TM) spent fuel panels in a treated water environment environment is loss of of material. The NRC staff, as documented documented in Section 2.2 of the Safety Evaluation Evaluation for the MetamicTM use of Metamic ' at CNS dated September September 6, 2007, has concluded Metamic' is concluded that MetamicTM

NLS2009061 Attachment Page Page 19 of 41 compatible with the environment compatible environment of the spent fuel pool and is not expected expected to exhibit degradation degradation which could impair design function of the racks.33 impair the design 1.b.

1.b. Qualification testing indicates no change in the neutron attenuation Qualification attenuation characteristics of characteristics of MetamicTm coupons under long-term thermal test conditions and accelerated Metamic' accelerated radiation radiation test conditions. The NRC staff, staff, as documented in Section 2.2 of the Safety Evaluation Evaluation for the use of MetamicTM Metamic' at CNS dated September September 6, 2007, has concluded 6,2007, concluded that Metamic MetamicTM ' is compatible with the environment of the spent fuel pool and is3 not expected to exhibit degradation which exhibit degradation which could impair the could impair function of design function the design the racks.

of the racks. 3 As stated in LRA Section 3.3.2.2.6, the NRC staff has accepted the position that Boral spent fuel panels do not degrade as a result of long-term long-term exposure to radiation radiation (documented in Section (documented 3.5.2.4.2 of the license renewal Safety Evaluation Report (SER)

Section 3.5.2.4.2 for VC Summer Summer [NUREG-1787]).

[NUREG-1787]). The potential potential aging effects resulting from sustained irradiation of Boral werewere previously evaluated evaluated by the staff (in BNL-NUREG-25582, BNL-NUREG-25582, 1979) and determined to be insignificant. Metamic dated January 1979) MetamicTM ' material composition composition is an improvement improvement to the Boral design that provides reduced neutron neutron streaming. This is based in part on the more homogeneous homogeneous mixture of aluminum and boron carbide carbide powders powders in MetamicTM Metamic' made possible by a smaller boron carbide carbide particle particle size. Therefore, reduction of neutron absorption capability is not an aging effect requiring management management for the Metamic' MetamicTM panels at CNS.

To underscore underscore the differences in the material material properties of Metamic properties ofMetamic' as compared compared to Boral, LRA Sections 3.3.2.2.6 and Table 3.3.2-9 have been revised revised (see Attachment Attachment 3, Changes 4 and 5). 5).

2.a. As indicated indicated in LRA TableTable 3.3.2-9, loss of material for aluminum aluminum / boron carbide carbide (Metamic T M

(Metamic')) spent fuel panels panels in treated treated water is managed managed by the Water Chemistry Chemistry Control Control- - BWR Program. As stated in LRA Section B. 1.39, the Water Chemistry B.1.39, Control - BWR Program Program minimizes the potential potential for loss of material by limiting the levels of contaminants contaminants that could causecause loss of material. The LRALRA notes that the program is consistent consistent with the program described in NUREG-1801, NUREG-180 1, Section XI.M2, "Water XLM2, "Water Chemistry."

Chemistry." The program relies on monitoring and control of water chemistry chemistry based on EPRI Report 1008192 (BWRVIP-130). As stated in NUREG-1801, NUREG-1801,Section XI.M2, XLM2, the guidelines include EPRI guidelines include recommendations recommendations for controlling controlling water chemistry in the spent fuel pool. Spent fuel pool parameters parameters monitored monitored include conductivity, chloride content, sulfate sulfate content, sodium content, silica content, total organic organic carbon, and total activity.

3 Amendment 227, Carl F. Lyons to Stewart B. Minahan, "Cooper Nuclear Station - Issuance Amendment Re:

3 Amendment 227, Carl F. Lyons to Stewart B. Minahan, "Cooper Nuclear Station of Amendment Onsite Spent Fuel Storage Storage Expansion," September 6, 2007, (ADAMS Accession Expansion," September Accession Numbers ML072130026 and Numbers ML072130026 ML072130023).

ML072130023).

NLS2009061 Page 2020 of41 of 41 The One-Time Inspection Program, described in LRA Section B.l.29, B. 1.29, includes effectiveness of the Water Chemistry Control-inspections to verify the effectiveness Control - BWR Program by confirming that unacceptable loss of material is not occurring. The combination combination of of Control - BWR Program and One-Time Inspection Program is Water Chemistry Control-NUREG- 1801, consistent with NUREG-lS0 1, Volume 2 line item VII.A4-5 for managing loss of of material of aluminum in treated borated water. Metamic material MetamicTM ' coupons installed as part of of the original installation completed on January 15, 15, 200S, 2008, will provide inspection locations for confirming that unacceptable loss of material is not occurring. The coupons are installed on a coupon tree in one of the cells of the spent fuel racks, fully exposed to the spent fuel pool water. This confirmation confirmation will be provided prior to the period of extended extended operation.

2.b. As indicated in LRA Sections B.1.39 and B.1.29, the ten elements elements of the aging management management programs for MetamicTm Metamic' are provided in NUREG-1801, provided NUREG-lS0 I,Section XI.M2, Water Chemistry and Section XI.M32, One-Time Inspection.

2.c. The MetamicTM Metamic' panels and coupons in the CNS spent fuel pool are not vented.

2.d. The MetamicTM Metamic' panels were installed in the CNS spent fuel pool in January 2008.

January 200S.

2.e. The MetamicTM Metarnic' surveillance surveillance approach used in the cited AMPs is described in the NUREG-1801 NUREG-lS0l sections sections referred referred to in the response to item 2.b.

2.f.

2.f. The MetamicTM Metamic' coupons are designed to representrepresent the condition condition of the Metamic' ~anels MetamicTM panels in the storage racks. However, measurement racks. However, measurement of of physical properties of physical properties of the MetamicTM the Metamic M coupons is not part of the aging aging management programs creditedcredited to manage the effects effects ofof aging on the Metamic MetamicTM' panels.

2.g. As stated stated in Section X-3.2 of the CNS USAR, the high density spent spent fuel storage storage racks are designed designed to maintain maintain spent spent fuel assemblies assemblies in a sub subcritical critical configuration configuration having a keff

< 0.95 for all normal and abnormal

S abnormal configurations.

configurations. Qualification Qualification testing indicated no detectable change detectable change in the neutron attenuation attenuation characteristics characteristics of MetamicTM Metamic' coupons coupons under long-term thermal test conditions and accelerated radiation test conditions.

long-term thermal test conditions and accelerated radiation test conditions.

2.h/i/j. The 2.hli/j. The NRC staff, staff, as documented documented in Section 2.2 of the Safety Evaluation Evaluation for the use of of Metamic Metamic' at CNS dated SeptemberSeptember 6, 2007, 2007, has concluded concluded that MetamicTM Metamic' is is compatible compatible with the environment environment of of the the spent spent fuel pool environment environment and is not expected expected to exhibit exhibit degradation degradation which couldcould impair impair the design design function of the racks.44 of the 4 Amendment 227, Carl F. Lyons to Stewart B. Minahan, "Cooper Nuclear Station- Issuance of Amendment Re:

4 Amendment 227, Carl F. Lyons to Stewart B. Minahan, "Cooper Nuclear Station - Issuance of Amendment Onsite Spent Fuel Fuel Storage Storage Expansion,"

Expansion," September September 6, 2007, (ADAMS Accession 6,2007, Accession Numbers Numbers ML072130026 ML072130026 and and ML072130023).

ML072130023).

NLS2009061 Page 21 of 41 Based on the known operating characteristics of the Metamic MetamicTM ' material, no aging effects have been identified other than those managed managed by the Water Chemistry Control - BWR One-Time Inspection Program. Therefore, no other aging Program as verified by the One-Time management activities are proposed. Monitoring of Metamic MetamicTM ' coupons is not credited for managing the effects of aging on Metamic' TM panels in the CNS spent fuel pool.

2.k. Relevant operating experience experience applicable to the Metamic' MetamicTM panels and coupons was provided in the response to l.b. 1.b.

NRC Request: RAI3.3-7

Background

For the following descriptions For thefollowing descriptionsplease answer the questions please answer thatfollow:

questions thatfollow:

• In LRA Table'3.3.2-12, In Table'3.3.2-12, the Periodic PeriodicSurveillance Surveillance and and ?reventative PreventativeMaintenance Maintenance program program was credited for managing credited for managing loss of material for gray material for gray cast iron pump casings iron casings in air-indoor(internal) an air-indoor (internal)envirOnment environment and and reference reference LRA Table 3.2.1 Item# 3.2.1-32 and LRA Table GALL aging management review (AMR) Item# VD2-16.

aging management VD2-16.

• In LRA Table 3.3.2-13, LRA Table 3.3.2-13, the External ExternalSurfaces Monitoringprogram Surfaces Monitoring program was creditedfor creditedfor managing managing loss of material materialfor gray cast iron gray cast iron valve bodies in an air-indoor (internal) air-indoor (internal) environment environment was credited credited for managingfor loss of for managing ofmaterial and reference material and reference LRA Table Table 3.2.1 Item# 3.2.1-32 andand GALLAMR GALL AMR Item# VD2-16. VD2-16.

• In LRA Table 3.3.2-05, LRA Table 3.3.2-05, the External ExternalSurfaces Monitoringprogram Surfaces Monitoring program was creditedfor creditedfor managing managing loss of materialfor material for gray cast iron gray cast ironflame arrestors arrestors in an air-outdoor air-outdoor (internal)

(internal) environment environment andand reference reference LRA Table 3.4.1 Item# 3.4.1-30 and LRA Table and GALL AMR AMR Item#

VIII. B-6.

VIII.B1-6.

The GALLReport GALL Report recommends the program program XI.M38, "Inspection ofInternal XI.M38, "Inspection Internal Surfaces in Miscellaneous Miscellaneous Piping Piping and Ducting Components Components""for for aging aging management each instance described instance described above.

above.

Issue The program program descriptions descriptions of of the Periodic Periodic Surveillance Surveillance and Preventative PreventativeMaintenance Maintenance program program and External ExternalSurfaces Surfaces Monitoring Monitoring program state these programs program state programs are credited creditedfor managing managing loss of ofmaterial materialfor the internal internal surfacefor for situations situations where the external external and internal internal material material and environment combinations combinations are the same such that that the external external surface is representative representative of of the internal surface condition. It is internal surface condition. It unclearunclear to the staff if (f the conditions of conditions of the internal and internal and external environment of these components are are the same, because the internal internal environment may contain contain contaminants contaminants and stagnant air stagnant air which is not the same as freely circulating air circulating air on the external surface.

surface.

NLS2009061 Page 22 of 41 Request Please describe Please describe in detail detail the conditions that exist in the internal conditions that internal environment of the components described compares with the external above and how it compares described above external environment. please justify the environment. Also, please credited manage aging ability to manage credited AMPs ability aging of the internal inspecting the external internalsurface by visually inspecting external surface, program recommended by the GALL Report.

surface, in lieu of as the program Report.

NPPD Response:

LRA Table 3.3.2-12 3.3.2-12 The gray cast iron pump casings in LRA Table 3.3.2-12, 3.3.2-12, Plant Drains, refer to portable gasoline powered pumps that can be used, if needed, for external external flood control. The pumps are stored stored installed system. The pump is normally drained indoors and are not part of an installed drained and free of water maintenance. Therefore, air-indoor (int) is the appropriate except during periodic maintenance. appropriate environment.

Although the internal and external surfaces of the pump casings are exposed to the identical environment of indoor air, only the external surface is coated. Accordingly, environment Accordingly, the Periodic Surveillance Surveillance and Preventive Program will inspect both the internal and external Maintenance Program Preventive Maintenance surfaces of the pump casing to manage loss of material. LRA Section B.l.31 surfaces B. 1.31 has been revised to (see Attachment 3, Change reflect this (see Attachment Change 12). 12).

LRA Table 3.3.2-13 3.3.2-13

-

component type valve body listed in LRA The gray cast iron component LRA Table 3.3.2-13 (Nitrogen System) is nitrogen system as shown on drawing LRA-2022-SHO part of the nitrogen LRA-2022-SHOI. 1. These valves and associated piping supply nitrogen gas to the drywell. The component component type valve body is exposed exposed to gas andand not air indoor internal. LRA Table Table 3.3.2-13 has been revised to reflect reflect this (see Attachment Attachment 3, Change 6).6).

LRA Table Table 3.3.2-5 The flame arrestors in LRA Table 3.3.2-5,3.3.2-5, Fuel Oil System, are aluminum rather than gray cast iron. See the previously submitted response to RAI 3.4.2.1-2 for the associated changes to the LRA. 5 NRC Request:

Request: RAI3.4.2.1-1 RAJ 3.4.2.1-1

Background

Background StandardReview Plan Standard for Review of License Renewal Application Plan for Application forfor Nuclear Nuclear Power Plants Power Plants (SRP-LR) and LRA LRA Table 3.4.1-28 address materialdue to general address the loss of material generalcorrosionfrom corrosionfrom the surfaces ofsteel components exposed to uncontrolled external surfaces external uncontrolledindoor indoor air, outdoor air air, outdoor air or 5

5 NLS2009055, Stewart B.

NLS2009055, Stewart B. Minahan to USNRC, Minahan to Response to USNRC, Response Request for to Request for Additional Information for License Additional Information License Renewal Application," July 29,2009 Renewal Application," 29, 2009 (ADAMS Accession Number ML092090276).

Accession Number ML092090276).

NLS2009061 Attachment Page 23 of 41 condensation.

condensation. Both the SRP-LR and and LRA Table Table 3.4.1-28 propose propose the use of the Aging Management Program Management Program "External "ExternalSurfaces Surfaces Monitoring" Monitoring" (LRA B.l.14 B.]. 14 and GALL Report Report Volume 2 Chapter ChapterXIM36)

XI M3 6) to manage manage the agingagingprocess. However,for process. However, at least some LRA for at Table 2 items LRA Table subordinateto LRA subordinate LRA Table 3.4.1-28, 3.4.1-28, the applicant applicantproposes proposes that no agingaging effect is present present and that no aging aging management managementprogram required(generic program is required (genericnote 1).I).

Issue Issue In its review of LRA Table 3.4.1-28, LRA Table 3.4.1-28, the staffnoted noted that the applicant's basisfor stating applicant's basis stating that no aging aging effect was present present was that the temperature temperatureof the components under consideration consideration was above the dewpoint.

dewpoint. The GALL Report Reportfinds thatthat the aging aging effect ofof loss of material materialdue to exposure of steel surfaces indoor air, surfaces to indoor air, which can can result result in condensation condensation but only rarely, rarely,should considered.

be considered.

Request Please Please justify why aging aging management management is not required requiredfor for these components given that, during that, during normal plant events such as normal plant as refueling, refueling, the components under under consideration consideration will be at or near ambient temperature.

ambient temperature.

NPPD Response:

As reflected in LRA Table 3.4.2.1 3.4.2.1 (MSIV Leakage Pathway), where no aging effect is identified identified for carbon carbon steel main steam isolation valve (MSIV) leakage leakage pathway pathway components components exposed exposed to indoor air, Plant Specific Specific Note 403 is applied. Note 403 at the end ofLRA of LRA Table 3.4.1 (Steam (Steam and Power Conversion Systems, NUREG-1801 NUREG-1801 Vol. 1), 1), on Page 3.4-35 states:

component surface "High component surface temperature precludes moisture accumulation that could result in corrosion."

Note 403 applies to carbon steel components of the main steam steam system with high operating operating temperatures temperatures (> 212 'F)

OF) that have external surfaces external surfaces exposed to indoor air. During normal operation, these components are at temperatures temperatures where moisture moisture deposition is not possible.

Without the presence presence of moisture, corrosion corrosion is not possible. Although these components components are at or near (but seldom if ever below) ambient temperatures during shutdown ambient temperatures shutdown conditions, such as refueling outages, these conditions are comparatively comparatively brief.

brief. Any minor moisture accumulated accumulated during shutdown is quickly evaporated evaporated during startup. Operating experience experience has shown that these components components are not subject subject to loss of material due to corrosion of the external surfaces.

NRC Request:

Request: RAI3.4.2.1-4 RAI 3. 4. 2.1-4

Background

Background LRA and SRP Tables 3.4.1-32 address LRA and address the loss of material material due to pitting, pitting, crevice, crevice, and microbiologicallyinfluenced corrosion microbiologically corrosionas well as asfoulingfor fouling for stainless and copper stainless steel and copper alloy

NLS2009061 Attachment Page 24 of 41 .

Page

piping, piping, piping piping components, components, and pipingpiping elements exposed to raw raw water..

water. The applicant applicantproposes proposes manage this aging to manage process through agingprocess through the use of of its aging management program, aging management program, "Periodic "Periodic Surveillance Surveillance and Preventive Maintenance" and Preventive Maintenance" (LRA B.1.31).B. 1.31). The GALL Report recommends that aging process this aging process be managed through the use of the aging managedthrough aging management program, "Open managementprogram, "Open Cycle Cooling Water System" Cooling Water System" (GALL Report Vol. 2 XI.M20).

(GALL Report X.M20). The proposed proposed aging management aging management programis not consistent program consistent with the aging aging management management program program proposed proposed by the GALL Report.

GALL Report.

As As a result, applicantproposes result, the applicant proposes that the agingaging management management review items associated associatedwith Table Table 3.4.1-32 areare consistent consistent with the GALL Report in terms of material, GALL Report environment, and aging material,environment, effect but a different d(fJerent aging management program aging management program is credited (generic note E).

credited (generic Issue In its review ofLRA Table 3.4.1-32, LRA Table 3.4.1-32, the staff noted that that the item under under consideration consideration is tubing serving the circulating serving water system. The staff also circulating water also noted thatthat the aging aging effect under consideration is loss ofmaterial.

consideration material. The staff further noted that stafffurther that at many plants plants portions portions of the circulating circulating water water system are are considered considered to be safety related related due to their their relationship relationship with the service water water system. Based on the information informationpresented presented in the application, application,the staff mustmust assume thatthat the applicant applicantcorrectly correctly chose to apply Table 3.4.1-32 to this component. component. In the absence absence of additional information, the staff must also additional information, also assume that thatgeneric generic letter applies to letter 89-13 applies the component under consideration.

consideration.

Request Please Please propose aging managementprogram propose an aging equivalent to the open cycle cooling water AMP program equivalent orjustify or justifY why generic letter 89-13 does not apply to this system.

generic letter NPPD Response:

The response to RAI 3.4.2.1-3 3.4.2.1-3 was previously previously submitted submitted and justifies why GL 89-13 89-13 does not 66 apply to this system. .

NRC Request: RAI 3.4.2.2-1 Request: RAI3.4.2.2-1

Background

LRA and LRA and SRP Sections 3.4.2.2.3 refer to LRA and SRP Tables 3.4.1-8.

LRA and 3.4.1-8. These tables tables address address the loss of material loss material due to general, pitting, crevice, and microbiologically influenced general, pitting, crevice, and microbiologically influenced corrosion corrosion (MIC), as well as fouling (MIC), fouling in steel piping, piping, piping piping components and piping piping elements exposed to raw raw water.

water. These tables tables recommend 'further evaluation "further evaluation "on "on the part part of the staff staff. The applicant applicant proposes manage this aging proposes to manage aging process process through through the use of its aging managementprogram, aging management program, "PeriodicSurveillance "Periodic Surveillance and and Preventive Preventive Maintenance" Maintenance" (LRA B. 1.31). The GALL Report B.1.31).

recommends that this this aging agingprocess process be managed managed through through the use of a plant-specific aging plant-specific aging management management program. applicantproposes program. The applicant proposes that the aging management review items aging management 66 NLS2009055, Stewart B.

NLS2009055, Stewart B. Minahan to Minahan to USNRC, Response USNRC, Response to to Request for Additional Request for Additional Information Information for License Renewal Application,"

Application," July 29, 2009 29,2009 (ADAMS Accession Number ML092090276).

(ADAMS Accession Number ML092090276).

NLS2009061 Attachment 2 Page 25 of 41 associatedwith Table associated Table 3.4.1-8 areare consistent consistent with thethe GALL Report Report in terms of material, material, environment, and environment, and aging aging effect but a different aging management program is credited but a different aging management program is credited (generic (generic note E).

Issue Issue In its review In review ofLRA ofLRA Table Table 3.4.1-8, 3.4.1-8, the staffnoted staff noted that that the components underunder consideration considerationareare part part of the circulating water system. The staff also circulating water system. also noted noted that that the GALL Report Report recommends recommends a plant-specificaging plant-specific aging management managementprogram because at least program because least most of the circulating circulatingwater water system is not within within the scope scope of the GALL AMP, AMP, "open "open cycle cooling cooling water".

water ". The stafffurther stafffurther noted that materialsand that the materials and environments environments currently under consideration currently under considerationare areprobably identicalto the probably identical materials materials and environments environments for for which the recommended recommended AMP is open cycle cooling water. The cooling water.

concludes that staff concludes that an appropriate appropriateAMP for for this service would include include most of the key points points included included inin the open cycle cooling cooling water water AMP.

AMP. Lastly the staff noted noted that that the proposed proposed program program is only aa visual visual inspection inspectionprogram.

program.

Request Pleasepropose Please propose an an aging aging management management programprogramwhich is substantially consistent with the open substantially consistent open cycle cooling cooling water waterAMP or orjustifying justifying how the proposed program proposed program will adequately manage adequately manage internal internal corrosion corrosion of the components under under consideration.

consideration.

NPPD Response:

As stated in Element 4 of LRA Section B.1.31, B. 1.31, the Periodic Surveillance Surveillance and Preventive Preventive Maintenance Maintenance Program uses established established techniques techniques such as visual inspections to detect component degradation degradation prior prior to loss of intended intended functions. This can be contrastedcontrasted with the discussion discussion in Element Element 4 of NUREG-1801 (GALL) ofNUREG-1801 (GALL) Volume 2 Chapter XI.M20 "Open-Cycle "Open-Cycle Cooling Water Water System" which states "Visual "Visual inspections are typically performed."

performed." In both programs, programs, nondestructive nondestructive testing, such as ultrasonic ultrasonic testing and eddy current current testing can also be used. Thus, the methods for managing managing loss of material material are consistent consistent between the two programs.

programs. SinceSince loss of material material is the only aging effect effect for which line item 88 of LRA Table 3.4.1 (Steam ofLRA (Steam and Power Power Conversion Conversion Systems, NUREG-1801 NUREG-1801 Vol. 1) is applied for the components components under consideration consideration inin the circulating circulating water system, this is an appropriate appropriate aging management approach.

management approach .

. NRC Request: RAI4.1-1 RAI 4.1-1 Boiling water reactor Boiling water reactor vessels internals internals project project (B WR VIP)-25, "B (BWRVIP)-25, "BWRWR Core Core Plate Inspection and Plate Inspection Flaw Flaw Evaluation Evaluation Guidelines."

Guidelines. "

The core The core plate plate hold-down hold-down bolts connecting connecting the coreplate plate to the core shroud shroud are initially initially preloaded preloaded during during installation.

installation. These bolts are subject to stress relaxation relaxation due to thermal thermal and irradiation irradiation effects. Section 4.1 item (4) of staff's license renewal renewal safety evaluation evaluation (SE)(SE) dated December 7, 2000, for the B 2000,for WR VIP-25 report, BWRVIP-25 "B WR Vessel Internal report, "BWR Internal Project, Project, B WR Core BWR Core plate plate

NLS2009061 Attachment Page 26 of 41 Inspection Inspection and Flaw Flaw Evaluation Evaluation Guidelines, identifies that Guidelines," identifies that the loss of preload over time in core ofpreload core plate hold-down plate hold-down bolts due to stress stress relaxation relaxationis considered consideredas a time-limited time-limited aging analysis aging analysis (TLAA).

(TLAA). Therefore, Therefore, the staff requests requests that that the applicant applicantmake a commitment to provide provide a TLAA TLAA analysisfor analysis for the core core plate-hold plate-holddown bolts bolts to the stafffor stafffor review and approval approval prior entering prior to entering license renewal into license renewalperiod. applicantshall period. The applicant shall provide a commitment to sub. sub. The staff expects that that this analysis analysis shall shall use projected projected neutron values to the end of the extended period fluence values neutronfluence period of of operation.

operation. Since core plate wedges are are not installed installedat CNS, consistent at CNS, consistent with the inspection inspection guidance guidance specified in item 10 of Table 3-2 of the BWRVIP-25 B WR VIP-25 report, report, the applicant applicantshall shall continue continue enhanced visual inspection enhanced visual inspection (EVT-1) of the core plate plate hold-down bolts. Therefore, bolts. Therefore, the staff requests that requests that the applicant applicant confirm that it will continue performing performing EVT-1 of the core coreplate hold-hold-down bolts and use ultrasonic ultrasonic testing (UT)from a location testing (UT) location above the core plate plate when the UT technique is developed by the industry.

technique industry.

NPPD Response:

Section 4.1 item (4) of staffs license Section license renewal safety evaluation evaluation (SE) dated December 7, 7, 2000, for for the BWRVIP-25 BWRVIP-25 report, "BWR Vessel Internal Project, Project, BWR BWR Core Plate Inspection and Flaw Evaluation Guidelines," referencing the BWRVIP-25 Guidelines," identifies that applicants referencing BWRVIP-25 report for licenselicense evaluate the projected stress relaxation as a potential TLAA renewal should identify and evaluate TLAA issue.

NPPD evaluated this potential TLAA issue and concluded concluded that CNS has no TLAA for the core plate hold-down hold-down bolts because because the existing analysis is not a 40-year 40-year analysis. By definition, in 10 CFR 54.3, 54.3, a TLAA is an analysis that involves time-limited time-limited assumptions defined by the current operating term, tenn, for example, 40 years. The core plate hold-down bolt analysis analysis only covers operation through 2010. NPPD must complete operation complete a new analysis prior to 2011. 2011. That analysis will operation through the period of extended cover operation extended operation.

As stated stated in Appendix Appendix C to the LRA (BWRVIP-25 (BWRVIP-25 Applicant Applicant Action Item #5),"#5)," NPPD has committed committed to implement the BWRVIP-25 BWRVIP-25 recommendations regarding the rim hold-down recommendations regarding hold-down boltbolt inspections, following resolution resolution of a related generic issue by the BWRVIP.BWRVIP. The BWRVIP-25 examination examination has been deferred until the technology is available for examination."

examination." At present, unavailable to do either technology is unavailable either the enhanced enhanced visual inspection (EVT (EVT--1)1) from below the core plate or ultrasonic testing (UT) from above the core plate. NPPD will perfonn perform an inspection inspection when an approved approved method is developed by the industry.

NRC Request: RAI 4.1-2 RAI4.1-2

Background

Title 10, Section 54.21(c) (1), of the Code of Federal 54.21(c)(1), FederalRegulations Regulations (10 CFR CFR 54.21(c)), requires requires that that the applicant provide applicant provide an evaluation of evaluation ofTLAATLAA and a list of the TLAA applicable TLAA applicable to the plantplant defined in 10 CFR as defined CFR 54.3, "Definitions." CNS LRA Section 4.1, Identification LRA Section of TLAA, Identification ofTLAA, discusses the TLAA discusses TLAA process and Table process and Table 4.].]

4.1.1 lists the CNS TLAA.

NLS2009061 Attachment Page 27 of 41 Issue Issue Through review of the LRA Through LRA and and the TLAA documen'tation including TLAA documentation including CNS License Renewal Report CNS-RPT-07-LRD03, Revision 1, TLAA CNS-RPT-07-LRD03, TLAA and Evaluation Results, and Exemption Evaluation Results, and and in discussions discussions with CNS cognizantpersonnel, personnel, the staff identified or was informed that certain ififormed certain CNS items involving calculations calculations or analyses were not determined or analyses determined to be a TLAA.

TLAA. The staff review of these items indicates indicates that a TLAA TLAA may be required.

required.

Request Please Please review the following items for the appropriateness appropriateness of their addressed as TLAA their being addressed TLAA or not. If not. determined to not be a TLAA, If determined TLAA, please justify why.

pleasejustify

1. Review the B WR VIP items in LRA BWRVIP LRA Appendix C, C, Response to B WR VIP Applicant Action BWRVIP Items, in particular B WR Items, particular BWRVIP-25 VIP-25 (4) regarding regarding susceptibility the rim susceptibility of rim hold-down bolts to stress relaxation.

stress relaxation.

2. Review Review Items in CNS-RPT-O-LRD03, CNS-RPT-O-LRD03, Revision 1, Attachment 4 - Updated Updated Safety Analysis Report Results, Results, in particular:

particular:

a.

a. Section # IV-6.3 Description Description(isolation (isolationvalve)

b. Section # VI-4.1.1 VI-4. 1. High Pressure PressureCoolant Coolant Injection Injection System Components Components

c. Section A-3.1.2 Corrosion Corrosion and Erosion Erosion

3. Also identify where corrosion allowance is described corrosion allowance describedand is not contained containedin a TLAA.

TLAA.

Address how corrosion allowances are corrosion allowances are incorporated incorporatedin AMP, AMP, and and the basis basis for for it.

it.

NPPD Response:

1. NPPD has reviewed the applicant applicant action items for the BWRVIP BWRVIP reports approved approved for license renewal, as reported in LRA Appendix C. Those reviews are documented documented in CNS license renewal basis documents. NPPD has re-reviewed re-reviewed the responses to the BWRVIP Applicant Action items given in Appendix Appendix C to the LRA, and has not identified a need for any changes.

In particular, the analysis analysis of stress relaxation relaxation for core plate rim hold-down hold-down bolts is not a TLAA as discussed discussed in the response response to RAI 4.1-1.

4.1-1.

2.a. Two MSIVs are installed on each main steam steam line. One valve in eacheach line is located inside the primary containment, the other outside. These valves act automatically automatically to close off the reactor coolant coolant pressure boundary in the event a pipe break occurs pressure boundary downstream of the valves. This action limits the loss of coolant and the release downstream release ofof

NLS2009061 Attachment Page 28 of 41 radioactive radioactive materials from the nuclear system. In the event that a main steam line break occurs occurs inside the primary containment, isolation valve outside the containment, closure of the isolation containment acts to seal the primary containment containment itself.

containment itself.

As described in USAR Section Section IV-6.3, IV-6.3, the original design objective for the main steam isolation isolation valves was a minimum of40 of.40 years service at the specified operating conditions.

The originally originally estimated estimated operating cycles per year is 100 cycles during the first year and operating cycles 50 cycles per year thereafter, thereafter, for a total of2050 of 2050 cycles. A review of plant operating operating experience experience indicates that there were 185 cycles of each each MSIV from 1974 thru 2006, or or less than 6 cycles cycles per year. Changes Changes to surveillance surveillance testing procedures procedures and decreases in in operational cycles have resulted in projecting operational projecting only 3.26 cycles cycles per year through the period of extended extended operation, for a total of 88 cycles cycles during 2007 through 2034. The total projection of 273 cycles per valve valve through the period of extended extended operation is far below the 2050 design cycles for the valves.

This USAR statement statement is not a TLAA, as there is no analysis or calculation calculation supporting the design cycles of the MSIVs.

2.b. As stated in LRA LRA Section 4.3.2, the design of ASME III Code Class 22 and 33 piping systems incorporates incorporates the Code stress reduction reduction factor for determining determining acceptability of of piping piping design with respect to thermal stresses. In general, 7000 7000 thermal cycles cycles are assumed, allowing allowing a stress reduction factor of 1.0 in the stress analyses. NPPD evaluated evaluated the validity of this assumption for 60 years of plant operation. The results of this evaluation are that the 7,000 thermal cyclecycle assumption will not be exceeded for 60 years of operation. Therefore, the pipe stress calculations calculations remain valid for the period of of operation in accordance extended operation accordance with 10 CFR 54.21 (c)(1)(i).

54.21(c)(1)(i).

In particular, the steam steam supply to the high pressure pressure coolant coolant injection injection (HPCI)

(HPCI) pump turbine susceptible to fatigue due to thermal cycling. The HPCI turbine is operated during is susceptible testing and is used to mitigate design basis events. The pump is tested quarterlyquarterly (no more than 240 cycles in 60 years) at high pressure Specification Surveillance pressure (Technical Specification Surveillance Requirement (SR) 3.5.1.7)

Requirement 3.5.1.7) and each each refueling refueling outage outage (approximately (approximately 42 cycles in 60 60 years) years) at low pressure Specification SR 3.5.1.8). The plant is restricted to 242 pressure (Technical Specification reactor reactor scrams. Thus the total number of cycles (524) for the HPCI system is expected to be significantly significantly below below 7,000 equivalent equivalent full temperature cycles during the period of of extended operation. The HPCI piping analysis remains valid for the period of extended extended operation in accordance accordance with 10 10 CFR 54.21 (c)(1)(i).

NPPD has identified identified no non-class non-class 1 components, components, other than piping system components, components, built to codes requiring a fatigue analysis. NPPD identified no fatigue analyses analyses for components and therefore, identified no fatigue components other than piping system components fatigue

NLS2009061 Attachment Page 29 of 41 TLAAs. In particular, the HPCI turbine casing (a Terry turbine) was reviewed and no fatigue analyses were identified.

2.c. See the response to Part 3 below.

3. Most pressure pressure retaining components components are constructed with a wall thickness in excess of of minimum minimum required required wall thickness for that component. This excess wall thickness provides allowance to assure that minimum wall thickness provides a corrosion allowance requirements are thickness requirements met during component component service. NPPD reviewed individualindividual corrosion allowances for components in the scope of components license renewal. While USAR Table C-3-7 lists many oflicense corrosion allowances allowances for CNS components, components, there are no analyses concerning these corrosion allowances allowances and hence no analyses based on time-limited time-limited assumptions.

Loss of material is an aging effect requiring management management and is addressed addressed in individual AMRs for each system. The results of these reviews presented in LRA Section 3.0.

reviews are presented The management management of loss of material material ensures that components components remain acceptable acceptable for continuing service. Loss of material is managed by several programs including BWR BWR Water Chemistry, Flow Accelerated Accelerated Corrosion, Inservice Inspection, etc., based on the material and environments involved. The management management of loss of material material is consistent consistent with the guidance provided in Section IV ofNUREG-1801.

of NUREG- 1801.

NRC Request: RAI4.3.1-8 RAI4.3.1-8

Background

Note 2, beneath beneath LRA LRA Table 4.3-2, indicates indicates there are are 12 components components in the reactor reactorvessel which were exempted from cumulative usage usagefactor (CUF)calculation factor (CUF) as per calculation as per the guidance guidance of of Paragraph Paragraph N-415.1 of the 1965 edition edition of Section III of the American Society of Mechanical Mechanical Engineers (ASME) Code.

Engineers (ASME) Code.

Issue LRA Table 4.3-2 shows the CUF LRA Table CUFfor Class Class 1 components.

components. All critical criticalcomponents within Class Class ]1 pressure boundary pressure boundary must have usage evaluated.

evaluated.

Request Please Please provide ParagraphN-415.1 provide Paragraph N-415.] ofASME III (1965 edition) edition) and and show the basis basis that that the targeted components targeted components could be exempted from fatigue evaluation.

fatigue evaluation.

NPPD Response:

Section Section NN-415.1

-415.1 of the 1965 Edition of Section III of the ASME Boiler and Pressure Vessel Vesse1 Code is provided as Enclosure 1 to this Attachment. Contrary to the statement statement in the issue section of the RAI, Section Section N-415.1 of the Code says that an analysis for cyclic operation (i.e., (i.e., a

NLS2009061 Attachment 2 Attachment Page 30 of 4141 thereof that meets the six requirements of fatigue analysis) is not required for a vessel or part thereofthat of Section N-415.1.

N-415.1. Note that this statement exists in more recent versions of the ASME code in Section NB-3222.4(d).

The original reactor vessel stress report documents the review of each of the six criteria ofN- of N-415.1 for each component and concluded concluded that each component was exempt from detailed fatigue cumulative usage factor (CUF)). This report is available on site for analyses (calculation of a cumulative review. Some of the N-415.1 criteria use the number of cycles anticipated for the vessel in the calculation. However, as the limiting values are far beyond the actual cycles anticipated, they do not represent 40-year design numbers and the report is thus not a TLAA.

NRC Request: RAI4.3.1-9 RAI 4.3.1-9

Background

LRA Section 4.3.1.3 states LRA Section states that that no plant-specific plant-specificfatigue analysis of the entire fatigue analysis entire reactor reactorvessel internals internals was performed.

performed. In addition, addition, in the same paragraph, same paragraph, the LRA states that LRA states that the only time-limited aging limited aging analysis analysis (TLAA)

(TLAA) associated associatedwith fatigue fatigue of the reactor reactorvessel internals internalsat Cooper Nuclear Station (CNS)

Nuclear Station (CNS) are are the analyses for analyses for the core plate plugs.

core plate plugs.

Issue Even though though being being non-pressure boundary components, non-pressure boundary components, Class Class 1 components components are are subject to fatigue requirements. For fatigue requirements. For old vintage vintageplants, plants, there may be casescases where explicitfatigue usage fatigue usage evaluation are evaluation are not required, Reactor required, Reactor Vessel Internals Internals were implicitly designed designed for low cycle fatigue fatigue based based upon the reactorreactorcoolant design transient coolant system design transient projections projections for for 40 years.

years.

Therefore,

. Therefore, the staff believes fatigue for staffbelievesfatiguefor reactor reactor vessel (RV) internals is a TLAA.

(RV) internals Request Provide basis tojustify Provide basis to justify why only core plate plate plugs plugs were identified identifiedas TLAA.

TLAA.

NPPD Response:

Response

NPPD NPPD agrees that the CNS reactor vessel internals internals were were implicitly implicitly designed designed for low cycle fatigue and not explicitly explicitly designed designed for fatigue. Consequently, Consequently, no fatigue analysis of the reactorreactor vessel internals was identified identified in the CNS current current licensing basis. Regulations in 10 CFR 54.3 state:

"Time-limited aging "Time-limited aging analyses, for the purposes purposes of this part, are those licensee calculations and licensee calculations analyses analyses that: ..."

... " and then gives the six conditions conditions of a TLAA. As there are no licensee licensee calculations calculations and analyses, analyses, there are no TLAA.

The core plate plugs were installedinstalled after after initial construction construction as aa modification.

modification. At the time of the the modification, modification, the designers designers opted to perform perform an an analysis considering considering fatigue, embrittlement, embrittlement, and and other other factors to confirm confirm the design. This analysis analysis meets the 10 10 CFR 54 54 definition definition for a TLAA, TLAA, and therefore, therefore, is identified identified in the the LRA LRA as the onlyonly TLAA for the the reactor reactor vessel vessel internals.

NLS2009061 Attachment Page 31 of 41 Page Request: RA14.3.1-10 NRC Request: RAI4.3.1-10

Background

This item has two components:

components:

(a)

(a) In Section Section 4.3.1 of the LRA, states that "... For LRA, it states H ... For eNS, CNS, two transients transients(normal (normalstartup startup and turbine and turbine roll) roll) are are expected to exceed theirtheir analyzed value prior prior to the end of the period period of extended operation.

operation. Specifically, normal startups Specifically, normal project to reach startupsproject reach the analyzed number of cycles for for the feedwater feedwater piping, piping, feedwater feedwater nozzles, main steam piping piping and and core core piping during spray piping period of extended operation during the period operation... ... ".

"

(b) In addition,LRA In.addition, LRA Section 4.3.1.1 states states that the actual actual numbers numbers of transient transientcycles remain remain within analyzed values usedfor reactorvesselfatigue for reactor fatigue analyses.

analyses.

Issue (a)

(a) It It appears appears that the quoted statement in the first first part Background requires part of Background requiressome clarification.

clarification.

(b) addition, Table In addition, Table 4.3-1 shows thatthat the projected 60-year cycles for projected 60-year for the startup startupand Turbine roll Turbine transientsexceed the analyzed cycles, which contradicts roll transients contradicts what the LRA Section 4.3.1.1 stated.

stated.

Request (a)

(a) Provide basis, Provide basis, for for the two particular transientsmentioned in the first particular transients first part part of Background, Background, why only the feedwater feedwater piping, piping, feedwater feedwater nozzles, main steam piping piping and and core core spray spray piping piping would exceed the analyzed number of cycles and and other other components would not. not.

(b)

(b) Please correct Please correct the inconsistency inconsistency between the LRA Section 4.3.].]

LRA Section statement summarized 4.3.1.1 statement in the second part part of ofBackground Background and the transient transientcycle condition condition summarized summarized in the secondpart of Issue.

part Issue.

NPPD Response:

(a) As shown in USARUSAR Table 1II-3-1, 111-3-1, there are two analyzed values for each design cycle at CNS. As explained explained in the footnote to Table 111-3-1, and supported by the calculations Table III-3-1, calculations of of record, the first values given in Table 111-3-1 111-3-1 are the numbers of cycles analyzed for the feedwater feedwater nozzles, nozzles, reactor reactor pressure pressure vessel (RPV) internals, and Class IN piping while the parenthetical parenthetical values are the numbers of cycles analyzed for other parts of the reactor cycles analyzed reactor vessel. For normal startup, the analyzed analyzed value for the feedwater feedwater piping, feedwater feedwater nozzles, nozzles; main steam piping and core spray piping is 229 cycles, cycles, while the analyzed analyzed value for the rest of the reactor vessel is 400 cycles. Per LRA Table Table 4.3-1 (CNS Projected Projected Cycles for 60 Years), the projected projected number of startups startups for 60 years years at CNS is 245, which which

NLS2009061 Attachment Page 32 of 41 exceeds the 229 cycles analyzed for the feedwater nozzle and piping, but does not exceed the 400 cycles analyzed for the rest of the reactor vessel.

(b) In part due to the difference difference in analyzed numbers numbers of cycles, NPPD separated the fatigue discussion in the LRA into Section Section 4.3.1.1 for the reactor vessel excluding the feedwater feedwater nozzles and Section 4.3.1.2 for the feedwater nozzles. This does vary from the historical documentation documentation that considers the feedwater feedwater nozzle as part of the vessel. The statement statement at of LRA Section 4.3.1.1 was intended to apply only to those parts of the vessel the end ofLRA discussed in 4.3.1.1 and not to the feedwater nozzle discussed in 4.3.1.2. Within this context context the statement is correct. The portions of the reactor reactor vessel discussed in LRALRA Section 4.3.1.1 are analyzed to 400 startups/shutdowns startups/shutdowns and that value is not projected to be exceeded in 60 years. The last paragraph paragraph of LRA Section 4.3.1.1 has been revised to clarify clarify the discussion discussion (see Attachment Attachment 3, Change Change 10).

RAI 4.3.1-11 (Formally NRC Request: RAI4.3.1-11 (Formally4.3.1-7, requestedinformation 4.3.1-7, the requested information has has not been provided provided by the applicant) applicant)

Background

LRA LRA Section 4.3.3 discusses discusses TLAA TLAA concerning concerningeffects of reactor reactorwater environment environment onfatigue on fatigue life. LRA Table 4.3-3 shows the projected LRA Table 60-year environmentally projected 60-year environmentally assisted assisted fatigue usage, fatigue usage, environmentally assistedfatigue environmentally assisted fatigue CUF, CUF, asas well as the 60-year 60-yearprojected CUF without considering projected CUF considering the reactor reactorwater effects, and the Fen values valuesfor for all NUREG/CR-6260 NUREGICR-6260 locations.

locations. Note 1, 1, which is intendedfor the results results of the 60-year 60-year CUF CUFwithout considering considering the reactor water effects, reactor water states that states that the values were "recalculated "recalculatedfor license renewal by removing conservatism conservatism and using the projected projected 60-year 60-year cycles from Table 4.3-1 from Table 4.3-1"".

Issue Issue Clarificationrequired.

Clarification required. In addition, addition, LRA Table 4.3-3 reported LRA Table reportedFenFen value for Alloy 600.

600. The LRA made no mention aboutabout how it was calculated.

calculated.

Request (a)

(a) Specify SpecifY the elements that that constitute "conservatism",and constitute the "conservatism", and describe analysis methods describe analysis used in the recalculation that helped you to achieve the goal recalculation that goalfor lowering lowering the CUF value.

value.

(b) Please explain why Please "removing conservatism" couldn't bring why "removing bring down 60-year 60-year CUF CUFfor Core spray reactor Core spray reactor vessel nozzle as expected. In as expected. fact,fact, the recalculated recalculated value is now much greaterthan greater than the 40-year 40-year design design CUF.

CUE.

(c) Provide Provide technical basis that technical basis that supports supports the calculation of Fenfor Alloy calculation ofFen 600.

Alloy 600.

NLS2009061 Attachment Page 33 of 41 NPPD Response:

(a) As a result ofCNS of CNS being evaluated for Thermal Power Optimization Optimization (TPO), some of the governing usage factors for the RPV and piping were revised from those in the original-governing original stress reports. The results of those evaluations were used in the reactor water water environmental fatigue assessment for CNS. Some "refinements" environmental "refinements" were made to the usage factor calculations during the TPO assessments, and further refinements refinements were mademade during the reactor water environmental fatigue assessment.

during The general general approach approach for the TPO assessments was to utilize scale factors based on on increases in pressure, temperature, flow rate, and other loads. These factors were applied applied to the stress due to pressure or pressure difference, thermal transients, and other mechanical mechanical loads, as applicable. Stresses were combined per perthethe governing stress report for the component component being evaluated, evaluated, and a revised revised usage factor was determined.

In some cases, the grouping of transients (i.e.,

(i.e., evaluating all transients as the most severe transient) contributed contributed to the conservatism of the analysis, and ungrouping the transients and separately evaluating the less severe transients led to significantly separately evaluating significantly lower fatigue primary source of reducing conservatism in the TPO assessments.

usage. This was the primary Another, less significant significant method conservatism was using logarithmic method of reducing conservatism logarithmic interpolation of the fatigue curve as opposed to approximating interpolation approximating the allowable allowable number of of cycles cycles by reading reading from the fatigue curve directly.

For the reactor water environmental environmental fatigue assessment, the rules of the 2000 Addenda of of ASME Code,Section III were used which superseded the edition of the ASME Code which superseded originally calculations (for example, the CNS RPV was designed in originally applied in the calculations in accordance accordance with the 1965 Edition with AddendaAddenda through Winter 1966 of the ASME Code). The revised revised rules include a revised fatigue curve and use of Young's Modulus and elastic-plastic elastic-plastic (K,)

(Ke) correction correction factors for determining alternating stress intensity, determining alternating which were not in the rules in the original Code of Record. These methods are consistent with the approach approach described in the fatigue evaluations documented documented in NUREG/CR-6260, NUREG/CR-6260, which forms the basis for the approach used for the CNS reactor water environmental fatigue assessment.

(b) Based on the preceding preceding discussion, the following approach approach was applied applied to the core spray spray nozzle evaluation. .

• A stress multiplier of 1.006 was applied to the transient alternating alternating stresses stresses for this location location to account for TPO.

• Ke was calculated calculated for this location based on use of the ASME Code, 2000 Addenda.

NLS2009061 Attachment Page 34 of 41

• The 60-year projected number of transients transients was used to compute the 60-year 60-year Primary transients affecting CUF. Primary affecting the core spray nozzle are startups and shutdowns. The 60-year shutdowns. projected numbers of cycles for startups and shutdowns 60-year projected is about a factor oftwo of two greater greater than the values values used in the previous analyses. This led to a significant increase increase in the CUF for this location compared to the 40-year40-year design CUF.

design Using these refinements, refinements, the 60-year CUF was calculated calculated as 0.1451 for this location.

The intent of the evaluations evaluations performed performed for CNS was to perform perform initial environmentally environmentally assisted assisted fatigue screening based screening based on information information available in the governing stress report for each each location. If possible, conservatism conservatism was removed removed as a part of these initial assessments. However, in the event acceptable acceptable usage usage factor results when considering considering environmental environmental effects could not be achieved (as (as is the case for the core spray nozzle),

further refined analyses analyses will address address those components.

components. This further evaluation evaluation is is expected expected to drop the fatigue usage for the core spray nozzle nozzle and is part of the Fatigue Fatigue Monitoring Monitoring Program discussed in the LRA LRA in Section 4.3.3 and Appendix B. 1.5.

Appendix B.1.5.

(c)

(c) The Fen for Alloy 600 was calculated calculated in accordance accordance with the method described in NUREG/CR-6335, NUREGICR-6335, which includes specific specific information information for Alloy 600.

NRC Request: RAI4.6-1 RAI 4.6-1

Background

CFR 54.21 (c) require 10 CFR require thatthat each LRA LRA must contain contain an an evaluation evaluation of TLAA. In Section 4.6 of ofTLAA. of applicanthas referenced the CNS LRA, the applicant referenced CNS Plant Plant Unique Unique Analysis Reportfor Mark Mark]1 ContainmentProgram Containment Program and and Fatigue Fatigue Management Programas Management Program as the basis basisfor satisfying satisfying the requirements 54. 21 (c).

requirements 10 CFR 54.21(c).

Issue Issue The staff needs to review the CNS Plant Plant Unique Unique Analysis Reportfor Mark Containment Mark 1 Containment Program determine if Program to determine if the TLAAfor TLAA for the CNS torustorus shell, supports, and vent system comply shell, supports, requirements of 10 CFR with the requirements CFR 54.21(c).

Request Provide a copy of the CNS Plant Provide Unique Analysis Report, Plant Unique MarkI Containment Report, Mark ContainmentProgram, Program,

Revised, Revised, February 26, 2007 (Reference February 26,2007 (Reference 4.6.1 in the CNS LRA).

LRA).

NPPD Response:

A copy of the CNS Plant Unique Analysis Report, Mark I Containment Program, Revised, February February 26, 2007, is provided as an enclosure 26,2007, enclosure to this Attachment.

NLS2009061 Page 35 of 41 NRC Request: RAI RAI4.7-1 4.7-1 TLAA Section 4.

In TLAA 7.1, the applicant 4.7.1, applicantstated that the current stated that current analysis analysisfor the core plate plugs is plate plugs for 32 EFPY validfor years) and these EFPY (effective full power years) these plugs are susceptible to radiation are susceptible radiation embrittlement, embrittlement, fatigue, spring relaxation fatigue, spring relaxationand and intergranular intergranularstress-corrosion stress-corrosioncracking cracking (IGSCC).

(IGSCC).

The CUF fatigue analysis related to fatigue CUFrelated analysis exceeds the maximum limit of 1.0 1. 0 before the CNS unit reaches EFPY. Hence, reaches 54 EFPY. Hence, the staff requests that the applicant requests that applicantprovide provide a new analysis that takes analysis that into account account the aforementioned aforementioned agingaging effects for for the extended period period of operation.

operation. This analysis requires analysis requiresstaff's approval prior to entering approvalprior entering into the extended periodperiod ofoperation. If too operation. If are to be plugged, many holes are plugged, anan explanation explanation is required requiredto justify this modification modification as plugging as plugging too many core coreplate holes may lessen the core bypassflow resulting resulting in boiling boiling in the spaces spaces between fuel channels.

channels.

NPPD Response:

As stated in LRA Section 4.7.1, NPPD plans to manage the effects of aging on the core plate Section 4.7.1, plugs per 10 CFR 54.21 (c)(I)(iii)

(c)(1)(iii) rather than attempt to extend extend the current analysis beyond 32 32 EFPY. NPPD will manage the plugs by replacing them prior to reaching reaching 32 EFPY. They will be replaced replaced with plugs of the same same design (NPPD has already already purchased the replacement replacement plugs).

The like-for-like replacement plugs will be covered like-for-like replacement covered by the existing analysis, and will thus be acceptable for another acceptable another 32 EFPY after installation, i.e., i.e., through the period of extended extended operation.

There are currently currently 88 plugs installed. A non-time non-time limited analysis performed by General Electric shows that these 88 plugs result in the desired flow distribution within the core. As the plugs are being replaced one for one, without any change to the number of holes being plugged; bfholes this calculation calculation will remain applicable.

NPPD has committed committed to replace the core plate plugs in LRA commitment NLS2008071-04.

LRA commitment NLS2008071-04.

NRC Request: RAI RAIB.1.9-4 B.1. 9-4 (Follow up to RAI B.-1.9-3)

(Follow B.l.9-3)

Background

According According to GALL GALL AMRAMR line item IVBI-14, cumulativefatigue IV B 1-14, cumulative evaluation as part fatigue evaluation part of a TLAA TLAA for core shroud for core shroud components is recommended.

recommended.

Issue In Section Section 5.5 of the applicant's applicant'sreport report CR-CNS-07-LRD04, CR-CNS-07-LRD04, "CNS Licensing Licensing Renewal Project Project- -

TLAA-Mechanical Fatigue," the applicant applicantstated stated that that the fatigue evaluation thefatigue evaluation of the core core shroud components is not based on the life of the plantplant and, and, therefore, therefore, it is not a TLAA.

TLAA.

NLS2009061 Attachment Page 36 of 41 Request Provide Provide anan explanation explanationfor notperforming for not TLAA evaluationfor performing TLAA evaluationfor thethe core core shroud components. If shroud components. If this is this is not aa TLAA, TLAA, how the degradation degradationdue due to fatigue fatigue is managed managedfor for the core core shroud shroud components.

components.

NPPD Response:

As stated in the response to RAI 4.1-2, 10 CFR 54.21(c) does not require that TLAAs be created created for license renewal, but that TLAAs that are part of the current licensing basis be evaluated. For searched for current licensing basis analyses that meet the definition of license renewal, NPPD searched of TLAA and need to be evaluated for the period of extended operation. The first line item entry in in (Reactor Vessel Internals Summary of Aging Management Evaluation),

LRA Table 3.1.2-2 (Reactor Evaluation), LRA 3.1-45, compares to NUREG-1801 Page 3.1-45, NUREG-1801 item IV.Bl-14 IV.BI-14 and Table 3.1.1 (Reactor Coolant System, NUREG-1801 Vol. 1) line item 5 which refers to section 3.1.2.2.1 (Cumulative Fatigue Damage) that says that fatigue of all RV internals is discussed in Section 4.3 4.3.1.3

.1.3 (Reactor Vessel Internals). NPPD has searched the current licensing basis and found no TLAA for fatigue of the shroud. The only fatigue analysis found for the internals was for the core plate plugs, as discussed in LRA Section 4.3.1.3.1.

4.3.1.3.1.

The shroud support is considered considered part of the vessel and is included in the vessel fatigue analysis as reported in LRALRA Table 4.3-2.

As shown in LRA Table 3.1.2-2 (Reactor Vessel Internals), LRA LRA Page 3.1-51, 3.1-51, cracking of the shroud shroud (due to any mechanism) is managed managed by the BWR Vessel Internals Internals Program and Water Chemistry Chemistry Control Control- - BWR Program consistent with NUREG- NUREG-1801 1801 IV.B 1-3.

IV.BI-3.

NRC Request: RAI B. 1.31-1 RAI B.1. 31-1

Background

LRA LRA Section B1.31 statesstates each inspection inspection or test occurs occurs at least least once every five years. staff years. The staff noted that that the corresponding corresponding portion portion of of CNS-RPT-07-LRDO7, CNS-RPT-O 7-LRDO 7, Revision 2, "Aging ManagementManagement Program Program Evaluation Evaluation Results - Non-Clases Non-Clases 1 Mechanical," Section 4.8, 4.8, "Periodic "PeriodicSurveillance Surveillance and Preventive Maintenance,""stated Preventive Maintenance, stated each inspection inspection or test occurs at least once every 110 0 years.

years.

In addition, addition, the staff noted in Attachment 2 of the same report, report, the inspection inspection of the high high pressure pressure coolant coolant injection injection turbine turbine lube oil cooler heat heat exchanger exchanger tubes was specified as once every six years.

years.

Issue Based on the information information provided to the staff staff, it is not clear clear at whatfrequency frequency the noted inspections inspections or tests will be performed.

performed.

NLS2009061 Attachment Page 37 of 41 Request Provide information Provide information to confirm the frequency frequency ofeach inspection inspection or test discussed discussed in LRA LRA Section B1.31 for the periodic Bl.31 surveillanceand preventive maintenance periodic surveillance maintenanceprogram.

program.

NPPD Response:

Response

As stated in Element 4 of LRA B.1.31, B. 1.31, Periodic Surveilance and Preventive Periodic Surveilance Preventive Maintenance, Maintenance; each inspection or test occurs inspection occurs at least once every five years.

Request: RAI NRC Request: B.l.38-2 RAI B. 1.38-2

Background

LRA B.1.38, "Water Chemistry LRA Section B.l.38, Chemistry Control-Control -Auxiliary Auxiliary Systems" descriptionstates Systems" description states in part:

part:

"Programactivities "Program activities i1Jclude include sampling sampling andand analysis analysis of water water in auxiliary auxiliary condensate drain system condensate drain components, auxiliary components, auxiliarysteam system components, components, and and heating and ventilation heating and ventilation system components components to minimize component exposureexposure to aggressive environments."

aggressive environments." Under Under "3. Parameters Parameters Monitored/Inspected, Monitored/Inspected, "'"it states in part: accordancewith industry part: "In accordance recommendations, industry recommendations, auxiliary condensate auxiliary drainsystem and auxiliary condensate drain auxiliarysteam system waterparameters monitored are parameters monitored are pH, conductivity, pH, phosphate, sulfite, conductivity,phosphate, and'iron." Furthermore, sulfite, andiron." Furthermore,it also states states that that "In accordance accordance industry recommendations, with industry recommendations,heating heating and and ventilation ventilation systems parameter monitoredis sodium parameter monitored sodium nitrite (NaN02).

nitrite (NaNO2).""

Under "10. Operating Under "10. OperatingExperience, Experience,"" it states part: "The results states in part: for the condensate results for condensate and steam and steam system indicated indicated no variance variance form limits in pH or conductivity with occasional occasionalvariance variance in iron, iron, phosphate phosphate and sulfite.

sulfite. Also, the results resultsfor for the admin admin chiller chillersystem indicated indicatedno variance variance from from limits in conductivity with occasional variance in sodium nitrites.

occasional variance nitrites."

"

Issue

• • It is not clear clear to the reviewer reviewer the reason(s) reason(s)why a plant-specific plant-specific water water chemistry control program necessaryfor program is necessary auxiliarysystems.

for the auxiliary

• The LRA LRA did not include include a reference reference to the aforementioned aforementionedindustry recommendations.

industry recommendations.

• The LRA LRA did not provide details details on the equipment equipment operating operatingcharacteristics characteristics (e.g., boiler pressure), parametermonitoring pressure), parameter monitoring program program (e.g., frequency water samples frequency of water samples being collected),

collected), or description description on those those incidences incidences where the parameters parameters (e.g., phosphate phosphate and sulfitefor the boilers, boilers, and sodium nitrites sodium nitrites for the admin chillers) exhibited varianceand admin chillers) exhibited variance the associated' associated'corrective actions to return corrective actions return them within the limits.

limits.

NLS2009061 Attachment Page 38 of 41 Request Please Pleaseprovide provide more details (iJ steam details on (i) pressure, (iiJ steam pressure, water samples being (ii)frequency of the water collected, (ii) collected, (i) the nature, nature,frequency of those incidences incidences where variances varianceshad occurred, occurred,as as well as as the outcome andand efficacy of the corrective corrective actions.

actions.

NPPD Response:

LRA Section As stated in LRA Section B. 8, the Water 1.38, B.1.3 Control - Auxiliary Water Chemistry Control- Auxiliary Systems Program is program that includes sampling and analysis of water in auxiliary an existing program condensate drain auxiliary condensate drain components, auxiliary steam system components, and heating system components, heating and ventilation ventilation system components.

components.

(i) As stated in USAR Section X- 0.1.1, the operating pressure X-I10.1.1, auxiliary steam system pressure of the auxiliary is 150 psig. Steam pressure reducing stations are provided provided to reduce reduce this initial pressure to 50 and 15 psig.

(ii) The auxiliary steam system is sampled weekly when in operation. The chilled water water for the heating heating and ventilation ventilation system is sampled semi-annually. This is consistent with the standards on which this program is based, as discussed in the NPPD response industry standards response to 7

8-1 submitted previously. The auxiliary condensate drains B. 1.38-1 RAI B.l.3 drains system is used to ventilation system and from steam lines of the condensation from the heating and ventilation remove condensation auxiliary steam system; therefore, auxiliary water chemistry therefore, its water reflected in the sampling done chemistry is reflected for these systems.

(iii) Heating ventilation system (chilled water)

Heating and ventilation Low sodium nitrite levels were noted in the chilled water for the heating and ventilation ventilation September 2006. Sodium nitrite was added to the system in March 2006 and again in September system corrosion inhibitor. The principle control for this system is restore the level of corrosion system to restore blended glycol chemistry, which was maintained within specificationspecification during this period.

Nitrite is provided as an additional corrosion inhibitor, and the impact on the system from corrective actions as described below have the low levels was insignificant. Additional corrective better manage the systems and reduce chemistry parameter been taken to better parameter deviations.

Auxiliary steam system (heating boiler C) specification four times in heating boiler During a five-year period, iron level was out of specification blowdown rate was raised to lower C. The boiler blowdown lower the iron concentration. Sulfite level specification on ten analyses during this period. For nine of the samples, the was out of specification specification by the next sample. In March concentration was returned to specification sulfite concentration March 2006, specification as the boiler was being shut down for the summer, the sulfite was low out of specification 7

7 NLS2009040, Stewart NLS2009040, Stewart B. Minahan to B. Minahan to USNRC, "Response to USNRC, "Response to Request Request for for Additional Additional Information Information for License License Management Programs, Renewal Application - Aging Management 15, 2009 (ADAMS Programs, June 15,2009 Accession.Number (ADAMS Accession.Number ML09160050).

ML09160050).

NLS2009061 Page 39 of 41 and was restored when boiler operation was resumed resumed later that year. Additional corrective actions as described below have been taken to better manage the systems and corrective reduce chemistry parameter parameter deviations.

Auxiliary steam system (heating (heating boiler D)

D)

During a five-year five-year period, iron level was greater than the chemistry chemistry warning warning limit (CWL)

(CWL) two times. In both cases, cases, the boiler blowdown blowdown rate was raised to lower the iron concentration, and the iron concentration concentration, concentration was below the CWL on the next sample.

Phosphate Phosphate level was iow low out of specification specification once during this period, as the boiler was being shut down for the summer. The level was restored when boiler operation was resumed later that year. Sulfite was low out of specification specification for eleven samples during this period. Six of those samples occurred occurred in October October to November 2006, when the heating boiler blowdown blowdown line experienced experienced leaks that required required it be taken out of service service for repair. During the period, chemical chemical addition was limited to control conductivity conductivity and as a result, sulfite could not be raised. Once the blowdown blowdown line was repaired, the blowdown blowdown was started and chemical concentration was returned to specification. The five other chemical concentration times sulfite was out of specification, specification, it was returned returned to specification specification by the next sample.

Additional Additional corrective actions as described below have been taken to better manage the systems and reduce chemistry parameter parameter deviations.

Additional corrective corrective actions were taken to improve improve internal communications communications and individual accountability accountability of the chemistry department staff by completing completing training on on better communication communication techniques techniques and human performance.

performance. In addition, the chemistry department discusses human performance performance tools at each chemistry chemistry morning meeting.

Periodic meetings with system engineering to review chemistry chemistry data, including excursions in the levels of corrosion corrosion inhibitors, were initiated. This serves to identify maintenance and testing activities which may affect system chemistry, and provides maintenance provides opportunities for the engineers to give feedback on the aging management of their assigned systems.

The routine routine confirmation confirmation of water quality and use of appropriate corrective action appropriate timely corrective accordance with the industry recommendations ensure that the program is conducted in accordance recommendations on which it is based.

NRC Request: RAIB.1.40-4 RAI B.1.40-4

Background

LRA Section B. 1.

LRA 1.40 states the chemistry activities 40 states activities for this this program programareare based on Electric Electric Power Research Institute Research (EPRI)TR-1007820, Institute (EPRI) "Closed Cycle Cooling TR-1007820, "Closed Cooling Water Water Chemistry,"

Chemistry,"Revision 1, Revision 1, datedApril 2004, dated 2004, which supersedes supersedes EPRI TR-107396, TR-107396, "Closed "Closed Cycle Cooling Cooling Water Water Chemistry Chemistry Guideline,"Revision Guideline," Revision 0, 0, issued issued November 1997.1997. GALL AMP XM M21, "Closed-cycle XIM21, "Closed-cycle Cooling Cooling Water System, ""states that it "relies states that "relies on maintenance maintenance of system corrosion corrosioninhibitor inhibitor

NLS2009061 Attachment Page 40 of 41 concentrationswithin concentrations within the specified specified limits limits ofEPRI of EPRI TR-107396 TR-10 7396 to minimize corrosion corrosionandand stress-stress-corrosion cracking."

corrosion cracking. "

Issue Issue GALL Report The GALL Report does does not recommend recommend the use of late late revisions revisions ofEPRI ofEPRI TR-107396.

TR-107396. The applicant'sprogram applicant's program is implemented using using the later later revision, revision, EPRI EPRI TR-l TR-1 00 7820, rather 007820, ratherthan than the edition referenced in edition referenced the GALL Report, Report, EPRI EPRI TR-l TR-107396.

0 7396. The staffnoted staff noted the use ofEPRI of EPRI TR-1007820 may potentially impact the program potentially impact programelements, elements, "Preventative "PreventativeActions" and and "Acceptance "Acceptance Criteria" Criteria" of the applicant's program, since applicant's program, since the corresponding program elements corresponding program elements in the GALL Report reference reference the limits on corrosion inhibitorconcentrations corrosion inhibitor concentrationsspecified specified in EPRI EPRI TR-107396.

TR-107396.

Request Justify this this deviation deviationfrom from the GALL Report and and discuss impact on the program discuss its impact program elements, elements, Preventative Preventative Actions and Acceptance Acceptance Criteria, Criteria,with reference reference to limits limits on specific specific corrosion corrosion inhibitorlevels, monitoring inhibitor monitoringfrequencies, and operating frequencies, and operatingparameters.

parameters.

NPPD Response:

Revision 1 of the EPRI Closed Cycle Cooling Water Chemistry guidelines guidelines (TR-1007820) provides more detail on the various water treatment methods used at nuclear nuclear power plants plants and includes more detailed information information on control and diagnostic parameters, parameters, monitoring frequencies, frequencies, operating operating ranges, and action levels. There There is no impact on the elements for preventive actions and acceptance preventive acceptance criteria in NUREG-NUREG-1801 1801 (GALL) Volume 2 Chapter XI.M2 XLM21, 1, including the application application and control of corrosion corrosion inhibitors stipulated in these elements.

The NRC staff, staff, as documented documented in Section 3.0.3.2.4 of the license renewal SER for Vogtle Electric Electric Generating Plant, NUREG-1920, NUREG-1920, concluded that the use of EPRI TR-I007820 TR-1007820 provided provided guidance guidance consistent with the recommendations recommendations in GALL AMP XI.M21 XLM21 and offered offered more detail detail on the various water treatment methods used at nuclear nuclear power plants, as well as control control and and diagnostic diagnostic parameters, parameters, monitoring frequencies, frequencies, operating operating ranges, ranges, and action action levels.

levels. On On this basis, the staff concluded concluded that the use of EPRI Report No. TR- 1007820 was an acceptable TR-I007820 acceptable alternative alternative industry industry guideline guideline for the closed closed cycle cooling cooling water systems.

Accordingly, Accordingly, the use of EPRI TR- 1007820 as the basis for the Water Chemistry TR-I007820 Chemistry Control Control- -

Closed Cooling Water Program Program provides provides reasonable reasonable assurance assurance that the effects effects of aging are are managed managed such these components components will continue to perform perform their intended intended functions consistent consistent with the the current current licensing basis through the period of extended extended operation.

NLS2009061 Attachment Page 41 of 41 Page Enclosures to Attachment 2 Enclosures

1. ASME Boiler and Pressure Pressure Vessel Code,Section III, 1965 Edition, Paragraph Paragraph N-415.1

2. Cooper Nuclear Station, Plant Unique Analysis Report, Mark Mark 1 Containment Containment Program, Revised, February 26,2007 26, 2007 (Provided on a compact compact disk)

I, jI,'<;,+OY) ~ C\.l i Copied 10 -..5 -'16

/ 0-5-q*

If'tXcopy Check OSSD-RAS For Latest Issue

,

,NUCL-E'AR ,{

ENG I N E£ R1NG \NI)EX OUT VESSELS OUT /l,UG '"EX gijR'"

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'.'. 'i-b :2/. I P

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I I

ARTICLE44 DESIGN ARTICLE DESICN L-415. I - N-415.2 ""

N-4J5.1 Vessels N-415.1 Not RequiringAnal>sis Vessels NotRequiring Anal)sis for lor (d) The (d) temperature difference The temperature in deg F be-.

diHercnce 2 in deg F b~~,

Cyclic Operation- - An CyclicOperation analysisfor Ananalysis cyclicopera-for cyclic opera- tween tween any any two two adjacent adjacent points puints 2 of of thethevessel vessel 3

tion isis not tion required, and notrequired, and ititmay may be be assumed assumedthat that does does not change 3 during not change normal operation' during.h,ormol operation I by by thethe peak stress limit peak stress discussed inin N-414.5 limit discussed N-414.5 has has more more than than'the'thequantityý quantity;S./(2E.), 5,,/(2£.),where whereS.5" isisthe the satisfiedfor been satisfied been vesselororpart fora avessel partthereof thereofby by com-coin- value valueobtained obtainedfrom fromthe' 8~pll~.abledesign

~h~applicable designfatigue fatigue pliance pliance with with the the applicable requirements for applicable requirements ma- curve forma-. curvefor forthe tot~Jsplecifidýi thetotal IIpec:W~4 :number umber ofofsignificant significant terials, £abr:catioD,testing,and design,fabr:cation,.testing, terials,design, Bndinspection temper~ture-dif(er~ncefluctuations.A inspection. . temperature-difference n':l~~ualions. Atemperature- temperature-of this Subsection, provided of this Subsection, provided the spedfje~ ope~ the specified opera- difference fluctuation shall difference fluctuation 'shall bebe considered consideredtotobe be tionofofthe tion vesselororpart the vessel thereofmeets part thereof meets all, allofof the significant ifHits the significant its total aiiiiibraic range lotol )iJRol1raic range exceedsexceeds following followingconditions:

conditions: . the qluantity the quantityS/2E, S!2E"'. where wh!!re~:;i S'i .. the value oforS.Saob-the value ob-tained from.

tained from,the applicobrei design fatigue

,the applicubl'i-;design fatigue curve curve (a) The specifif.d number (a) The specifif!d Dumber of times (induding of times (including for for lO0lOllcycles"<ý

,cycles;; ',;~~;,~q startup and startup shutdown) that and shutdown) thal, the pressure will the pressure wiB be be cycled from cycled atmospheric: pressure from atmospheric operating of (e) presllure to1,0 operating (e) For :c:omJlon~n'~,J~~;ikoted For 'componeitsi- fabiicated from frommaterials malerials of differing moduli' of elauileity and/or djffering'moduIiLpr~I""tl,~ilY and/or coeffi-coeffi-pressure and pressure and back back to to atmospheric abnoBpliericpressure pressure does does cients cients ofof thermal expamnstion the' total lhermal~.xpIl1lIii9n.:the total algebraic algebraic exceed the notexceed not numberofofcycles the number cycl<<;scin on the the applicable applicable range of temperature Iluctuution, fatigue curve fatigue curVe (Fig. N-415{a)or (Fig.N-415(a) or(b)) corresponding' ,perienced (b) corresponding range of temper~tureJliic(~*'ion in de deg FF ex- ex-perienced by*.

by, tlie.vess:el t1ie' *tiung normal ves,seFdurlrig normal operation operation toto anan S.Sa~al~i yalie of times the of33 times the S.S"j*value value of ofTable Ta~le the. magnitude does not does not exceed exc~e.d.tlie. ,mllsnitude SA/2(Eat,- 5a /l2(E,.,":-

N-421, N-42, N-421, ýor N-423, N~4~~:'or N423,for forthe niaterial at thematerial atoperat-operat- E a- ) ], wheree Sno is -thte value obtained ing temperature.

ing temperature. E 2 2-2) 2 1, where5a is'~e ,value obtained from from the:

tlie Bppli cable design-applicable fatiguee-r`ve for design *rllli~:e'i~rve forthe the total total spe-spe-cified cified numbernumber of of significant-. emperature fiuctua-8igi1ific:~~f,lemperatare (b)

(b) The specified full The specified range of full range pressure fluc-of pressure fluc- Oactua-tuations during tuations du~ng normal normal operation' operation 'does does not not ex- ex- tions, E, and E2 a~i.hemci~~li of tdios, E, and E, are the u-toduli elasticity. and orelasticity, and ceed the ceed qU~tity(l/3)xdesign the qu'antity(1/3)x pressure xx (S./S,)

designpressure si (Sa/s.,> thermal "" and and -,-2 are are the the mean melllii'lin,ear coefficients ofof linear coefficients where'Sa where'Sa is is, the value obtained the value obtained from from the the applic-applic- thermal 'expansion expansion over the-tiemperature range OVf!rl~c(~emperature range idi- id-able design fatigue curve for the total-specified volved volved 'for

'for the the two two matericl. !of construction. (See material~iotcopstruction. (See able design fatigue cUr:Ve for ,the tolal, sped fled number of number fjigniflcant pressure of significant fluctuations and pressure fluctuations and TablesN~4~ and Tables-N-426 N::427Y1i temperature and N.427.Y)r temperature fluctua- fluctua-Sm is the Sitress from Table N-421, N-422, S", is the stress from TableN-42l, N-422, or total excursion exceeds,-the quantity or tion tion shall shall bebe consideredl con~id~re~d.~"he significant ifif its obe significant its N-423, N-423, for for thethe, material material at operating temperature.

at operating temperature. E,. total excu..sio,n ex,c:ee,d1l"th~\quantity S/2(Et-i 5/2(E,-, --

IfIf the the total total specified specified number olsignHicant pres-numberof'significant pres- the is ihe`' valuetof Sa where 'S'Sis*thc';vahii:;of E2 ..22)) where obtained from Sa obtained from fluctuations exceeds 106, the So value at the applicable applicable design des;gllTaligue!fatigi*e curve curve for for 10' 1011 cy-cy-sure sure fluctuations exceeds 10*, the Sa value at cles. If the two, materials.ua,.d have different 101l'inay be' NN == l0O-many be used. Significant pressure used. Significant pressure fluctu-fluctu- plicablecles. If th e two m,a~erjIlJs, u!,.~d have different ap- ap-ations are ations Bre those those for whi'ch the for which total excursion ex-thetotal,excilrsion ex- plicabledesignJ design, fatigue curves, the Cali me 'curv~8, the lowerlower value value ceeds the quantity.

ceeds the quao'tity. .

of of SoSa shall shall bebe used used in

i~ applying llPply'j~8 the the rules rules of this of this paragraph.

paragraph. . ' , ,  ;  : '

, , , 1 YS Design Pressure Design Pressure xx aX 5", ' * ({)'f) The .specified full The specified range of fulj,,.~ge of mechanical mechanical loads. excluding loads, pre'~sureliiJI .including pipe excluding pressurepii-including pipe re- re-where S = the value of S.

where 5 = the value of Sa obtained from the ap- obtained from the ap- actions. does not result ifiLJi}ad stresses whose actions, does not result itiýUiid stresses whose plicable design plicable design fatiguefatigue curvecurve for for 10' 1011 cycles.

cycles. range exceeds range ,exceeds the t~e S,dSa v'val\l"e[~~tBined atuiel'odtained from {rom the the ap-ap-F be- plicable plicable design de~ign fatigue"curve*

fatigut:':cury~:ror ofr the the total total speci-speci-(c)

(c) The tefuperature difference The temperature difference inin deg deg F be-tween any tween lidjacent points two adjacent any two pointsa2of of the ve,ssel during the vessel during fied' number of fied number of significant:

significB'1t'lp'od nuctuations. If load fluctuations. If normal operation and during startup and shutdown the the total total specified spedfiednilmher::QfnUumber'o*f significantsignificant load load normal operati~n and during startup and shutdown operation operation does does not not exceed exceed S,/(2E-),S,.I(2E.). where where S. 5" is is fluctuation exceeds'106',the fluctuation may be used.'

exc~~d.s:i06, ~h~s A Iad 'fluctuation

..

Sa valuevalue at shall at NN ==10O be 10 6 con-the value obtained from the the value obtained from the applicable design £a- applicable design 'fa- may be used.' A .Jo,ad,nuc~u,a:tion shall be con-tigu e curve tigue curve for for the specifjed':nurnber of the specified',number of startup.

startup~ sidered to sidered to be significant if b,e, significuiant if 1th e total

~ti~ excursion of total excursion of shutdown cycles, shutdown cycles. and and -.. and Bnd ..,EE are taken from are taken from load load stress.exceeds, stressexceeds.thevalue.e:,{ the valuee of So obtained from Sa obtained from Tables N-426 Tables N-426 and N-427 for and N-427 the mean for the mean valuevalue of of the applicable desig the applicable 'design fMteigue cUr've for filti8'.Je'~,lirve for 10' 10 6 cycles.

cycles.

the the temperatures temperatures at at the the two two points.

po'ints. N*415.2 D~sign, 10;"- Cydi~;Loading - If N-415.2 Design for'-Cyciiýý Loading - If the the sped fied operation Of the ve~sel does not meet specified operation of the vessel does not meet defined as operation isis defined 1 Normal operation

'Normal ** any .et of aDJ' set operating condi-of operating condi-the conditions of the conditions N-'415,.1. thee of N-415.1, ability of thf'ability of thethe ves-ves-tions other than startup and shutdown which tione other than startup aDd .butdowD which, .re specified are specified sel to withstand thle specified sel to withstand t~:especiried cyclic operation cyclic operation for the for vesseJ to vessel lbe (3)).

N-.412(n) perform its to perform function (see intended function it. intended (see wit~!>ut fatigue without Jailur~ :shall fatigue 'failure ,shall :be detennined as be determined as N-41~n)(3)).

hereinafter,. The provided hereinafter provided determination shall Thed~te.rmination shall be be inade on made on the basis of the basis of the stresses at the ,sfresses point of at aa point of 2

Adj.c~nt points 2 Adjacent points are 8re defined defined as as points which are points which are spaced spaced the the vessel, vessel. and and the allowable. stress cycles the allowable-stress cycles shall shall less tben the Jess than distance 2:2,!Rj tbe distance ,'¶i fromfrOID each eech other, where otb ...... here RRandand I, are are the th~ mean radius and mean radius thie1r:*be-** , respectively, and thickness, re!l~e*ctivdy. of of thethe "vessel, f]enge. or nozJie, flange,

'Vessel. nozzle, or other component in otber component in which which the the 3 The algebraic range of the difference shall be used.

points points areate located.

located. 3 The algebraic renge of the difference .hall b~ used.

21 i

NLS2009061 Page 11 of 4 Attachment 3 Attachment Changes to the License Renewal Application Cooper Nuclear Station, Docket No. 50-298, DPR-46 Application based on the responses to This attachment provides changes to the License Renewal Application the RAIs provided in Attachments 1 and 2, as well as for other clarifications. The changes are presented in underline/strikeout fonnat.

presented format.

1.

1. Table 2.4-1, 2.4-1, Page 2.4-24, is revised to add the following line item:

Component Component I Intended Function Steel and and other other!metals J'metals Roof decking I Pressure boundary, Shelter and protection protection

Reference:

Response to RAI 2.4-2.

2. LRA Table 2.4-3, 2.4-3, Page 2.4-30, is revised to add the following line item.

Component Component  ![ Intended Intended Function Function Steel and Other Other Metals Metals Steel Piles  ! Support for criterion criterion a(3) a(3) equipment

Reference:

Response to RAI 2.4-8.

Reference:

3. Plant-Specific Note Plant-Specific Note 104 on Page 3.1-28 is revised to read:

"The loss of material material is a potential aging aging effect for carbon steel surfaces surfaces in air where the surface temperatures surface temperatures are near ambient temperature. belew belo'li the lecal local dew dew point."

point."

Reference:

Response to RAI 3.1.2.3-1.

Reference:

3.1.2.3-1.

4.

4. Revise Section 3.3.2.2.6 to read:

Revise "Loss of "Loss is an material is of material an aging effect requiring aging effect management for requiring management and MetamicTM Bora1 and for Boral Metamic' spent fuel storage racks racks exposed exposed to a treated treated water water environment. For Boral, this aging aging effect is managed managed by the Neutron Neutron Absorber Absorber Monitoring Monitoring and Water Chemistry Contro1-Water Chemistry Control -

TM BWR BWR Programs.

Programs. For MetamicT, Metamic', this aging effect effect is managed managed by the Water Chemistry Chemistry Control - BWR BWR Programs.

Programs.

NLS2009061 Attachment Attachment 3 Page 2 of4 of 4 Reduction Reduction of neutron-absorbing neutron-absorbing capacity is insignificant insignificant and requires no aging management. The potential for aging effects due to sustained sustained irradiation of Boral was previously previously evaluated evaluated by the staff (BNL-NUREG-25582, (BNL-NUREG-25582, dated January 1979; NUREG-1787, VC Summer Summer Safety Evaluation Evaluation Report Report (SER), paragraph paragraph 3.5.2.4.2, page 3-408) and determined to be insignificant. CNS plant operating operating experience with Boral Boral coupons inspected in 2002 is consistent with the staffs conclusion and an aging management management program is not required required for this effect. Similarly, significant reduction reduction of neutron-MetamicTM is not expected. However, in accordance absorbing capacity of Metamic' accordance with License Amendment Amendment 227, the neutron absorption neutron absorption capability Metamic' materials is capability of MetamicTM periodically tested."

Reference:

Response to RAI 3.3.2.2.6-2.

3.3.2.2.6-2.

5.

5. Revise Table 3.3.2-9 to read:

Panel Neutron Neutron Aluminum/boron Aluminumlboron Treated Loss of Water VII.A2-3 3.3.1-13 E absorption carbide (Boral) carbide (Bora!) water material material Chemistry (A-89)

(ext) Control -

Control-BWR Panel Neutron Aluminum/boron Al uminurnlboron Treated Loss of Neutron VII.A2-3 VILA2-3 3.3.1-13 E absorption carbide (Boral) carbide (Bora!) water material material Absorber Absorber (A-89)

(ext) Monitoring Panel Neutron Aluminum/boron Aluminumlboron Treated Loss of Water ----- ----

-

F absorption carbide carbide water material material Chemistry Chemistry (Metamic (MetamicTM)TM) (ext) Control -

Control-BWR BWR

Reference:

Response to RAI 3.3.2.2.6-2 3.3.2.2.6-2

6. Table 3.3.2-13 3.3.2-13 on Page 3.3-153 3.3-153 is revised to read:

Valve Pressure Pressure Gray cast o* indeoeor-int)

Air-1 dr indoor (int) Lesse-of boss External

.g*temal Surfaces Sl:lffaees V"D2 1-6

V.In Ie 3.2. 32 3.2.1 .g E

body body boundary iron Iron Gas (int) matefiNa material Menitefing Monitoring (E-29)

(.g 29) 3.3.1-97 3.3.1-97 A None None VII.J-23 VIU-23 (AP-6)

Reference:

Response to RAI 3.3-7.

NLS2009061 Attachment 3 Attachment Page 33 of4 of 4

7. Table 3.5.2-1, 3.5.2-1, Page 3.5-60, is revised to add the following new line item:

Table 3.5.2-1:

3.5.2-1: Reactor Building and Primary Containment Reactor Containment Structure Structure NUREG NUREG and/or Intended Aging Effect Aging -1801 Table Intended -1801 Table Component Function Material Environment Environment Requiring Requiring Management Vol. 2 1 Item Notes or Function Management Programs Vol.

Item2 litem or Management Programs Item Commodity Commodity III.A3-Carbon Air - indoor Loss of Structures 3.5.1-3.5.1-decking Roof decking EN,PB, EN, P1, steel uncontrolled material Monitoring (T11.l 25 A steel uncontrolled material Monitoring 25 (T -11)

Reference:

Response

Response to RAI 2.4-2.

8. Table 3.5.2-3, Page 3.5-70, is revised to add the following line item:

Table 3.5.2-3, Steel SRE Carbon Carbon Soil None None 1,50 SRE steel Soil None None I, 505 piles steel The Notes for Table 3.5.2-1 through 3.5.2-4, Page 3.5-55, is revised to add:

"505. Because "505. Because steel piles driven into undisturbed soils are unaffected unaffected by corrosion and and because because steel piles driven into disturbed soils have experienced experienced only minor to moderate moderate corrosion corrosion that does not significantly significantly affect continued continued safety function function

. nerformance performance during during the license renewal renewal term. management is reouired."

term, no aging management required."

Reference:

Response to RAI 2.4-8.

9. Section 3.6.2.2.3, Section 3.6.2.2.3, Page 3.6-5, 3.6-5, is revised to read:

Loss of Conductor Conductor Strength Strength (Corrosion)

"CNS "CNS SSST high-voltage side is connected connected to the 161 kV switchyard switchyard via overhead overhead transmission lines. The 161 kV overhead overhead transmission transmission conductors 886.4 336.4 conductors are &844 336.4 thousand circular circular mils (MCM) ~

2-64 26/7 ACSR."

ACSR."

Reference:

Typographical correction.

Reference:

NLS2009061 Attachment Page 4 of4 Page of 4

10. Section Section 4.3.1.1, 4.3.1.1, last paragraph, paragraph, is revised to read:

"The actual numbers of transient cycles cycles remain within analyzed values used for reactorreactor vessel fatigue analyses excluding excluding the feedwater nozzles discussed discussed in Section 4.3.1.2.

CNS will monitor these transient cycles using the Fatigue Fatigue Monitoring Program Program and take action if any of the actual cycles cycles approach approach their analyzed numbers. As such, the FatigueFatigue Monitoring Monitoring Program will manage the effects of aging due to fatigue on the reactor reactor vessel in accordance with 10 CFR 54.21 (c)(1)(iii)."

(c)(l)(iii)."

Reference:

Response to RAI 4.3.1-10.

Reference:

Response

11.

11. Section A. 1.1.377 is revised to read:

A.I.I.3

"(a)

"( a) identification identification of susceptible components components determined detennined to be limiting from the standpoint of ofthenna1 thermal aging susceptibility (i.e.,

(i.e., ferrite and molybdenum molybdenum contents, casting process, and operating temperature) anLef casting ftfltbLef accounting accounting for the synergistic synergistic effects of ofthenna1 thermal aging and neutron irradiation embrittlement embritt1ement (neutron fluence),

and"

Reference:

Response

Response to RAI B. 1.37-3.

B.1.37-3.

12. B. 1.31, the third paragraph Section B.1.31, paragraph of the tabular listing of program activities for the plant drains system, is revised to read:

"Perform "Perfonn visual inspection of the inside and outside surface of gasoline-powered gasoline-powered gray cast iron pump casings exposed to air - indoor to manage manage loss of material."

material."

Reference:

Response

Response to RAI 3.3-7.

Nebraska Public Power District Cooper Nuclear Station PLANT UNIQUE ANALYSIS REPORT Mark II Containment Program Revised February 26, 2007

• ABSTRACT ABSTRACT Nebraska Nebraska Public Power District District (NPPD) has completed the reevaluation reeva.1uation of the Cooper Nuclear Station (CNS) (CNS) Mark I containment containment system.

system. This reevaluation reevaluation was was performed performed in in response response to the Nuclear Regulatory Regulatory Commission's (NRC)

(NRC) requirements requirements for resolving the Safety "Unresolved Safety Issue" designation (pursuant to Section 210 of the Energy Energy. Reorganization Reorganization Act of 1974) 1974) as itit pertains to CNS.CNS. The NRC requirements resulted resulted from the identification identification of of suppression suppression pool hydrodynamic hydrodynamic loads not considered considered in in the original boiling containment design.

water reactor Mark I containment design.

This Plant Plant Unique Analysis Report describes describes the evaluations evaluations performed performed by NPPD to demonstrate demonstrate that the plant modifications modifications installed installed at CNS in response, to in response to the NRC requirements requirements are sufficient sufficient to restore the original margins of safety for the containment containment system. This report coverscovers the CNS plantplant unique unique suppression pool hydrodynamic suppression hydrodynamic load definitions, definitions, the structural structural assessments assessments for these load definitions, evaluation of the structural response definitions, and the evaluation against the Mark I Program Structural Acceptance Program Structural Acceptance Criteria.

Criteria. These evaluations These evaluations consider consider the plant configuration configuration after after the installation of extensive modifications to upgrade the safety margins of the CNS containment modifications containment for the loads.

newly defined loads.

The results of the plant unique containmentcontainment evaluations indicate that the modifications installed at CNS are sufficient modifications satisfy the Mark II Long-Term sufficient to satisfy Long-Term criteria. Completion Program criteria. Completion of these modifications by September these modifications September 1982 thereby satisfies the requirements requirements of the NRC for restoration restoration of the original margins

• original margins of safety safety for the CNS containment containment system.

system.

/

-i-

-i 04/29/82

• W Abstract Abstract TABLE OF TABLE OF CONTENTS CONTENTS Page i

SECTION 1 INTRODUCTION SECTION INTRODUCTION AND DESIGN DESIGN CRITERIA

1.1 INTRODUCTION

INTRODUCTION 1-1 1-I 1.1.1 Objective Objective and Scope i-I 1-1 1.1.22 1.1. Problem Definition Problem Definition 1-1 1-I 1.1.33 1.1. Short-Term Program Short-Term Program 1-2 1-2

,1.1.4

.1.1.4 Long-Term Program Long-Term Program 1-3 1-3 1.2 CRITERIA DESIGN CRITERIA 1-3 1-3 1.2.1 1.2.1 Design Specifications Design Specifications 1-4 1-4 1.2.1.1 1.2.1.1 Specifications Original Specifications 1-4 1-4 1.2.1.2 1.2.1.2' Specifications for Modifications Specifications Modifications 1-4 1-4 1.2.2

1. 2.2 LTP Design Requirements Design Requirements 1-4 1-4 1.2.2.1 1.2.2.1 New Design Requirements Requirements 1-4 1-4 1.2.2.2 Exceptions to Design Requirements Requirements 1-5

• 1.2.2.2 Exceptions to Design 1-5 1.3 CONTAINMENT AND MODIFICATION CONTAINMENT DESCRIPTION MODIFICATION DESCRIPTION 1-6 1-6 1.3.1 1.3.1 General General 1-6 1-6 1.3.1.1

1. 3 . 1. 1 Drywell 1-6 1-6 1.3.1.2 Wetwell Wetwell 1-7 1-7 1.3.1.3 1.3.1.3 Vent Vent System 1-7 1-7 1.3.2

1. 3.2 Structural Components Components 1-7 1-7 1.3.2.1 Torus Supports Torus Shell and Supports 1-7 1-7 1.3.2.2 Vent Supports Vent System and Supports 1-9 1-9 1.3.2.3 1.3.2.3 Miscellaneous Miscellaneous Torus Internals Internals 1-11 1-11 1.3.3

1. 3.3 Piping Systems 1-12 1.3.3.1 Safety/Relief Valve Discharge Safety/Relief Discharge Piping 1-12 1.3.3.2 Torus Torus Attached Attached Piping 1-14 1.3.3.3 Torus Torus Internal Internal Piping 1-15 1-15 1.3.4 1.3.4 Miscellaneous System Modifications Miscellaneous Modifications 1-16 1-16 1.3.4.1 1.3.4.1 Drywell/Wetwell Pressure Differential Drywell/Wetwell Pressure Differential 1-16 1-16 1.3.4.2 1.3.4.2 S/RV Low-Low S/RV Low-Low Set Relief Relief Logic 1-17 1-17 1.3.4.3 1.3.4.3 Level Level 11 MSIV MSIV Trip Trip Setpoint 1-18 1-18

.'

1.3.4.4 1.3.4.4 Torus Torus Temperature Monitoring System Temperature Monitoring System 1-18 1-18 1.3.5 1.3.5 Modification Summary Modification Summary 1-19

-1 04/16/02

• 1.4 1.4

SUMMARY

OF 1.4.1

1. 4.1 OF RESULTS RESULTS Results Results and TABLE TABLE OF CONTENTS CONTENTS (Continued) and Conclusions Conclusions Page 1-19 1-19 1-19 1-19 1.4.2

1. 4.2 Conformity Conformity with with Project Project Requirements Requirements 1-20 1-20

• 04/16/02 04/16/02

• p

2.1 INTRODUCTION

INTRODUCTION TABLE OF CONTENTS (Continued)

TABLE OF CONTENTS (Continued)

SECTION 22 LOADS AND LOAD COMBINATIONS SECTION COMBINATIONS Page 2-1 2-1 2.2 PLANT THERMAL-HYDRAULIC THERMAL-HYDRAULIC PARAMETERS PARAMETERS 2-1 2-1 2.3 2 .3 ORIGINAL DESIGN LOADS ORIGINAL 2-2 2-2 2.4 LOCA-RELATED LOCA-RELATED LOADS 2-2 2.4.1 Containment System Pressure and Temperature Containment Temperature Response 2-4 2-4 2.4.1.1 2.4.1.1 Design Design Basis Basis Accident Accident 2-4 2-4 2.4.1.2 2.4.1.2 Intermediate Break Intermediate Accident Break Accident 2-5 2-5 2.4.1.3 2.4.1.3 Small Break Break Accident Accident 2-5 2-5 2.4.2 Vent System Thrust Thrust Loads Loads 2-5 2-5 2.4.2.1 2.4.2.1 Analysis Analysis Methods Methods and Results Results 2-5 2-5 2.4.2.2

,2.4.2.2 Load Application Application 2-5 2-5 2.4.3 Loads Associated Associated With (Pool (Pool Swell 2-6 2-6

• 2.4.3.1 2.4.3.1 2.4.3.2 2.4.3.3 2.4.3.3 2.4.3.4 2.4.3.4 2.4.3.5 2.4.3.5 2.4.3.6 2.4:3.6 2.4.3.7 Torus Torus Net Torus Impact, Froth LOCA LOCA Net Vertical Water LOCA Air Vertical Loads Torus Shell Pressure Impact, Drag, Froth Impingement Loads Pressure Histories Jet-Induced Histories Drag, and Fallback Loads Loads Impingement and Froth Fallback Loads LOCA Water Jet-Induced Loads Fallback Loads Bubble-Induced Drag Loads Air Bubble-Induced Interference Effects Interference Loads Loads 2-6 2-6 2-7 2-7 2-8 2-8 2-10 2-10 2-10 2-11 2-11 2-11 2-11 2.4.4 Loads Associated Associated with Condensation Condensation Oscillation Oscillation 2-12 2.4.4.1 2.4.4.1 Torus Shell Loads Loads 2-12 2.4.4.2 2.4.4.2 Vent System Loads Loads 2-13 2.4.4.3 2.4.4.3 Downcomer Downcomer Lateral Lateral Loads Loads 2-13 2.4.4.4 2.4.4.4 Structure Loads Submerged Structure Loads 2-13 2.4.5 Loads Associated Associated with Chugging Chugging 2-14 2-14 2.4.5.1 2.4.5.1 Torus Shell Loads Loads 2-15 2.4.5.2 2.4.5.2 Vent System Loads Loads 2-16 2.4.5.3 2.4.5.3 Downcomer Downcomer Lateral Lateral Loads Loads 2-16 2.4.5.4 2.4.5.4 Structure Loads Submerged Structure Loads 2-17 2.5 DISCHARGE-RELATED LOADS S/RV DISCHARGE-RELATED 2-18 2-18 2.5.1 S/RVDL-Clearing S/RVDL-Clearing Transient Transient Loads Loads 2-19 2.5.2 S/RVDL Reflood Reflood Transient Transient 2-20 2-20 Thrust Loads Loads on T-Quencher 2-21 2-21

• 2.5.3 T-Quencher Arms 2.5.4 Torus Shell Pressures Pressures 2-22 2.5.5 Loads on Submerged Structures Structures 2-24 2-24 04/16/02

TABLE OF CONTENTS CONTENTS (Continued)

Page 2.5.5.1 2.5.5.1 T-Quencher Water T-Quencher Jet-Induced Drag Water Jet-Induced Drag Loads Loads )2-24 j2-24 2.5.5.2 2.5.5.2 T-Quencher T-Quencher Air Bubble-Induced Drag Loads Bubble-Induced Drag Loads 2-25 2-25 2.5.5.3 2.5.5.3 T-Quencher Differential Loads T-Quencher Air Bubble Differential Loads 2-25 2-25 2.5.5.4 22.5.5.4 Interference Effects Interference Effects 2-25 22.6

.6 OTHER LOADS LOADS 2-26 2.6.1 2.6.1 O.ther Other Operating Operating Loads Loads 2-26 2.6.2 Other Secondary Secondary Loads Loads 2-26 2.6.3 Steam Discharge Condensation Loads Discharge Condensation Loads 2-26 2-26 2.7 LOAD COMBINATIONS COMBINATIONS 2-27 2.7.1 Torus Shell Shell 2-27 2.7.2 Vent System Vent System 2-27 2.7.3 Internal Structures Internal Above Pool Structures Above Pool 2-27 2.7.4 Submerged Structures Submerged Structures 2-27 2.7.5 S/RVD Piping S/RVD 2-27 2.7.6 Attached Piping Torus Attached 2-28 2-28 2.7.7 Fatigue Design Fatigue Design Basis Basis 2-28 2-28

• 04/16/02

3.1 INTRODUCTION

TABLE OF CONTENTS (Continued)

SECTION 33 TORUS SHELL AND SUPPORTS SECTION SUPPORTS Page 3-1 3-1 33.2

. 2 TORUS SHELL 3-1 3-1 3.2.1 3.2.1 Design Combinations Design Load Combinations 3-1 3-1 3.2.2 3.2.2 Design Allowables Design Allowables 3-1 3-1 3.2.2.1 3.2.2.1 Shell Shell Stress Stress Intensity Intensity Allowables Allowables 3-1 3-1 3.2.2.2 Buckling Allowables Allowables 3-1 3-1 3.2.3 3.2.3 Analysis Analysis Methods Results Methods and Results 3-3 3-3 3.2.3.1 Mathematical Models Torus Mathematical Models 3-3 3-3 3.2.3.2 Analysis Procedures Procedures and Results Results 3-4 3-4 3.2.4 3.2.4 Code Code Evaluation 3-8 3-8 3.2.4.1 Shell Shell Stress Stress Intensities Intensities 3-8 3-8 3.2.4.2 Fatigue Evaluation 3-8 3-8 3.2.5 3.2.5 Torus Torus Re-Analysis to Establish

• Establish Corrosion Allowance Allowance 3-8 3-8 3.2.5.1 Mathematical Models Torus Mathematical Models 3-8 3-8 3.2.5.2 load Combinations load Combinations 3-9 3-9 3.2.5.3 Loads Loads 3-9 3-9 3.2.5.4 3.2.5.4 Analysis Analysis 3-10 33.3

.3 SYSTEM TORUS SUPPORT SYSTEM 3-10 3.3.1 3.3.1 Design Design Load Combinations, Load Combinations. 3-10 3.3.2 3.3.2 Design Design Allowables Allowables 3-10 3.3.2.1 Columns Support Columns 3-10 3.3.2.2 Anchorage Anchorage Assembly Assembly 3-11 3.3.2.3 Seismic Ties Seismic 3-11 3.3.2.4 Ring Girder Saddle Saddle 3-11 3.3.3 Analysis Methods

.Analysis Methods and Results Results 3-11 3.3.3.1 Column Column and Anchorage Anchorage Evaluation 3-11 3.3.3.2 3.3.3.2 Seismic Tie Evaluations Evaluations 3-12 3.3.3.3 3.3.3.3 Ring Saddle Evaluation Ring Girder Saddle 3-13 3.3.3.4 3.3.3.4 Nonlinear Support Assessment Nonlinear Support Assessment 3-14 3.3.4 Code Evaluation Evaluation 3-14 3.3.4.1 3.3.4.1 Column Column and Anchorage Anchorage 3-14

• 3.3.4.2 3.3.4.2 Seismic Ties Ties 3-15 3.3.4.3 3.3.4.3 Ring Girder Ring Girder Saddles Saddles 3-15 3.3.4.4 Fatigue Evaluation 3-15 5-04/16/02

• 33.4

.4 RING GIRDER 3.4.1 3.4.2 GIRDER TABLE OF CONTENTS (Continued)

Design Load Combinations Combinations Allowables Design Allowables 3-15 3-15 3-15 3.4.2.1 3.4.2.1 Ring Girder Girder Web and Flange Flange 3-15

- 3.4.2.2 3.4.2.2 Ring-Girder-to-Shell Ring-Girder-to-Shell Weld 3-16

,

3.4.3 Analysis Methods and Results Results 3-16 3.4.3.1 3.4.3.1 Ring Girder Girder In-Plane Loading In-Plane Loading 3-16 3.4.3.2 3.4.3.2 Ring Ring Girder Girder Lateral Lateral Load 3-16 3.4.3.3 3.4.3.3 Ring Ring Girder Girder Attachments Attachments 3-16 3.4.4 3.4.4 Code Evaluation Evaluation 3-17 3.4.4.1 3.4.4.1 Ring Ring Girder Girder Web and Flange Flange 3-17 3.4.4.2 3.4.4.2 Ring Ring Girder-to-Shell Girder-to-Shell Weld 3-17 3.4.4.3 3.4.4.3 Fatigue Evaluation Evaluation 3-17 3.5 PENETRATIONS AND ATTACHMENTS TORUS SHELL PENETRATIONS ATTACHMENTS 3-17 3-17 3,.5.1 3.5.1 Design Design Load Combinations Load Combinations 3-18 3-18 3.5.2 Design Desigh Allowables Allowables 3-18 3-18 3.5.3 Analysis Methods Analysis Methods and Results 3-18 3-18

• 3.5.4 3.5.4 3.5.3.1 3.5.3.2 3.5.3.3 3.5.3.3 Torus Torus Attached ECCS Piping Supports Code Evaluation Supports Penetrations Attached Piping Penetrations Monorail Supports Monorail Supports 3-18 3-18 3-19 3-19 3-19 3-19 3-19 3.5.4.1 Torus Attached Attached Piping Penetrations Piping Penetrations 3-19 3.5.4.2 Torus Stress Intensities Torus Shell Stress Intensities at Attachments Attachments 3-19 3-19 3.5.4.3 Fatigue Evaluation Fatigue Evaluation 33:"'19 L19

• 04/16/02

4.1 INTRODUCTION

INTRODUCTION TABLE TABLE OF CONTENTS SECTION CONTENTS (Continued)

SECTION 4 VENT SYSTEM AND SUPPORTS SUPPORTS Page 4-1 4-1 4.2 4.2 VENT HEADER AND MAIN VENT 4-1 4-1 4.2.1 Design Load Combinations Combinations 4-1 4-1 4.2.2 Allowables Design Allowables 4-1 4-1 4.2.2.1 4.2.2.1 Vent Header Header and Main Vent 4-1 4-1 4.2.2.2 4.2.2.2 Vent Header Header and Main Vent Penetrations Penetrations 4-1 4-1 4.2.2.3 4.2.2.3 D rywell Penetration Drywell Penetration 4-2 4-2 4.2.2.4 4.2.2.4 Main Main Vent Bellows 4-2 4-2 4.2.3 Analysis Methods Methods and Results Results 4-2 4-2 4.2.3.1 4.2.3.1 Vent System Mathematical Mathematical Models 4-3 4-3 4.2.3.2 4.2.3.2 Vent Header Header and Main Vent 4-4 4-4 4.2.3.3 4.2.3.3 Vent Header Header and Main Vent Penetrations Penetrations 4-9 4-9 4.2.3.4 4.2.3.4 Drywell Penetration Drywell Penetration 4-10 4.2.3.5 4.2.3.5 Main Main Vent Bellows Bellows 4-10 4.2.4 Code Evaluation Evaluation

• 4-11 4.2.4.1 4.2.4.1 Main Vent 4-11 4.2.4.2 4.2.4.2 Vent Header Header 4-11 4.2.4.3 4.2.4.3 Main Vent/Vent Main Vent/Vent Header Intersection Header Intersection 4-12 4.2.4.4 4.2.4.4 Vent Header Vent Header and Main Vent Penetrations Penetrations 4-12 4.2.4.5 4.2.4.5 Drywell Penetration Drywell Penetration 4-13 4.2.4.6 4.2.4.6 Main Vent Bellows Bellows 4-13 4.2.4.7 4.2.4.7 Shell Buckling Assessment Buckling Assessment 4-13 4.2.4.8 Fatigue Fatigue Evaluation Evaluation 4-13 4.3 . DOWNCOMERS DOWNCOMERS AND TIEBARS 4-14 4.3.1 Design Design Load Combinations Combinations 4-14 4.3.2 4.3.2 Design Allowables Design Allowables 4-14 4.3.2.1 Downcomer/Vent Header Downcomer/Vent Header Intersection Intersection 4-14 4.3.2.2 Downcomers Downcomers 4-15 4.3.2.3 Downcomer Tiebar Downcomer 4-15 4.3.3 4.3.3 -Analysis Analysis Methods and Results 4-15 4.3.3.1 4.3.3.1 Downcomer/Vent Header Intersection Downcomer/Vent Intersection 4-15 4.3.3.2 4.3.3.2 Downcomers Downcomers 4-17 4.3.3.3 4.3.3.3 Downcomer Tiebar 4-18 4.3.4 Code Evaluation Evaluation

• 4-18 4.3.4.1 4.3.4.1 Downcomer/Vent Header Intersection Downcomer/Vent Intersection 4-18 4.3.4.2 4.3.4.2 Downcomers Downcomers 4-18 i

I 04/16/02

• 4.3.4.3 4.3.4.4 TABLE OF CONTENTS (Continued)

Downcomer Tiebar Fatigue Evaluation Evaluation Page 4-19 4-19

4. 4 4.4 VENT DRAIN LINE 4-19 4.4.1 4."4.1 Combinations Design Load Combinations 4-19 4.4.2 Allowables Design Allowables 4-19 4.4.3 4.4.3 Analysis Analysis Methods and and Results Results 4-20 4.4.4 Code Evaluation Evaluation 4-20 4.5 4.5 VENT HEADER DEFLECTOR 4-20 4.5.1 Design Design Load Combinations Combinations 4-20 4.5.2 Design Allowables 4-20 4.5.3 Methods and Results Analysis Methods Results 4-20 4-20 4.5.4 Code Evaluation Evaluation 4-20 4-20 4.6 4.6 VENT HEADER SUPPORT SYSTEM 4-20 4-20 4.6.1 Design Load Combinations Combinations 4-21 4-21 4.6.2 Allowables Design Allowables 4-21 4-21 4.6.3 Analysis Methods Results Methods and Results 4-21 4-21 4.6.4 Code Evaluation Evaluation 4-21 4-21

• -8 04/16/02

TABLE OF CONTENTS (Continued)

SECTION 5 S/RV DISCHARGE PIPING PIPING Page 5.1

5.1 INTRODUCTION

5-1 5-1 5.2 5.2 PIPING DRYWELL S/RVD PIPING DRYWELL 5-1 5-4 5.2.1 Design Load Combinations Combinations 5-1 5-1 5.2.2 Design Allowables Allowables 5-1 5-1 5.2.2.1 5.2.2.1 Piping Stress Stress Allowables Allowables 5-1 5-1 5.2.2.2 5.2.2.2 Support Allowables Allowables 5-2 5-2 5.2.3 5.2.3 Analysis Methods'and Analysis Methods'and Results Results 5-2 5-2 5.2.3.1 5.2.3.1 S/RVD Piping Models Models 5-2 5-2 5.2.3.2 5.2.3.2 Piping Analysis Procedures Procedures and Results Results 5-2 5-2 5.2.3.3 5.2.3.3 Drywell Piping Support Evaluation Piping Support 5-4 5-4 5.2.4 5.2 . .4 Code Evaluation 5-6 5-6 5.2.4.1 5.2.4.1 Safety/Relief Safety/Relief Valve Back Pressure Pressure 5-6 5-6 5.2.4.2 5.2.4.2 S/RVD piping Piping 5-7 5-7 5.2.4:.3 5.2.4:.3 Drywell Supports Drywell Pipe Supports 5-7 5-7

• 5.3 5.3 5.2.4.4 5.2.4.4 5.2.4.5 5.2.4.5 WETWELL S/RVD PIPING 5.3.1 5.3.2 Drywell Drywell Liner Drywell PIPING Liner Drywell Steel Framing Design Load Combinations Combinations Allowables Design Allowables Framing 5-7 5-7 5-7 5-7 5-8 5-8 5-8 5-8 5-8 5-8 5.3.2.1 5.3.2.1 Allowables Piping Stress Allowables 5-8 5-8 5.3.2.2 5.3.2,.2 Allowables Support Allowables 5-9 5-9 5.3.2.3 5.3.2.3 Fatigue Fatigue Considerations Considerations 5-9 5-9 5.3.3 Methods and Results Analysis Methods Results 5-9 5-9 5.3.3.1 5.3.3.1 Piping Models S/RVD piping Models 5-9 5-9 5.3.3.2 5.3.3.2 Piping Analysis Procedures Procedures and Results Results 5-9 5-9 5.3.3.3 5.3.3.3 T-Quencher T-Quencher Evaluation 5-13 5.3.3*.4 5.3.3.4 Wetwell Piping Support Wetwell Support Evaluation Evaluation 5-14 5.3.4 Code Evaluations Evaluations 5-14 5-14 5.3.4.1 S/RVD Piping 5-14 5.3.4.2 T-Quencher T-Quencher Assembly Assembly 5-15 5.3.4.3 Wetwell Supports Wetwell Pipe Supports 5-15 5.3.4.4 T-Quencher Supports T-Quencher Supports 5-15 5.4 BREAKERS 5-15

• 5.4 S/RVDL VACUUM BREAKERS 5.4.1 5.4.1 Design Design Criteria Criteria 5-15 5.4.2 Analysis Methods Methods and Code Code Evaluation 5-15 04/16/02

• TABLE OF CONTENTS TABLE CONTENTS (Continued)

(Continued)

SECTION 66 TORUS SECTION TORUS ATTACHED ATTACHED PIPING PIPING AND AND TORUS TORUS INTERNAL STRUCTURES STRUCTURES Page 6.1

6.1 INTRODUCTION

INTRODUCTION 6-1 6-1 6.2 PIPING SYSTEMS EXTERNAL TO TORUS 6-1 6-1 6.2.1 6.2.1 Design Load Combinations 6-1 6-1 6.2.2 6.2.2 Design Allowables 6-2 6-2 6.2.2.1 6.2.2.1 Piping Stress Allowables 6-2 6-2 6.2.2.2 Support Allowables 6-2 6-2 6.2.2.3 Considerations Fatigue Considerations 6-3 6-3 6.2.3 6.2.3 Analysis Analysis Methods and Results 6-3 6-3 6.2.3.1 6.2.3.1 Piping Models 6-3 6-3 6.2.3.2 6.2.3.2 Coupling of Torus and Piping System 6-4 6-4 6.2.3.3 6.2.3.3 Analysis Procedures Procedures and Results 6-5 6-5 6.2.3.4 6.2.3.4 External Piping Support External Support Evaluation 6-7 6-7 6.2.3.5 6.2.3.5 Evaluations Branch Line Evaluations 6-7 6-7 6.2.3.6 6.2.3.6 Torus Attached Torus Attached Piping Piping Valve Evaluations 6-8 6-8 6.2.3.7 6.2.3.7 ECCS Pump Pump and Turbine End Load 6-9

• ECCS Load Evaluations 6-9 6.2.4 6.2.4 Code Evaluation Code Evaluation 6-9 6-9 6.2.4.1 6.2.4.1 External Piping External Piping 6-9 6-9 6.2.4.2 6.2.4.2 External Piping External Supports Piping Supports 6-10 6.2.4.3 6.2.4.3 Branch Lines Branch 6-10 6.2.4.4

. 6.2.4.4 Torus Attached Piping Valves Valves 6-10 6.2.4.5 ECCS Pumps and Turbines 6-10 6.3 6.3 PIPING SYSTEMS INTERNAL PIPING INTERNAL TO TORUS 6-10 6.3.1 6.3.1 Design Design Load Combinations Load Combinations '- 6-10 6.3.2 6.3.2 Design Design Allowables Allowables 6-11 6.3.2.1 Piping Piping Stress Stress Allowables Allowables 6-11 6.3.2.2 6.3.2.2 Support Support Allowables Allowables 6-11 6.3.2..3 6.3.2 .. 3 Fatigue Considerations Fatigue Considerations 6-11 6.3.3 6.3.3 Analysis Methods Analysis Methods and Results Results 6-11 6.3.3.1 Piping Models Models 6-11 6.3.3.2 6.3.3.2 Analysis Analysis Procedures Procedures andand Results Results 6-12 6.3.3.3 6.3.3.3 Internal Piping Internal Piping Support Support Evaluation Evaluation 6-14 6-14 6.3.4 6.3.4 Code Code Evaluation Evaluation 6-14 6-14 6.3.4.1 Internal Piping 6-15

• 6.3.4.1 Internal Piping 6-15 6.3.4.2 6.3.4.2 Internal Internal Piping Supports Supports 6-15 6-15 04/16/02

• 6.4 6 .4 TORUS INTERNAL TORUS 6.4.1 TABLE INTERNAL STRUCTURES Design STRUCTURES OF CONTENTS TABLE OF CONTENTS (Continued)

(Continued)

Page 6-15 6.4.1 Design Load Load Combinations Combinations 6-15 6-15 6.4.1.1 6.4.1.1 Platform platform System System 6-15 6-15 6.4.1.2 6.4.1.2 Monorail Monorail Beam Beam 6-16 6-16 6.4.2 6.4.2 Design Design Allowables Allowables 6-16 6-16 6.4.3 6.4.3 Analysis Analysis Methods Methods and and Results Results 6-16 6-16 6.4.3.1 6.4.3.1 Platform platform System System 6-16 6-16 6.4.3.2 6.4.3.2 Monorail Monorail Beam Beam 6-17 6-17 6.4.4 6.4.4 Code Code Evaluation Evaluation 6-17 6-17 6.4.4.1 6.4.4.1 Platform Platform System System 6-17 6-17 6.4.4.2 6.4.4.2 Monorail Monorail Beam Beam 6-17 6-17

• ii 04/16/02 04/16/02

TABLE OF TABLE OF CONTENTS CONTENTS (Continued)

SECTION SECTION 77 POOL POOL TEMPERATURE TEMPERATURE EVALUATION EVALUATION Page Page 7.1

7.1 INTRODUCTION

INTRODUCTION 7-1 7-1 7.2 7.2 POOL POOL TEMPERATURE TEMPERATURE MONITORING MONITORING SYSTEM SYSTEM 7-1 7-1

• 08/13/02 08/13/02

• TABLE OF CONTENTS CONTENTS (Continued)

SECTION 88 APPENDICES APPENDICES AND REFERENCES REFERENCES Page APPENDICES APPENDICES Appendix A: Adaptation Appendix Adaptation of the SRSS Method Method for for Combined Torus Shell Shell Pressures Pressures Following Multiple S/RV Multiple S/RV Actuations Actuations A-1 A-I Appendix B: Descriptions Appendix Descriptions of Major Major Computer Computer Programs Programs B-1 B-1 Appendix C: Modeling Appendix Modeling of Fluid Structure Structure Interaction Effects Using EDS-SNAP Effects EDS-SNAP C-1 C-I Appendix Combination of Dynamic Appendix D: Combination Dynamic Structural Structural Responses Responses D-1 D-I REFERENCES REFERENCES R-1 R-1

• 1 04/29/82

LIST OF TABLES LIST TABLES Table No.

Table No. Title Title Page 1.1 S/RVD S/RVD Lines in in the Drywell Drywell - Summary of Support Support 1-21 1-21 Modifications/Additions Modifications/Additions 1.2 1.2 Torus, Torus Pipe Penetrations Penetrations 1-22 1-22 1.3 1.3 Summary of Pipe Support Support Modifications Modifications for Torus Attached 1-23 1-23 (External) Piping 1.4 1.4 Torus Torus Internal Internal Piping Piping Systems Systems 1-24 1.5 1.5 Proposed Low-Low Set Set Safety/Relief Safety/Relief Valve System System 1-25 1.6 1.6 Results S/RV Load Case Analysis Results 1-26 1-26 1.7 1.7 MSIV MSIV Water Level Trip 1-27 1-27 1.8 1.8 Summary of Containment Summary Containment and Piping Piping Modifications Modifications 1-28 1-28

-1 04/16/02

• Table No.

2.1 2.1 No. Title Title LIST OF TABLES LIST Containment Hydrodynamic Containment Hydrodynamic Data TABLES Data Page 2-29 2.2 2.2 Proposed Low-Low Set Safety/Relief Safety/Relief Valve System System 2-30 2-30 2.3 2.3 Plant. Conditions at Instant Plant, Conditions Instant of DBA Pipe BreakBreak 2-31 2-31 2.4 2.4 Plant Conditions Conditions at Instant Instant of IBA/SBA Pipe Break Break 2-32 2-32 2.5 2.5 Structures Subjected Structures Subjected to Pool Swell Impact, Drag, and Impact, Drag, and 2-33 2-33 Fallback Loads Loads 2.6 2.6 Structures Subjected Structures Subjected to Froth Impingement Impingement and Froth Fallback 2-34 2-34 Loads Loads 2.7 2.7 Structures Structures Subjected Jet-Induced Drag Loads Subjected to LOCA Water Jet-Induced Loads 2-35 2-35 2.8 2.8 Structures Subjected Structures Subjected to Submerged Submerged Structure Drag Loads Structure Drag Loads and 2-36 2-36 Interference Factors Interference Factors 2.9 2.9 Condensation Oscillation Condensation Oscillation Baseline Rigid Wall Pressure Baseline Rigid 2-37 Amplitudes Amplitudes on Torus Shell Bottom Dead Dead Center Center

• 0 2.10 2.11 2.12 2 .12 Condensation Oscillation Condensation Oscillation Oscillation Onset and Duration Vent System Downcomer Lateral Load Oscillation Frequencies for Condensation Vent System Load Amplitudes and Frequencies Condensation Load Due to Condensation Condensation 2-39 2-39 2-40 2-40 2-41 2.13 Chugging Onset and Duration Chugging 2-42 2.14 Post-Chug Rigid Wall Wall Pressure Pressure Amplitudes Amplitudes on Torus Shell Shell 2-43 Bottom Bottom Dead Center Center 2.15 Vent System Load Amplitudes Amplitudes and Frequencies Frequencies for Chugging Chugging 2-44 2.16 Distribution Distribution of Downcomer Lateral Lateral Load Reversals Reversals Due to to 2-45 Chugging Chugging 2.17 2 .17 Structures Subjected Structures Subjected to T-Quencher T-Quencher Water Jet Loads Loads 2-46 2.18 Fatigue Fatigue Design Including DBA Event Design Basis Including Event 2-47 2.19 Fatigue Fatigue Design Including IBA/SBA Event Design Basis Including Event 2-48 2-48

• 04/16/02

• Table No.

Table 3.1 3.1 No. Title Title LIST OF TABLES Design Load Combinations TABLES Combinations and Service Service Level Limits for Class MC Components and Internal Structures Structures for Page 3-21 3-21 3.2 3.2 Bounding Load Bounding Load Combinations Combinations for Torus ShellShell Evaluations Evaluations 3-22 3-22 3.3 3.3 Allowable Allowable Stress Intensities Intensities for the Torus Shell Shell 3-23 3.4 3.4 Bounding Load Combinations Bounding Torus Support Column Combinations for Torus Column 3-24 3-24 Evaluations Evaluations 3.5 3.5 Bounding Load Combinations Bounding Torus Saddle Evaluations Combinations for Torus Evaluations 3-25 3-25 3.6 3.6 Bounding Load Combinations Combinations for Ring Girder Girder Evaluation 3-26 3.7 3.7 Bounding Load Combinations Combinations for Torus Shell Penetrations Penetrations and 3-27 Attachments Attachments 3.8 3.8 Local Stress Stress Intensities of Torus Attached Piping 3-28 Penetrations Penetrations

• 04/16/02

• 4.1 No.

Table No. Title Title Design Design Load LIST OF TABLES LIST TABLES Combinations and Corresponding Load Combinations Limits for the Vent Header and Main Corresponding Service Level Vent Main Vent Level Page 4-22 4-22 4.2 Allowable Stress Allowable Stress Intensities Intensities for Vent System Class MC MC 4-23 Components Components 4.3 Vent System Design Temperatures Temperatures 4-24 4.4 Frequencies and Mode Shapes Frequencies Shapes of 1/16 Vent System ModelModel 4-25 4.5 Modified Modified Downcomer Sway Frequencies Accounting Sway Mode Frequencies Accounting for for 4-26 Gusset Reinforcement Gusset Reinforcement 4.6 Compressive Membrane Maximum Compressive Membrane Stresses Stresses in in Vent System Vent System 4-27 Components Due to Pool Swell Loads Loads 4.7 Vent Vent System System Downcomer Downcomer Lateral Lateral Load Due to Condensation 4-28 Oscillation 4.8 S/RV S/RV Discharge-Related Discharge-Related Drag Loads on Vent Components Vent System Components 4-29 4.9 Equivalent Static Loads Equivalent Loads on Downcomers Downcomers Due to S/RV Discharge 4-30 Bubble Drag

• 4.10 4.11 4.12 Bounding Boundi0g Load Combinations Design Stress Allowables Maximum Stresses at th~

Corresponding Service Combinations and Corresponding Limits for Downcomers Downcomers and Tiebars Tiebars Allowables for Downcomer Downcomer Tiebars the Downcomer/Vent Service Level Tiebars Level Downcomer/Vent Header Intersection 4-31 4-31 4-32 4-33 4-33 for Unit Load Analyses Analyses 4.13 Summary of Downcomer Summary Downcomer Lateral Loads Lateral Loads 4-34 4.14 Oscillation Pressure Condensation Oscillation Pressure Amplitudes Amplitudes in in the 4-35 Downcomers Downcomers 4.15 Stress Intensity Stress Intensity Allowable for Design Load Combinations for Combinations for 4-36 Main Vent Main ~ent Drain Line 4.16 Stress Intensity Allowables Stress Allowables for the Vent Deflector Vent Header Deflector 4-37 4.17 Design Loads and Load Combinations Combinations for Vent Vent System Support Support 4-38 Columns Columns

• 04/16/02

• Table No.

Table 5.1 No. Title Title Combinations and Event Combinations 3 Piping LIST LIST OFOF TABLES and Service Levels for Class 2 and Page 5-17 5-17 5.2 5.2 Bounding Load Bounding Load Case Case Combinations Combinations for S/RVD S/RVD Lines in in the 5-18 5-18 Drywell Drywell 5.3 5.3 Allowables S/RV Discharge Piping Stress Allowables 5-19 5-19 5.4 5.4 Maximum Maximum Pipe Stresses Due Pipe Due to S/RVD Thrust Loading in in Drywell 5-20 5-20 Routing of S/RVDLs S/RVDLs 5.5 5.5 S/RVDLS in S/RVDLS in the Drywell - Maximum Maximum Stress as a Percentage Percentage of 5-21 Allowable for Bounding Load Combination Allowable Combination 5.6 5.6 Results of Code Results of Code Evaluation Evaluation - Maximum Maximum Interaction Interaction Ratios Ratios 5-22 5.7 5.7 Bounding Load Combination for S/RVD Lines in Bounding Load in the Wetwell 5-23 5.8 5.8 Representative Maximum Representative Maximum Pipe Stress for the Wetwell Routing Routing 5-24 of the S/RVD Lines

• -5 04/16/02

• 6.1 6.1 No.

Table No. Title Title LIST OF TABLES TABLES Bounding Load Case Combinations for Torus Attached External Piping External Page 6-18 6.2 6.2 Torus' Attached Piping Torus Piping Stress Allowables Allowables 6-19 6.3 6.3 Torus Pipe Penetrations and Associated Analysis Models for for 6-20 External Piping 6.4 6.4 Large Bore Torus Attached External Piping Representative Large 6-22 Maximum Stresses Maximum Stresses 6.5 6.5 Scale Factors to be Used on Coupled S/RV Responses to Obtain 6-23 all all S/RV S'/RV Load Cases Cases 6.6 6.6 Large Bore Torus Attached External Piping - Maximum Maximum Stress Stress 6-24 6-24 as a Percentage Percentage of Al~owables Allowables for Bounding Load Combinations Combinations 6.7 6.7 Combination for Torus Attached Bounding Load Combination Attached Internal Internal Piping 6~25 6-25 6.8 6.8 Torus Pipe Penetrations Penetrations and Associated Analysis Analysis Models for for 6-26 6-26 Internal Interhal Piping l

\

6.9 6.9 Design Load Cases for Platform Support Columns Support Columns 6-27

'-'

• 04/16/02

LIST OF TABLES Table No.

No. Title Title Page 7.1 Environmental Requirements Environmental Requirements for Devices to be Mounted Mounted in in 7-3 7-3 Harsh Harsh Environments Environments

• 08113/02 08/13/02

LIST OF TABLES TABLES No.

Table No. Title Title Page Page A.I A.l Summary of Peak Peak Pressure Pressure Comparison A-7 A-7 D.l D.1 Non-Exceedance Non-Exceedance Probabilities Probabilities D-4 D-4 04/16/02

• Figure No.

No. Title Title LIST OF FIGURES FIGURES Section 1)

(At End of Section 1)

Page Page 1.1 Cross Section - Composite Plant Layout Cross Section Layout 1-30 1-30 1.2 1.2 Cross Section Cross Wetwell Section - Wetwell 1-31 1-31 1.3 1.3 Torus Support Column Torus Support 1-32 1-32 1.4 1.4 Torus Saddle Torus Saddle 1-33 1-33 1.5 1.5 Section Section -- Vent Vent System System 1-34 1-34 1.6 1.6 Partial Plan - Vent System Partial Plan System 1-35 1-35 1.7 1.7 Elevation - Downcomer Downcomer Reinforcement Reinforcement 1-36 1-36 1.8 1.8 Section - Vent Header Section Header Deflector Deflector 1-37 1-37 1.9 1.9 Vent Header Support Columns Support Columns 1-38 1-38 1.10 1.10 Drywell/Wetwell Vacuum Breaker Drywell/Wetwell Reinforcement Breaker Reinforcement 1-39 1-39

• 1.11 1.12 1.13 1.14 Plan --

Elevation Service Platform Service Cross Section Wetwell Platform Elevation - Service Service Platform Section - Service Platform Service Platform Wetwell Routing of S/RVDLs S/RVDLs Platform 1-40 1-41 1-42 1-43 1.15 T-Quencher T-Quencher Support Support Structure Structure 1-44 1-44 1.16 Elevation - RHR Pump Elevation Pump Test Return Line Line Modification 1-45 1-45 1.17 HPCI HPCI Turbine Turbine Exhaust -- Reroute and and Resupport Resupport 1-46 1.18 1.18 RCIC Turbine Exhaust - Reroute and Resupport Turbine Exhaust Resupport 1-47 1.19 Core Spray Pump Test Test Return Return Truncation.

Truncation. 1-48

• 04/16/02

LIST OF FIGURES (At End of Section 2) 2)

Figure No.

Figure No. Title Title Page 2.1 2.1 DBA Containment Pressure Pressure Response Response 2-49 2.2 DBA Containment Temperature Temperature Response Response 2-50 2.3 IBA Containment Pressure Pressure Response Response 2-51 2.4 IBA Containment Temperature Temperature Response Response 2-52 2.5 SBA Containment Pressure Pressure Response Response 2-53 2.6 2.6 SBA Containment Temperature Temperature Response Response 2-54 2.7 2.7 Vent System Thrust Load Application 2-55 2.8 Single Main Vent ForcesForces (0-30 (0-30 sec),

sec), Zero AP ~P 2-56 2.9 Vent Header ForcesForces per Miter Bend (0-30 sec), sec), Zero ~p AP 2-57 2.10 2 .10 Single Downcomer ForcesForces (0-30 sec), Zero AP (0-30 sec), ~P 2-58 2-58 2.11 2 .11 Total Total and Net Vertical Forces Forces (0-30 sec),

sec), Zero AP~p 2-59 2.12 2 .12 Net Torus Vertical Load, Load, Zero AP

~P 2-60 2.13 2 .13 Corrected Corrected Torus Net Vertical Vertical Loads (NRC),

(NRC), Zero AP

~P 2-61 2.14 2 .14 Corrected Corrected Average Submerged Submerged Pressure Pressure due to Pool SwellSwell 2-62 (NRC),

(NRC), Zero ~PAP 2.15 Corrected Corrected Torus Airspace Pressure Pressure due to Pool Swell Swell. (NRCi, (NRC), 2-63 Zero ~P AP 2.16 Location Location of Impact/Drag Impact/Drag Pressure Pressure Transients Transients on Vent Header Header 2-64

.~

2.17 Pool Swell Impact/Drag Impact/Drag Load Transients Transients on MainMa~n Vent, Vent, 2-65

~P = 1.

AP 1.00 psid psid 2.18 2.18 Vent Header Deflector Loads Loads 2-66 2.19 Definition Definition of Froth Impingement Impingement Regions Regions 2-67 2.20 Definition Definition of Froth Load Applications Applications and Transients Transients 2-68 2.21 Torus Pressure Pressure Amplitude Distribution Distribution for Condensation Condensation 2-69 Oscillation 04/16/02

• Figure No.'

No.- Title LIST OF FIGURES FIGURES (CONT'D)

(CONT'D)

(At End of Section 2)

Section 2)

Page 2.22 Asymmetric Circumferential Torus Asymmetric Distribution for Pre-Chug Circumferential Distribution Pre-Chug 2-70 Pressure Amplitude Pressure Amplitude 2.23 Sectors Sectors Used to Define Define Directions Directions of Lateral Lateral Loads on on 2-71 Downcomer End Downcomer End 2.24 Typical Typical Torus Torus Shell S/RV Pressure Time Histories Generated Generated 2-72 using QBUBS03 QBUBS03 and QBUBS03.

QBUBS03.

2.25 Torus Shell Load Load Combinations Combinations for LOCA-DBA 2-73 2.26 Torus Shell Load Load Combinations Combinations for LOCA-IBA 2-74 2.27 Torus Shell Shell Load Combinations for LOCA-SBA LOCA-SBA 2-75 2 .28 2.28 Vent System Load Combinations for LOCA-DBA LOCA-DBA 2-76 2.29 2.29 Combinations for LOCA-IBA Vent System Load Combinations 2-77 2-77 2.30 2.30 Combinations for LOCA-SBA Vent System Load Combinations 2-78 2-78 2.31 Load Combinations Combinations for Structures Structures Above Above HWL HWL for LOCA-DBA 2-79 2-79 2 .32 2.32 Submerged Structures Submerged Structures Load Combinations for LOCA-DBA 2-80 2 .33 2.33 Submerged Structures Submerged Structures Load Combinations for LOCA-IBA 2-81 2.34 2.34 Submerged Structures Submerged Structures Load Combinations for LOCA-SBA 2-82 2.35 S/RV Discharge Loads on Submerged Submerged Structures Structures 2-83 0

04/16/02

• Figure No.

Figure No. Title Title FIGURES LIST OF FIGURES (At End of Section Section 3) 3)

Page 3.1 Section Torus 1/32 Section Torus Model Model 3-30 3-30 3.2 3 .2 90° 900 Section Section Torus Torus Model Model 3-31 3.3 1/32 Section Section Torus Model Model with Detailed Detailed Ring Girder Girder Saddle 3-32 3.3 3-32 3.4 Load Combinations Load Combinations Used inin Saddle Saddle Evaluation Evaluation 333 3.4 3-33 3.5 3.5 1/16th 1/16th ANSYS Model for Torus Reanalysis Reanalysis 3-34 3-34 Torus Reanalysis 3-35 3.6 3.6 1/16th Model Water ANSYS Model 1/16th ANSYS Elements for' Water Elements for Torus Reanalysis 3.7 1/16th ANSYS Model Ring Girder and Suppor't 1/16th Suppoft . Elements Elements for 3-36 3.7 3-36 Torus Reanalysis Torus Reanalysis

• 04/16/02

• Figure No.

Figure No. Title Title LIST OF LIST (At End of OF FIGURES of Section 4) 4)

j Page 4.1 4.1 1/ 1 6 th 1/16 th Finite Element Shell Model of Vent System System 4-39 4.2 4.2 18000 :Vent 180 Vent System Beam Model Model 4-40 4.3 4.3 Vent System Pressurization Pressurization Following a DBA 4-41 4.4 4.4 Vertical Thrust Load Transient on Main Vent End Cap Vertical Cap 4-42

(~p=b.O)

(AP=6.0) 4.5 4.5 Sequence and Duration of Pool Swell Load Sequence Load 4-43 4.6 4.6 Vertical Displacement Vertical Displacement Time History at Main Vent S/RVDL 4-44 Penetration 4.7 4.7 Vertical Acceleration Response Vertical Acceleration Response Spectrum Spectrum at the Vacuum Vacuum 4-45 Breaker Penetration Breaker

"

4.8 4.8 Configurations of Downcomer Possible Configurations Downcomer Pressure Pressure Differential Differential 4-46 for Condensation Condensation Oscillation Oscillation Downcomer Downcomer Lateral Load 4.9 4.9 Chug'Synchronization Chug Synchronization Loads Loads 4-47 4.10 Development of Scale Factors Development Factors Chug Synchronization Load Synchronization Load 4-48 4-48 4.11 Typical S/RV Discharge Discharge Drag Load Transient Transient for Submerged Submerged 4-49 Downcomer Segment Downcomer Segment 4.12 Downcomer/Vent Header Downcomer/Vent Reinforcement Design Header Gusset Reinforcement 4-50 4.13 Detailed Downcomer/Vent Header Detailed Downcomer/Vent Header Intersection Intersection Model Model Including Including 4-51 Gusset Gusset PlatePlate Stiffeners Stiffeners 04/16/02 04/16/02

• Figure No.

Figure No. Title Title (At LIST OF LIST (At End End of OF FIGURES FIGURES Section 5)5) of Section Page 5.1 5.1 S/RVD Line Drywell S/RVD Representative Drywell Representative (Line 71G)

Model (Line Line Model 71G) Before Before 5-25 5-25 and After Modifications and After Modifications 5.2 5.2 S/RVD Line S/RVD (Wetwell Routing)

Models (Wetwell Line Models Routing) 5-26 5-26 04/16/02 04/16/02

• No.

Figure No. Title Title (At LIST LIST OF (At End End of OF FIGURES FIGURES of Appendix A)

Page A. I A.1 Suppression Pool Geometry and S/RV Discharge L'ines Suppression Lines A-8 A-8 A. 2 A.2 Typical Pressure WaveWave A-9 A-9 A. 3 A.3 Sequence Sequence of S/RV Discharge Discharge Events Events A-10 A-10 A. 4 A.4 Probability Density Distribution Probability Distribution for the Reactor Pressure A-ll A-11 Rise Rate Rate A. 5 A.S Frequency Distribution Frequency Distribution of Combined Combined Peak Pressure Pressure Ratios - A-12 MVA 8 MVA

• 04/16/02

• Figure No.

Figure No. Title Title LIST OF FIGURES FIGURES

• (At End of Appendix D)

'(At Page D.1 D.l Illustration Illustration of CDF Computation Computation D-5 D-5 D.2 Typical Typical CDF for Mark Mark I Data D-6 D-6 04/16/02

• PAGE PAGE Abstract Abstract CNS CNS PLANT PLANT UNIQUE LIST LIST OF DATE DATE UNIQUE ANALYSIS ANALYSIS REPORT OF EFFECTIVE EFFECTIVE PAGES PAGE PAGE Section PAGES REPORT Section 11 (Continued) (dontinued)

DATE DATE ii ...... .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. . .. .. . .. .. .. .. .. 04/29/82 04/29/82 11-9

- 9 ................ .. .. .. .. .. .. .. .

. ... ... .. .. .. .. .. 04/16/02 04/16/02 1-10 1-10 ...................

. . . . . . . . . . . . . . . . . . . ...... . . 04/16/02 04/16/02 Table Table of of Contents Contents' 1-11 .......................

1-11 ....................... 04/16/02 04/16/02 1-12 1-12 .......................

....................... 04/16/02 04/16/02 11 .... .. .. .. .. .. .. .. .. . . .. .. .. .. . . .. .. .. .. .. .. .. .. .. .. 04/16/02 04/16/02 1-13 1-13 .......................

....................... 04/16/02 04/16/02 22 .... .. .. .. .. .. .. .. .. .. .. .. .. . . . . .. .. .. .. .. .. .. .. .. .. 04/16/02 04/16/02 1-14 1-14 .......................

....................... 04/16/02 04/16/02 33 .... .. .. .. .. .. .. .. .. .. . . ... .. .. . .. .. .. .. ....... . . . . . 04/16/02 04/16/02 1-15 1-15 .......................

....................... 04/16/02 04/16/02 44 .... .. .. .. .. .. .. .. .. .. .. .. .. . . . . .. .. .. .. .. .. .. .. .. .. 04/16/02 04/16/02 1-16 1-16........................

....................... 04/16/02 04/16/02 55 .... .. .. .. .. .. .. .. .. .. .. .. .. .. . . .. .. .. .. .. .. .. .. .. .. 04/16/02 04/16/02 1-17 1-17 .......................

....................... 04/16/02 04/16/02 66..........................

.......................... 04/16/02 04/16/02 1-18 1-18 .....................

. . . . . . . . . . . . . . . . . . . . .*.. .. 04/16/02 04/16/02 77 .... .. .. .. .. .. .. .. .. .. .. .. .. . . .. . . .. .. .. .. .. .. .. .. .. 04/16/02 04/16/02 1-19 1-19 ................

............... .....

. . . . ..... . 04/16/02 04/16/02 88 .... .. .. .. .. .. .. .. .. .. .. .. .. . . . . .. .. .. .. .. .. .. .. .. .. 04/16/02 04/16/02 1-2 1-20 0 ...............

. . . . . . . . . . . . . . . ..... . . . . . ..... . 04/16/02 04/16/02 99 .... .. .. .. .. .. .. .. .. .. .. .. .. . . .. .. .. .. .. .. .. .. .. .. .. 04/16/02 04/16/02 1-21 1-21.........................

...................... 04/29/82 04/29/82 1100 .... .. .. .. .. .. .. .. .. .. .. .. .. . . .. .. .. .. .. .. .. .. .. .. 04/16/02 04/16/02 1-22 1-22 .......................

....................... 04/29/82 04/29/82 1111 ...... .. .. .. .. .. .. .. .. .. .. .. . . ... .. .. .. .. . .. .. .. .. 04/16/02 04/16/02 11-23

-2 3 .............

. . . . . . . . . . . . . ........ . . . . . . ..... . 04/29/82 04/29/82 1122 .... .. .. .. .. .. .. .. .. .. .. .. .. . . ... . .. .. .. .. .. .. .. .. 08/13/02 08/13/02 1-24 1-24 .......................

....................... 04/29/82 04/29/82 1133 .... .. .. .. .. .. .. .. .. .. .. .. .. . . .. .. .. .. .. .. .. .. .. .. 04/29/82 04/29/82 1-25 1-25 .......................

....................... 04/29/82 04/29/82 1-2 1-26 6 .......

. . . . . . .....

. . . . ... . ......

. . . . . . ...... . . 04/29/82 04/29/82 List List of of Figures Figures 1-1-272 7 ......... .... ....... .. .. .. .. .. .. .. .

. .. .. .. .. .. 04/29/82 04/29/82 1-1-28 2 8 ............... ........... .. .. .. .. .. .. .. .. .. .. 04/29/82 04/29/82 11 ............ .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. 04/16/02 04/16/02 1-29 1-29 ..... . . ...........

. . . . . . . . . . ....... . . . . . ..... . 04/29/82 04/29/82 22 ...... .. .. .. .. .. .. .. .. .. .. .. . . . . .. .. .. .. .. .. .. .. .. .. 04/16/02 Figure Figure 1.1 1.1 ................. 04/29/82

• 04/16/02 ................. 04/29/82 33 ...... .. .. .. .. .. .. .. .. .. .. .. .. . . ... .. . .. .. .. .. .. .. .. 04/16/02 04/16/02 Figure Figure 1.2 1.2 .................

................. 04/29/82 04/29/82 44 ........ .. .. .. .. .. .. .. .. . . .. ... .. .. .. . .. .. .. .. .. .. .. 04/16/02 04/16/02 Figure Figure 1.3 1.3 .................

................. 04/29/82 04/29/82 55 .............. .. .. .. .. .. . . .. ... .. .. .. .. .. . .. .. .. .. .. 04/16/02 04/16/02 Figure Figure 1.4 1.4 .................

................. 04/29/82 04/29/82 66 . .. .. .. . .. .. .. .. .. .. .. .. .. .. .. .. .. . . .. .. . . .. .. .. .. .. 04/16/02 04/16/02 Figure Figure 1.5 1. 5 .................

................. 04/29/82 04/29/82 77 . .. . . . . . . . . . . . ..............

......... .............. 04/16/02.

04/16/02. Figure Figure 1.6 1. 6 .................

................. 04/29/82 04/29/82 8 ........................ "

8 . . . . . . . . . . . . . . . . . . . . . . . . . . 04/16/02 04/16/02 Figure Figure 1.7 1.7 .................

................. 04/29/82 04/29/82 Figure Figure 1.8 1.8 .................

................. 04/29/82 04/29/82 List List of of Tables Tables Figure Figure 1.9 1.9 .................

................. 04/29/82 04/29/82 Figure Figure 1.10 1.10 ................

................ 04/29/82 04/29/82 11 . .. .. .. .. .. . .. .. .. .. .. .. .. .. .

. . . .. .. .. .. . . .. .. .. .. .. 04/16/02 04/16/02 Figure Figure 1.11 1.11 ................

................ 04/29/82 04/29/82 2 2 . .. .. .. .. .. . .. .. .. .. .. .. .. .. .

. . . .. .. .. .. . . .. .. .. .. .. 04/16/02 04/16/02 Figure Figure 1.12 1.12 ................

................ 04/29/82 04)29/82 33 . ... . .. .. .. . .. .. .. .. .. .. .. .. .. . . .. .. .. .. . . .. .. .. .. .. 04/16/02 04/16/02 Figure Figure 1.13 1.13 ................

................ 04/29/82 04/29/82 44 . .. .. .. ..... .. .. .. .. .. .. . . .. .. . . .. .. .. .. . . .. .. .. .. .. 04/16/02 04/16/02 Figure Figure 1.14 1.14 ................

......... : ...... 04/29/82 04/29/82 55 . .. .. .. ......... .. .. . . .. .. .. .. . . .. .. .. .. . . .. .. .. .. .. 04/16/02 04/16/02 Figure Figure 1.15 1.15 ................

................ 04/29/82 04/29/82 6 ..........................

6 . . . . . . . . . . . . . . . . . . . . . . . . . . 04/16/02 04/16/02 Figure Figure 1.16 1.16 ................

................ 04/29/82 04/29/82 7 ..........................

7 . . . . . . . . . . . . . . . . . . . . . . . . . . 08/13/02 08/13 /02 Figure Figure 1.17 1.17 ................

................ 04/29/82 04/29/82 8 8 . .. .. .. .. .. .. .. ... .. .. .. .. .. .. . . .. .. .. .. . . .. .. .. .. .. 04/16/02 04/16/02 Figure Figure 1.18 1.18 ................

................ 04/29/82 04/29/82 Figure Figure 1.19 1.19 ................

................ 04/29/82 04/29/82 List List of of Abbreviations Abbreviations Section Section 22 1 1 . ................... . . .. .. .. .. . . .. .. .. .. . . .. .. .. .. .. 04/29/82 04/29/82 22 . .. .. .. ........... .. .. .. . . .. .. . . .. .. .. .. . . .. .. .. .. .. 04/29/82 04/29/82 22-1

- 1 ...................... .. .. .. .. .. .. .. .. .. . . .. .. .. 04/16/02 04/16/02

, 33 . ................. .. . ...............

. . . . . . . . . . . . . . . . 04/29/82 04/29/82 22-2

-2 .................. .. .. .. .. .. .. .. .. . .... .. . .. .. .. 04/16/02 04/16/02 22-3

- 3 .................. .. .. .. .. .. .. .. .. .. .

.. .. . .. .. .. 04/16/02 04/16/02 Section Section 11 22-4

-4 .................. .. .. .. .. .. .. . . ... ... .. .. .. .. .. 04/16/02 04/16/02 22-5

- 5 ............. ... .. .. .. .. .. .. .. .

. .. .. .

. .. .. .. ... . 04/16/02 04/16/02 1-1 . .. .. .. .. ....... .. .. .. .. .

1 - 1 . . . .. .. .. .. . . .. .. .. .. .. 04/29/82 04/29/82 22-6

- 6 ...................... .. .. .. .. .. .. .. . .. .. . .. .. .. 04/16/02 04/16/02 11 2 ................ .. .. .. .. . . . .. .. .. .. . .. .. .. .. .. .. 04/29/82 04/29/82 22-7

- 7 ...................... .. .. .. .. .. .. .. . .. .. .. . .. .. 04/16/02 04/16/02 11 3 ................ . . .. ... .. .. . .. .. .. .. .. .. .. .. .. .. 04/29/82 04/29/82 22-8

- 8 ....... ........ ... .. .. ... . .. .. .. .. .

. .

. .. .. .. .. .. 04/16/02 04/16/02 1-4 1-4................

........................ 04/29/82 04/29/82 22-9

- 9 ................ .. .. .. .. .. .. .. .. ... ... .. .. .. .. .. 04/16/02 04/16/02 11 5 .................... .. .. . . . .. .. .. .. . .. .. .. .. .. .. 04/29/82 04/29/82 2-10 2-10 .......................

....................... 04/16/02 04/16/02 1-6 . ....

1-6 ........

'.' . . . ...............

.............. 04/16/02 04/16/02 2-11 2-11 .......................

....................... 04/16/02 04/16/02 1-7 ..... . . ..... . ......

1-7 ...... ...... . . . . ......

....... 04/16/02 04/16/02 2-12 2-12 .......................

....................... 04/16/02 04/16/02 1-8 . . . ...... . . ...... . . . .

1 - 8 . ... ...... . . . . ....... . . . . . . 04/.16/02 04/16/02 2-13 2-13 .......................

....................... 04/16/02 04/16/02 Page Page 11 of of 44 02/26/07 02/26/07

PAGE PAGE ~~DATEPAEDT PAGE DATE PPAGE AGE DATE DATE

• W Section 22 (Continued)

Section 2-14..........................

2-14 . . . . . . . . . . . . . . . . . . . . . . . 04/16/02 2-15..........................

2-15 . . . . . . . . . . . . . . . . . . . . . . . 04/16/02 2-16..........................

2-16 . . . . . . . . . . . . . . . . . . . . . . . 04/16/02 2-17 . . . . . . . . . . . . . . . . . . . . ~ .. 04/16/02 2-17..........................

2-18..........................

2-18 . . . . . . . . . . . . . . . . . . . . . . . 04/16/02 04/16/02 04/16/02 04/16/02 04/16/02 04/16/02 Section Section 22 (Continued)

Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure (Continued) 2.25..................

2.25 . . . . . . . . . . . . . . . .

2.26..................

2.26 . . . . . . . . . . . . . . . .

2.27..................

2.27 . . . . . . . . . . . . . . . .

2.28..................

2.28 . . . . . . . . . . . . . . . .

2.29..................

2.29 . . . . . . . . . . . . . . . .

04/29/82 04/29/82 04/29/82 04/29/82 04/29/82 04/29/82 04/29/82 04/29/82 04/29/

04/29/8282 2-19.................

2-19 . . . . . . . . . . . . . . . . . . . . . . . 04/16/02 04/16/02 Figure Figure 2.30..................

2.30 . . . . . . . . . . . . . . . . 04/29/82 04/29/82 2-20...............04/16/02 2-20 . . . . . . . . . . . . . . . . . . . . . . . 04/16/02 Figure Figure 2.31..................

2.31 . . . . . . . . . . . . . . . . 04/29/82 04/29/82 2-21 2-21... . . . . . . . . . . ................

. . . . . . . . . . . . 04/16/02 04/16/02 Figure Figure 22.32

.32..................

................ 04/29/

04/29/8282 2-22 2-22 ...' . . . . .. . . ... . . ... . . . . .. . . . ..04/16/02 04/16/02 Figure Figure 2.33..................

2.33 . . . . . . . . . . . . . . . . 04/29/82 04/29/82 2-23...............04/16/02 2-23 . . . . . . . . . . . . . . . . . . . . . . . 04/16/02 Figure Figure 2.34..................

2.34 . . . . . . . . . . . . . . . . 04/29/82 04/29/82 2-24 2-24 . . . . . . . ...................

. . . . . . . . . . . . . . . 04/16/02 04/16/02 Figure Figure 2.35..................

2.35 . . . . . . . . . . . . . . . . 04/29/82 04/29/82 2-25...............04/16/02 2-25 . . . . . . . . . . . . . . . . . . . . . . . 04/16/02 2-26 2-26 . . . . . . ....................

. . . . . . . . . . . . . . . . 04/16/02 04/16/02 Section Section 33 2-27......................

2-27 . . . . . . . . . . . . . . . . . . . . . . . 04/16/02 04/16/02 2-28 2-28 . . . . . . ....................

. . . . . . . . . . . . . . . . 04/16/02 04/16/02 3-1...........................

3-1 . . . . . . . . . . . . . . . . . . . . . . . . 04/29/8204/29/82 2-29 2-29 . . . . . .....................

. . . . . . . . . . . . . . . . . 04/29/82 04/29/82 3-2...........................

3-2 . . . . . . . . . . . . . . . . . . . . . . . . 04/29/82 04/29/82 2-30...

2-30 . . . . . . . . ....... . . . . . . . . . 04/29/82

' . . . . ........ 04/29/82 3-3...........................

3-3 . . . . . . . . . . . . . . . . . . . . . . . . 04/16/0204/16/02 2-31.................

2-31 . . . . . . . . . . . . . . . . . . . . . . . 04/29/82 04/29/82 3-4...........................

3-4 . . . . . . . . . . . . . . . . . . . . . . . . 04/16/0204/16/02 2-32 2-32... . . . . . . . ...................

. . . . . . . . . . . . . . . 04/29/82 04/29/82 3-5...........................

3-5 . . . . . . . . . . . . . . . . . . . . . . . . 04/16/0204/16/02 2-33..........................

2-33 . . . . . . . . . . . . . . . . . . . . . . . 04/29/82 04/29/82 3-6...........................

3-6 . . . . . . . . . . . . . . . . . . . . . . . . 04/16/0204/16/02 2-34..........................

2-34 . . . . . . . . . . . . . . . . . . . . . . . 04/29/82 04/29/82 3-7...........................

3-7 . . . . . . . . . . . . . . . . . . . . . . . . 04/16/0204/16/02 2-35..........................

2-35 . . . . . . . . . . . . . . . . . . . . . . . 04/29/82 04/29/82 3-8.......... . . . . . . . . . . . . . . . . 04/16/02 3-8 . . . . . . . .................. 04/16/02 2-36..........................

2-36 . . . . . . . . . . . . . . . . . . . . . . . 04/29/82 04/29/82 3-9....................

3-9 . . . . . . . . . . . . . . . . . ;......; . . . . . . 04/16/02 04/16/02 2-37..........................

2-37 . . . . . . . . . . . . . . . . . . . . . . . 04/29/82 04/29/82 3-10..........................

3-10 . . . . . . . . . . . . . . . . . . . . . . . 04/16/02 04/16/02 2-38...........................

2 - 38,. . . . . . . . . . . . . . . . . . . . . .. 04/29/82 04/29/82 3-11..........................

3-11 ....' . . . . . . . . . . . . . . . . . . . 04/16/02 04/16/02

.2-41..

2-39..........................

2-39 . . . . . . . . . . . . . . . . . . . . . . . 04/29/82 2-40..........................

2-40 . . . . . . . . . . . . . . . . . . . . . . . 04/29/82 04/29/82 3-12..........................

3-12 . . . . . . . . . . . . . . . . . . . . . . . 04/16/02 3-13..........................

3-13 . . . . . . . . . . . . . . . . . . . . . . . 04/16/02 04/16/02

• 04/29/82 04/16/02 2-41 . . *........................

. . . . . . . . . . . . . . . . . . . . . 04/29/82 04/29/82 3-14..........................

3-14 . . . . . . . . . . . . . . . . . . . . . . . 04/16/02 04/16/02 2-42...........................

2-42 . . . . . . . . . . . . . . . . . . . . . . . 04/29/82 04/29/82 3-15..........................

3-15 . . . . . . . . . . . . . . . . . . . . . . . 04/16/02 04/16/02 2-43..........................

2-43 . . . . . . . . . . . . . . . . . . . . . . . 04/29/82 04/29/82 3-16..........................

3-16 . . . . . . . . . . . . . . . . . . . . . . . 04/16/02 04/16/02 2-44...........................

2-44 . . . . . . . . . . . . . . . . . . . . . . . 04/29/82 04/29/82 3-17..........................

3-17 . . . . . . . . . . . . . . . . . . . . . . . 04/16/02 04/16/02 2-45..........................

2-45 . . . . . . . . . . . . . . . . . . . . . . . 04/29/82 04/29/82 3-18...........................-

3 -18 . . . . . . . . . . . . . . . . . . . . . . . _04/16/02

.04/16/02 2-46..........................

2-46 . . . . . . . . . . . . . . . . . . . . . . . 04/29/82 04/29/82 3-19..........................

3-19 . . . . . . . . . . . . . . . . . . . . . . . 04/16/0204/16/02 2-47..........................

2-47 . . . . . . . . . . . . . . . . . . . . . . . 04/29/82 04/29/82 3-20..........................

3-20 . . . . . . . . . . . . . . . . . . . . . . . 04/16/0204/16/02 2-48..........................

2-48 . . . . . . . . . . . . . . . . . . . . . . . 04/29/82 04/29/82 3-21..........................

3-21 . . . . . . . . . . . . . . . . . . . . . . . 04/16/02 04/16/02 Figure Figure 2.1....................

2.1 . . . . . . . . . . . . . . . . . 04/29/82 04/29/82 3-22..........................

3-22 . . . . . . . . . . . . . . . . . . . . . . . 04/16/02 04/16/02 Figure Figure 2.2....................

2.2., . . . . . . . . . . . . . . . . 04/29/82 04/29/82 3-23..........................

3-23 . . . . . . . . . . . . . . . . . . . . . . . 04/16/02 04/16/02 Figure Figure 2.3....................

2.3 . . . . . . . . . . . . . . . . . 04/29/82 04/29/82 3-24..........................

3-24 . . . . . . . . . . . . . . . . . . . . . . . 04/16/ 04/16/02 02 Figure Figure 2.4....................

2.4 . . . . . . . . . . . . . . . . . 04/29/82 04/29/82 3-25..........................

3-25 . . . . . . . . . . . . . . . . . . . . . . . 04/16/0204/16/02 Figure Figure 2.5....................

2.5 . . . . . . . . . . . . . . . . . 04/29/82 04/29/82 3-26..........................

3-26 . . . . . . . . . . . . . . . . . . . . . . . 04/16/0204/16/02 Figure Figure 2.6....................

2.6 . . . . . . . . . . . . . . . . . ,04/29/82 04/29/82 3-27..........................

3-27 . . . . . . . . . . . . . . . . . . . . . . . 04/16/0204/16/02 Figure Figure 2.7....................

2.7 . . . . . . . . . . . . . . . . . 04/29/82 04/29/82 3-28..........................

3-28 . . . . . . . . . . . . . . . . . . . . . . . 04/1,6/0204/16/02 Figure Figure 2.8....................

2.8 . . . . . . . . . . . . . . . . . 04/29/82 04/29/82 3-29.........

3-29 ..... ~ ..................

. . . . . . . . . . . . . . . . 04/16/02 04/16/02 Figure Figure 2.9....................

2.9 . . . . . . . . . . . . . . . . . 04/29/82 04/29/82 Figure Figure 3.1...................

3.1 . . . . . . . . . . . . . . . . . 04/16/02 04/16/02 Figure Figure 2.10...................

2.10 . . . . . . . . . . . . . . . . 04/29/82 04/29/82 Figure Figure 3.2...................

3.2 . . . . . . . . . . . . . . . . . 04/16/02 04/16/02 Figure Figure 2.11...................

2.11 . . . . . . . . . . . . . . . . 04/29/82 04/29/82 Figure Figure 3.3...................

3.3 . . . . . . . . . . . . . . . . . 04/16/02 04/16/02 Figure Figure 2.12...................

2.12 . . . . . . . . . . . . . . . . 04/29/82 04/29/82 Figure Figure 3.4...................

3.4 . . . . . . . . . . . . . . . . . 04/16/02 04/16/02 Figure Figure 2.13...................

2.13 . . . . . . . . . . . . . . . . 04/29/82 04/29/82 Figure Figure 3.5...................

3.5 . . . . . . . . . . . . . . . . . 04/16/02 04/16/02 Figure Figure 2.14...................

2.14 . . . . . . . . . . . . . . . . 04/29/82 04/29/82 Figure Figure 3.6...................

3.6 . . . . . . . . . . . . . . . . . 04/16/02 04/16/02 Figure Figure 2.15...................

2.15 . . . . . . . . . . . . . . . . 04/29/,82 04/29{82 Figure Figure 3.7...................

3.7 . . . . . . . . . . . . . . . . . 04/16/02 Figure Figure 2.16...................

2.16 . . . . . . . . . . . . . . . . 04/29/82 04/29/82 Figure Figure 2.17...................

2.17 . . . . . . . . . . . . . . . . 04/29/82 04/29/82 Section Section 44 04/16/02 Figure Figure 2.18...................

2.18 . . . . . . . . . . . . . . . . 04/29/82 04/2~/82 Figure Figure 2.19 2.19;.................

. . . . . . . . . . . . . . . 04/29/82 04/29/82 4-1...........................

4-1 . . . . . . . . . . . . . . . . . . . . . . . . 04/29/82 04/29/ 82

. Figure Figure 2.20...................

2.20 . . . . . . . . . . . . . . . '.04/29/82 04/29/82 4-2...........................

4-2 . . . . . . . . . . . . . . . . . . . . . . . .

4-3...........................

04/29/82 04/29/82

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2.21 . . . . . . . . . . . . . . . . 04/29/82 04/29/82 4-3 . . . . . . . . . . . . . . . . . . . . . . . . 04/29/82 04/29/82 Figure Figure 2.22...................

2.22 . . . . . . . . . . . . . . . . 04/29/82 04/29/82 4-4...........................

4-4 . . . . . . . . . . . . . . . . . . . . . . . . 04/29/82 04/29/82 Figure Figure 2.23...................

2.23 . . . . . . . . . . . . . . . . 04/29/82 04/29/82 ,'4-5...........................

4-5 . . . . . . . . . . . . . . . . . . . . . . . . 04/29/82 04/29/82 Figure Figure 2.24...................

2.24 . . . . . . . . . . . . . . . . 04/16/02 04/16/02 4-6...........................

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Section 4 Section 4-7..............

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04/29/82 04/29/82 04/29/82 04/29/82 04/29/82 Section 5 Section 5-12 (Continued) 5-12 ...... . . . . . . . . . . . . . . . . . . . . .

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5-13 5-14 ...... . . . . . . . . . . . . . . . . . . . . .

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................ 04/29/82 6-15 . . . . . . . . . . . . . . . . . . . . . . . 04/29/82 Figure 4.2 .......

Figure ................ 04/29/82 6-16 . . . . . . . . . . . . . . . . . . . . . . . 04/29/82 Figure 4.3 .......

Figure ................ 04/29/82 6-17 . . . . . . . . . . . . . . . . . . . . . . . 04/29/82 Figure 4.4 .......

Figure ................ 04/29/82 6-18 . . . . . . . . . . . . . . . . . . . . . . . 04/29/82 Figure 4.5 .......

Figure ................ 04/29/82 6-19 . . . . . . . . . . . . . . . . . . . . . . . 04/29/82 Figure 4.6 .......

Figure ................ 04/29/82 6-20 . . . . . . . . . . . . . . . . . . . . . . .

6-20 04/29/82 Figure 4.7 .......

Figure ................ 04/29/82 6-21 . . . . . . . . . . . . . . . . . . . . . . . 04/29/82 Figure 4.8 .......

Figure ................ 04/29/82 6-22 . . . . . . . . . . . . . . . . . . . . . . . 04/29/82 Figure 4.9 .......

Figure ................ 04/29/82 6-23 . . . . . . . . . . . . . . . . . . . . . . . 04/29/82 Figure 4.10 ......

Figure ............... 04/29/82 6-24 . . . . . . . . . . . . . . . . . . . . . . . 04/29/82 Figure 4.11 ..

Figure .... , . . . . . . . . . . . . . 04/29/82 6-25 . . . . . . . . . . . . . . . . . . . . . . . 04/29/82 04/29/82 Figure 4.12 ......

Figure ............... 04/29/82 6-26 . . . . . . . . . . . . . . . . . . . . . . . 04/29/82 Figure 4.13 ......

Figure ............... 04/29/82 6-27 . . . . . . . . . . . . . . . . . . . . . . . 04/29/82 Section 5 Section Section 7 5-1 . . . . . . . . .' . . . . . . . . . . . . . . . 04/29/82 5-1 . . . . . . . . . . . . . . . . . . . .....

7-1 ............ ... 08/13/02 55 2 . . . . . . . . . . . . . . . . . . . . . . . .0 '04 4// 229/82 9 / 82 . . . . . . . . . . . . . . . . . . . .....

7-2 ............ ... 08/13/02 5-3 . . . . . . . . . . . . . . . . . . . . . . . . 04/29/82 5-3 7-3 7-3 . . . . . . . . . . . . . . . . . . . . .....

........... ... 08/13/02 08/13/02 5-4 . . . . . . . . . . . . . . . . . . . . . . . . 04/29/82 5-4 5-5. . . . . . . . . . . . . . . . . . . . . . . . . 04/29/82 5-5 Appendix A 5-6. . . . . . . . . . . . . . . . . . . . . . . . . 04/29/82 5-6 5-7 . . . . . . . . . . . . . . . . . . . . . . . . 04/29/82 5-7 A-I A-i . ...........

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• Appendix A A- 6 .

A-6 A-7 A -7 .

Figure

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Figure A..1 Figure Figure A.22 Figure Figure A.3 A (Continued)

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04/29/82 04/29/82 04/29/82 04/29/82 04/29/82 Figure Figure A.4 A.44 . .................

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B-1 . . . . . . . . . . . . . . . . . . . . . . . 04/29/82 B-2 ..... . . . . . . . . . . . . . . . . . . . . . . 04/29/82 B-2 B-3 ..... . . . . . . . . . . . . . . . . . . . . . . 04/29/82 B-3 B-4...

B-4 . . . . . . . . . . . . . . . . . . . . . . . . 04/29/82 B-5

-c.--- . . . . . . . . . . . . . . . . . . . . . . . . 02/26/07 Appendix Appendix C C-I .

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• D-4........

D-4 Figure

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Figure D.1 Figure Figure D.2 References References R-1 .......

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D.1 . . . . . . . . . . . . . . . . .

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04/29/82 04/29/82 04/29/82 04/29/82 R-2 .......

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• Page 4 of 4 02/26/07

LIST OF ABBREVIATIONS ABBREVIATIONS ABSS Absolute Sum Absolute Sum ADS Automatic Automatic Depressurization Depressurization System System AISC American American Insti1tute Institute Steel Construction of Steel ASME American Society of Mechanical American Society Engineers Mechanical Engineers BWR Boiling Water Water Reactor Reactor CDF Cumulative Distribution Cumulative Distribution FunctionFunction CNS Cooper Nuclear Nuclear Station CO Condensation Condensation Oscillation CVA Consecutive Valve Actuation Consecutive Valve DBA Design Basis Accident Accident DLF Dynamic Load Factor Factor DOF Degree of Freedom Freedom ECCS Emergency Emergency Core Coolant System System EPRI Electric Electric Power Research Institute Power Research Institute FSAR Safety Analysis Report Final Safety Report FSI Fluid Structure Structure Interaction FSTF Full Scale Scale Test Facility Facility GE General Electric HPCI High Pressure Pressure Coolant Injection HWL High Water Level Water Level Hz Hertz IBA Intermediate Intermediate Break Accident Accident Kip Kilopound Ksi Kilopound Per SquareSquare Inch Lbf Pound Force Force

-1 04/29/82

LIST OF ABBREVIATIONS ABBREVIATIONS (CONT'D)

LDR Definition Report Load Definition Report LOCA Loss of Coolant Accident Accident LOOSP Loss of Off-Site Off-Site Power Power LTP Long-Term Program Long-Term Program MSIV Valves Main Steam Isolation Valves MSL Main Steam Lines Lines MVA MVA Multiple Valve Actuation Multiple MWe Megawatt Electric Megawatt Electric MWt Megawatt Thermal Megawatt Thermal NEP Non-Exceedence Probability Non-Exceedence NOC Operating Conditions Normal Operating Conditions NPPD Nebraska Public Power Nebraska District Power District

• NPSH NRC OBE PAS Positive Suction Head Net positive Nuclear Regulatory Operating Head Commission Regulatory Commission Operating Basis Earthquake Pump Around System System Earthquake Psi Pounds Per Square Square Inch Psia Pounds Per Square Square Inch (Absolute)

Psid Pounds Per Square Square Inch (Differential)

Psig Pounds Per Square Square Inch (Gauge)

PSTF Pressure Suppression Test Facility Pressure Suppression PUAAG Plant Unique Analysis Analysis Application Applicati.on Guide Guide PULD.

PULD* Plant Unique Load Definitions Definitions QSTF Scale Test Quarter Scale Test Facility RCIC Reactor Reactor Core Core Isolation Isolation Cooling RHR Residual Residual Heat Removal Removal RPV Reactor Pressure Vessel Reactor Pressure Vessel 04/29/82

LIST OF ABBREVIATIONS ABBREVIATIONS (CONT'D)

SBA Small Break Break Accident Accident SER Safety Evaluation Report Report SORV Stuck-Open Relief Valve Stuck-Open Relief Valve SRSS Square Root of the Sum of the Squares Squares S/RV Safety/Relief Valve Safety/Relief Valve S/RVD Safety/Relief Valve Discharge Safety/Relief Discharge S/RVDL Safety/Relief Valve Discharge Safety/Relief Discharge Line SSE Safe Shutdown Earthquake STP Short-Term Short-Term Program Program SVA Single Value Actuation TAP Torus Torus Attached Attached Piping WRC Welding Research Welding Research Council Council

• 04/29/82

• COOPER NUCLEAR NUCLEAR STATION PLANT UNIQUE ANALYSIS PLANT UNIQUE ANALYSIS REPORT REPORT SECTION 1 INTRODUCTION DESIGN CRITERIA INTRODUCTION AND DESIGN

• 1.1 1.1.1 i.1.1 The INTRODUCTION Objective and Scope Objective objective of the Plant The objective compliance with Mark compliance Scope Plant Unique Analysis Mark I Containment Containment Analysis Report (PUAR)

Program requirements Program (PUAR) is is* to document requirements for the Cooper document Cooper Nuclear Nuclear Station (CNS)

(CNS) containment containment system and associated associated piping.

piping. These These requirements involve requirements involve demonstration demonstration that the originally originally intended intended design safety margins margins are restored are restored for hydrodynamic hydrodynamic loads which were not explicitly explicitly included included in In the original original design.

design. This reassessment reassessment was made using conservative conservative load definitions, definitions, analysis methodologies, methodologies, and structural structural acceptance acceptance criteria criteria that are both consistent with applicable applicable codes and standards and appropriate standards appropriate for the life life of the facility.facility.

Submittal of this report report is Nebraska Public is Nebraska Public Power Power District's District's response (NPPD) response to to the Nuclear Nuclear Regulatory Regulatory Commission's Commission's (NRC) (NRC) letters letters transmitted in transmitted in February February and and April 1975 (References 11 and 2)

(References 2) relating to hydrodynamic hydrodynamic loadings associated associated with Safety/Relief Safety/Relief Valve Valve (S/RV)

(S/RV) discharges and the Loss of Coolant Coolant Accident Accident (LOCA) (LOCA) events. events. The The report report also also satisfies satisfies NPPD's commitment to the NPPD' s commitment Commission Commission as a member of the Mark I Owners Owners Group. Group. Review and approval approval of of this report this report will eliminatewill eliminate the "Unresolved Safety Issue" designation (pursuant to (pursuant to Section Section 210 210 of Energy Reorganization of the Energy Reorganization Act of 1974) 1974) assigned to this program as it it pertains to CNS. CNS.

The report consists of eight major sections:

The report sections:

Section Section 1 includes includes the design criteria, criteria, the containment description the containment (including (including recent modifications),

recent modifications), and a summarysummary of the requalification requalification results; results; Section Section 2 includes includes thermal-hydraulic thermal-hydraulic parameters, parameters, original design loads, LOCA LOCA and S/RV discharge-related load definitions, discharge-related definitions, and load load combinations combinations for the major containment containment system components; components; Sections Sections 33 through through 66 describe the design load combinations, combinations, allowable allowable

'stresses,

, stresses, analysis analysis methods and results, results, and ASME Boiler Boiler and Pressure Pressure Vessel Vessel Code Code evaluations evaluations for the torus shell and supports, supports, vent system, system, S/RV discharge S/RV discharge piping, piping, torus attached attached piping, piping, and torus internal internal structures; structures; Section 7 discusses Section discusses the suppression suppression pool temperaturetemperature evaluation;evaluation; Section 8 includes Section includes references references and appendices.

appendices.

I The PUAR summarizes more than five years of complex analysis analysis and design design work state-of-the-art using state-of-the-art analytical tools and techniques analytical techniques. .. Thousands of manhours manhours were expended were expended in in response to response to NRC concerns with containment NRC concerns containment integrity.

integrity. The The primary objective primary objective was was to to enhance enhance the the performance performance of the pressure suppression system system and and improve improve design design safety safety margins margins through component modifications modifications or or the addition of new systems. systems.

1.1.22 1.1. Problem Problem Definition

.

• The The original original design of the CNS Mark I containment containment system considered postulated postulated accidentaccident loads previously associated with a LOCA, previously associated LOCA, seismic loads, dead loads, dead loads, jet-impingement j et- impingement loads, loads, hydrostatic loads due to water in hydrostatic in the suppression chamber (torus),

suppression (torus), overload pressure pressure test test loads, loads, and construction 1-1 1-1 04/29/82

• loads.

loads.

additional additional concept However, However, concept utilized since the establishment loading conditions utilized in in conditions the establishment of the original Mark Mark I identified. These additional loads result from dynamic effects and steam being rapidly forced into LOCA LOCA and from suppression associated associated containment containment into the suppression suppression pool response to S/RV operation with the original design criteria, the pressure-suppression system system design have been criteria, pressure-suppression effects of drywell air suppression pool during a postulated operation associated associated with been air plant transient operating conditions. Because these hydrodynamic operating conditions. hydrodynamic loads were were not explicitly explicitly considered considered in in the original design of the containment containment system, NPPD NPPD received received NRC requests requests in in early early 1975 that that these loads be quantified and an assessment be performed performed of the effects effects of these loads loads on the Cooper Cooper Station containment containment components. components.

Recognizing Re.cognizing that these evaluation evaluation efforts would be similar for all all Mark I Boiling Boiling Water Water ReactorReactor (BWR) (BWR) plants, plants, NPPD joined joined an ad hoc hoc Mark I Owners Group with General General ElectricElectric (GE) (GE) as the lead technical technical organization.

organization. The objectivesobjectives of of the the Owners Owners Group Group were were to determine the magnitude magnitude and significance significance of these these dynamic dynamic loads loads and to identify courses of action action needed to resolve outstanding safety concerns.

concerns. The Mark Mark I Owners Group Group divided divided this task into into two two programs:

programs: aa Short-Term Short-Term Program (STP) (STP) for early assessment of critical early assessment critical components and a Long-Term components Long-Term Program Program (LTP) (LTP) for final resolution resolution of the issues. issues.

1.1.33 1.1. Short-Term Program Program The The objectives objectives of the Short-Term Short-Term Program were to verify that the CNS Mark I containmeht system containment system would maintain its its integrity and functional functional capability when when subjected subjected to the most probable loads induced induced by a postulated design-basis design-basis LOCA LOCA and and to to verify that continued continued plant operation operation was not not

'inimical to

'inimical to the the health health and safety safety of the public. public. The The STP justified justified interiminterim plant operation while plant operation while further further tests tests and evaluations evaluations were conducted conducted during during the comprehensive comprehensive LTP. LTP.

The The STP STP evolved evolved into into two two areas areas of investigation:

investigation: (1) an evaluation of loads (1) on structures on structures within within the torus, and (2)

(2) an evaluation evaluation of the integrated integrated loads on on the torus structure the torus structure which which are transmitted transmitted to' toits its supports.

supports. The loads loads on on the structures within the torus were based on impact impact data developed developed from from Mark III Mark III containment containment tests tests conducted at the GE Pressure conducted Suppression Test Pressure Suppression Test Facility Facility (PSTF) (PSTF) coupled coupled with with pool swell velocity pool swell velocity data data derived derived from scaled Mark II test Mark facilities.

test facilities. The loads The loads on on the the torus torus structure structure and its external its external supports were supports were based based on series series of tests performed tests performed in in a 1/12-scale 1/12-scale facility facility representing representing a segment of a typical typical Mark I torus. torus.

The The STP STP task evaluating the integrity task of evaluating integrity of the torus internal structures for internal structures for Mark II BWR Mark BWR facilities facilities is is documented documented in in a five volume volume report which which was was submitted submitted to the NRC in September 1975 in September 1975 (Reference 3) 3).. On December 2, 2, 1975,1975, GE GE submitted submitted Addendum Addendum 1 (Reference (Reference 4) 4) to this report, report, which addressed addressed potential potential pool swell impact impact on S/RV S/RV discharge discharge piping and the vent system bellows bellows assembly assembly within within the the torus. Additional information information was provided provided in response to in response to NRC questions NRC questions on on the the STP STP Final, Report. These responses Final* Report. responses were were compiled in in a letter letter to the NRC dated September September 9, 9, 1976 (Reference (Reference 5) 5) which was submitted by GE on behalf behalf of the Mark I Owners Group. '

Owners Group.

During the STP review, structural structural safety margins were increased increased by by

.

implementation of implementation of procedures procedures to maintain maintain a differential differential pressure pressure of at least least

• one one pound per square inch between between the drywell drywell and the torus during during reactorreactor operation.

operation. These procedures procedures currently remain in in effect.

effect. In In addition, addition, during the the course course of the STP review, review, NPPD performed modifications to the containment performed modifications containment support support system to provide provide additional additional design design safety margins. margins.

1-2 04/29/82

• As a result Mark I BWR response required required result that system and piping attached summary of the actions of differences facilities BWR facilities response of the torus support NPPD differences in perform NPPD' perform in the design of the torus support and due to the sensitivity support system a plant attached to the torus.

sensitivity system to variations variations in unique analysis unique analysis torus. In In April 1976, actions being taken by the Mark I Owners Group to complete of 1976, support systems of the predicted in applied applied loads, the systems at structural predicted structural loads, the NRC GE submitted a support torus support complete the at STP evaluations, evaluations, including including a description description of the program program for the plant plant unique analyses of the torus support support system and external external torus attached piping (Reference 6).

(Reference 6). Subsequently, Subsequently, this report and its its associated associated acceptance acceptance criteria criteria were revised to incorporate incorporate the results of discussions discussions held in in several several meetings between the Mark Mark I Owners Group and the NRC staff. staff. As As revised, reVised, the plant unique analysis Structural Acceptance analysis Structural Acceptance Criteria require require a factor of safety safety against failure of two for each each component component of the torus support support and piping piping systems.

systems.

The STP analysis analysis work and evaluations evaluations were were performed in in mid-1976, mid-1976, using using loadsloads and and methodology methodology defined in in Addendum 22 Addendum (Reference (Reference 7) 7) and Addendum 3 (Reference (Reference 8) 8) to to the the STP Final Report. Report. The STP report was submitted submitted to the NRC in in July 1976 (Reference (Reference 9). 9). The staff staff concluded that a sufficient concluded sufficient margin margin of safety had of safety had beenbeen demonstrated demonstrated to assure assure the functional performance performance of the containment containment system and, and, therefore, therefore, any undue risk to the health health and safety safety of of the public was precluded precluded (Reference (Reference 10). Subsequently, the staff 10). Subsequently, staff granted NPPD exemptions exemptions relating relating to the design design margin requirements requirements of 10 CFR 50.55 50.55(a).(a) .

exemptions These exemptions were granted granted for an ,interim interim period period while while the more more comprehensive comprehensive LTP LTP was was being being conducted conducted and modificationsmodifications to the containment containment and piping piping systems systems were completed.'

completed.

.

• 1.1.4 The Long-Term The life life design Long-Term Program Long-Term Long-Term Program of the LTP were to establish of each design safety margins Program Program activities activities establish design basis each Mark I BWR facility facility margins for each Mark I containment initiated were initiated basis loads in June in 1976. The objectives June 1976.

loads that are appropriate and to restore restore the originally containment system.

objectives appropriate for the originally intended system. These objectives intended objectives were satisfied satisfied through through extensive extensive testing and analytical analytical programs programs that that led to to development of generic methods the development methods for the definition definition of suppres~ion suppression pool hydrodynamic hydrodynamic loading loading events and the associated associated structural structural assessment assessment techniques. The program techniques. program also included included establishment establishment of structural structural acceptance acceptance criteria criteria and evaluations evaluations of both both load mitigation devices and system system modifications to improve margins modifications margins of safety. safety.

The generic The generic aspects aspects of the LTP were completed completed with submittal submittal of Revision 0 of of the Load Definition Definition Report Report (LDR) (LDR) by GE in in December December 1978 (partial) (partial) and inin March 1979. 1979. 'In In July 1979, 1979, the structural acceptance crit'eria structural acceptance crit'eria and plant unique unique analysis applications applications guidelines guidelines were submitted submitted to the NRC NRC for review. review. The The staff staff reviewed reviewed the experimental experimental and analytical analytical programs, programs, assessment assessment procedures, procedures, and acceptance criteria.

acceptance criteria. The NRC documented documented their their findings and modifications modifications to this material material in in the Safety Safety Evaluation Evaluation Report (SER) (SER) for the LTP (Reference (Reference 11). 11) . With very few few exceptions, exceptions, the requirements requirements resulting from from the staffstaff evaluation evaluation were were used to perform the plant plant unique reassessment of unique reassessment of the CNS containment containment and piping piping systems and to design plant modifications modifications which satisfy which satisfy all all LTP criteria.

criteria.

.

1.2 1.2 DESIGN CRITERIA CRITERIA

• This subsection containment subsection reviews containment LTP these criteria criteria reviews the design criteria LTF and used in are also in the CNS structural summarized in also summarized criteria established in this subsection.

1-3 1-3 established for the Mark I structural reevaluation.

reevaluation. Deviations from subsection.

from 04/29/82

. 1.2.1 1.2.1 1.2.1.1 1.2.1.1 Design Specifications Design Specifications Original Specifications Original Specifications The original The original design design of of thethe drywell, drywell, wetwell, wetwell, and and vent system system was performedperformed in in accordance accordance with the ASME Boiler and Pressure Vessel Code, Code, Section III Section III (Reference 12).

(Reference 12) . The original code code of record record included included the latest latest addenda as of of June 1967 June 1967 and included Code Code Cases Cases 1330-1 and 1177-5. 1177-5.

Piping Piping systems systems were were designed designed using using USAS B31.1 (1967)

(1967) and andUSAS USAS B31. B31.7 7 (Feb. 1968)

(Feb. 1968) Power Piping 'Codes Codes (References 13 13 andand *14).

.14) . As-built verification verification of these of these pipingpiping syste~ssystems as as required required by IE IE bulletins bulletins 79-02 and 79-14 79-14 w~s was considered separate considered separate from from any any Mark I program design criteria. criteria. Completion of Completion of the 79-02 the 79-02 and and 79-14 79-14 programs programs on on the the torus attached piping systems preceded preceded the reanalysis the reanalysis and and modification modification of these these systems systems for LTP requirements. requirements.

Original design Original design requirements requirements for for pipe supports and other structural pipe supports structural members members were obtained were obtained from from the AISC Code (Reference (Reference 15) 15).

Design information Design information regarding regarding containment containment and ECCS performance performance was obtained from the CNS Final Safety from the CNS Final Safety Analysis Report (FSAR) Analysis (FSAR) (Reference 16). 16). Technical Technical Specification requirements Specification requirements through Ainendment 77 through Amendment 77 were used in in the containment containment evaluations.

evaluations. Changes Changes to to CNSCNS Technical Specifications either Technical Specifications either resulting resulting from from the Mark the Mark II LTP LTP studies studies or occurring simultaneously simultaneously with the studies were were factored into the design basis. basis.

1.2.1.2 1.2.1.2 Specifications for Modifications Specifications Modifications Modifications Modifications to to containment containment components components and supports, supports. were designed, fabricated, and fabricated, and installed installed in in accordance with the requirements accordance requirements of the ASME

'Boiler and Pressure Vessel Code,Section III (including Summer Summer 1977 1977 Addenda).

Boiler and Pressure Vessel Code"Section III (including Addenda).

Modifications involving Modifications involving new new structural structural componeDts components (including new new pipe supportsupport installations) installations). were were also also designed, designed, fabricated fabricated and installed installed to these these requirements.

requirements.

Modifications to Modifications existing structural to existing structural components components were were designed, designed, fabricated fabricated and installed installed to to the the requirements requirements of of the original original code code of record. record. This code of of record was record was typically typically the latest latest edition edition of the AISC Code Code..

.'

1.2.2 1.2.2 LTP LTP Design Design Requirements Requirements Design criteria Design criteria for for the the MarkMark II Long-Term Program include Long-Term Program include both the definition definition of of the the newly-identified newly-identified hydrodynamic hydrodynamic loads loads and the code code evaluation evaluation requirements requirements for containment components.

for containment components. These criteria These criteria are summarized in are summarized in this this subsection.

subsection. Any Any alternative alternative approachesapproaches or interpretations or interpretations of of these these criteria cri teria used used in in thethe CNSCNS reevaluations reevaluations are are summarized summarized in in this subsection.

subse"ction.

1.2.2.1 1.2.2.1 New Design Requirements Design Requirements The The load load definition definition procedures procedures for for suppression suppression pool pool hydrodynamic hydrodynamic loads loads used in the CNS containment In the CNS containment reevaluations were reevaluations were taken from from the Load Load Definition Report Report (LDR), (LDR) , Revision Revision 2, 2, November November 1981 1981 (Reference (Reference 17) 17).. In..In .. cases cases where the NRC NRC concluded concluded that that the the LDR LDR procedures procedures were were unacceptable, unacceptable, the requirements requirements of of

. . the the NRC criteria NRC Acceptance Acceptance Criteria is provided provided as Criteria .(Reference as an

.(Reference 18) an appendix

18) were appendix to the were followed.

followed. This acceptance Safety Evaluation acceptance Evaluation Report

• criteria is the Safety Report (NUREG-0661)

(NUREG-0661) which which provides provides the the bases bases for for thesethese requirements.

requirements. The NRC NRC Acceptance Acceptance Criteria Criteria used used in in thetheCNSCNS containment containment reevaluations reevaluations was was Revision Revision 1, 1, dated dated February February 1980. 1980. These revisions revisions of of the SER and and Acceptance Acceptance Criteria Criteria did did 1-4 1-4 04/29/82

not address the final downcomer lateral lateral load definition definition for condensationcondensation osci llation oscillation (CO)

(CO) nor did they address the final Full Scale Test Test Facility (FSTF)

Facility (FSTF) tests tests for CO. CO. The The CNS reevaluations reevaluations used design design loadsloads developed by the Mark I program developed program in in response to NRC concerns concerns as referenced referenced in in this this' report.

report. This approach anticipates anticipates NRC acceptance acceptance of these load definitions in definitions in the final revision revision of the SER to be issued by the NRC at a later date.

later date.

These criteria These criteria address only those events events or event combinations combinations which involve suppression suppression pool hydrodynamic hydrodynamic loads. loads. OtherOther loads loads inin the event combinations combinations were reviewed were reviewed and approved by the NRC in in the FSAR FSAR for CNS. CNS. However, However, these these loads are discus'sed discussed in in the SER because because improved improved analysis analysis techniques techniques have evolved since since the time the FSAR was reviewed. reviewed. Unless otherwise otherwise specified, specified, any any loading condition condition or structural analysis technique not addressed analysis technique addressed in the SER in the are defined in in accordance accordance with the approved approved FSAR for CNS. CNS.

The structural structural and mechanical mechanical acceptanceacceptance criteriacriteria and the general analysis general analysis techniques techniques were were obtained obtained from the Mark I LTP Structural Structural Acceptance Criteria Acceptance Criteria Plant Plant Unique Analysis Application Application Guide (PUAAG) (PUAAG) (Reference 19). 19). The The PUAAG was was also reviewed reviewed by the NRC and accepted accepted for use without modification modification in in plant plant unique analyses.

analyses. The ASME Boiler and Pressure The Pressure Vessel Vessel Code,Code, Division I, 1, Section Section III, III, including including Summer 1977 Addenda is is generally used in in demonstrating the margins margins of safety safety required for steel structures structures and piping. piping. This criteria criteria is referred is referred to as "the Code" throughout this report. report.

1.2.2.2 1.2.2.2 Exceptions to Design Requirements Requirements In In several cases, cases, direct application application of the LTP design requirements resulted requirements in unusual in unusual hardship hardship without a compensating dompensating increase increase in in plant safety margins.

safety margins.

Alternate analytical Alternate analytical approachesapproaches or interpretations interpretations were used in in these cases.

cases.

These approaches have already already been been identified to the NRC in NRC in Reference Reference 20. 20.

These approaches approaches are summarized summarized again below. below.

(1)

(1) In In the analyses of structures structures for CO loads, loads, the 50 individualindividual load load harmonics were were combined using a realistic realistic phasing technique. technique.

I This phasing procedure procedure has already been been justified justified through through both analytical and empirical analytical empirical studies, studies, and in in combination with other other conservatisms conservatisms in in the CO analysis procedure, procedure, still still produces a produces conservative design basis for evaluating conservative evaluating containment containment components.

components.

(Subsection 3.2.3.2.4)

(2)

(2) In In the the calculation calculation of torus torus shell pressure loads due to multiple actuations, a modified SRSS technique using a 1.2 multiplier S/RV actuations, multiplier has been has been used.used. instead instead of the absolute sum combination method. method.

Plant unique statistical unique statistical studies show that that the modified SRSS SRSS method method bounds bounds peakpeak pressures pressures with an appropriate appropriate confidence confidence level level (Appendix A) A)..

(3)

(3) For piping analyses, analyses, dynamic responses responses due to S/RV discharge discharge and and LOCA LOCA loads were combined were combined by a modified'SRSS modified SRSS method with a multiplier multiplier of 1.1 on the SRSS of the response of the two loads. loads.

This This approach is is an extension of the CDF procedure procedure allowedallowed by the Structural Structural Acceptance Acceptance Criteria and is is supported by further supported further statistical statistical studies studies (Appendix D) D). .

• (4)

(4 ) ASME ASME Code evaluation evaluation allowables allowables for shell buckling of the torus shell. shell.

1-5 1-5 buckling were not used in Generic analyses Generic performed in analyses performed in the in the 04/29/82

Mark I program have demonstrated demonstrated that torus buckling buckling will not not occur occur as a result result of LOCA and S/RV S/RV discharge discharge dynamic loads. loads. SinceSince the CNS torus shell shell geometry geometry has a lower diameter/thickness diameter/thickness ratio ratio than the torus shell considered considered in in the generic generic study, the results results of this study can be conservatively conservatively applied to the CNS CNS configuration.

configuration. This approach approach is is in in accordance accordance with the intention of the ASME code (Subsection 3.2.2.2). 3.2.2.2).

(5)

(5) The LDR procedure procedure for defining torus shell pressure defining pressure loads loads following an S/RV S/RV actuation actuation assumes assumes that pure air air mass is is inin the S/RVDL S/RVDL prior prior to the valve opening. opening. For S/RV discharge load load cases cases involving ADS actuation actuation during an IBA/SBA event, event, torus shellshell pressure loads were defined using an initial initial 30% relative 30% relative humidity in in the S/RVDL (Subsection 2.5.4). 2.5.4).

(6)

(6) An alternate alternate SRV shell pressure pressure load load definition on the torus shell shell was used in in the re-analysis re-a'nalysis of he lower lower half of the torus shell shell as described described in in Section 3.2.5. 3.2.5. This alternate alternate load definition definition is is in in accordance accordance with with Appendix Appendix A, A, section section 2.13.9 of of NUREG-0661.

NUREG-0661. The program QBUBS03 was used to generate generate the torus shell SRV time histories. histories. An in-plant in-plant test test was not performed performed as as required required per Appendix Appendix a, a, Section 2.13.9 of NUREG-0661. NUREG-0661. Rather, confirmation confirmation of this method method was based on comparison comparison to in-plant in-plant tests tests performed performed at other other Mark I plants. plants. It It was concluded concluded from from the review of these tests tests that all all of the criticalcritical parameters parameters were bounded, were bounded, and and thatthat these tests tests as a group, group, provide similar similar confirmation confirmation that the loadings calculated calculated for Cooper are conservative.

conservative. Thus the use of the QBUBS03 software software has been approved approved by the NRC for the intended application application at other other facilities.

facilities.

The appropriate The appropriate subsections subsections of this this reportreport where further description and further description justification justification for each approach approach can be found are are shown above in parentheses in parentheses following each e,ach approach.

approach.

1.3 1.3 CONTAINMENT AND MODIFICATION CONTAINMENT MODIFICATION DESCRIPTION 1.3.1 1.3.1 General General Cooper Nuclear Station Station is is a BWR 4 4 Mark I operating power plant owned owned by NPPD.NPPD.

It It waswas built built in in the the early 1970's, has a net generating early 1970's, generating capacity capacity of 778 MWe. MWe.

CNS has been been in in operation since July 1974. 1974. The primary primary containment containment components components are the are drywell, the drywell, wetwell, wetwell, and an interconnecting interconnecting vent system which are typical of a GE Mark typical of a GE Mark I BWR containment containment design. design. A A composite composite of the containment containment system is is shown in in Figure Figure 1.1.

1.3.1.1 1.3.1.1 Drywell The The drywell drywell is is aa steel steel pressure pressure vessel supported in supported in concrete, concrete, with a spherical lower spherical lower section section and a cylindrical cylindrical upper portion.

portion. The shell is is fabricated fabricated of of SA-516 SA-516 Grade 70 70 steel steel and has a nominal nominal shell thicknessthickness of 3/4 3/4 to 1-1/2 inches.

to 1-1/2 inches. The drywell drywell houses the biological biological shield wall, wall, reactor, reactor, reactor pedestal, reactor pedestal, reactor reactor coolant recirculation recirculation system system and other other piping,

valves, valves, and and equipment essential essential to system system functions.

functions.

1-6 1-6 04/16/02

• , 1.2 1.3.1.2 1.3 The wetwell containing Wetwell Wetwell wetwell is a

containing a large is a toroidal large LOCAs and S/RV discharges.

cylindrical toroidal cylindrical shell located pool discharges.

of cylindrical segments and has a centerline The torus is constructed of SA-516 is constructed water for The torus is pressure centerline elevation located below suppression below the drywell pressure suppression during postulated is fabricated fabricated from sixteen drywell sixteen mitered elevation of 876 feet 7-1/2 inches.

SA-516 Grade 70 steel and has a shell thickness inches.

thickness of 0.616 0.616 and 0.688 inches inches at the top and bottom half, respectively. The shell half, respectively. shell is stiffened by sixteen internal is stiffened internal ring girders girders located at each miter joint of joint of the torus.

torus. The torus is supported by saddle is supported saddle assemblies assemblies which transmit transmit operational, operational, accident, accident, and seismic loads to the reinforced reinforced concrete concrete foundation slab foundation slab ofof the reactor building. The~e reactor building. These supports supports consist of a pair of of columns connected connected by saddles saddles at each miter joint. joint. In In addition addition to its its pressure suppression functions, the torus houses suppression functions, houses S/RV discharge devices, vent system discharge devices, system components, components , protective protective structural structural members, members, Emergency Em"ergency Core Coolant Coolant (ECCS) suction System (ECCS) suction nozzles, nozzles, turbine exhaust exhaust piping, coolant coolant recirculation piping, monitoring piping, accessories, and other monitoring accessories, non-essential structures.

other non-essential structures. The basic geometry geometry and components components internal to the torus are shown shown in in Figure 1.2.

1.2.

1.3.1.3 Vent System System In the event In event of a LOCA,LOCA, the vent system provides provides a flow path to the wetwell wetwell suppression suppression pool for condensation condensation of steam steam released released in in the drywell.

drywell. At the end of a LOCA transient, transient, when when ECCS water spills out of the break and rapidly reduces reduces thethe drywell pressure, pressure, vacuum breakers breakers installed installed on the vent system system equalize the pressure equalize the pressure between between the two vessels, vessels, thereby protecting protecting the drywell drywell and vent and system from vent system from negative pressures pressures in in excess excess of designdesign values.

values. TheThe

• eight eight S/RV discharge discharge lines (S/RVDLs)" (S/RVDLs)- are also routed through through the main vent vent and terminate and terminate in in aa quencher quencher discharge discharge devicedevice located located in in the suppression suppression pool.pool.

The vent The system provides vent system provides aa contained contained path for the maintenance maintenance of a pressurepressure differential between the drywell differential drywell and the wetwell. wetwell.

The vent system The system consists of eight main vents connecting connecting the drywell air space space to the wetwell.

wetwell. These vent lines extend approximate centerline extend to the approximate centerline of the torus, where they torus, where connected to a common vent header they are connected header located above the suppression suppression pool.pool. The vent header is is supported supported by a pair of hangers at each each ring girder girder location.

location. The vent system includes includes forty pairs of partially submerged submerged downcomers connected to the vent header.

downcomers connected header. The vent system also has has twelve twelve vacuum breaker valves, vacuum breaker valves, two each at six of the main vent vent intersections intersections on the vent header.

header. The vent header header is is protected protected from LOCA-related LOCA-related pool swell pool swell impact loads by a deflector deflector devicedevice suspended suspended below the header. header.

1.3.2 1.3.2 Structural Components Structural Components 1.3.2.1 1.3.2.1 Torus Shell and SupportsSupports The The torus torus has an inside radius of 14 feet" feet* 4-1/2 4-1/2 inches and a toroidal toroidal centerline radius of 50 feet 10-1/2 inches centerline inches from the centerline centerline of the reactor. The original reactor. construction of the torus support system consisted original construction consisted of of

\

two columns at each miter :Joint. joint. Each column was fabricated fabricated from a W14x136 Wl4x136 rolled shape rolled shape of A-36 material, material, exceptexcept for a short upper portion interfacing with the with the torus shell.

shell. This upper section was fabricated fabricated plate, equivalent to plate, equivalent to aa W14x136 Wl4xl36 of SA-516 SA-516 Grade 70 material. material. The upper end of the columns was was welded to welded to the torus shell. shell. The column column base plates bear on lubri lubritete plate assemblies assemblies which allow for thermal expansion expansion of the torus. torus. The base of the column was stabilized stabilized by means of diagonal diagonal bracing bracing of double angles angles connected to the shell.

shell. As a result of torus requalification requalification for new loading JJ 1-7 1-7 04/16/02

conditions, conditions, three major modifications modifications were were made to the original torus support support modifications are:

system. These modifications (1)

(1) Reinforcement of Reinforcement of the column support configuration configuration to to improve safety margins for LOCA and S/RV discharge loads. loads.

(2)

(2) Addition of saddles saddles connecting the two columns at* sixteen ring at *sixteen ring girder locations to enhance enhance the response response characteristics characteristics of the torus structure structure during dynamic events. events.

(3)

(3) Stiffening of the ring girder Stiffening girder web to achieve a load transfer transfer mechanism for LOCA and S/RV mechanism S/RV discharge drag loads. loads.

1.3.2.1.1 1.3.2.1.1 Support Column Modifications Torus Support Modifications The torus The torus support support columns columns were were modified modified to to increase increase their their original capacity capacity for for new new design design loads.

loads. Basically, Basically, the modifications modifications consistedconsisted of the following:

(1)

(1) Reinforcement Reinforcement of of the the basic basic column column section to increase increase its its structural structural strength.

(2)

(2) Addition of Addition of base base anchorage anchorage assemblies assemblies to provide provide resistance resistance uplift against uplift forces.

forces.

(3) )

(3 Reinforcement to Reinforcement to the the weldment weldment connecting connectLng the column to the torus shell .

shell.

• The strength of the outside columns two I-inch two such two the 1-inch xx 16-inch such that that aa box two 3/4-inch 16-inch A-36 box section 3/4-inch xx 16-inch the reinforcing 16-inch A-36 reinforcing plates was transfer transfer of of the A-36 reinforcing section was A-36 plates the column tensile load.

columns was increased reinforcing plates formed. The was formed.

plates in in all.

increased by means of welding plates between the opposite flanges, The inside columns were an identical connected to the base plate was connected manner. The identical manner.

flanges, reinforced with were reinforced The bottom edge of plate for all.

load. As a result of this reinforcement, an effective reinforcement, the of cross-sectional cross-sectional area area of of the the columns columns was was increased increased by by 80% 80% and 60% 60% for the outside and outside and inside inside column, column, respectively.

respectively.

The The base base anchorage assembly at anchorage assembly at each column location each column location consisted consisted of four 2-inch diameter A-615 Grade 75 anchor bolts grouted diameter A-615 Grade 75 anchor bolts grouted in core-drilled holes in in core-drilled in the reinforced reinforced concreteconcrete foundation mat. mat. A A box beam beam assembly or a bracket bracket arrangement arrangement of of various configurations was various configurations was installed installed on on top of the base plate and and around around the the column, column, to to transfer transfer the the column column tension tension reaction reaction to the the anchor anchor bolts. The bolts. The anchor bolt nuts anchor bolt nuts were were torqued torqued "snug-tight" and backed backed off 1/2 turn to to allow allow the the columns columns to to translate translate in in a radial direction as aa result radial direction result of of torus thermal thermal expansion.

expansion. The variations variations in in the configuration of the box beam the configuration beam assemblies and assemblies and thethe anchor anchor bolt locations locations at each each column column base base were were due due toto limitations limitations on on the the cutting cutting of of reinforcing reinforcing steel in in the the foundation foundation slab during the core core drilling process.

drilling process.

The The weldment weldment connecting connecting the support columns the support columns to to the the torus torus shell shell was reinforced reinforced by by means means of additional of additional full full penetration penetration weld over an arc length length of of 23 1/2 inches. The outside column web interfacing 23 1/2 inches. The outside column web interfacing with the torus shell was with the torus shell was reinforced reinforced with with twotwo 3/4-inch 3/4-inch SA-516 SA-516 GradeGrade 70 70 plates plates to provide provide the additional additional weldment.

weldment. The The web reinforcement reinforcement for the inside inside columncolumn consists consists of of

• two 1/2-inch SA-516 two 1/2-inch SA-516 Grade Grade 70 plates. plates. Details Details of a typical typical reinforced reinforced torus support support column column are shown shown in in Figure Figure 1.3. 1.3.

1-8 1-8 04/16/02 /

1.3.2.1.2 1.3.2.1.2 Torus Saddles Saddles As part of the torus support modifications, modifications, saddle supports supports were were installed installed at at each of the sixteen each sixteen ring girder girder locations.

locations. The primary reason for installing installing the saddles was the inadequacy inadequacy of the original original support configuration'configuration to to inhibit inhibit the tendency of the torus torus, shell to ovalize ovalize at frequencies frequencies close to to the predominant predominant frequen'cies frequencies of the new hydrodynamic hydrodynamic loads. loads. The addition addition of of the saddles saddles altersalters stiffness characteristics the stiffness characteristics of the torus, torus, thereby inhibiting this ovaling mode of response. response. This reduced ovalization resvlts reduced ovalization results in in a significant significant reduction reduction in in shell shell stresses.

stresses. Additionally, Additionally, the torus saddle saddle shares the overall overall compression compression reaction loads with the torus columns, columns, relieving the highly relieving highly stressed region at the column column connection connection to the shell. shell.

Figure Figure 1.4 1,4 shows a typical saddle saddle configuration configuration consisting consisting of a contoured saddle saadle web plate, a 20-inch-wide 20-inch-wide flange plate, and stiffener stiffener plates at plates at various , locations.

various locations. The saddle saddle is is fabricated from 1 1/2-inch 1/2-inch thick SA-299 plate,plate, has two intermediate intermediate bearings bearings located on the foundation slab, slab, and connects and connects to the torus support support column at the edges. edges. TheThe web of the saddles saddles is aligned with the web is web of the internal internal ring girder girder and is connected to the is connected torus shell by a partial partial penetration penetration weld with fillet fillet reinforcement.

reinforcement. Prior to to welding, welding, a weld overlay overlay was applied to the torus shell shell to protect the shell shell plate material.

material. Connection Connection of the saddle web to the the torus column column flange is is by by means of two 3/4-inch 3/4-inch fillet fillet welds. The intermediate welds. intermediate bearings co,nsist consist of a 1/2-inch self-lubricating 1/2-inch self-lubricating bearing plate bearing installed between a base p1at,e, plate installed plate, and a sole plate.

plate. The base plate is is a 1-1/2 1-1/2 x 29 x 36-inch 36-inch plate anchored to the plate anchored foundation slab slab for seismic resistance. The seismic resistance. Th)e sole plateplate is is 3-1/2 x 22 x a 3-1/2.

42-inch plate with with a machined machined surfa~esurface that that bears bears on the lubricated lubricated plate.

. Each Each bearing bearing location stabilization.

web stabilization.

location has three stiffener stiffener plates for load distributiondistribution and and 1.3.2.1.3 1.3.2.1.3 Ring Girder Modifications Modifications The ring girders 'were were strengthened strengthened to resist resist additional reaction additional reaction loads loads from from miscellaneous pipe miscellaneous pipe supports supports inside the torus.

torus. Web stiffeners stiffeners were added added between the top flarige between flange of the ring ring girder girder and an,dthe torus shell.

-the torus shell. Also, Also, the existing weld connecting the ring girder gird~r web to the torus shell was locally reinforced reinforced with additional additional fillet fillet welds at the platform platform support support column locations. Web stiffeners locations. stiffeners were added added at eight eight locations locations on each each ring girder, girder to resist resist various drag loads and to transfer transfer the ring girder reactions to the saddles.

saddles.

1.3.2.2 Vent System System and Supports Supports The maj'or components of the vent system are majbr components are the main vent, vent, bellows assembly, assembly, vent headerheader and downcomers,downcomers, deflector, deflector, vent supports, supports, and drywell/wetwell drywell/wetwell vacuum breakers.

breakers. A A description description of these components components and Mark I program program modifications modifications are provided provided below. below.

1.3.2.2.1 1.3.2.2.1 Main,Vent Main.Vent There are eight main vents equally There equally spaced around the base of the drywelL drywell.

Figure Figure 1.5 1.5 shows an elevation elevation of a typical main vent (one of four with S/RV S/RV discharge discharge line penetrations).

penetrations). The 5-foot 11-inch 11-inch inside-diameter inside-diameter main vent vent is is constructed constructed of SA-516 SA-5.16 Grade 70 steel with a nominal nominal thickness of 1/2-inch 1/2-inch

• inside the torus >and 3/8-inch external and 3/8-inch' external -to -to the torus (the four main vents vents

• without the S/RV discharge discharge line penetrations. penetrations, have a nominal thickness thickness of of 1/4 inch inside the torus). torus). The bottom section of the main vent in in the region of the two S/RV discharge t~o S/RV discharge piping piping penetrations penetrations is is 1-inch thick.

1-9 1-9 04116/02 04/16/02

1.3.2.2.2 Bellows Assembly p 1.3.2.2.2 Bellows Assembly An expansion expansion bellows bellows is is installed installed on each main vent at the torus penetration to isolate isolate the two components components thereby thereby preventing preventing interaction interaction during differential differential thermal thermal movements and dynamic excitation. excitation. The bellows bellows are approximately 39 inches long and 80 inches in approximately in diameter, diameter, and consist of of two stainless steel steel sections, sections, each having four convolutions convolutions (I ply, (1

1-1/2-inch l-l/2-inch pitch, pitch, 2-inch height) protected protected by a 1I8-inch1/8-inch thick carboncarbon steel steel cover cover plate.

plate. The bellows assembly assembly has the following design characteristics:

characteristics:

• Ply thickness. 0.078 inch

• Axial Axial extension extension 0.375 inch

• Axial Axial compression compression 0.875 inch

• Lateral displacement displacement +/-+/- 0.625 inch

• • Axial spring rate 8,770 pounds/inch

• • Lateral spring rate 75,700 pounds/inch 1.3.2.2.3 1.3.2.2.3 Vent Header Header and and Downcomers Downcomers A plan A plan view view ofof a typical vent a typical vent header header segment is is shown in in Figure 1.6. .The Figure 1.6. The figure shows the details of the transition transition from the 4-foot 2-inch 2-inch diameter diameter vent header to the 5-foot 5-foot 11-inch diameter main vent intersection, intersection, including the T junction and associatedassociated Y stiffeners.

stiffeners. The vent header circumscribes the header circumscribes torus centerline elevation torus at a centerline elevation of 880 feet 11 inches (5 (5 feet 99 inches aboveabove the pool high-water high-water level) as shown in in Figure Figure 1.2.

1.2.

Forty Forty downcomer pairs are located located on the vent header as shown in in Figure 1.6.

Figure 1.6.

A typical typical elevation elevation of a downcomer downcomer pair is is shown in in 1.7.

Figure 1.7. Each Each downcomer downcomer has been modified modified with reinforcing reinfording pads and stiffener stiffener plates (5/8-inch SA-516 Grade 70 plate) to reduce stresses at the intersection. intersection. The The original downcomer tie angle original downcomer connection rings have been angle and connection been replaced replaced with the new tiebar configuration shown tiebar configuration shown in in the figure.

figure. In In addition, the originaloriginal downcomer downcomer maximum submergence submergence of 4 feet 4-1/2 inches has been reduced to to 3 feet 4 inches inches by truncating downcomer legs.

truncating the downcomer legs.

1.3.2.2.4 1.3.2.2.4 Vent Header Header Deflector Deflector A vent header header deflector deflector device was installed installed to protect the 1/4-inch-thick 1/4-inch-thick vent header header from pool swell impact loads resulting resulting from a design basis LOCA.. LOCA ..

The underside underside of the deflector deflector pipe is is approximately approximately 4 inches above the suppression suppression pool '(at (at maximum water level) . Details of the deflector and the water level).

support support arrangement arrangement are shown in in Figure 1.8. 1.8. The deflector supports are welded welded to the clevis assembly assembly at the 'top top of the original pipe support support columns.

columns.

1.3.2.2.5 1.3.2.2.5 Vent Vent System Supports System Supports The original original vent header header supports consisted of two 6-inch diameter schedule diameter schedule 80 pipes connecting

.80 connecting the vent collar collar to the web extension plate plate at each ring ring girder location.

location. The top and bottom of the support columns were connected support columns connected by by means means of! ofý a clevis clevis and pin arrangement arrangement which allowed column column rotation to to accommodate thermal expansion acconunodate expansion of the vent system. system. In In their original original location,

• these these columns Reinforcement Reinforcement the larger columns were subjected for these larger submerged surface subjected to high submerged loads would increase surface area.

area. Therefore, structure drag submerged structure increase the severity severity of .the Therefore, the vent header 1-10 1-10 loads.

loads .

the loads due to header support support system to system 04/16/02

modified by removing was modified removing the columns and suspending the vent header header from each each ring girder.

girder. Figure 1.9 shows the modified support system geometry. geometry. The The modification consists of two 6-inch diameter schedule modification schedule XXS pipes suspended suspended by by means means of a 2-3/4-inch 2-3/4-inch diameter diameter pin connectionconnection at the top and and bottom.

bottom. The The original upper clevis clevis connection connection to the vent vent header collar collar was retained as as part of the support part support for the deflector deflector pipe.pipe.

1.3.2.2.6 1.3.2.2.6 Vent System Vacuum Breakers Vent Breakers Tl~e The vent system is is equipped equipped with twelve 18-inch 18-inch GPE vacuum breakers. breakers. These These check check valvesvalves (normally closed) are located located in in pairs pairs at six of the eight eight main main vent/vent vent/vent header header intersections.

intersections. The vacuum breakers breakers maintainmaintain the wetwell wetwell pressure at a value less less than than or equal to the drywell drywell pressure pressure by permitting air air flow from the wetwell to the drywell when the wetwell is is pressurized pressurized and the drywell is is slowly depressurized.

depressurized. This vacuum relief relief function .prevents prevents pool water from entering the vent system and limits the negative pressure differential on the drywell differential drywell and vent system. system.

Since the vacuum vacuum breaker valves valves are are cantilevered cantilevered from the vent vent system and located near the centerof center,of a vent vent bay, bay, they are subjectedsubjected to high high pool swell swell impact and impact and froth froth impingement impingement loads during during a DBA.

DBA. The valves were modified by by installing installing vertical stiffener vertical stiffener and vent pad platesplates as shown in in Figure Figure 1.10.

The stiffeners stiffeners were fabricated fabricated from S/8-inch 5/8-inch thick SA-516 SA-S16 Grade 70 steel steel plate. The valve modifications plate. modifications were necessary necessary to satisfy satisfy the Code pressure pressure boundary requirements requirements at the vent penetrations. penetrations.

1.3.2.3 Miscellaneous Miscellaneous Torus Internals Internals

• t.

• This subsection addresses addresses only torus internal structural structural components; components; other other nonstructural internals piping and nonstructural internals are are described described in in Subsection Subsection 1.3.3.1.3.3.

1.3.2.3.1 1.3.2.3.1 Service Platform Platform The service service platform is is a 3-foot wide catwalk installed wide catwalk installed above the pool pool surface surface inside the torus. torus. It It hashas an extended work area area at six locations locations in in vicinity the vicinity of the the main vent/vent header intersection intersection for access to the drywell/wetwell drywell/wetwell vacuum breakers. The platform vacuum breakers. platform is is fabricated fabricated from structural structural channels channels and angles, angles, and supported supported from below by angle posts connected connected to the ring girders or torus shell. shell. An An analysis to evaluate evaluate safety margins of the various platform platform components components for LOCA pool swell impact impact and drag loads loads indicated indicated unacceptable unacceptable levels of deformation deformation for these these components.

components.

Accordingly, modifications Accordingly, modifications were made to restore structural structural safety margins margins to to an acceptable acceptable level. level. In In summary, summary, the modifications modifications consisted consisted of replacement replacement of the angle posts and channel channel support framing at the ring girders, girders, installation installation of stronger stronger and additional supports, additional supports, platform platform horizontal horizontal bracing, bracing, and provisions provisions for additional anchorage anchorage of the grating grating to the channel framing members.

channel members.

The existing existing angle posts were were replaced by a 4-inch-diameter 4-inch-diameter schedule XXS pipe welded welded to a pipe sleeve connected connected to the ring girder girder flange. The existing existing channel channel cross-beam cross-beam was replaced by a 4xlOx1/2-inch 4xlOxl/2-inch tubular section at each each ring girder.

girder. The stringer stringer channelschannels were braced with wi th 2x2xl/4-inch 2x2x1 /4- inch tubular tubular

.

sections for lateral sections lateral stability.

stability. Also, these channels Also, channels were supported by by additional diagonal additional diagonal supportssupports of 3- 3- or 4-inch diameter schedule schedule XXS*XXS pipe at

• at the tbe approximate third points to reduce reduce the span length length and to transfer the upward pool swell impact impact reaction to the ring girder. girder. The existingexisting grating was further secured secured by installing installing a 2-1/2 xx 22 x 6-inch-long 6-inch-long angle piece piece 1-11 1-11 04/16/02

welded to the grating and the existing toe plate.

welded plate. This tie-down tie-down installation installation

• was repeated at 12-inch 12-inch intervals intervals around the perimeter perimeter of the platform. platform.

Figures 1.11, 1.11, 1.12, 1.12, and 1.13 show the typical typical modified modified platform platform arrangement arrangement various components.

and its various components.

l.3.2.3.2 1.3.2.3.2 Monorail Monorail The 3603606 monorail Q

monorail beam is is located approximately approximately 11 feet above and 5 feet feet outward outward from the centerline centerline of the torus. torus. The original construction construction consistsconsists of an S12x31.8 S12x3l.8 rolled shape supported supported by two welded connections connections to the shell shell in in every torus bay. bay. During a postulated postulated LOCA, LOCA, some of the rising water, water, after after impacting impacting the vent header deflector, deflector, gets detached detached from the bulk pool surface and forms into froth.

and froth. When evaluated evaluated for the froth impingementimpingement load, load, the monorail monorail was found to be structurally structurally overstressed.

overstressed. Modifications Modifications were made made to reduce the unsupported unsupported span length of the beam. beam. The modification modification consistsconsists of an additional additional support at the midpoint of the monorail monorail beam in each bay.

in each bay.

The support support was fabricated from a 4-inch diameter pipe 4-inch diameter (SA-106, Grade pipe (SA-106, Grade B) B) with a 6-inch 6-inch diameter sleeve, sleeve, and was connectedconnected to the torus shell with a 1-1/2 x 18-inch 1-1/2 18-inch diameter reinforcing pad plate (SA-299).

diameter reinforcing (SA-299).

1.3.3 piping Systems Piping 1.3.3.1 Safety/Relief Valve Discharge Safety/Relief Discharge Piping discharge piping The S/RV discharge piping consists of eight eight 10-inch lines routed routed from the S/RN/s S/RVs in in the drywell, through penetrations tl1e drywell, penetrations in main vents in the main to the wetwell, wetwell, where they are are terminated terminated at the steam quencher devices in in the the suppression

• pool. The original, pool.

the exception penetration, original line configuration exception S/RVDL configurations of a penetration, and included schedule short schedule included a ramshead steam.

configurations are often designated by the' which the line is consisted of schedule configuration consisted is routed. The S/RVs are designated terminology should not be confused terminology schedule 80 segment through steam discharge discharge device.

device.

the* number the piping, with 40 piping, main vent number of the S/RV from designated as -71A confused with the designation

-71A through -71H.

designation of the wetwell

-71H.

wetwell piping vent from This This configurations as discussed configurations discussed below.

below.

Extensive modifications were Extensive modifications were made to the S/RVD lines in in order to accommodate accommodate the newly defined defined S/RV S/RV discharge and LOCA-related LOCA-related hydrodynamic hydrodynamic loadings.

loadings.

These modifications modifications were: were:

(1)

(1) Drywell routing (a)

(a) Addition of two 10-inch10-inch vacuum vacuum relief relief valves on each S/RVDL in order in order to to reduce reduce the the amount of water reflood reflood in in the lines S/RV closure.

following S/RVclosure.

(b)

(b) Addition of pipe supports, supports, as well relocation well as relocation and reinforcement existing supports, reinforcement of existing supports, in in order order to accommodate accommodate S/RVD thrust loads.

S/RVD thrust loads or loads transmitted or loads transmitted to the S/RVDLs to the S/RVDLs i.by by motion of the main vent. Table 1.1 provides motion of the main vent. Table 1.1 provides a line-by-line a line-by-line summary summary of the pipe supportsupport modifications modifications in in the drywell.

drywell.

(c)

(c) Portions Portions of the drywell drywell framing were reinforced reinforced for for reactions reactions from S/RVD piping supports. supports. A A W12x27 W12x27 laterallateral

• (

member spanning azimuths Four spanning between between the upper level azimuths 212 and 240 degrees required Four end brackets supporting level radial beams required minor supporting lower level radial 1-12 beams at minor axis bracing.bracing.

radial beams at 04/16/02 at at

the reactor pedestal pedestal between azimuths azimuths 189 and 212 degrees degrees were also reinforced.

were reinforced.

(2)

(2) Wetwell routing Wetwell (a)

(a) Rerouting of the piping piping to minimize load effects effects from pool pool swell impactimpact and submerged structure structure drag loads.

drag loads. The The modified modified pipe routing in In the wetwell is is shown in in Figure 1.14.

1.14.

After After rerouting rerouting of the wetwel.l wetwell portion of portion S/RVDL, S/RVDL, two distinct distinct wetwell wetwell piping configurations configurations exist exist at eNS. CNS.

One configuration configuration routes routes directly directly to the T-quencher T-quencher discharge device in in the same bay as the main vent vent penetration.

penetration. This configuration configuration is is referred to as the short short S/RVDL S/RVDL (or S/RVDL "A"). "A") . The second configuration configuration routes routes from the main vent penetration, penetration, through through the torus airspace of the adjacent adjacent non-vent bay and into the next vent bay where where it it descends into the submerged descends submerged T-quencher T-quencher discharge device.

device. This configuration configuration is is referred to as the long S/RVDL S/RVDL (or S/RVDL "B"). "B"). This terminology for the wetwell wetwell portion portion of the S/RVDL should not be confused confused with the line line designations based on the S/RV number (as discussed above) above). .

When When designating designating the line line by S/RV S/RV number, number, the number 71 71 will always precede precede the letter letter designation.

designation.

(b)

(b) Replacement Replacement of of all all schedule 40 piping with schedule schedule schedule 80 80..

• (c)

(c) Addition Addition of T-quencher discharge devices.

The T-quencher discharge device are shown in standard standard Owners Owners Group.

in Figure 1.15.

T-quencher assembly Group.

1.15.

assembly developed The T-quencher devices.

device and support configuration The design is developed T-quencher arms are stainless is based upon the for the Mark stainless Mark II steel steel TP316L 12-inch schedule TP316L 12-inch schedule 80p'ipes 80.pipes capped capped at the end with 794 holes holes per arm. arm. On one one end cap cap 40 holes are located while the other end cap is is closed.

closed. The end cap cap holes are intended to intended to provide provide betterbetter thermal mixing mixing during extended S/RV blowdown.

blowdown. The T-quencher T-quencher arms are connected connected to the S/RVDL by a ramshead componentcomponent and a 12 x 10 reducer reducer component,.

component.

The The T-quencher T-quencher support arrangement arrangement is is shown in in Figure Figure 1.15.,1.15.

The The support support consists of a 24-inch 24-inch diameter diameter schedule schedule 100 pipe extending 100 extending across across each vent bay at bottom bottom dead center. A 10-inch schedule center. A 10-inch schedule 80 pipe is is provided provided in in each each non-vent bay to act as a brace brace for the large large support support pipe. pipe.

An extension extension plate on the ring girder was installed installed to to accommodate accommodate the 24-inch diameter diameter pipe pipe attachment above the ring girder flange. flange. Support plates plates act as guides for the T-quencher arms.

T-quencher arms. Axial restraint Axial restraint is provided is provided by the the shear shear key key attached to the lower gusset plate plate on the ramshead. ramshead. All All eight T-quencher discharge eight T-quencher discharge devices have have the same same support support

• configuration .

configuration.

1-13 1-13 04/16/02

• (d) Addition of pipe Addition Three supports wetwell. A wetwell.

the piping slightly restraint restraint spanned pipe supports supports were slightly supports. .

were installed A normal restraint installed on each restraint each long S/RVDL in was located below the bend in below the torus high water level.

was tied to a 16-inch diameter support spanned between the two ring girders girders in in the level. This support pipe which in the bay. bay. An axial This axial in restraint restraint and a guide are are provided provided at the ring girder girder location location above the high water water level.

level. No supports are provided on the short S/RVDL between between the main main vent and the T-quencher.

T-quencher.

1.3.3.2 1.3.3.2 Torus Attached Attached Piping A total A total of 19 large bore (greater than 66 inches) and 25 small small borebore (less than or equal to 6 inches) pipes penetrate penetrate the torus shell. shell. The torus attached piping systems are piping systems are listed listed by penetration penetration number number and functionfunction in in Table 1.2. 1.2.

The large bore large bore lines have primarily primarily ECCS functions while while the small bore bore lines instrumentation and vacuum breaker have instrumentation breaker actuation actuation functions.

functions.

Modifications Modifications were made to the torus attached attached piping systems systems to ensure *that that the originally originally intended intended design safety safety margins were restored under under the new new hydrodynamic hydrodynamic loads transmitted transmitted to the piping through through the torus shell shell vibrations.

vibrations.

modifications are:

The modifications (1)

(1) Addition Addition of of new pipe supports reinforcement supports or reinforcement of existing supports were performed supports performed on nearly all all torus attached piping systems.

systems. For the large bore lines, lines, a totaltotal of 14 new supports supports were added and 137 of the existing existing 239 supportssupports were were reinforced for the new increased loads. loads. Existing dead weight weight supports of the rod hanger type were typically typically replaced by sway struts' struts to to accommodate dynamic, accommodate dynamic, reversing reversing loads. loads. For the small bore torus attached piping, attached a total total of 60 new and modified modified supports were were installed. A summary installed. A summary of these these pipe support modifications support modifications is is presented presented in in Table 1.3. 1.3.

(2)

(2) The major portions of of the torus liquid level indicator piping was level indicator was rerouted to isolate isolate the piping from the torus torus) motion effects. effects.

This isolation was accomplished accomplished by installing installing in-line in-line anchors to anchors to the reactor the reactor building building wall. wall. Expansion loops were added between between the anchors anchors and the torus shell to accommodate accommodate the torus shell shell displacements.

displacements.

(3)

(3) One One torus drain drain line and one atmospheric atmospheric instrumentation instrumentation line line were rerouted.

rerouted.

(4)

(4) 25 new or modified supports supports on branch piping piping (less thanthan four inch diameter) were diameter) were installed.

installed.

(5) 13 valves valves on large large bore piping piping systems were stiffened in in the

(5 )

valve valve yoke area. area. These modifications modifications consist of a 3/8" bent plate bolted bolted to the' operator operator flange at the existing bolt and at the available available bolt bolt below below the yoke yoke leg. leg.

1-14 1-14 04/16/02

• (6) )

(6 Three torus (X-223A torus attached (X-227B).

penetration attached piping penetrations penetrations are for the two core penetrations (X-223A and and X-223B)

(X-227B). Four 5/8 inch and penetration with welding pads included the piping and torus shell. shell.

penetrations were reinforced.

core spray pump test one core spray inch gusset plates reinforced. These test spray pump suction plates were located around each included between return lines return suction line between the gussets and These line each and (7)

(7) supports on the four RHR pumps were reinforced The supports reinforced for high shear shear loads loads on the baseplate bolts. For each baseplate bolts. each pump, pump, four 4" 4" x 7" x 1" I" angle brackets brackets were welded welded to the edge of the baseplate baseplate and then fit fit over the edge of the pump foundation. foundation.

1.3.3.3 1.3.3.3 Torus Internal Torus Internal Piping The torus internal internal piping systems systems are are listed listed by function function and penetration number in in Table 1.4.1.4.

with With the exception exception of the containment containment spray s~ray header, header, which which extends around around the top of the torus and penetrates penetrates the torus at two locations, locations, torus the torus internal piping consists exclusively exclusively of qf short, submerged submerged suction strainers strainers partially submerged discharge pipes.

and partially pipes.

Structural Structural modifications modifications performed performed on the torus internal internal piping are summarized below:

below:

(1)

(1 ) The discharge configuration The discharge configuration of of the the Residual Residual Heat Heat Removal (RHR) (RHR) pump test pump test return line was modified. modified. The existing 10-inch existing 10-inch

• discharge discharge elbow elbow isis replaced replaced by a 14-inch 14-inch elbow with its its discharge oriented oriented 67.52 67.5° below below a horizontal horizontal plane in in the torus.

torus. The The existing 18" 18" x 10" 10" reducer reducer and support located on the 10-inch 10-inch portion of the piping piping is is also replaced replaced with components which accommodate accommodate the the 14-inch 14-inch elbow elbow (Figure 1.16). 1.16) . The increased increased elbow elbow size is is intended to improve thermal thermal mixing in in the suppression pool.

pool.

A guide is A is also located near near the elbow to reduce'pipe reduce' pipe stresses due to submerged submerged structure structure drag loads..

drag loads (2)

. (2) The High Pressure The High Pressure Coolant Injection Coolant Injection (HPCI)

(HPCI) and Reactor Reactor Core Core Isolation Cooling (RCIC) (RCIC) turbine turbine exhaust piping were rerouted and were rerouted resupported resupported close to the ring girders to minimize minimize their their exposure structure drag to submerged structure drag loa~s loads (Figures 1.17 and 1.18). 1.18).

\

(3)

(3) The two 10-inch diameter core spray spray pump test pump test lines lines are truncated to discharge discharge into the suppression suppression pool at elevation 872' 872' 3/4".

7-3/4". This modification modification involves involves removal removal of a 2' 2' - 6" 6" portion of the line between the existing existing discharge discharge outlet outlet and the specified elevation specified (Figure 1.19).

elevation (Figure 1.19). The existing 45 452Q elbow located at the discharge outlet is relocated at the new discharge is to be relocated elevation. Truncation of these lines reduces elevation. Truncation reduces reaction reaction loads at at the torus the penetration due to drag loads on the submerged torus penetration submerged portion of the line. line. The discharge outlet is still is still two feet below the suppression suppression pool pool low low water level.

water level.

• (4)

(4 ) The 2-inch condensate are cantilevered condensate drain lines for the HPCI and RCIC systems cantilevered from the torus penetrations into the suppression pool. pool. V-type 1-15 1-15 penetrations (X-221 and X-222)

V-type guides consisting consisting of 2-inch systems X-222) 04/16/02

• (5)

(5) diameter diameter struts stresses the struts bracing at torus elevation 4-inch 4-inch reinforced.

bracing back to the torus shell are to be located elevation 875' stresses due to submerged diameter reinforced. A 1/2-inch 875' - 3 1/4".

submerged structure The 16 existing U-shaped hangers containment containment l!2-inch gusset plate 1/4".

plate is These guides reduce pipe structure drag loads. loads.

hangers provided at each spray each ring girder for spray header are is to be welded from the to for be be existing support to the ring girder girder flange on the inboard inboard side of of each support.

each support. The reinforced reinforced supports are designed designed for reactions reactions due to differential differential thermal motion between between the piping and torus shell.

shell.

1.3.4 Miscellaneous Modifications Miscellaneous System Modifications 1.3.4.1 1.3.4.1 Drywell/Wetwell Pressure Differential Drywell/Wetwell Differential To maintain a pressure pressure differential differential of 1.0 1.0 psid between between the drywell drywell and wetwell wetwell as a condition limiting condition for plant operation, plant operation, a Around Pump Around (PAS) was installed.

System (PAS) installed. The purpose of this pressure pressure differential differential is is to to reduce the water level level within the submerged submerged portion of the vent system system downcomers, downcomers, LOCA-generated thereby reducing LOCA-generated loads on torus structural structural components.

components.

The PAS consists of aa piping loop between between the drywell drywell and torus. The piping loop includes dual motor-operated motor-operated isolationisolation valves valves at existing torus and penetrations.

drywell penetrations. The PAS is is isolated from primary containment upon primary containment upon initiation initiation of a Group II II isolation signal from the Primary Containment Primary Containment

• Isolation System. Two air-cooled Isolation System. air-cooled compressors, compressors, each with a capacity capacity of 100 cfm 100 cfm at 7 psid, are located in in series with the piping piping loop to provide the motive force for the gas. gas. The compressors compressors take suction from the torus and discharge to the drywell.

drywell. To dampen compressor compressor pulsations, pulsations, a surge chamber is is located in in the compressor compressor outlet piping.

All piping and valves in in the PAS system are ASME Section III, III, Class II, II, with a Seismic Category I rating. compressors were seismically rating. The compressors seismically qualified qualified in in conformance with IEEE Standard conformance Standard 344-1975 344-1975 to the applicableapplicable response spectrumspectrum curve, The PAS is curve. is designed designed with sufficient redundancy so that no single sufficient redundancy active system conmponent component failure can degrade degrade the Primary Containment Isolation Primary Containment System.

System.

Electrical power for the PAS components is Electrical is supplied supplied from the critical power critical power supply. The instrumentation supply. instrumentation automatically automatically controls the differential differential pressure between between the torus and the drywell. drywell. Pressure Pressure sensors sensors convert differential convert the differential pressure between the torus and drywell into pneumatic pressure between pneumatic signals to load and and unload the compressors.

compressors. Instrumentation Instrumentation is is provided provided to measure measure the temperature, temperature, pressure, differential differential pressure (two (two monitoring channels),

channels),

recirculation recirculation flow rate, and the position position of all isolation valves. valves.

1.3.4.1.1 1.3.4.1.1 Normal System Operation Operation Operation of the PAS is is from the control room. room. System operation is is initiated by the remote manual opening opening of isolation valves and starting isolation starting the compressors. Recirculation compressors. Recirculation begins when the low differential differential set point is is reached.

reached. At this point, the pressure pressure switches close, close, energizing energizing the

• electrical solenoid valves supplying electrical unloader valves.

unloader valves.

pressure pressure from the compressor Energizing supplying pneumatic Energizing the solenoid compressor unloaders, pressure to the*

pneumatic pressure solenoid valves removes the pneumatic unloaders, and the compressors begin 1-16 1-16 the* compressor compressor pneumatic begin to pump 04/16/02

• from the torus to the drywell.

is is reached, reached, deenergized.

deenergized.

terminating circulation terminating 1.3.4.1.2 1.3.4.1.2 the pressure Pressure is Pressure circulation flow.

Accident Operation drywell. When pressure is Operation When the high differential switch opens and the supplied to.

supplied differential pressure to the compressor pressure set point solenoid valves solenoid unlo~ders, compressor unloaders, point thereby are The occurrence occurrence of low reactor water water level level and high drywell drywell pressure pressure (Group 2 isolation isolation signal) indicates indicates the possibility possibility of a LOCA requiring requiring the isolation isolation of the primary primary containment.

containment. The PAS suction line from' from' the torus is is isolated isolated by the two motor-operated motor-operated isolation valves upon upon receipt of the Group.2 Group 2 isola,tion signal.

isolation signal. The same signal also closes motor-op~rated valves closes the two motor-operated valves on the 'compressor

'compressor discharge discharge line line to the drywell. drywell. These valves valves remain remain closed until until the Group Group 2 isolation signal clears clears and is is reset, reset, or the valves are opened manually opened manually for PAS operation. operation.

The system would operate in in the same manner during loss-of-off-site loss-of-off-site power power since one valve in in each pair of isolation isolation valves is is AC-powered AC-powered from Bus 1-F, 1-F, and one valve is is powered powered by the 250 V V DC bus. bus.

1.3.4.2 S/RV Low-Low Set Set Relief Logic Logic General Electric General Electric recentlyrecently completed completed an evaluation of the LDR S/RV Load Cases C3.1, Cases C3.1, C3.2, C3.2, and C3.3 (defined in in Subsection Subsection 2.5) for Cooper Nuclear Nuclear (Reference 21).

Station (Reference 21). The purpose purpose of this evaluation evaluation was to identify identify design changes that will mitigate changes mitigate S/RV subsequent actuation-induced actuation-induced loads during

• postulated postulated Intermediate Intermediate Break Accident/Small Accident/Small Break Break Accident (IBA/SBA)

• LOCA events.

events. The primary primary concernsconcerns are the potential potential high thrust thrust loads on the discharge discharge piping piping (Load Cases C3.1 and C3.3), C3.3), and the high frequency pressure pressure loading on the containment containment (Load Case C3.2). C3.2) . GE concluded concluded that that delayed achieved by means of a Level isolation achieved Level 1 Main Isolation Valve (MSIV)

Main Steam Isolation water level level triptrip set point point (Subsection 1.3.4.3), 1.3.4.3), combined with a 100 psi combined psi low-lOW low-low set relief set relief logic, produced logic, produced the maximum potential potential benefit. The benefit. The planning planning and procurement procurement necessary necessary for installation installation of these design design changes changes is is currently currently in progress.

in progress.

The proposed proposed low-low set relief relief logic system is is shown shown in in Table 1.5. 1.5. When the logic is armed by actuation is armed actuation of any S/RV and a high reactor pressure scram scram signal, the logic will lower the opening and closing signal, closing set points of valves valves D and H arid H to new preset pressures pressures which are sufficiently sufficiently below below the set points points of of the remaining remaining values.

values. The opening opening and closing closing set ~oints points for valves valves 71D and 71H 71H will will be separated separated by 100 psi as indicated indicated in in the table.

table. Thus, Thus, more energy will be released released each each time time an S/RV S/RV actuates actuates and more energy energy will be required" required' for repressurization repressurization before an S/RV opens. opens. If If the amount of energy energy release is is sufficient to prevent sufficient prevent reactor reactor repressurization repressurization to a level where the low-low low-low set valve reopens, reopens, then subsequentS/RVsubsequent S/RV actuations actuations can can be prevented.

prevented. If If the amount of energy release is energy release is insufficient insufficient to prevent subiequent actuation, the subsequent actuation, low-lOw set relief low-low relief logic will delay S/RV reopening reopening by virtue virtue of the the longer longer required to repressurize time required repressurize the reactor. reactor.

For an anticipated anticipated operational oper~tional transient event, event, such as a 3-second MSIV closure, closure, the relief relief logic extends extends the minimum time between between actuations actuations to to

.

approximately approximately 36 seconds. seconds. If If there is is no loss of offsite offsite power (LOOSP) power (LOOSP) or or

• early early MSIV isolation during a LOCA event, event, subsequent subsequent S/RV actuations actuations will not not occur occur for any break break size.size. If If LOOSP does occur, occur, the relief logic extends extends the minimum minimum time between actuations actuations to approximately approximately 31 seconds seconds for break sizes sizes 2

smaller than 0.20 smaller 0.20 ft ft2. . No subsequent actuations actuations will occur for breaks of of 1-17 1-17 04/16/02

2 0.20 ft 0.20 ft 2 or or larger larger (see Table 1.6). 1.6). The time intervals described above effectively effectively mitigate mitigate the S/RV discharge loading conditions of concern concern (Subsection 2.5.2).2.5.2).

A more A more detailed detailed description description of the the low-low low-low set relief relief system can system can be found in in

-Reference 21.

-Reference 21. AlsoAlso included included in in thisthis reference reference is is an an evaluation of the design changes with changes with respett respect to plant operations and other safety systems, as well as as analysis results analysis results for S/RV for S/RV system system performance performance with the low-low set relief relief logic.

logic.

1.3.4.3 1.3.4.3 Level 1 MSIV' Level MSIV Trip Setpoint Setpoint The proposed The proposed new new MSIV MSIV trip trip set point is is shown in in Table 1.7. 1.7. The lower trip trip setpoint will setpoint will mitigate mitigate subsequent subsequent S/RV actuation actuation load cases because of the slower repressurization slower repressurization rate rate due due to to the lower reactor decay heat rate after delayed isolation. In order delayed isolation. In order to obtain the maximum to obtain ma'ximum benefit of this change, change, the water level water level trip trip is is to be to lowered to be lowered to reactor reactor vessel vessel Levell.

Level 1. However, However, this maximum benefit maximum benefit can can be be realized realized only only if if early early isolation isolation due to LOOSP does not not occur.

occur. Nevertheless, Nevertheless, the the Levell Level 1 MSIV trip trip does reduce S/RV challenges, challenges, increase plant increase plant availability, availability, and and rnitigate mitigate S/RV load case C3.3.

case C3.3.

Lowering the Lowering the MSIVMSIV trip trip set point set point to to Level Level 1 will potentially eliminate eliminate S/RV actuations actuations for for break break sizessizes of 0.15 ft ft 22 or larger, if if earlier earlier isolation isolation due to to LOOSP does LOOSP does not not occur.

occur. When combined When combined with the low-low low-low set rel reliefief logic, logic, transient analysis transient analysis results results indicate indicate that subsequent subsequent S/RV actuations actuations will not not

.

occur for occur for any any break break size.size. AlthoughAlthough aa significant significant amount of energy energy is is released from the from the vessel vessel without without heating heating the the suppression suppression pool pool by by implementing implementing both of of these design these design changes,changes, it it is is ADS initiation initiation that prevents prevents the future subsequent S/RV subsequent actuations.

S/RV actuations. If If ADS were not initiated, initiated, the time interval interval between subsequent between subsequent actuationsact,uations would would be be approximately approximately 51 seconds seconds for a break size approaching zero.

size approaching zero. This This interval interval is is more than sufficient sufficient to mitigate the S/RV discharge load cases S/RV discharge load cases of concern. of concern. Additional Additional information information on on S/RV system system performance with the performance with the Level 1 MSIV trip, Level 1 MSIV trip, installed independently independently or in in combination combination with with the low-low set relief the low-low relief logic, logic, can be found in in Table Table 1.6 1.6 (summary)

(summary) and and Reference Reference 21. 21.

1.3.4.4 1.3.4.4 Torus Temperature Monitoring Torus Temperature Monitoring System System To To comply comply withwith the the requirements requirements of of the the NRC NRC described described in in the the SER, a SER, a new new torus torus temperature temperature monitoring monitoring system system was was installed installed at CNS. CNS. This This monitoring monitoring systemsystem replaces replaces the the previous previous (water) (water) torus torus temperature temperature monitoring monitoring system system whichwhich consisted consisted of, of, sixsix sensors, sensors, three three for for water and and three for air, air, monitored monitored in in panel VBD-J panel VBD-J in in the control control room. room.

Although Although not not required required by by the the SER, SER, the the new temperature monitoring system new temperature system is is designed as designed as IE IE qualified.

qualified. This This allowsallows the the system system to be upgraded to a safety be upgraded related system should related system should NRC regulations regulations require require this at a later later date.

date.

This This new new system system consists consists of of sixteen qualified sixteen qualified Pyco resistance resistance thermometers thermometers (RTDS), (RTDS), eight qualified eight qualified Foxboro Spec Foxboro Spec 200 200 input input converters, converters, eight eight qualified qualified Foxboro Foxboro Spec 200 200 isolated isolated output output buffersbuffers and and oneone Leeds Leeds and and Northrup Northrup Speedomax Speedomax 250 250 series series recorder.

recorder.,

. The The RTDs are housed housed in in thermowells thermowells installed installed at 16 separate separate locations

• RTDs are locations on on the drywell drywell side side of of thethe torus.

torus. The The thermowells thermowells are are located located in in pairs pairs at a location which which is approximately at is approximately at the middle of the middle of the T-quencher arm hole the T-quencher hole pattern pattern on on the downstream arm of the the downstream arm of the quencher (Downstream refers quencher (Downstream refers to the bulk bulk flowflow 1-18 1-18 04/16/02

• direction in direction level.

level.

The o0 to 10 in the pool located approximately approximately The power for the RTDs is 10 volt signal signal is signal is then pool created created by T-quencher signal to represent T-quencher discharge) . The thermowells five feet below the suppression is supplied from the input converters, represent the temperature then fed to the isolated output suppression pool minimum temperature reading converters, which reading of the RTD.

buffers, which produce output buffers, thermowells are minimum water which produce water produce a RTD. This produce a 4 to This to 20mA signal.

20mA signal. This This signal signal is is then taken to panel VBD-J and connected to the and connected recorder.

recorder. Also, Also, the capability capability of connecting connecting a computer computer at a later later date date is is provided with provided with the the addition appropriate dropping addition of the appropriate dropping resistor resistor to the signal signal current loop.

loop.

System operation System operation is is continuous continuous with the multipoint multipoint recorder recorder sequentially stepping through stepping through each of each of the sixteen RTD inputs and, plotting the sixteen plotting its its measured measured temperature.

temperature. When any of these temperatures these temperatures exceeds exceeds the alarm setpoint alarm setpoint on the recorder, annunciator point on panel recorder, an annunciator panel VBD-J is is energized.

energized. The recorder recorder willwill continue to plot all continue all of the sixteen RTD inputs. inputs.

Bulk pool temperatures, Bulk pool temperatures, which will will be calculated calculated by the future future plant process process computer, computer, will allow the operatoroperator to anticipate anticipate local local pool temperatures temperatures and to take actions actions to keep them below below Technical Specification limits.

Technical Specification limits.

1.3.5 Modification Summary Modification Summary The containment, The containment, piping, piping, and system modification modification descriptions descriptions discussed in in

.

the previous paragraphs the previous paragraphs include include the majority of the Mark Mark I containment containment program modifications installed (or to to be installed) at Cooper Nuclear

• program modifications installed Nuclear Station. Table Station. Table 1.81.8 summarizes summarizes the complete CNS modification modification program. program. The The table provides aa brief table description, brief description, including the purpose or primary including primary load event dictating. the event dictating. the change, change, and the completion completion time frame for for. the modifications.

modifications. All the All the modification modification work is is scheduled scheduled for completion completion by by September 1982 September 1982 with with the exception of the exception of thethe low-low low-low set relief set relief logic and reduced MSIV trip trip setpoint, setpoint, which will be installed installed in in 1983.

1983.

1.4 Summary of Results Results 1.4.1 Results and Conclusions Conclusions The obj The objective ecti ve of of the the Mark containment LTP for CNS is Mark I containment restoration of is the restoration of originally originally intended design safety margins for the new suppression suppression pool pool hydrodynamic loads.

hydrodynamic loads. These These margins margins are are identified identified through through the application application of of the design design loads to the CNS plant unique containment containment configuration configuration and comparison comparison of of the resulting resulting responses responses against established structural against established structural and and.

mechanical acceptance criteria.

mechanical acceptance criteria. The required evaluations have been required evaluations been completed completed for for CNS. results CNS. The results indicate that the CNS containment containment configuration configuration as of of September 30, September 1982, 30, 1982, will satisfy satisfy all all established design criteria established criteria (with the exceptions exceptions noted noted in in Subsection Subsection 1.2.2.2).

1.2.2.2).

To meet To meet thethe objectives objectives of of the LTP, NPPD the LTP, NPPD has performed extensive modification performed extensive work work on CNS containment components.

containment components. This work has been performed performed over the last last three three years years during during scheduled plant plant outages and, and, in in several instances, instances, during plant during plant operation.

operation. This modificationmodification program has been responsive to NRC

.

concerns on containment concerns containment integrity integrity by providing providing timely improvements in timely improvements in safety margins without adversely

• margins without adversely impacting normal plant plant operation.

operation. This This responsiveness is responsiveness is further illustrated illustrated by the fact that NPPD will be the first first Mark Mark I containment containment owner owner to complete complete the installation installation of all all LTP-related LTP-related modifications.

modifications.

1-19 1-19 04/16/02

In conclusion, In conclusion, the CNS containment containment system has been shown through analysis, analysis, including the necessary including necessary modification modification work, work, to meet the objectives objectives of the Mark I containment containment LTP.

LTP.

4.2 1.4.2

1. Conformity Project Requirements Conformity with Project Requirements The PUAR for CNS is is submitted ,in in partial partial fulfillment of the requirements requirements of of the NRC for the Mark I LTP. LTP. The PUAR summarizes the work which PUAR summarizes which demonstrates demonstrates that with the containment containment modifications modifications identifiedidentified inin Subsection Subsection 1.3 all all established design criteria establjshed criteria are satisfied.

satisfied. Therefore, Therefore, completion completion of these modifications modifications will result result in in conformity conformity with the requirements requirements of the NRC-issued NRC-issued Order Modification Order for Modification of License License and Grant of Extension Extension of of Exemption to NPPD Exemption NPPq as holder of Facility Operating License DPR-46 for CNS.

Facility Operating CNS. As As required required by this order, order, all all modifications modifications are to be installed by installed' by September 30, September 30, 1982.

1982.

Subsequent review and approval Subsequent approvCl.1 of this report of*this report will eliminate eliminate the "Unresolved Safety Safety Issue" designation designation (pursuant to Section 210 Section of the Energy Energy Reorganization Act of 1974)

Reorganization 1974) as it it pertains pertains to CNS. CNS .

• 1-20 1-20 04/16/02

Table 1.1.

1.1 S/RVD LINES IN THE DRYWELL DRYWELL

SUMMARY

OF

SUMMARY

OF' SUPPORT MODIFICATIONS/ADDITIONS MODIFICATIONS/ADDITIONS Number of Supports SuDDorts Line Line No.

No. New/Added New/Added Modified 71A 99 6 71B 11 11 6 71C 4 5 71D 4 4 71E 71K 3 4 71F 4 3 71G 5 6 71H 9 6

• 0 1-21 1-21 04/29/82

• Penetration Line TORUS Table Table 1.2 1.2 TORUS PIPE PENETRATIONS PENETRATIONS Size Number Number ~(in) Description X-203A 11 Oxygen Analyzer Analyzer X-203B 1 Oxygen Analyzer Analyzer X-205 20 20 Vacuum Relief from Bldg.

Bldg. And And Vent Purge Inlet Inlet X-206A 1 Liquid Level Indicator Indicator X-206B 1 Liquid Level Indicator Indicator X-206C X-206C 1 Liquid Level Indicator Indicator X-206D X-206D 11 Liquid Level Indicator Indicator X-209A 11 Air and Water Temperature Temperature X-209B 11 Air and Water Temperature Temperature X-209C 11 Air and Water Temperature Temperature X-209D 101 Air and Water Temperature Temperature X-210A X-210A 18 18 RHR Pump Test Line Line X-21-0B X-210B 18 RHR Pump Test Line Line X-211A 6 Cooling to Spray Header Containment Cooling Header X-211B 66 Containment Cooling Cooling to Spray Header Header X-212 12 12 2 RCIC Turbine Exhaust Exhaust X-213A 88 Torus Drain 88

• X-213B X-213B Torus Drain X-214 X-214 24 24 HPCI Turbine Exhaust Exhaust X-215 X-215 1 Atmospheric Atmospheric Pressure Instrumentation Instrumentation X-220 X-220 16 16 Outlet Vent Purge Outlet X-221 X-221 22 RCIC Condensate Condensate Drain Drain X-222 X-222 22 HPCI Condensate Condensate Drain Drain X-223A 10 Core Spray System Pump Test Test Line Line X-223B 10 Core Spray System Pump Test Core Test Line Line X-224 X-224 66 RCIC Pump Suction X-225A 20 20 RHR Pump Suction X-225B 20 20 RHR Pump Suction X-225C 20 20 RHR RHR Pump Suction X-225D 20 20 RHR RHR Pump Suction X-226 X-226 16 16 HPCI Pump Suction HPCI X-227A 16 16 Core Core Spray Pump Suction X-227B 16 16 Core Spray Pump Suction Core Suction X-228 X-228 10 10 Demineralized Demineralized Water Inlet Inlet X-229A 11 Vacuum Breaker Vacuum Breaker Actuating Air Air X-229B 1 Vacuum Vacuum Breaker Breaker Actuating Air Air X-229C 11 Vacuum Vacuum Breaker Breaker Actuating Air Air X-229D 1 Vacuum Vacuum Breaker Breaker Actuating Air Air X-229E X-229E 1J. Vacuum Breaker Vacuum Breaker Actuating Air Air X-229F X-229F 11 Vacuum Vacuum Breaker Breaker Actuating Air Air X-229G 11 Vacuum Vacuum Breaker Breaker Actuating Air Air X-229H 11 Vacuum Vacuum Breaker Breaker Actuating Air Air X-229J X-229J 1 Vacuum Vacuum Breaker Breaker Actuating Air Air X-229K 11 Vacuum Vacuum Breaker Breaker Actuating Air Air

• X-229L 11 Vacuum Vacuum Breaker Breaker Actuating Air Air X-229M X-229M 1 Vacuum Vacuum Breaker Breaker Actuating Air Air 1-22 1-22 04/29/82

• OF PIPE

SUMMARY

OF

SUMMARY

1.3 Table 1.3 PIPE SUPPORT SUPPORT MODIFICATIONS MODIFICATIONS FOR TORUS ATTACHED (EXTERNAL)

FOR (EXTERNAL) PIPING PIPING Number of of Supports Supports Lines Lines New Modified Modi-fied X-205 X-205 11 6 X-206A/}

X-206A/B 11 11 0 X-206C/I X-206C/D 13 13 0 X-209 6 0 X-210A, X-211A X-210A, 2 10 X-210B, X-211B X-210B, 1 7 X-212 0 3 X-213A, X-213B X-213A, 0 0 X-214 2 15 15

• X-215, X-203 X-215, X-220 X-220 X-221 X-221 X-222 12 12 7

1 5

0 1

0 0

X-223A 22 12 12 X-223B X-223B 00 17 17 X-224 X-224 00 15 15 X-225A, X-225A, X-225B 4 12 12 X-225C, x-225C, X-225D 11 18 18 X-226 X-226 00 7 X-227A, X-227A, X-227B X-22.7B 00 14 14 X-229 X-229 6 0 Branch Branch Lines Lines 88 17 17

• 1-23 1-23 04/29/82

Table 1.4 1.4 TORUS INTERNAL INTERNAL PIPING PIPING SYSTEMS Line Penetration Size Size Number Number ~(in) Description X-210A X-210A 18 18 RHR Pump Test Line X-210B 18 18 RHR Pump Test Line X-211A 6 Containment Containment Cooling to Spray Header Header X-211B 6 Containment Cooling to Spray Header Containment Header X-212 12 12 RCIC Turbine Exhaust Exhaust X-214 X-214 24 24 HPCI Turbine Exhaust Exhaust X-221 X-221 2 RCIC Condensate Condensate Drain X-222 2 HPCI Condensate Condensate Drain X-223A 10 Core Spray Pump Test Line

• X-223B X-224 X-224 X-225A X-225B 10 6

20 20 Core Spray Pump Test Line RCIC Pump Suction RHR Pump Suction RHR Pump Suction X-225C 20 RHR Pump Suction X-225D 20 Pump Suction RHR Pump Suction X-226 X-226 16 16 HPCI Pump Pump Suction X-227A 16 16 Core Spray Spray Pump Pump Suction X-227B 16 16 Spray Pump Suction Core Spray X-228 X-228 10 Demineralized Demineralized Water Water Inlet Inlet

• 1-24 1-24 04/29/82

e PROPOSED LOW-LOW Table 1.51.5 LOW-LOW SET SAFETY/RELIEF SAFETY/RELIEF VALVE VALVE SYSTEM SYSTEM S/RV S/RV A

A B CC D D E E F GG H(1)

H___

Pressure Relief Pressure Relief X X x X x X x .X x X x X xX xX Function I I

I x xX xX  ! x ADS Function X x X x X X Low-Low Set Relief Relief xX X x

Function Valve Group III III III III II I I II II II II II III II Steam Pilot Steam pilot Opening 1125 1125 1125 1125 1115 1115 1105 1115 1115 1125 1105 1105 (psig)

Set Point (psig)

Set Steam Steam pilot Pilot Closing 1091 1091 1091 1091 1082 1082 1072 1082  : 1082 1091 1072 1072 Set Set Point (psig)

(psig)

Low-Low Set Open Open 1045 1045 - 1075 1075 (psig)

(psig)

Low-Low Set Close Close 945 945 - 975 975 (psig)

(psig)

Note:

Note:

(1)

(1) Valve H isis currently designated as an ADS valve. valve. Since it it is is necessary separate ADS valves from low-low to separate low-low set* set valves, valves, and since it it is is desirable desirable to use the lowest lowest group group valves for low-low set, the ADS function for valve H will be assigned function assigned to valve valve F.F.

1-25 1-25 04/29/82

• Suction Line S/RV Table 1.61.6 S/RV LOAD CASE ANALYSIS RESULTS RESULTS Break MSIV Low-Low Low-Low Subsequent Subsequent Area Area Trip Set Set Isolation Isolation(ni II) Actuation

((ft 2 ft2) ) Level Level L\p (psid)

AP (psid) mechanism Mechanism Time (sec) Remarks Remarks 0.0 0.0 2 Not Not Used L 14 14 As-is Case Case 0.01 2 Not Not Used L 13 13 As-is'Case As-is'Case 0.05 2 Not Not Used L 14 14 As-is Case Case 0.10 0.10 2 Not Not Used L 16 16 As-is Case Case 0.15 0.15 2 Not Not Used Used L 22 22 As-is Case Case 0.20 2 Not Not Used L 26 26 As-is Case Case 0.0 0.0 1 Not Not Used L 22 22 Level Level 1 Trip 0.01 1 Not Not Used L 21 21 Level Level 11 Trip 0.05 1 Not Not Used L 22 22 Level Level 11 Trip 0.10 1 Not Not Used L 20 20 Level Level 11 Trip 0.15 1 Not Not Used L o0 00 Level Level 11 Trip 0.0 0.0 2 100 100 L 31 31 2-Valve 2-Valve Low-Low Set Set

0. 01 0.01 2 100 100 L 33 33 2-Valve 2-Valve Low-Low Set Set 0.05 2 100 100 L 39 39 2-Valve 2-Valve Low-Low Set Set e 0.10 0.10 0.15 0.20 2

2 2

100 100 100 100 100 100 L L

L 46 46 56 56 00 00 2-Valve 2-Valve 2-Valve 2-Valve 2-Valve 2-Valve Low-Low Low-Low Low-Low Set Set Set Set Set Set 0.0 0.0 2 100 100 L 35 35 1-Valve 1-Valve Low-Low Set Set 0.01 2 100 100 L 34 34 1-Valve 1-Valve Low-Low Set Set 0.0 0.0 1 100 100 L 00 Level 1 + Low-Low Set Set 0.01 1 100 100 L 00 Level 11 + Low-Low Set Set 0.0 0.0 11 100 100 L 51 Level 1 + Low-Low Set Set ADS Off ADS Off 0.0 0.0 1 100 100 M (2.0) 34 34 LOOSP + 2-Valve 2-Valve Low-Low SetSet 0.0 0.0 1 100 100 M M (6.0) 33 33 LOOSP + 1-Valve LOOSP 1-Valve Low-Low SetSet Note:

Note:

(1)

(1) L L = Isolation Isolation due to water water level trip. trip.

M =

M Isolation due to loss Isolation loss of of reactor reactor protection protection system MG set. set. Assumed Assumed time of isolation isolation in in parentheses.

parentheses .

• 1-26 1-26 04/29/82

Table'1.7 Table 1.7 LEVEL TRIP MSIV WATER LEVEL TRIP Reactor Vessel Vessel Inches Above Above Levels Levels Vessel Zero Vessel Description Description of Trips Trips 8

8 575.25 575.25, Reactor Feed Pump Trip Reactor Close Main Close Main Steam Turbine Turbine Stop Valves Valves Trip RCIC and HPCI Turbines Trip Turbines 7 559.25 559.25 High Water Level Alarm High Alarm 5,

5, 6 Normal Water Level Normal Level 4 554.25 554.25 Low Level Low Level Alarm Alarm 3 529.25 529.25 Scram Scram Reactor Reactor 2 479.75 479.75 Initiate Initiate HPCI, HPCI, RCIC Close MSIVMSIV

'Trip

,Trip Recirculation Recirculation Pumps Pumps I1 371.25 371.25 Initiate Initiate RHR and Core Spray Spray Systems Contribute Contribute to ADS ADS

• PROPOSED PROPOSED AS NEW NEW MSIV MSIV TRIP TRIP 352.5 352.5 Top of Active Fuel Active Fuel 1-27 1-27 04/29/82

• SUl'1MARY

SUMMARY

OF OF CONTAINMENT

• Table 1.8 Table CONTAINMENT AlliD

1. 8 AND PIPING r10DIFICATIONS MODIFICATIONS

• I' COI'!?LETIO COMPLETIO COMPONENT NAME COMPON2NT NAME NATURE OF MODIFICATION PRIr1ARY PRIMARY LOAD OR PURPOSE PURPOSE ND.~.TE NDATE STRUCTURAL COMPONENTS STRUCTURAL COMPONENTS Torus Shell and SupportsSupports Torus Support Torus Support Column Co'l UIfu'l reinforcement to column web and flanges Plate reinforcement flanges Increase coluITw column capacity capacity Spring 77 77 Column Anchorage Anchorage Installed Installed anchor anchor bolts, brackets, brackets, and box beam assemblies assemblies Resist LOCA uplift uplift forces Spring 77 77 Column-to-Torus Connection CoIQ~-to-Torus Additional full Additional full penetration weldment oenetration weldment Increase connection connection capacity Spring 76 76 Torus Saddle Saddle Full saddles connecting torus support columns saddles connecting columns Improve dynamic responseresponse Surnmer Summ er 8181 Column Anchorage Column Anchorage Reinforcement Reinforcement Reinforcement of box beams and bracket weldments Reinforcement weldments Resist LOCA uplift uplift forces Spring 82 82 Ring Girder Girder -, Web stiffeners; stiffeners; local reinforcement reinforcement of weld to shell shell Pool drag loads; attachment loads Pool I uoads Fall 8181 Vent System System Vent Header/Downcomer Vent Header/Downcomer Reinforced 80 penetrations Reinforced penetrations with stiffener stiffener plates and pads plazes Chugging & & S/RV discharge loads Fall 8181 Intersection Intersection Downcomers Downcomers downcomer submergence Reduced downcomer submergence by truncation Mitigate blowdown load Mitigate DBA blowdown Spring 80 Spring 80 Downcomer Downcomer Ties Ties Installed Installed tie tie bar and ring assembly at each each downcomer downcomer CO and Chugging chugging lateral lateral loads loads Spring 80 80 pair pair Vent Header Deflector Deflector Installed Installed deflector assembly defleccor in all assembly in all torus bays bays swell impact Pool swell impact load Spri:1g 80 Spring 80 Supports Vent Header Supports Removed existing supports; Removed existing supports; resupported resupported from girder above Pool drag loads loads Spring 81 Spring 81 DW/WW DW/WW Vacuum Breakers Breakers Reinforced Reinforced 12 vacuum breaker penetrations breaker penetrations Poo 1 s',ve Pool III fro th impac swell/froth impactt loads loads Fall 8181 Miscellaneous Miscellaneous Torus Torus Internals Internals Monorail Honorail Installed Installed midbay supports in in all torus bays Froth impingement impingement load Spring 81 Spring 81 Service Service Platform Platform Replaced Replaced existing supports; added new supports, supports, bracing Pool swell swell impact/drag impact/drag loads loads Spring 82 Spring 82 and grating tie-down Drywell Drywell Steel Steel Framing Reinforcement Reinforcement of beam connections and framing beam seat connections S/RV pipe pipe support _loads loads Spring 82 Spring 82 members members

" MISCELLANEOUS MISCELLANEOUS SYSTEM SYSTEM MODIFICATIONS HODIFICATIONS Drywell/Wetwell Drywell/Wetwell Pressure Installed Installed Pump Around System System Mitigate LOCA Mitigate LOCA blowdown blowdown vent vent Spring 76 Spring 76 Differential Differential -clearing clearing Torus Torus Temperature Monitoring Temperature Honitoring Installed Installed monitoring monitoring system system and instrumentation instrumentation Monitor pool temperature Monitor Summer 82 Summer 82 System System S/RV Low-Low Set S/RV Low-Low Set Logic Logic' Will install install control logic logic and instrumentation instrumentation for safety . Mitigate/eliminate Mitigate/eliminate S/RV Spring 83 Spring 83

- relief valves subsequent relief valves subsequent actuation loads actuation loads MSIV MSIV Trip Set Point Trip Sec Point Will will lowerlower set set point to reactor reactor level level 1I Reduce S/RV Reduce S/RV Challenges Challenges Spring 83 Spring 83 1-28 1-28 04/29/82

• 0

SUMMARY

• 0 Table 1.8 (Cont'd)

SU1VjjVL\RY OF CONTAINNENT AND PIPING 1'lODIFICATIONS CONTAINMENT AND MODIFICATIONS

• COMPLETION COMPONENT NAtVIE COMPONENT NAME NATURE OOF 1'lODIFICATION MODIFICATION PRIMARY LOAD OR PURPOSE PURPOSE DATE PIPING SYSTEMS S/RV Discharge Piping Wetwell Piping Wetwell Rerouted with stronger stronger pipe; added added 12 new supports supports Pool swell impact/drag loads impact/drag loads Spring 80 80 T-Quencher Discharge T-Quencher Discharge Device Device Installed Installed T-quencher T-quencher device device on each S/RV line line Mitigate water/air clearing Mitigace water/air clearing loads spring Spring 80 T-Quencher Support T-Quencher Support Installed Installed guencher support quencher support assembly assembly inin 88 bays bays Support Supporc quencher device quencher device Spring 80 80 Quencher Quencher Support Bracing Installed Installed quencher support bracing bracing in in 88 bays bays Distribute quencher Distribute quencher reactions reactions Spring 80 80 Vacuum Vacuum Breakers Breakers Installed Installed two, 10-inch vacuum breakers two, la-inch breakers on each lineline Prevent excessive Prevent excessive reflood in in line line Spring 80 Pipe Supports and Restraints Installed Installed 89 new or modified modified supports supports inin drywell drywell S/RV biowdown blowdown thrust loads loads 80, 81 80, 81 &

&

82 82 Torus Attached Attached Piping Large Bore Supports Supports Installed Installed 151 151 new or modified modified supports supports LOCA &

Torus motions due to LOCA & S/?V S/RV loads Summer Summer 82 82 Small Bore Supports Bore Supports installed Installed new supports 54 ne~ supports Torus motions due to LOCA LOCA && S/RV loads Summer Summer 82 Small Bore Bore Rerouting Rerouted 5 lines Rerouted Torus motions due to LOCA LOCA && S/RV loads Spring 82 Branch Line Supports Supports installed>25 new or modified supports Installed/25 supports Torus motions due to LOCA LOCA && S/RV loads Summer Summer 82 Torus Penetrations Torus Penetrations Reinforced Reinforced three large large bore torus penetrations penetrations pipe reactions Pipe reactions from LOCA & & S/RV loads Spring 82 Valve Operator Valve Operator Supports Supports Reinforced Reinforced 13 valve valve yolks Torus motions due to LOCA LOCA && S/rzV S/RV loads Summer Summer 82 82 Pump Anchors Anchors Modified anchorage of 4 RHR Nodified anchorage RHR pumps pumps reactions at nozzles Pipe reactions nozzles Summer Summer 82 82 Torus Internal Torus Incernal Piping HPCI Turbine Exhaust Turbine Exhaust Rerouted resupported HPCI Rerouted and resupported HPCI sparger sparger Pool drag loads Pool loads Fall 81 81 RCIC Turbine Turbine Exhaust Exhaust Rerouted Rerouted and resupoorted RCIC sparger and resupported sparger Pool drag loads loads Fall 8181 Core Spray Return Test Line Core Truncated Truncated test test lines lines Pool drag loads loads spring Spring 82 82 RHR RHR Return Test Line Installed Installed reducer, reducer, discharge discharge elbow, elbow, and new supports supports thermal mixing Pool thermal Sprirc.g Spring 82 82 Spray Header Header Reinforced Reinforced exiscing existing supports supports Thermal loads Thermal Spring Spring 82 82 Vent Drain Drain Line Rerouted Rerouted lines and installed installed supports supports Pool drag loads loads Spring Spring 80 80 1-29 1-29 04/29/82

If DRYWELL&

DRYWELl &

• REACTOR

. REACTOR EL. 990'-7'/."

EL. 990'-7/'

REACTOR VESSEL REACTOR VESSEL--------

DIA. 35'--7"

.---------- ---DIA. 35'-7" BIO. SHIELD SHIELD WALL WALL - - - - - - - f - - .

DR YWE LL

---DRYWEll DIA. 65'-0" DrA.65'-0" FRAMING STEEL FRAMING

- - ' - PEDESTAL J>EDEST Al ;'

E L. 911'-0"*

EL. 91 1'-0",

MAIN VENT

~q_ WETWELL WETWElL

• WETWELL WETWELl DIA. 28'-9" DrA.28'-9" 876'-71/"

EL. 876'-7Y,'

El.

EL. 859'-9" 859'-9"

~ l'----5-0'~O;,,,

s

, --.'

50'- 10 1'/"

- - -.. _. --.. - .....

---~ -- .....

_11 E FOUNDATION SLAB FOUNDA nON s~.-

FIGURE 1.1

• SECTION - COMPOSITE PLANT LAYOUT CROSS SECTION 1-30 1-30 LAYOUT 04/29/82

• (j2 WETWELL WETWELL TORUS SHELL------~ ~--~ RING GIRDER" VENT HEAD'ER SUPPRESSION CHAMBER

..------~ DOWNCOMER EL 880'-11" PENETRA TlON PLATFORM--~'I--#-~~

HWL EL 875'-2" PLATFORM-SUPPOR'T SUPPORT COLUMN SADDLE ----- ArJCHOR ASSEMBLY I IH4---ANCHOR BOLT SADDLE BEARING SADDLE BEARING - - - - I

/ i1+---. -.-13'-63/16" I

- - - - -.. ----.

~

1. VENT VENT HEADER HEADER DEFLECTOR DEFLECTOR 5.

5. TT QUENCHER QUENCHER 2.

2. VENT VENT HEADER HEADER SUPPORT SUPPORT 6.

6. TT QUENCHER QUENCHER SUPPORT SUPPORT

.. ' 3.

3. SPRAY S~RAY HEADER HEADER 7.

7. DOWNCOMER DOWNCOMER TIE TIE 4.

4. MONORAIL MONORAIL 8.

8. INTERNAL INTERNAL PIPING PIPING FIGURE 1.2 FIGURE 1.2 CROSS SECTION CROSS SECTION -- WETWELLWETWELL 1-31 1-31 04/29/82 04/29/82

r---GIRDER RING T REINF. AT WELD REINF.

COL TO SHELL CONN.

COL.

AT TORUS _ _~

SHELL

--.--

.. . ,

-' - -

~ 1

,

WEB WEB REINF.

REINF.

PLATES PLATES I L .WEB REINF. Pl Y 2 " INSIDE Yz" INSIDE eOlS. COLS.

3/4" OUTSIDE eOlS.

y." COLS.

SUPPORT

--~ ~.- --~~

SUPPORT COLUMN -C-'-~

COLUMN - --

I W14" W14" xx 136" 136"

...--+1t- COL REINF. PL . III ~ I 2-16" x JI,' INSIDE COL

~ ---< jr ~

- ~~

'.2-16" x 1" OUTSIDE CO l., I II 'I ~-'- ~ ~f' tl .-

- J ~.-iE=--:" r~ t:==='c"!! 1~1-1 fl ANCHOR ANCHOR BOLTS 01 I! j 4-2"4" cI> 1\

4-2'; ~'

-

~ ,I II II II BOX - I_~

BEAM

.1' =

i

! .9 =.::k~ -11==,- I:

t~~

, i:i I -u- . III

-~ ~-

II

,I

-'--.--. - --~

!:: s-- .~ f:j PLAN PLAN TYPICAL TYPICAL COL. COL ANCHOR ANCHO~ ASSEMBLY ASSEMBLY FIGURE 1.3 FIGURE 1.3 TORUS SUPPORT SUPPORT COLUMN COLUMN 1-3-2 1-3-2 04/29/82

• * *

<k .COLUMN COLUMN ~

TORUS TORUS L

I 13'-6 3/16" 13'-63/16"

- -----J':

i RING r

"

GIRDER TORUS.

GIRDER GIRDER SHELL FLANGE OVERLAY FLANGE 9" x1V/2" WELD 9" x 1Y,"

WEB REINF.

WEB REINF 11/2" STI FF.

- --- lY," STI FF"

//

0 I TYPICAL TYPICAL' SUPPORT SUPPORT COLUMN COLUMN in I

LUBR. PL 4-7/8" d ANCHOR BOLTS 1/22" SELF y," SELF LUBR. PL FLANGE FLANGE PL PL SOLE SOLE

• PL PL x 3'-6" BASE PL 11/2* x 20" 3'/2" x 22" Yy," WEB PL 2 " WEB PL 1/" x 29" x 3'-0" 1'h" x 20" 3%" x 22" x 3 '-6" FIGURE 1.4 FIGURE 1.4 TORUS SADDLE TORUS SADDLE 1-33 04/29/82 1-33 04/29/82

• * *

~ TORUS &

TORUS &

VENT HEADER VENT HEADER

---

DRYWELL DRYWELL SHELL TORUS SHELL

,,--TORUS SHELL VENT HEADER HEADER

\----- BELLOWS BELLOWS

\.

\

S/RVDL PIPING

\.

....-- ..

_.. ,

-' ---- \

--=:::::t:::::::3.----.-.---------

VACUUM

.BREAKER

\~/-// /'

-- ,

\

FIGURE 1.5 FIGURE 1.5 SECTION - VENT SECTION VENT SYSTEM 1-34 1-34 04/29/82 04/29/82

• * *

\TORUSBAY VENT VENT HEADER HEADER COLLAR

• COLLAR

/ \\

/,/ \,~ DOWNCOMER

. DOWNCOMER

-~-'-~'

__ --~---- //'! VENT VENT HEADER HEADER

/' _/~'~S -- INTERSECTION INTERSECTION

/'

BELLOWS ASSEMBLY

-+----1<

• - *- MAIN VENT 8<

MAIN VENT&

'TORUS BAY

• TORUS BAY DRYWELLIWETWELL VACUUM BREAKER

.. I. ll.T FIGURE 1.6 FIGURE 1.6 PARTIAL PARTIAL PLAN PLAN -- VENTVENT SYSTEM SYSTEM 1-35 1-35 04/29/82 04/29/82

• VENT HEADER

{ VENT HEADER

• 5/8" PAD AND.

-5/S"PAD AND _

STIFFENER PL

/ - - STIFFENER PL

,------- E L. 880' - 11" DOWNCOMER DOWNCOMER REINF.

REINF. 5/8" 5/8" PL PL 3/8" 3/8" DOWNCOMER DOWNCOMER LEG LEG (TYPICAL)

(TYPICAL)

Y4"

%"

~~1~~

3"ý SCH. 80 TIE

- - - 3", SCH, 80 TIE 4"-

4"cp SCH.

SCH. 120 120 SLEEVE SLEEVE 3/8" 3/8" RING RING

".~__-,---__ ~:_-_O'_'

4'-0'" ____ +_ 4'-0"

• FIGURE 1.7 FIGURE 1.7 ELEVATION ELEVATION -- DOWNCOMER DOWNCOMER REINFORMCEMENT REINFORMCEMENT 1-36 1-36 04/29/82 04/29/82

• {

VENT HEADER VENT HEADER I

2%'t PIN ...----

• EL. 879'-7Y" 2-%" PL ---~

2-*"PL

• 2-4xx44xx5/8 2-4 ANGLES ANGLES 5/8 IQ-----

%"x 21" x l'-O" END PL

%" x 21" x 1'-0" END PL EL. 876'-2%"

EL. 876'-2¥t" 16"+ SCH. 80 DEFLECTOR WITH 2-8 x 8 x %

ANGLES HWL EL. 875'-2" HWL EL. 875'-2".

FIGURE 1.8 FIGURE 1.8 SECTION - - VENT SECTION HEADER DEFLECTOR VENT HEADER DEFLECTOR 1-37 1-37 04/29/82 04/29/82

• TORUS

{ TORUS I

-- RING GIRDER

___RING GIRDER

'_PLATE!

I, SUPPORT VH SUPPORT

~

<:>

I 0 I l - - - - - 6': +

6"; + SCH SCH XXS XXS I

in 8" +SLEEVE

• 14----- -

---

,2:y..

- 2%"l.. ~ PIN PIN

, 4 1" PLATE 1 4 - - - - - ' -1" PLATE 2'-6" EL. 8801-11"

_ . - -_ _ { VENT HEADER'

• --*_VENT HEADER

• FIGURE 1.9 FIGURE 1.9 HEADER SUPPORT COLUMNS VENT HEADER COLUMNS 1-38 1-38 04/29/82

{ VENT HEADER HEADER DRYWELL/WETWELL DRYWELL/WETWELL VACUUM BREAKER VACUUM BREAKER

--- '/.."

• EL. 880'-11" 5/8" 5/8" PAD PAD AND AND STIFFENER PLPL

• DRYWELL/WETWELL FIGURE 1.10 FIGURE DRYWELL/WETWELL VACUUM 1.10 VACUUM BREAKER 1-39 1-39 BREAKER REINFORCEMENT REINFORCEMENT 04/29/82

\ 5 BRACING TS 2 x 2 x BEAM C9 x 13.5

. VENT

\__ O~_OOO r_1::.:~OO.~

• CROSS BEAM 4 x 10 BEAM TSCROSS x 1/2

\-- 1'" GRATING BAY

~ BAY°<-i_ _ _ _ 0 0

• PLAN -

FIGURE 1-40 1-40 1.11 FIGURE 1.11 SERVICE PLATFORM PLAN - SERVICE PLATFORM 04/29/82 04/29/82 '

I

~ BAY V3 BAY GRATING TIE GRATING TIE DOWN DOWN

, - - - - - HAND HAND RAIL RAIL I 2% x 22 x 5/16 5/16 ANGLE ANGLE

/ 6" LONG @

6" CTR.

12" CTR.

@ 12" f----II------ - - -----F--

/

71

~_l-~.-- - - -"'-----+--

_* El. 878'-7}2" EL. 878'-:7'/2" I~_ _ _ _ _ _ _ CROSS CROSS BEAM BEAM TS 4 x 10 TS4x x}2 10x1z C9 x 13.5 INSIDE DIAG.

INSIDE DIAG. BRACING BRACING - - - L4- ~ RING RING GIRDER GIRDER 4"

4" OR OR 3"4-3"ý SCH. X X XS XS PIPE PIPE OUTSIDE DIAG.

DIAG. BRACING BRACING -.~'

-- - - - - - - - ' ______ VERTICAL VERTICAL POST POST 3"$ SCH. X 3"4 SCH. X XS PIPE 4.... SCH.

4"74 SCH. XX XS PIPE-'

PIPE-

~-- . - - 6"t 5", SLEEVE TORUS TORUS SHELL

- \ ' I ---==="'"

I _:--

L. - - - --- -==-~"Ti-=~

uL!

• FIGURE 1.12 ELEVATION - SERVICE PLATFORM 1-41 1-41 PLATFORM 04/29/82 04/29/82

HAND RAIL HAND RAIL TOE PL&

TOE PL& ANGLE ANGLE -----tt---.

-

,EL.878'-7Yz" EL. 878'-71/2"

--\T--""*""--=----.-

CROSS BEAM -

CROSS BEAM - -,----.J TS4x10x TS /,

4 x 10 x Yz

• VERTICAL POST

• DlAG.

4" OR 4"

4"*

OR 3"4)

SCH. X XS PIPE 4"~ SCH.

DIAG. BRACING 3"4> SCH.

SCH. X XS PIPE -----+-tt+

1" CONN.

1" CONN. PLPL RING RING GIRDER GIRDER -

..~

/'.,

~~~~~ -.--------->--- '~3~~~'~~~~~T~~8~S~ONG

'WELD REINF. (NS,FS) 13/16" FILLET-18" LONG

~~./:~<'

• FIGURE 1.13 FIGURE 1.13 CROSS SECTION CROSS SERVICE PLATFORM SECTION -- SERVICE PLATFORM 1-42 1-42 04/29/82 04/29/82

~ REACTOR REACTOR

!

"LLS' INDICATES

'LLS' INDICATES 'A'INDICATES SW--LOW

.W~LOW SET SET FUNCTION FUNCTION A" INDICATES

.ADS ADS FUNCTION FUNCTION

\

0 1800 180 I

~, ....-----\ -~. ---.~---- ....... ~ /-

~% TORUS TORUS ~ ---:'-.-------- \ JI / j-

....

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-\--- . I

!

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~1-LINE DESIGNATION DESIGNATION .

cP 00 00 - - - - - S Esr' T POINT PRESSURE POINT PRESSURE (PSIG)

(PSIG)

T-QUENCHER-T-OUENCHER - -

S/RVDL (A (A TO i-I)

TO H) 10" 4>, SCH 10" SCH 40 40 - DRYWELL DRYWELL 10" 4>, SCH 10" SCH 80 - WETWELL WETWELL FIGURE FIGURE 1.14 1.14 WETWELL WETWELL ROUTING ROUTING OF OF S/RVDLS S/RVDLS 1-43 1-43 04/29/82 04/29/82

• *

• I T-Quencher 8'-11H omitted 4"-1 3/4""

for clarity 1'-1 1/2" 24"9Pipe

---

:..,-

,

,,

,

I 22~30' 22230' 11°.:.1S'Typ I PLAN

~- 81 ~,( "1 Bl °1 1'-'1 j..:'*-'.1

"-,y--"--' - .. '-rr-" .-.t-EL.867'-9t, I - - - - r i < - --ffl--~': I -- --fI!---~----j ---E L.8 67'- 9"

.J 12t'¢ 122"0 T-Quencher T-Quencher

-=-y, _,110"o 0 ¢ t t Pipee Pip

• "-~_ - " t ' - - - - - > t , , - - - ' t ' - - - - \ - f \ - - - ' l ' - - - - L . - - ' t ' - - -b\,.----'j...... - - ' 1 1 0 - - _':'-+_'>-+/-:~---,+~E L L.8 S'-5*

.8 6651- t, 24"¢ Support Pipe 26"¢ Pipe Sleeve

" Ring Girder Torus Shell ELEVATION FIGURE 1.15 FIGURE T-QUENCHER SUPPORT T-QUENCHER SUPPORT STRUTURE STRUTURE 1-44 1-44 04/29/82

FIGURE 1.16 ELEVATION ELEVATION - RHR PUMP TEST RETURN LINE MODIFICATION 1-45 04/29/82

• *0 *

.. f! R ING GIRDER RING SPARGER 8cSPARGER TORUS BAY TORUSBAV PLATFORM PLATFORM

.f--. '1'+-----

-~ TORUS TORUS

... _. _,__24'0 ",,---- HPCIOISCHARGE 24" 4SCH 40

~-

- - 24" +SPARGI1R SUPPORT ~ ___

ASSEMBLY

• L* *STIFFENERS STIFFENERS - - - - - t " i l

• 1%" PL 1%"PL

.,

ýo TORUS PEN.

X214 X214 d .

PLAN SE4TON SEeTION FIGURE 1.17 FIGURE 1.17 HPCI TURBINE HPCI EXHAUST -- REROUTE TURBINE EXHAUST RESUPPORT REROUTE RESUPPORT 1-46 04/29/82

• 0 *

.~ RING GIRDER RING GIRDER

&&SPARGER SPARGER PLATFORM Fcýý' , -PLA'FORM c---

~.-

RCIC DISCHARGE 12" cp SCH 40 12" q, 12" 4 SPARGER SPARGER RING GIRDER GIRDER TORUS PEN..

rORUSPEN

. X212 X212 1+------' STIFFENERS ll1;,"PL PLAN PLAN SECTION SECTION FIGURE FIGURE 1.18 1.18 RCIC TURBINE RCIC TURBINE EXHAUST EXHAUST -- REROUTE REROUTE AND AND RESUPPORT RESUPPORT 1-47 1-47 04/29/82 04/29/82

• ýTOR} U6

---~~:-~

, ,

!- 11~i-I"'~~-~ -

, _----I -- R __ -.:..J

---.,.------------t--i--I

- ~----t--l--I I

I

~

~

, f WI!L.r? E><'IGt:

-"} I IEL BOW 10 PIPE.

POf!..7ItJN~of AT £,AfGE()

~)(/~1. 10 11 4' PIPe eLevAiltJN

0 E7E

. fi?1! MoV!3!)

• FIGURE 1.19 CORE SPRAY PUMP TEST CORE TEST RETURN RETURN TRUNCATION TRUNCATION

• 1-48 1-48 04/29/82

• COOPER NUCLEAR STATION COOPER PLANT UNIQUE ANALYSIS REPORT PLANT SECTION 2 SECTION LOADS AND LOAD COMBINATIONS COMBINATIONS

• 2.1

2.1 INTRODUCTION

This section section describesdescribes - the design loads and load load combinations combinations used in in performing the Mark II* containment performing containment reevaluation reevaluation for Cooper Nuclear Nuclear Station.

Station.

These loads These loads are determineddetermined using the criteria criteria established established in in the NRC Safety Saf~ty Evaluation Evaluation Report (SER) (SER) (Reference 11). 11). These ~riteria These criteria are based on the are General Electric General Electric Load Load Definition Report Report (LDR)

(LDR) for the Mark I program program (Reference (Reference 17),

17), the Mark Mark I ContainmentContainment Program Plant Unique Unique AnalysisAnalysis Application Guide (PUAAG)

Application (PUAAG) (Reference 1'9), 19), and the NRC Acceptance Acceptance Criteria Criteria fbr for the MarkMark I ,Containment Long-Term Long-Term Program Program (Reference (Reference 18). 18) . The latestlatest available available revisions of each of these documents were used in revisions in determining determining design design loads loads and load and load combinations/.

combinations;.

The information The information in in this sectionsection relates to the procedures procedures used to apply apply the load definition definition criteria criteria to plant unique unique thermal-hydraulic thermal-hydraulic parameters parameters and and structural configurations structural configurations at Cooper Nuclear Station. Station. Where Where direct application of these criteria criteria resulted resulted in in the need need for excessive structural structural modifications, modifications, alternative alternative criteria criteria were were developed.

developed. These These alternative alternative criteria criteria are summarized summarized in in Subsection Subsection 1.2.2.2; 1.2.2.2; justification justification is is provided where appropriate in where appropriate in the is is section. Important section. Important results are summarized summarized to to indicate load magnitudes indicate magnitudes on selected selected structures.

structures.

This section is is divided divided into a description description of plant thermal-hydraulic thermal-hydraulic parameters parameters related related to containment containment load load definitions, definitions, design loads used in in the original containment original containment design, design, hydrodynamic hydrodynamic loads associated associated with LOCA LOCA and and S/RVS/RV discharge discharge events, events, and load combinations used in in the structural evaluations.

structural evaluations.

All load definitions pertain pertain to the final modified modified structural structural configurations.

configurations.

S In 1-996-1998 the CNS torus-was In 1996-1998 original corrosion the original torus was reanalyzed corrosion allowance allowance in reanalyzed (Reference in support (Reference 57) support

57) in of evaluations in order to restore evaluations to justify justify continued operations continued operations as a result of significant significant pitting pitting corrosion corrosion prevalent prevalent on the torus shell. shell. additional analysis is This additional is onlyonly applicable applicable to the stresses on the lower half of the torus.

stresses torus. See Section 3.2.5 for discussion of of the methods used in in this reanalysis.

reanalysis.

2.2 PLANT THERMAL-HYDRAULIC PLANT THERMAL-HYDRAULIC PARAMETERS PARAMETERS Cooper Nuclear Station Station is is a 778 Mwe boiling water water reactor (BWR (BWR 4) 4) with a Mark Mark II containment system. system. Containment Containment hydrodynamic hydrodynamic data data is is summarized in summarized in Table 2.1.

Table 2.1.

CNS is is currently currently operating operating with an initial initial drywell-to-wetwell drywell-to-wetwell pressure differential differential (Ap) (t.p) of 1.00 1.00 psid (nominal).

psid (nominal). However-, all However, all loads loads used used in in the containment containment structural structural evaluations evaluations are are defined defined for both both zero zero Ap t.p and the current current Ap. t.p. Structural evaluations are performed for the initial Structural evaluations initial condi tions conditions associated with the higher loads.

associated loads. -

The FSAR design temperature temperature for the wetwell wetwell is is 281'F. However, plant unique 281°F. However, transient analyses have transient demonstrated that have. demonstrated that suppression suppression pool temperatures temperatures remain below below 200°F 200'F for all all LOCA and S/RV discharge transients. Therefore, discharge transients. Therefore, temperature for the wetwell reevaluation design temperature reevaluation was taken as 200°F. 200'F.

• The plant is The Valves (S/RVs)

Valves opening opening set points.

is equipped equipped with eight pilot-operated (S/RVs).. The valves are divided into three points. The opening opening and closing pilot-operated Target Rock Safety/Relief closing set 2-1,-

2-- 1, three groups according set points points for each valve Safety/Relief according to the valve are 04/16/02

shown in in Table Table 2.2.

2.2. In addition to the safety and relief In addition relief function, six of the eight S/RVsS/RVs at CNS also serve serve as Automatic Depressurization System Automatic Depressurization System (ADS)(ADS) valves. These valves. These valves are in in all all three groups.

three groups. The ADS function for each each S/RV S/RV is performed is performed by a solenoid solenoid pilotpilot valve connected connected to a 90-psi air air supply.

supply.

Electrical power Electrical power for the ADS is is supplied by two separate separate d-c power stations stations with withswitchover capabilities in switchover capabilities in case of loss of power. power. The ADS valves will will actuate when the preset actuate preset delay delay time expires after after receiving receiving a high drywell drywell pressure signal and a low reactor water level signal (Level 1). 1) . The present present delay time is is nominally 120 seconds maximum. maximum.

The two Group Group I low-low set logic valves valves are indicated indicated in in Table 1.5 with their opening and closing set points.

their points. Low-low set logic and a reduced MSIV MSIV level trip level trip set point are to be implemented implemented as design changes changes to mitigate loads loads on the Mark I containment containment system system (description provided provided in in Section Section 1).1) .

Each of the eight S/RVs S/RVs at Cooper is is connected connected to a discharge discharge line (S/RVDL)

(S/RVDL) which routes through the drywell, drywell, main main vent, vent, and into the suppressionsuppression pool.pool. A A T-quencher discharge T-quencher discharge device is located at the outlet in is located in the suppression suppression pool. pool.

Each S/RVDL is equipped with pressure is equipped pressure sensors to detect S/RV opening. opening. Two Two 10-in. diameter 10-in. diameter vacuumvacuum breakers breakers are currentlycurrently inst~lled installed on each S/RVDL S/RVD~in in the drywell drywell close to the valve. valve.

2.3 2.3 ORIGINAL DESIGN LOADS ORIGINAL LOADS Original Original design criteria design criteria containment system for normal operating for the containment operating and acdident accident conditions conditions included the following load cases: cases:

• ( J..(1)

(2)

(2 (3)

(3)

(4)

(4)

)

)

Dead load Dead load of Seismic:

of the vessel, Seismic: vertical Design pressure vessel, attachments, Dead load of the suppression vertical and attachments, and piping systems suppression pool lateral and lateral pressure (positive pool (positive and negative) loads systems (5)

(5) temperature Design temperature (6)

(6) Vent Vent thrust thrust loads (7)

(7) Jet Jet forces on downcomer down corner pipes For the For the structural structural reevaluation reevaluation program,program, the first first three load cases cases (dead(dead loads and seismic) are considered with the newly defined defined loads.loads. The. remaining four load cases have been redefined redefined in LDR.

in the GE LDR.

Seismic loads on containment Seismic containment system components components are taken taken from the Cooper Cooper Station FSAR (Reference Station (Reference 16). 16) . Seismic Seismic loadsloads are defined in in the vertical vertical and and lateral directions for Operating lateral directions Operating Basis Earthquake (OBE)

Basis Earthquake (OBE) and Safe Shutdown Shutdown Earthquake (SSE).

Earthquake (SSE).

2.4 LOCA-RELATED LOADS LOCA-RELATED LOADS

. This subsection describes

• subsection describes the loads loads on structures structures in in the wetwell and vent vent system during a postulated LOCA. LOCA. In In the event event of a postulated postulated LOCA,LOCA, reactor reactor steam stearn and water water would would expand into the drywell atmosphere. atmosphere. Three Three categories categories of of a LOCA are are considered:

considered:

2-2 2-2 04/16/02

• *

• Design Small Break Small Basis Accident Design Basis Intermediate Accident Intermediate Break Accident Break Accident (DBA)

(DBA)

Accident (IBA)

Accident (SBA) (SBA)

(IBA)

The limiting loads The limiting loads for a particular particular containment containment componentcomponent can be generated generated by by combinations combinations involving involving one of these categories categories and other other containment containment loads. loads. A detailed detailed description description of of each each category category is is provided provided in in the LDR. LDR. A A summary summary description description isis given given below:

below:

(1)

(1) Design Design Basis Basis Accident Accident The The design design basis basis accident accident for a Mark Mark I BWR BWR is is the the instantaneous instantaneous double-ended double-ended guillotine guillotine break break of the recirculation recirculation pump pump suction line line at at the the reactor reactor vessel.

vessel. This This break break results resul ts in in the maximum flow rate flow rate of of primary primary systemsystem fluid fluid and and energy energy into the the drywell, drywell, through the vent* system and into through the vent' system and into the suppression chamber the suppression chamber (wetwell).

(wetwell). The The event.sequence event sequence is is divided divided into into three three phases, phases, which which are are identified identified as follows:follows:

(a)

(a) Pool Pool Swell, Swell, results results from from thethe airair in in thethe vent vent system system being being forced forced into into the the suppression suppression pool pool at a sufficiently sufficiently high rate rate that that the the upper upper water water volume volume of of thethe pool pool is is displaced displaced upward, upward, laterlater falling falling back back to its its original original position; position; (b)

(b) Condensation Condensation Oscillation, Oscillation, results results from from aa steam steam or or a steam-and-air steam-and-air mixture mixture flowing flowing through through the the vent vent system system at at a high high rate, rate, and and forming forming discharge discharge bubbles bubbles at at thethe endend of of the the downcomers downcomers which which oscillate oscillate in in size size and and pressure; pressure; (c)

(c) Chugging, Chugging, is is aa result result of of intermittent intermittent flow flow of of nearly nearly pure pure steam steam through through the the downcomer downcomer exits exits and and into into thethe suppression suppression pool, pool, forming forming largelarge bubbles bubbles which which expand expand and and then then rapidly rapidly collapse.

collapse, At At thethe end end of of the the LOCA, LOCA, whenwhen ECCS ECCS water water spillsspills out out ofof thethe break break and and rapidly rapidly reduces reduces the the drywell drywell pressure, pressure, the the suppression suppression chamberchamber isis vented vented to to thethe drywell drywell through through vacuum vacuum breakers breakers to to equalize equalize the the pressure pressure between between the the two two vessels.

vessels. The The ECCS ECCS cools cools the the reactor reactor core core and and transports transports the the heat heat to to the the water water in in thethe suppression suppression chamber,chamber, thus thus providing providing aa continuous continuous path path for for thethe removal removal of of decay decay heat heat from from the the primary primary system.

system.

(2)

(2) Intermediate Intermediate Break Break Accident' Accident' The The intermediate intermediate break break accident accident (IBA) (IBA) for for aa MarkMark II BWR BWR isis defined defined to 2 to bebe aa liquid liquid break break equalequal to 0.1 ft to 0.1 ft2.. This This break break is is large large enough enough such such thatthat the the HighHigh Pressure Pressure CoolantCoolant Injection Injection System System (HPCI)

(HPCI) cannot cannot maintain maintain the the coolant coolant level level in in the the reactor reactor vessel, vessel, but but the the reactor reactor pressure pressure isis not not substantially substantially reduced. reduced. The The break break isis ofof sufficient sufficient magnitude magnitude that that operation operation of of thethe ADSADS willwill occur occur soon soon after after the the break break and and will will result result in in reactor reactor depressurization.

depressuri~ation.

2-3 2-3 04/16/02 04/16/02 r

• Following sufficiently sufficiently does not does continues continues not lead pressure increases.

pressure the from slow t.he the break, break, slow th~t drywell the the that the clearing of lead to pool swell. swell. As to drywell As the to the wetwell, increases. Following the purge of air the flow through the vent system in the pool.

in pool.

of air the flow of pressure air of air, system becomes steam, which is from the air, wetwell, the wetwell air transient the vent system steam, and water wetwell airspace from the drywell, from system water drywell, is quenched is is The initiation The initiation of the ADS vents steam from the reactor vessel vessel directly into the suppression suppression pool through the S/RVDL.

S/RVDL. ADS ADS operation continues until until the reactor vessel is is depressurized.

depressurized.

The energy added to the pool via the ADS results in in a heating of of suppression pool and a small additional increase the suppression increase in in wetwell wetwell and drywell pressure.

pressure. When the reactor is is sufficiently sufficiently depressurized such that the low-pressure depressurized low-pressure ECCS water floods the vessel, liquid spills vessel, spills out the break and condenses steam steam in in the drywell.

drywell. drywell-to-wetwell vacuum breakers This causes the drywell-to-wetwell breakers to to open and equalizes the drywell and wetwell wetwell pressures.

pressures.

(3)

(3) Small Break Accident Small Accident The small The small break break accident accident (SBA) (SBA) for for a Mark I BWR is is defined defined to be be a 0.01 ft ft 22 steam steam break in in the primaryprimary system. Following the break, break, the drywell pressure slowly increases, increases, depressing the water level level in the in the vents vents untiluntil drywell air air and steam pass to the suppression pool.

pool. The steam is The is condensed and the air condensed air rises rises to the free airspace, resulting in airspace, resulting in wetwell pressurization. pressurization. Flow through the vent systemsystem and into the pool is sufficiently is sufficiently slow that no significant significant bubble or fluid dynamic dynamic loading occurs. occurs. At 10 minutes minutes after after the the break, break, the the operator operator initiatesinitiates the ADS,ADS, allowingallowing primary primary system system fluid to flow directly directly to the pool. pool. When the reactor reactor pressure is pressure sufficiently low, is sufficiently low, the the ECCS ECCS is is used used to to circulate circulate suppression suppression pool water into the reactor reactor and cool the pool water.

water.

The sequencing The sequencing of of the the LOCALOCA phenomena phenomena for for each category,category, and the duration duration of of each each LOCALOCA phenomenon, phenomenon, is is provided provided in in Subsection Subsection 2.7. 2.7.

2.4.1 2.4.1 Containment System Pressure Containment Pressure and and Temperature Temperature Response Response Containment pressure Containment pressure and temperature temperature transients for each each LOCA category category were were taken taken from from the the Plant Unique Load Definition Definition (PULD) (PULD) for CNS (Reference (Reference 22). 22).

The procedure The procedure used used to determine these to determine these transients transients is is given in in the the LDR and has has previously previously been been reviewed reviewed by by the NRC in the NRC in thethe Safety Evaluation Report.

Safety Evaluation Report.

2.4.1.1 2.4.1.1 Design Basis Accident Accident Initial conditions Initial conditions for for evaluating evaluating DBA DBA drywelldrywell and and wetwell wetwell pressure pressure and and temperature transients are temperature transients are shown shown in in Table 2.3. 2.3. Transients Transients were determined determined for for both both Ap=0 ~p=O and and Ap=l.0

~p=1.0 psid.

psid. The initial initial conditions conditions maximize maximize the initial the initial drywell drywell pressurization pressurization rate rate and and the vent vent system system thrustthrust loads. loads. To utilize To utilize aa bounding bounding wetwell wetwell pressurepressure response,response, 1.0 1.0 psi psi was was added to the calculated calculated pressure pressure transient transient for for the the time time period period less less than 30 30 seconds, seconds, and and 2.02.0 psi was was added to the wetwell pressure added to the wetwell pressure calculated at calculated at 30 seconds seconds for the the time time period beyond beyond 30 seconds.

30 seconqs.

2-4 2-4 04/16/02

• Figures 2.1 and 2.2 show the DBA pressure to being corrected 2.4.1.2 2.4.1.2 Initial corrected for .'bounding condition Ap=l condition ~p=l psid.

Initial conditions psid.

Intermediate Break Accident Intermediate conditions for evaluating Accident evaluating IBA drywell temperature transients pressure and temperature drywell and wetwell transients (prior pressure response) for initial

,'bounding wetwell pressure initial pressure and wetwell pressure temperature temperature transients are shown in in Table 2.4.2.4. Figures 2.3 and 2.4 show the IBA pressure and temperature transients for initial condition Ap=l temperature transients ~p=l psid.

Reducing the initial initial drywell-to-wetwell drywell-to-wetwell Ap insignificant changes

~p produces insignificant changes inin the transients.

transients. Peak containment pressures, containment containment pressures, temperatures at the containment temperatures end of reactor pressure pressure vessel (RPV) blowdown, and containment (RPV) blowdown, containment pressures pressures andand temperatures at the time of ADS initiation are identified temperatures identified on the figures.figures.

2.4.1.3 2.4.1.3 Accident Small Break Accident Initial conditions for evaluating Initial conditions evaluating SBA containment containment transients transients are the same same as those those used for the IBA transients (Table 2.4). 2.4). SBA transients transients are are insensitive to ~p; Ap; no significant significant changes are observed for ~p=O. Ap=0.

Figures 2.5 and 2.6 show the SBA pressure pressure and temperature temperature transients.

transients. Peak containment pressures, containment containment pressures, containment temperatures temperatures at the end of RPV blowdown, blowdown, and containment containment pressures pressures and temperatures temperatures at the time of ADS initiation are identified on the figures.

identified figures.

2.4.2 2.4.2 Vent System ,Thrust Vent Thrust Loads Loads Vent system thrust loads were defined defined for DBA conditions conditions only. These only. These conditions conditions involve the most rapid pressurization pressurization of the containmentcontainment system, the largest vent system mass flow rate, and, therefore, rate, and, therefore, the most severe severe vent vent system system thrust loads.

loads.

2.4.2.1 2.4.2.1 Analysis Analysis Methods and Results Results The procedure procedure for evaluating vent system thrust loads is evaluating is described in in Section Section 4.2 of the LDR. The procedure LDR. procedure uses thrustthrust equations equations which consider which consider forces due to both pressure pressure distribution and momentum,momentum, to definedefine horizontal horizontal and vertical vertical thrust forces on the main vents,vents, vent header, header, and downcomers downcomers as shown shown in in Figure 2.7.

2.7.

Initial conditions are the same as those used to predict Initial conditions predict DBA containment containment transients transients (Table 2.3). 2.3) . Analyses Analyses were were performed for the bounding bounding case of of

~p=O.

Ap=0. The transients transients were taken from the PULD and are are/'-shown I"shown in in Figures 2.8 Figures 2.8 to 2.10.

2.10.

2.4.2,2 2.4.2,2 Load Application The horizontal and vertical The horizontal vertical main vent thrust transients shown ,in -in Figure 2.82.8 represent the resolution of the thrust loads which which act on the end cap cap of the main vent.

vent. This loading loading is is actually actually distributed distributed over the end cap area. area.

The vertical horizontal vent header vertical and horizontal header thrust transients transients shown in in Figure Figure 2.9 2.9 represent the vent header loading per miter joint.

represent joint. Vertical Vertical loading loading is is due toto

• the contributions contributions of individual downcomer downcomer pairs, which which were assumed to be equal.

equal, 2-5 2-5 04/16/02

• momentum horizontal and The horizontal for a single Total vertical Total vertical and vertical single downcomer, downcomer, vertical thrust transients shown in momentum of the flow through the downcomer and and are thrust loads and net thrust entire vent system and are defined as follows:

are the resultant forces downcomer miter joint.

net vertical follows:

in Figure 2.10 are loads forces due to a change thrust thrust loads exist change in for for in the FlVlT == Main FIVIT Main vent end cap vertical vertical force multiplied by the number of of main vents.

vents.

F2VT = Vent header vertical vertical force per miter joint, multiplied by the number of vent header miter joints. joints.

F3VT F3VT = Downcomer miter joint vertical

= Downcomer vertical force multiplied by the number of of downcomers' downcomers~

FNETV = = FIVIT FlVlT + F2VT + F3VT Figure Figure 2.11 shows the total total net vertical thrust loads over a time period of of seconds.

30 seconds.

2.4.3 2.4.3 Loads Associated Loads Associated with Pool Swell Swell Immediately Immediately following following postulated a postulated DBA rupture, the pressure pressure rapidly increases in increases in thethe drywell drywell and and ventvent system, system, resulting resulting in in the water leg in the in the downcomers downcomers being being injected injected into into the the suppression suppression pool. pool. When this this clearing process is process is completed, completed, the the air air behind the downcomer behind downcomer waterwater slug slug produces produces a

• bubble bubble at at thethe end end of of the the downcomer.

downcomer. The The water water above above the the bubble bubble isis accelerated upward upward as as the bubble expands.

the bubble expands. As As the bubble bubble expansion continues, expansion continues, the pool the pool water rises water rises in in the the torus torus and and compresses compresses the airspace airspace above the pool surface. surface.

Eventually, Eventually, the bubble the bubble "breaks "breaks through" through" to to thethe torus airspace, airspace, and the displaced pool liquid displaced pool liquid settles back to itssettles back to its original level.

level.

Pool swell Pool phenomena swell phenomena are associated are associated only with a DBA event. event. Loads are generated generated on on thethe torustorus shell boundary shell boundary and and all all containment components containment components located within the within the torus.

torus. Plant Plant unique loads unique loads associated associated with pool pool swell are described in this in this section.section.

2.4.3.1 2.4.3.1 Torus Net Torus Net Vertical Vertical Loads Loads In the In the postulated postulated LOCA-DBA LOCA-DBA event, event, the downcomer air, the downcomer air, which which is initially is initially at at drywell drywell pressure, pressure, is injected into the suppression is injected suppression pool,pool, producing producing a downwarddownward reaction reaction force force on on thethe torus.

torus. The The subsequent subsequent bubble expansion causes bubble expansion causes the pool pool water to swell in the water to swell in the torus, compressing torus, compressing the airspace above airspace above the pool and and producing an producing an upward reaction force upward reaction force on on the the torus.

torus. These vertical vertical loads loads create aa dynamic dynamic imbalanceimbalance of forces on on the torus,torus, which act in in addition addition to the weight of the the water into the torus. torus.

The The torus torus net net vertical vertical dynamicdynamic loads/are loads)are defined defined as as load load time time histories.

histories. The The static loads (i.e., water and static loads (i. e., water and structural weights) are structural weights) are not included included in in these these load load histories.

histories. The The net net dynamic dynamic load load is is defined defined as an equivalent equivalent pressurepressure acting acting on the the projected projected plan plan areaarea of of the torus.

torus.

. The The torus torus net net vertical vertical loads, loads, based based on plant-specific plant-specific Quarter Quarter ScaleScale Test Test

• Facility (QSTF)

Facility (QSTF) data, data, are determined determined by spatial spatial integration integration of of the pressure pressure transducers transducers located located on on the QSTF torus shell. shell. These These load histories histories are corrected corrected for for water water mass mass inertia.

inertia. The assumptions used in The assumptions in modeling modeling the the actual actual 2-6 2-6 04/16/02

. plant In the QSTF facility and calculation of net torus load histories are given given in The is is taken in Section 4.3.1 of the LDR.

plant inthe QSTF facility The net toru~

torus load history for ~p=O taken from the PULD.PULD.

LDR.

and calculation of net torus load histories are Ap=0 is is given in in Figure 2.12.

In accordance with Section 2.3 of the NRC Acceptance Criteria, the following 2.12. ~his

'This transient transient In accordance with Section 2.3 of the NRC Acceptance Criteria, the following margins margins were applied to each loading loading phase:

phase:

UP UP == UP UPmean (UPmean )

mean + 0.215 (UPmean)

DOWNm,,,

DOWN == DOWN meall 10_-5(DOWNmea)

+ 2 xx 10- 0 (DOWNmeall ) 22 Where "UP" and "DOWN" Where "UP" indicate the peak upward and peak "DOWN" indicate peak downward torus torus net net vertical vertical pressures pressures (in (in lbf) with the additional additional NRC margins included, included, andand "mean" refers to the average "mean" refers average of QSTF test test results results (lbf). (lbf). These margins margins were were applied to the QSTF "mean" "mean" load function prior to scaling the load function to full-scale equivalent equivalent conditions.

conditions. The margin margin for the downward loading derived in function was derived in terms of a fraction of the load-at load at the time of the peak downward load, load, and that fraction fraction was applied to the entire entire downward downward loading phase.

phase.

transient with the margins applied is The pool swell transient is shown in in Figure 2.13 forfor Ap=0.

~p=O.

The plant plant unique QSTF test series for pool swell showed showed that the net verticalvertical

• upforce upforce applied applied to the torus exceeded exceeded the weight of the torus and its its contents, contents, and a net upward upward pressure pressure was measured. measured. To evaluateevaluate this event, event, itit was necessary necessary to account account for the reduction in in pool mass due to the mass of mass of water "in"in flight" flight" at the time of maximum upforce on the torus. torus. The reduced pool mass does not affect affect the torus forces presented presented above, above, since since these were were referenced referenced to the full water weight. weight. The effectiveeffective mass simply provides an estimate estimate of the vertical inertial force r,esisting resisting upward displacement displacement of the torus.

torus.

From the QSTF test data, the resultant weight fraction of the pool in in flight flight was found to be 59% 59% for, for Ap=0

~p=O psid.

All torus shell evaluations evaluations were performed for the initial condition Ap=O.

initial condition ~p=O.

The analyses are therefore therefore conservative conservative since they take no credit for the mitigating effects of the dryweil-to-wetwell mitigating effects drywell-to-wetwell pressure differential.

pressure differential.

)

2.4.3.2 2.4.3.2 Torus Shell Pressure Pressure Histories Torus shell structural evaluations shell structural evaluations were were' performed performed using local torus shell shell pressure histories. When integrated pressure time histories. integrated over the torus shell inside surface, surface, these local pressure pressure transients result in in the net torus vertical vertical load load due toto pool swell.

swell. Torus shell pressure histories histories were obtained from the CNS PULD were obtained based on plant unique QSTF tests with Ap=O. ~p=O. Pressure Pressure histories for the wetted portion portion of the shell and the airspace airspace are shown in in Figures 2.14 and 2.15, 2.15, respectively.

respecti vely. The initial static pressure pressure was subtractedsubtracted so that only the dynamic pressure dynamic pressure histories are shown. shown.

• In accordance In accordance with the NRC Acceptance Acceptance Criteria, Criteria, these averaged averaged submerged submerged and airspace pressure airspace pressure histories histories were modified modified to contain specified margins for contain specified for 2-7 2-7 04/16/02

• the torus net vertical 2.15 include The pool vertical downward include this modification.

pressure history transients pressure longitudinal downward and upward loading phases.

modification.

pool swell airspace pressure pressure transients transients longi tudinal and circumferential in in transients shown in at all points on the unwetted portion of the torus shell.

Figure Figure circumferential directions.

2.14, 2.14, phases.

however, however, directions. The longitudinal Figures 2.14 and in Figure 2.15 are the same shell. The submerged vary along the variation of longitudinal variation and same submerged of average submerged the average pressure is submerged pressure is based on 1/12 1/12 scale, scale, three-dimensional three-dimensional (3-D)

(3-D) test results results (Section 4.3.2.2 4.3.2.2 of the LDR) LDR), , and the circumferential circumferential variation is variation is based on 1/4 scale, scale, two-dimensional two-dimensional (2-D) test results. results. These These variations are given as multipliers variations multipliers to be applied average submerged applied to the average submerged histories.

pressure histories.

2.4.3.

2.4.3.33 Impact, Drag, Impact, Drag, and Fallback Fallback LoadsLoads During the LOCA-DBA pool swell transient, transient, the rising pool will impact impact structures structures above the initial pool surface. surface. As the pool surface surface rises and impacts the structures, structures, loadsloads are generated generated due to both the impact and drag. drag.

The timing and amplitude amplitude of the loading on a particular particular structure structure depends on depends on the velocity velocity of the pool surface surface as it it impacts impacts and flows past the structure.

structure.

Following the pool swell transient, transient, the pool water falls back to its its original original level, and in level, generates fallback loads on structures in the process generates structures inside inside the torus which are located located between the maximum bulk pool swell height and the downcomer exit level.

downcomer level. The fallback fallback load starts* starts-asas soon as the pool swell swell reaches its reaches its maximum maximum height and ends when when the pool surfacesurface falls past the structure structure of concern concern. .

• 2.4.3.3.1 2.4.3.3.1 The The load definition different Vent System System definition for the vent system impact and drag is different form for each of the three e.g., the main vent, e.g., vent, vent header, header, and downcomers.

downcomers.

is specified specified in components of the vent system, three major components in a The The CNS plant unique, unique, quarter-scale quarter-scale 2-D pool swell tests, the EPRI impact impact data, and the 1/12 1/12 scale, 3-D test data provide the primary basis for the vent system impact and drag load definition. definition. Vent system loads are provided in the PULD.

in PULD. Loads associated with Ap=0 ~p=O initial condition were used in in the structural evaluations, structural evaluations, with the exception exception of the main main vent impact and drag loads where where the boundingbounding initial condition of Ap=l initial condition ~p=1 psid was used.

used.

(1)

(1) Downcomers Downcomers The impact impact and drag loading loading on the downcomers downcomers was generically generically defined defined from the 1/41/4 scale tests.

tests. The downcomer pressure pressure transient with an amplitude of 8.0 psid as defined defined inin the LDR is is to be applied uniformly applied uniformly over the bottom 50' 50° sector of the angled portion of the down downcomer comer perpendicular perpendicular to the local downcomer downcomer surface. The impact surface. impact pressure pressure transient begins as soon as the rising rising pool reaches reaches the lower end end of the angled portion of the downcomer downcomer (0.20 sec), sec), and ends at the time of maximum pool swell swell (0.72 sec) sec). .

• 2-8 2-8 04/16/02

• (2)

(2 ) Vent Header The Header The local impact the QSTF measured impact and drag pressurepressure transients were obtained measured impact and drag pressures.

the vent header local impact triangular pulse load triangular load with impact and drag pressures. The general drag pressure with a duration of approximately obtained from general form of pressure transient transient is approximately 0.1 sec.

from is sec.

of a

The impact and drag pressure transient corresponds corresponds to an average downcomer downcomer spacing impact impact and drag velocity.velocity. Since the impact and and drag drag velocity varies along the length of the vent header, header, the local local impact impact and drag pressure pressure transients are adjusted adjusted for impact impact and drag velocity.

velocity.

Impact Impact and drag pressure transients were were developed deve~oped for eNS CNS at the vent vent header header locations shown shown in- in- Figure 2.,16.

2.16. The maximum pressure is is 17.7 psi at 60° 60' from bottom dead center center and at a longitudinal longitudinal location z/l location z/l of 0.92.

0.92.

(3)

(3) Main Vent Main Vent Main ventvent impact and drag loads were determined determined using the QSTF results results and the procedure procedure outlined in in Section 4.3.3.2 4.3.3.2 of the LDR.

LDR.

A three-foot A three-foot section of the main vent experiences experiences impact impact and drag loads. The net impact load transient is loads. is shown in in Figure Figure 2.17.

2.17.

2.4.3.3.2 2.4.3.3.2 Vent Header Header Deflector Deflector

• The pool the PULD shown inin 2.4.3.3.3 2.4.3.3.3 swell load transient for the vent header deflector based on QSTF measured measured impact and drag loads.

Figure 2.18 for the bounding Other bounding case of ~p=O.

Structures Above Other Structures Impact, drag, and fallback Above the Pool Pool Ap=0.

deflector is provided in is provided loads. This transient is in is Impact, fallback loads on structuresstructures other than the vent system system above the pool surface were determined determined using the following following procedure:

procedure:

(1)

(1) Pool swell impact impact velocity at any point in in airspace was the airspace was determined. This velocity is determined. is based based on velocity profiles profiles provided in in the PULD as a result of QSTF and 1/12-scale 1/12-scale 3-D tests. tests. The The results results of the EPRI main vent orifice tests orifice tests were included included in in this data.

data.

(2)

(2) Impact Impact, and and drag forces drag forces were calculated were calculated using using the procedure procedure described in in Section 2.7.

2.7, of the NRC Acceptance Acceptance Criteria.

Criteria.

(3)

(3) Pool fallback calculated using the fallback loads were calculated the procedure procedure described in Section 4.3.6 of the LDR.

in Section LDR. Fallback loads loads are are applied applied uniformly uniformly over the upper proj projected ected surface surface of the structure structure in in the most most critical critical direction.

direction.

All loads were defined defined for both initial initial conditions conditions Ap=0 ~p=O and ~p=l Ap=l psid. The The bounding bounding loads were were used in in the structural structural evaluations.

evaluations.

• Impact, Impact, drag,drag, and fallback loads were determined determined in in this manner manner for the structures structures indicated indicated in in Table 2.5.

2.5.

2-9 2-9 04/16/02

• 2.4.3.4 Froth impingement regions:

regions:

Froth Impingement Froth ImDinqement and loads were and Froth Froth Fallback defined Fallback Loads for structures structures Region I - Froth formed by the rising pool striking the bottom of the vent header and/or the vent header deflector. deflector.

above above the pool in in two Region 11- II- -Froth formed by the water

-Froth above the expanding pool and detached from detached from the bulk pool suiface surface These regions are shown in in Figure 2.19 for for CNS.

CNS.

Froth impingement Froth impingement loads loads were defined using the procedure procedure given in in Section Section 4.3.5.2 of 4.3.5.2 of the LDR, the LDR, as as modified by Section 2.8 of the NRC Acceptance Acceptance Criteria.

Criteria. Pool surface displacement and velocity profiles from the QSTF and EPRI tests EPRI tests were were givengiven in in thethe PULD.

PULD. The Region I froth impingement impingement loads were were determined from the QSTF plant-specific determined plant-specific high-speed high-speed films, as described in in Section 2.8 of the NRC Ac~eptance Section Acceptance Criteria.

Criteria.

Froth impingement Froth impingement and fallback loads are specified and fallback specified as rectangular rectangular load pulses of 80, of 80, 100, 100, and and 1000 1000 milliseconds milliseconds for Region Region I, I, Region II, II, and fallback loads, respectively.

loads, respectively. Figure Figure 2.20 shows the load transients and directions of of load application application for these loads. loads.

All loads All loads were defined for both initial were defined* initial conditions Ap=0 conditions ~p=O and ~p=l Ap=l psid. The The bounding load was usedused in in the structural structural evaluation.

evaluation. Table 2.6 indicates

• bounding load was indicates the structures structures in in the torus for which froth impingement impingement and fallback fallback loads were were defined. This table includes defined. This table includes all structures locatedall structures located in either Region I or II.

in either II.

2.4.3.5 2.4.3.5 LOCA LOCA Water Jet-Induced Loads Water Jet-Induced Loads As the As the drywell drywell pressurizes pressurizes during postulated LOCA-DBA, a postulated LOCA-DBA, the water slug water slug initially initially standing standing in in the submerged submerged portion of each each downcomer downcomer is is accelerated downward downward into the suppression suppression pool. pool. As the water slug enters enters the pool, pool, it it forms forms a water water jet jet which induces drag loads submerged structures.

loads on submerged structures.

The methodology to The methodology to determine determine the LOCA water water jet jet loads on the structures structures intercepted intercepted by by the jet jet is is given gi v~n inin Section Section 4.3.7 of the LDR.* LDR. In In accordance accordance with with the the NRCNRC Acceptance Acceptance Criteria, Criteria, the the load definition was extended load definition extended to all all submerged submerged structuresstructures which are within within four Ifdowncomerdowncomer diameters diameters below the downcomer downcomer exit exit elevation, elevation, even if if the structure structure is is not intercepted intercepted by the jet.

jet. The The extended extended methodology methodology defines defines the LOCA LOCA water water jet-induced jet-induced loads on on submerged submerged structuresstructures by generating generating a flow field in in the suppression pool the suppression pool induced induced by by expanding expanding and moving hemispherical caps moving hemispherical represent the jet caps which represent jet front and front and contain the contain the same amount of water water volume as as the jet jet at each each downcomer downcomer exit.

A A comparison comparison of of the the QSTFQSTF results results for zero zero and operating operating drywell-to-wetwell drywell-to-wetwell pressure differentials pressure differentials shows shows that the Ap=0

~p=O case results in case results in a longer longer jetjet penetration penetration than than the Ap=l

~p=l psid case.

psid case. Therefore, Therefore, only the the Ap=O ~p=O case waswas analyzed.

analyzed.

• There There are are no no submerged submerged structures structures experiencing experiencing direct direct jet jet impact impact loads; loads; however, however, drag drag loadsloads have have been been derived derived in in accordance accordance with with the NRC Acceptance Acceptance 2-10 2-10 04/16/02 04/16/02

Criteria. Table Criteria. Table 2.7 lists lists the structures structures for which loads were defined. defined. All All other submerged other submerged structures structures are outside of the jet jet load load zone.

zone.

Interference Interference effects effects on all all. LOCA' jet-induced loads were included water jet-induced LOCA 'water included as as multipliers on the loads determined by the procedure multipliers procedure described above described above (Subsection 2.4.3.7).

2.4.3.7).

2.4.3.6 LOCA Air Bubble-Induced Bubble-Induced Drag Loads Loads During the initial During initial phase of a postulated postulated LOCA-DBA, LOCA-DBA, the drywell air air space is is pressurized rapidly pressurized rapidly by flashing steam discharging from the ruptured ruptured pipe.pipe. Air Air is purged from the drywell is drywell and vent system system and and is is discharged through the discharged downcomers downcomers into the suppression suppression pool. pool. The charging, charging, expanding expanding bubbles at the end of the downcomersdowncomers create create velocity and acceleration a~celeration fields in in the pool,pool, thus inducing drag forces on structures structures initially initially submerged submerged in in the pool.

pool.

The computer The computer code LOCAFOR, LOCAFOR, developed developed by GE, GE, was used to calculate calculate the drag loads due to air air discharge discharge on submerged submerged structures.

structures. The bases of the flow flow model and the assumptions used in in the load evaluation evaluation for LOCA air air bubble-induced drag loads bubble-induced loads are described described in in Section Section 4.3.8.1 of the LDR. LDR.

The drag load formulation starts starts by considering considering an infinitesimal infinitesimal bubble bubble (point source) in in an infinite infinite liquid pool. pool. The mass/energy conservation conservation equation and the bubble-dynamics equation bubble-dynamics equation are solved simultaneously, equation simultaneously, to to obtain the radius radius of the bubble bubble as a function of time. The velocity and acceleration acceleration at any any time and location in in the infinite infinite pool are calculated from the time-history of the bubble bUbbl.e radius.radius. The equivalentequivalent velocity and and

• acceleration at any point acceleration surface surface is is obtain the total The calculation total drag force.

calculation is structure under consideration structure point in obtained by using the method obtained velocity and the acceleration

. obtain force.

is continued at every consideration or until in the idealized rectangular acceleration are calculated.

method of images.

every t{me until time step rectangular pool with a free images. Drag loads due to the calculated. The two components are added to step until until the bubbles coalesce.

touches the the bubble touches coalesce. When the bubble to bubble touches the structure, touches structure, the structure structure will not experience experience any more more load.

load. After After the bubbles coalesce, bubbles coalesce, the pool swell flow field above the downcomer exit exit elevation elevation is is derived from the QSTF plant unique test. test.

The analyses were done for both initial initial conditions Ap=O conditions t.p=O and Ap=l t.p=1 psid.

Table 2.8 lists lists the structures structures for which LOCA air air bubble drag loads were were defined.

defined.

Interference effects Interference effects on all all LOCA airair bubble drag loads were included as bubble as multipliers on the multipliers loads determined determined by the procedure described procedure described above above (Subsection (Subsection 2.4.3.7)2.4.3.7). .

2.4.3.7 2.4.3.7 Interference Interference Effects Effects In evaluating submerged structure In structure drag loads, loads, consideration consideration of interference interference effects effects is required is required by the NRC Acceptance Acceptance Criteria Criteria (Section 2.14.2).

2.14.2).

Interference effects Interference etfects are are applicable applicable to structures structures whose whose submerged submerged fluid loads may be influenced influenced by other other nearby structures.

nearby structures. Interference Interference effectseffects are generally generally caused by the production production of turbulent water flow on the downstream downstream

• side of a structure.

structure. Such Such effects effects are highly dependent on the location location and and orientation orientation of nearby structures with respect respect ,(to to the target target structures.

structures .

Table 2.8 summarizes summarizes the factors used in in the load load definitions.

definitions. The The 2-11 04/16/02

• interference effects interference according to the procedure where where interference the NRC were parallel.

parallel. In effects for .the interference effects procedure in were not applicable.

less than three average In applicable. Such these cases, the submerged in the NRC Acceptance effects must be considered cases, as required structures were usually evaluated submerged structures Acceptance Criteria.

Criteria. Situations considered but the techniques Situations existed techniques specified situations arise when two structures Such situations average diameters apart, but are not within required by the NRC, wi thin 30° specified by structures are 300 of being NRC, a detailed interferenceinterference by effects analysis effects analysis was performed. performed. The computer analysis, using a finite computer analysis, finite elementelement calculation technique, calculation technique, determined the increase determined increase of the loads due to the presence presence of another another nearby structure. structure.

2.4.4 2.4.4 Loads Associated with Condensation Loads Associated Condensation Oscillation Following the pool swell swell transient of a postulated postulated LOCA, LOCA, there is is a period during which during which condensation condensation oscillationsoscillations (CO) (CO) occur at the downcomer downcomer exits. exits.

Condensation oscillation Condensation oscillation loads on the torus shell, loads shell, submerged structures, and submerged structures, and in in the the vent vent system system are are caused caused by by periodic periodic pressure oscillations.

oscillations. These These pressure pressure oscillations oscillations are associated associated with the pulsating pulsating movement of the steam-water steam-water interface interface of the downcomer water water slug caused by variations variations in in the condensation rate.

condensation rate.

As discussed in As discussed in Section Section 4.4 4.4 of the LDR, of the LDR, the loads specifiedspecified for CO are are based on results from the Full on results from the Full Scale Test Facility Scale Test Facility (FSTF).

(FSTF) . ItIt was observed observed that the CO loads loads with the largest largest amplitude occurred occurred during the DBA event. event. CO loads during the during the IBA IBA are are bounded by chugging loads. Chugging loads are typically chug)jing loads. typically used used in in the the structural evaluations evaluations in in lieu lieu of IBA CO loads (see

• Subsection 2.4.5)

Subsection 2.4.5). .

S 2.4.4.1 2.4.4.1 Torus Shell Loads Loads The The CO CO loadload on on the submerged portion of the torus shell is the submerged is Em an oscillating oscillating load load caused by periodic periodic pressure oscillations oscillations superimposed superimposed upon the prevailing prevailing local local staticstatic pressures.

pressures. The The load is is defined as a rigid wall load which which is is to to be be used used in in conjunction conjunction with a flexible wall coupled coupled fluid-structure fluid-structure model model in in the structural evaluations.

structural evaluations.

The The values values of of pressure pressure amplitude amplitude versus frequency for the baseline baseline rigid rigid wall wall DBA DBA CO CO load load definition definition are given in in Table 2.9. 2.9. This load definition is is taken directly directly from from the the LDR LDR (Section 4.4.1.2.1)

(Section 4.4.1.2.1) and and isis based on FSTF test test data,data, which was which was corrected corrected to remove to remove effects effects of the FSTF wall flexibility flexibility (Reference 23).

(Reference 23). This CO load definition load definition includes the results results of the supplemental FSTF tests supplemental tests required by the NRC (Reference 24). 24) .

Three Three alternative alternative sets sets of spectral spectral amplitudes amplitudes are provided provided in in the range range from from 44 toto 1616 Hz,Hz, and and the the alternate alternate which which maximizes maximizes the responseresponse is is to be used. used. For For all all structural structural evaluations,evaluations, these these alternative alternative amplitudes amplitudes were enveloped, enveloped, resulting resulting in in aa conservative conservative torus shell loading. loading.

The The DBA DBA CO load is CO load spatially is spatially distributed uniformly distributed uniformly along the torus torus centerline centerline and and has a linear linear hydrostatic hydrostatic variation variation with depth as shown in in Figure 2.21. 2. 2l.

Also shown Also shown in Figure 2.21 in Figure 2.21 is is aa graphical graphical representation representation of the DBA CO data contained contained in in Table Table 2.9. 2.9. The The total spectrum from 0 to 50 Hz was considered.

total spectrum considered.

S

• Since the dimensions dimensions of the torus and the number of downcomers for CNS are different different from from those those of of the FSTF, the FSTF, the magnitude magnitude of the condensation condensation oscillation oscillation loads given given in in Table Table 2.9 were modified using a multiplication factor which factor which accounts*

accounts for the effect effect of the pool-to-vent pool-to-vent area ratio. ratio. The The 2-12 04/16/02

plant unique CO load on the torus shell is obtained by multiplying the S amplitudes amplitudes plant unique 0.91. The 0.91.

of the The resulting the load CO baseline resulting load is on therigidtorus is applied wall shell load given is applied to the prevailing local static in in Table Table by obtained 2.9 multiplying by a factor the static pressures pressures of of on the on the wetted wetted portion portion of of thethe torus shell shell at at the appropriate appropriate times times given in in 2.10.

Table 2.10.

2.4.4.2 Vent System Loads Vent Loads Oscillating loads Oscillating loads on on the the vent system during the condensation condensation oscillation oscillation phenomenon are caused phenomenon are caused by harmonic by harmonic pressure pressure oscillations oscillations superimposed superimposed on the prevailing prevailing local local static static pressures in in the vent system. system. The vent system system components subjected components subjected to to these loads include the main vents, vents, the vent header, header, and downcomers.

downcomers.

Table 2.11 Table 2.11 gives gives the the magnitudes magnitudes and and frequencies frequencies of this pressure pressure load for for both DBA and IBA CO.

both DBA and IBA CO. These loads are These loads are based on the data from FSTF test FSTF test M8 M8 (large liquid (large liquid break),break), as described in in Section 4.4.4.1 of the LDR. LDR.

The The CO pressure CO pressure load load specified specified for for the downcomers downcomers was used only to calculate the the circumferential structural circumferential structural response response (i.e., (i.e., hoop stress) of the downcomer, hoop downcomer, not not the vent system responses the vent system responses to lateral, to lateral, thrust, or other loads which are transmitted through trans~itted through the downcomers to other components. components.

2.4.4.3 Downcomer Lateral Lateral Loads Loads Downcomer lateral Downcomer lateral loads due loads due to CO to CO werewere defineddefined in in accordance with accordance the procedure in procedure in the the LDR.

LDR. These These loads are based on loads are based on FSTF test measurementsFSTF .test measurements correlated correlated with with results results from from aa structural structural model model of the FSTF vent system system (Reference 25).

(Reference 25 ) NRC review of NRC review of this load this load definition definition will be included included in in the SER supplement SER supplement to to be issued.

be issued.

Net lateral Net lateral loads on loads on thethe submerged submerged portions portions of of thethe downcomers downcomers during during CO arise arise due to differential pressure between due to differential pressure between two downcomers of a downcomer two downcomers downcomer pair. pair.

Additionally, Additionally, an oscillating an oscillating internal internal pressure pressure is simultaneously added to is simultaneously to both downcomers both downcomers in in thethe pair pair to to produce produce net vertical loads net vertical loads on the downcomer downcomer pair. Both pair. Both the the uniform uniform internal internal and differential and differential pressures are are defined defined in in the frequency domain, frequency domain, as summarized in as summarized Table 2.12.

in Table 2.12. In specifying the In specifying the differential differential pressures pressures in in aa number number of of downcomer downcomer pairs, pairs, the the load load application application which which maximizes maximizes the the vent vent system response must system response must be considered, be considered, as discussed discussed in in Subsection Subsection 4.2.3.2.4.

4.2.3.2.4.

2.4.4.4 2.4.4.4 Submerged Structure Submerged Structure Loads Loads Steam St~am condensation condensation begins begins after after the vent is the vent cleared of water is cleared water and the the drywell drywell air has been carried over into the air has been carried over into the suppression chamber. The suppression chamber. The CO phase induces phase induces bulk bulk water water motion motion and and creates creates drag loads on structures structures submergedsubmerged in in the pool. pool.

Submerged Submerged structure structure drag drag loads loads due due to to COCO are are defined on all structures listed all structures listed in Table 2.8.

in Table 2.8.

2.4.4.4.1 2.4.4.4.1 Drag Drag LoadsLoads The The computer computer code code CONDFOR, CONDFOR, developed developed by by GE,GE, was was used used to determine determine the CO loads

. loads on on submerged submerged structures.

structures. The The program program CONDFOR CONDFOR definesdefines loads loads in in the frequency frequency domain domain similar to thethe torus torus shell shell wall wall pressure pressure load load definition

• similar to definition (Subsection (Subsection 2.4.4.1).2.4.4.1). The The load load magnitude magnitude at 5 HzHz is is determined, determined, then then the remaining frequency components remaining frequency components are are scaled scaled according according to the the CO CO source source function amplitudes at corresponding amplitudes at corresponding frequencies. frequencies.

2-13 2-13 04/16/02

• Drag loads Section loads were considered:

considered:

(1)

(1) were defined in 2.14.5 of CO assuming in accordance the NRC assuming the average (oscillating in (oscillating accordance with the LDR methodology as modified by in phase).

Acceptance Criteria.

Acceptance phase) .

source Criteria.

strength strength Two conditions at conditions all all were were downcomers downcomers by (2)

(2) assuming the maximum CO assuming maximum source strength strength (twice the average average source' source strength) applied applied at the downcomer downcomer nearestnearest to the structure structure of of concern.

concern.

2.4.4.4.2 FSI Effects Effects required by the NRC Acceptance As required Acceptance Criteria, Criteria, fluid structurestructure interaction interaction (FSI) (FSI) effects effects were were included included for all all structural structural segments for which the local local fluid fluid acceleration is acceleration is less than twice the torus boundary boundary acceleration acceleration effects. effects. The The FSI effects effects were incorporated incorporated using using the following procedure: procedure:

(1)

(1 ) Generation Generation of the torus shell acceleration acceleration spatial spatial distribution distribution due to CO loads loads at 11 Hz frequency frequency intervals intervals from 00 to 50 Hz. Hz.

(2)

(2 ) Determination DeterminationI of fluid accelerations accelerations at all all points points in in the poolpool due to the boundary boundary accelerations accelerations determined in in Step 1, 1, using the methodology methodology in in Reference Reference 26. 26. This step is is done for each 1 Hz frequency interval.

frequency interval.

• (3)

(3 )

(4)

(4)

If If interval acceleration frequency Calculation acceleration determined the acceleration interval at a structure acceleration at using the procedureprocedure in determined in structure location is at that location total in Step (2) location predicted interval, the two accelerations frequency interval, Calculation of the total is accelerations are drag load from the (2) at a given frequency greater greater than one-half the predicted by by. CONDFOR the combined frequency CONDFOR for that absolutely.

are summed absolutely.

combined acceleration in the LDR as modified by the NRC Acceptance that Acceptance

\'

Criteria.

Criteria.

FSI effects are included for both CO load cases (maximum and average source average source strength) and for all all submerged structures.

submerged structures. The FSI effects determined determined in in this manner typically typically result in in increased increased submerged submerged structurestructure loads by by factors of 10 over those predicted CONDFOR. It predicted by CONDFOR. It can be be shown from energy energy considerations considerations that that the FSI effects effects are of the same order of magnitude magnitude as the loads producing producing this effect. effect. Thus,Thus, any FSI effect which which increases increases the CONDFOR load by anywhereanywhere near near a factor of 10 is is unrealistic.

unrealistic. Therefore,Therefore, an upper upper bound factor factor of 10 on FSI effects effects was used. used. This approach still still provides a provides rather rather conservative conservative treatment treatment of FSI effects. effects.

2.4.4.4.3 2.4.4.4.3 Interference Interference Effects Effects Interference effects Interference effects were included in all in all CO submerged submerged structurestructure drag loads loads as multipliers on the loads. loads. These multipliers multipliers were applied applied to the drag loads after FSI effects after effects were included. included. Interference Interference factors for the structures structures are tabulated tabulated in Table 2.8.

in Table 2.8.

2.4.5 Loads Associated Loads Associated with Chugging

• Chugging occurs Chugging system falls occurs during a postulated falls below below the rate postulated LOCA when rate necessary when the steam necessary to maintain steady 2-14 steam flow through the vent steady condensation condensation at the vent 04/16/02

• downcomer downcomer exit.

discussed in discussed exit. The corresponding of the CO phenomenon form at the downcomer begin to collapse corresponding flow rates for chugging are less than those phenomenon discussed previously.

downcomer exit, oscillate collapse independently in Section During the chugging independently in Section 4.5 of the LDR, previously. During chugging, oscillate as they grow to a critical in time.

chugging, steam bubbles time. The chugging load definitions, LDR, are based upon FSTF test chugging regime of a postulated postulated LOCA, test critical definitions, as dat~.

data.

LOCA, the chugging loads occur as bubbles size, and size, and as as aa series series of chug cycles, each of which chug cycles, which can be broken broken down into a pre-chug pre-chug and and a post-chug portion. The pre-chug post-chug'portion. pre-chug portion occurs occurs during the the initiation initiation of the chug.

chug. As the steam-water steam-water interface interface enters the pool, pool, a relati vely relatively low-frequency low-frequency pressure loading occurs. occurs. The interface interface eventually eventually becomes becomes unstable and breaks breaks up,up, producing a rapid underpressure underpressure as the chug chug occurs.

occurs.

The post-chug post-chug portion of the cycle is is a system system response response to the rapid underpressure caused underpressure caused by the breakupbreakup of the steam-water steam-water interface.

interface.

Chugging loadsloads areare observed during three LOCA categories: categories: DBA, DBA, IBA, lBA, and SBA. SBA.

Table 2.13 indicates indicates the onset time 'and and duration of chugging chugging loads for all all three break break sizes.

sizes.

2.4.5.1 2.4.5.1 Torus Torus Shell Shell Loads Loads The The pre-chug pre-chug and post-chug torus shell load definitions, definitions, as given by the LDR LDR (Section 4.5.1.2) 4.5.1.2) are provided below: below:

(1)

(1) Pre-Chug Load Pre-Chug Load Both Both aa symmetr/ic symmetric asymmetric and an asymmetric distribution load distribution were were

• evaluated torus independently.

evaluated independently.

amplitude ampli tude of +/-2.0 centerline centerline

+/-2. 0 psi uniformly distribution has a maximum spatial spatial distribution distributions have at The symmetric uniformly distributed axially bottom dead maximum pressure amplitude of +/-2.

as shown have a linear hydrostatic in in Figure Figure distribution symmetric distribution center.

center.

axially along the The 2.22.

2.22.

hydrostatic variation with depth, similar to the CO load, and are to be applied at the similar

+/-2.0 has asymmetric asymmetric 0 psi and a Both the frequency frequency an an load producing producing the maximum maximum response response between 6.9 and 9.5 Hz. Hz. The The pre-chug pre-chug cycle duration is is 0.5 secondsseconds every 1.4 seconds for the appropriate total appropriate total duration duration defined in in Table 2.13.

Table 2.13.

(2)

(2 ) Post-Chug Post-Chug LoadLoad The post-chug rigid The post-chug rigid wall pressure amplitudes are are defined over a 0o to to 50 Hz range and 1 Hz increments increments as given in in Table Table 2.14.

2.14.

Similar to Similar to the symmetric pre-chug the symmetric pre-chug load, load, the post-chug post-chug load varies uniformly uniformly along the torus centerline centerline and has a linear linear hydrostatic variation variation with depth. depth. The post-chug post-chug cycle duration is is 0.5 seconds seconds every 1.4 seconds for the appropriate appropriate duration defined in in Table Table 2.13.

2.13.

Similar Similar to the CO load definition, load definition, the structural structural response response effects unique effects unique to the FSTF data, including including FSI effects, FSl effects, are eliminated by defining the chugging load as a rigid eliminated rigid wall load.load.

The The load load cancan then be used used in conjunction with a flexible wall, in conjunction wall, plant unique torus model, model, which which includes inertial includes inertial effects effects due to to the torus fluid. Also similar similar to the CO load load definition, the

• chugging load on the submerged superimposed on the local superimposed submerged portion local static static 2-15 2-15 portion of the torus shell was pressures.

pressures.

04/16/02 was

• 2.4.5.2 2.4.5.2 Pressure (1)

(1 )

vent System Vent A

System Loads Pressure loadings are experienced These vent system gross Loads experienced by the vent system as a result of chugging.

vent separated into the following three system loads can be separated system pressurization during the pre-chug pressurization pressure pressure oscillation oscillation chugging.

three components:

components:

consisting consisting depressurization pre-chug portion and depressurization of of during during the post-chug post-chug portion portion of eacheach chug cycle.

cycle.

(2)

(2) An acoustic acoustic vent system pressure oscillation which is pressure oscillation is excited excited asas a result of the pressurization pressurization and depressurization depressurization of the vent vent system.

system.

(3)

(3) An acoustic downcomer downcomer pressure oscillation pressure oscillation which is is excited excited as a result result of the rapid depressurization depressurization at the downcomer exits.

downcomer exits.

The first first component of pressure component pressure loading is is applied relatively long applied over a relatively loading cycle which corresponds to the time between which corresponds between chug cycles. The second chug cycles. second and third pressure load components components are related to the acoustic acoustic response response frequencies frequencies in in the vent system system and downcomer, downcomer, and are are defined as a periodic periodic load with componentscomponents at the acoustic acoustic frequencies frequencies of the vent system system downcomers) and of the downcomers (including the downcomers) downcomers themselves.

themselves.

The The vent system chugging load definition definition was taken from Section Section 4.5.4.2 of of the LDR and and is is summarized summarized in in Table 2.15.2.15. The loads were applied applied individually individually about the local local pressures pressures at the appropriate appropriate times in blowdown, depending in the blowdown, on the size of the break, break, as shown shown in 2.13. .

in Table 2.13

• The chugging load specified for the downcomers The chugging calculate circumferential calculate vent transmitted circumferential structural system responses transmitted through 2.4.5.3 responses to lateral, through the downcomers lateral, downcomers in structural response thrust, thrust, downcomers to other components.

Downcomer Lateral Loads Downcomer Loads in Table 2.15 was used only to response (i.e. hoop stress) and not the or other loads which are components.

to A net lateral lateral load also exists exists on the submerged submerged portions portions of the downcomers downcomers due to chugging.

chugging. This loading lS is caused caused by vapor bubbles, bubbles, forming at the downcomer end, downcomer end, which which collapse suddenly suddenly and intermittently.

intermittently. From chugging chugging tests in in the FSTF, FSTF, this load was determineddetermined to be 3,046 lbs. lbs. This load is is applied randomly randomly at the downcomer end to maximize the stresses at the downcomer/vent downcomer/vent header header intersection.

intersection.

This load was applied as an equivalent equivalent static force at the ends of the downcomers.

downcomers. The magnitude of this load load was determined determined using the ratio of of downcomer downcomer frequency frequency to FSTF downcomer downcomer frequency as described in in Reference Reference 27 27 and modified by Section Section 2.12.2.1 of the NRC Acceptance Criteria.

Acceptance Criteria. This This evaluation is evaluation is described described in Subsection 4.2.3.2.5.

in Subsection 4.2.3.2.5.

Additionally, Additionally, the following following aspects of the chugging downcomer downcomer lateral lateral load considered in were considered in the vent system analysis:

(1)

(1) Chug Synchronization Synchronization The potential potential for a number number of downcomers downcomers experiencing experiencing a laterallateral

• load in in the same direction at the same time results in synchronization load on the vent system and its synchronization load was based on the procedure procedure in 2-16 2-16 in the LDR.

its supports.

in a chug supports. This LDR. The exceedance This exceedance 04/16/02

• (2) )

(2 probability used to calculate probability 10- 4 , as specified 10-4, Fatigue For fatigue considerations, chugging were chugging calculate the load on a single specified in the NRC Acceptance considerations, histograms single downcomer Criteria.

Acceptance Criteria.

histograms of load reversals were determined at the downcomer downcomer was reversals downcomer end from the FSTF test was for for test data, as data, described in as described in the LDR. These load reversals the LDR. reversals were applied over the time durations specified in durations specified in Table 2.13.

2.13. These load reversals reversals were appliedapplied as shown shown inin Table 2.16 and Figure 2.23. 2.23.

(3)

(3) Downcomer Tiebar Tiebar Load Load Dynamic forces in in the downcomer downcomer tiebar were calculated calculated using using the procedure defined procedure defined in in the NRC Acceptance Acceptance Criteria Criteria (Section 2.12.2.2).

2.12.2.2). These forces were used used to evaluateevaluate the tiebar tiebar when when only oneone downcomer downcomer of a tied downcomer downcomer pair pair is is loaded.

loaded.

2.4.5.4 2.4.5.4 Submerged Submerged Structure Structure LoadsLoads Steam chugging Steam chugging at the downcomersdowncomers creates bulk water motion, motion, and therefore induces drag loads loads on structures structures submerged in in the pool.

pool. The submerged submerged structure structure load definition method for chugging parallels parallels that used to predict predict induced drag drag forces caused by CO (Subsection 2.4.4.4). 2.4.4.4). Submerged Submerged structure drag loads due to chugging were were defined on the structures listed listed in in Table 2.8.

Table 2.8. .

.2.4.5.4.1

• 2.4.5.4.1 The computer (Subsection Drag Loads computer code.

submerged structures.

submerged Loads structures.

(Subsection 2.4.4.4.1) 2.4.4.4.1) frequency spectrum spectrum is corresponding to chugging.

corresponding CONDFOR was used to determine the chugging code CONDFOR is The method except except method is that is the same as that for CO loads the source proportional to the torus wall load measurement proportional chugging. For chuggingchugging drag loads, chugging loads loads on amplitude versus function amplitude loads, CONDFOR determines the on loads versus measurement load magnitude magnitude at 26 Hz and then the remaining remaining \ frequency frequency components are scaled according scaled according to the chugging source source function amplitudes amplitudes at corresponding corresponding frequencies.

frequencies.

Drag loads loads werewere defined in in accordance accordance with the LDR methodologymethodology as modifiedmodified by by Section Section 2.14.6 2.14.6 of the NRC Acceptance Acceptance Criteria.

Criteria. Three conditions conditions are considered for each considered each structure!

structure:'

(1)

(1) Pre-chug, Pre-chug, (2)

(2) Post-chug, Post-chug, using using the maximum source strength applied at the nearest downcomers nearest downcomers (oscillating in in phase),

phase), and (3)

(3 ) Post-chug, Post-chug, using the maximum source strength strength applied at the two nearest downcomers downcomers (oscillating 180 180'0 out of phase) maximizing the local local acceleration acceleration in eithe~ of the in-plane directions.

in either directions.

2.4.5.4.2 2.4.5.4.2 Effects FSI Effects

. FSI effects effects due to chugging loads submerged structures

• loads on submerged structures were were defined using the procedure procedure outlined outlined in in Subsection Subsection 2.4.4.4.2 for CO drag loads. loads. Torus Torus shellshell accelerations due to chugging accelerations chugging loads were were used in lieu of CO accelerations in lieu accelerations for for this effect.

effect.

2-17 04/16/02

• 2.4.5.4.3 2.4.5.4.3 Interference loads loads after after Interference Interference Effects Interference effects were included loads as multipliers on the loads.

structures are tabulated FSI effectseffects tabulated in Effects included in were were included.

in Table Table 2.8.

all chugging in all loads. These multipliers included.

2.8.

chugging submerged multipliers were Interference Interference factors structure drag submerged structure were applied applied to the drag for the 2.5 2.5 S/RV DISCHARGE-RELATED DISCHARGE-RELATED LOADS LOADS Cooper Nuclear Station Station is is equipped with S/RVs to control primary equipped primary system system pressure transients.

pressure transients. For these these transients, transients, the S/RVs S/RVs actuate actuate to divert divert partpart or or all all of of the the generated generated steam steam to the suppression-pool.

suppression-pool. The S/RVs either S/RVs will either self-actuate at self-actuate at aa pre-setpre-set pressure pressure or actuate by an external signal. signal. Six of of the S/RVs S/RVs are used for the ADS, ADS, which is is designed to reduce the reactor designed reactor system pressure pressure during during an IBA or SBA. SBA. The ADS performsperforms thisthis function by by automatically automatically actuating actuating specified the specified S/RVs, S/RVs, following following the receiptreceipt of of specific signals signals from the reactOr protection system.

reactor protection system.

Prior to Prior to the the initial initial actuation of an S/RV caused actuation caused by a normal operational operational transient, transient, the S/RVDLs contain air contain air and water in submerged portion of the in the submerged piping and piping and within within the the discharge discharge device. device. Following Following S/RV actuation,actuation, steam steam enters enters the S/RVDL, compressing the S/RVDL, compressing the air air and expelling expelling the water slug slug-into into the suppression pool. pool.

Following Following water water clearing, clearing, the the compressed air air is is accelerated accelerated into into the suppression p'ool suppression pool and forms forms high-pressure high-pressure air air bubbles..These bu.bbles.* These bubbles expand bubbles expand

• and contract aa number of times before and contract before they rise rise to the suppression suppression pool pool surface. The surface. The associated associated transientstransients create create drag loads submerged structures, loads on submerged structures, as as well as pressure pressure loads on the submerged submerged boundaries.

boundaries. These These loads are referred referred to as S/RV air-clearing air-clearing loads. loads.

Following Following the air-clearing phase, the air-clearing essentially pure steam is phase, essentially is injected injected into the pool.

pool. As As long long as as the local pool the local pool temperature temperature is is low, steam condensation condensation proceeds proceeds in in aa stable stable mannermanner and and no significant significant loads are experienced. experienced.

Continued Continued steam blowdown blowdown into the pool will increase the local local pool pool temperature. To temperature. To preclude preclude the possibility possibility of unstable steam condensation, condensation, pool pool temperature limits are temperature are established.

established.

This This subsection subsection describes describes the procedures procedures used to calculate calculate loads loads on on containment components related containment components related to S/RV discharge events. events. These loads include line line loads on the S/RVDL piping, pressures on the torus shell boundary, boundary, and and loads loads on on structures structures .submerged submerged in in the pool.pool.

magnitude and nature of the S/RV discharge The magnitude discharge loads loads depend upon the initialinitial conditions conditions used in in the analyses.

analyses. Load case case numbers numbers will be used to describe these initial these initial conditions.

conditions. The following load cases are defined:

L S/RV S/RV Load Load Case Initial Conditions Initial Conditions

.

A1.1 Al.l Actuation Actuation of of one S/RV resulting one S/RV resulting from operational transients from normal operational transients

• Al.2 Al.33 AI.

Actuation Actuation of one S/RV during an IBA/SBA Actuation Actuation of one S/RV during a DBA event 2-18 2-18 IBA/SBA event event event 04/16/02

e A2 . 2 A2.2 ADS actuation actuation (6 (6 S/RVs)

S/RVs) during an an IBA/SBA eventevent A3.1 A3.1 Actuation Actuation of all all 8 S/RVs S/RVs resulting resulting from normal operational operational transients transients A3.2 A3.2 Actuation of all Actuation all 88 S/RVs during an IBA/SBA lBA/SBA event (unrelated to ADS ADS actuation)

C3.1 C3.1 Subsequent Subsequent actuation actuation of all all 8 S/RVs resulting resulting from normal normal operational transients operational transients C3.2 C3.2 Subsequent Subsequent actuation actuation of all all 8 S/RVs during an IBA/SBA IBA/SBA event - S/RVDL atmosphere atmosphere 100% 100% airair C3.3 Subsequent Subsequent actuation actuation of all all 8 S/RVs during an IBA/SBA IBA/SBA event - S/RVDL atmosphere 100%

atmosphere stearn 100% steam For load case case A1.3,A1.3, significant significant containment containment loads are considered considered only during the pool swell event. event. Although Although. S/RV actuationsactuations can occur later later in in the event, event, resulting loads are negligible the resulting negligible since the air air and water initially initially in in the line will be cleared drywell-to-wetwell ~p cleared as the drywell-to-wetwell increases during Ap increases during the the DBA DBA transient.

transient.

S/RV discharge-related-S/RV discharge-related- loads are dependent dependent on the initial initial drywell-to-wetwell drywell-to-wetwell Ap.

~p. The ini initialtial condi conditions tions producing producing the bounding bounding load were used in in all all structural structural evaluations.

evaluations.

S 2.5.1 2.5.1 S/RVDL-Clearing S/RVDL-Clearing Transient Loads Loads When an S/RV opens, opens, the pressure pressure within wi thin the S/RVDL S/RVDL undergoes undergoes a transient transient prior to reaching a steady-state steady-state value. value. A transient pressure A transient pressure wave travels travels back and forth in in the line as the pressure pressure continues to increase, increase, untiluntil the inertia inertia of the water slug in in the submerged submerged portion of piping piping is is overcome.

overcome.

During the water-clearing water-clearing transient,transient, the pressures w~thin the discharge pressures wi.thin discharge pipe and, the T-quencher T-quencher reach reach their maximum values. values. Following Following expulsion expulsion of the water water slug, slug, the peak pressure pressure in in the discharge pipe decreases decreases to a quasi-steady-state value which is quasi-steady-state is a function function of the S/RV stearn steam flow rate and and friction frict~on along the lineline upstream upstream of the entrance entrance to the T-quencher.

T-quencher.

Similarly, the T-quencher Similarly, T-quencher internal pressure pressure increases increases and then decreases decreases to a quasi-steady-state quasi-steady-state, value which which is is a. a, function of the stearn steam flow rate and pressure pressure losses resulting resulting from flow through through the holes holes in in the T-quencher.

T-quencher.

During the early portion early portioh of this transient, transient, a substantial substantial pressure differential differential exists across across the pressure wave. wave. Therefore, Therefore, when when the wave is is within within an. S/RV pipe segment between a pair pair of elbows, elbows, there exists there exists a substantial substantial differencedifference ~n presiure applied to the interior in the pressure interior surface of the surface elbows on each end of the segment. segment. This pressure pressure differential, differential, plus momentum effects from steam effects stearn (or water in in initially initially submerged submerged pipe runs) flowing around around elbows in in the line, results in in transient thrust loads loads on the S/RV discharge pipe segments.

pipe segments. These loads were were considered in in the design design of S/RVDL pipe restraints, restraints, the connection connection of the S/RV to the 'main main stearnsteam line, line, and the

.

T-quencher support T-quencher system.

support'system.

• S/RVDL Section transient Section 5.2.1 of the LDR.

loads were defined using the procedure LDR. This procedure procedure and the assumptions 2-19 2-19 procedure described assumptions in described in in calculating 04/16/02 in

the loads have been reviewed,by the reviewed by the NRC in in the SER.SER. The computer code RVFOR04 RVFOR04 was used was used to predict to predict S/RVD line-clearing S/RVD line-clearing transient loads.

loads. RVFOR04 was was developed by developed by GE GE forfor determining determining these these loads,loads, using the analytical the analytical model model described in Reference 28. The described in Reference 28. The following conservative following conservative assumptions were assumptions were made made in defining these loads:

in loads:

(1)

(1) The S/RV The S/RV flow flow rate rate is is assumed to be 1.225 1.225 times the ASME-rated ASME-rated S/RV flow.

(2)

(2) The S/RV The S/RV main main disk-stroke disk-stroke time time is is assumed to be 0.02 seconds. seconds. TheThe S/RV loading most significantly significantly affected affected by the main disk stroke time is time is the transient wave thrust load. Shorter stroke times result result in higher in higher loading.

loading. The value of 0*.02 0..02 seconds seconds represents a lower bound lower bound of of main main diskdisk stroke times measured during performance performance testing of S/RVs of similar design to those installed testing installed in in Mark I plants.

plants.

(3)

(3) The suppression The suppression pool water level is is at the maximum value value allowed by technical by specifications.

specifications. This assumption results results in in the maximum initial maximum initial water leg water leg in in the S/RV discharge discharge line, which, which, inin turn, turn, results results in in thethe highest highest water-clearing water-clearing loads on the S/RVDL discharge device.

and discharge device.

(4)

(4) The S/RVDL The S/RVDL vacuum vacuum breaker breaker does does not leak. leak. By assuming the vacuum vacuum breaker does breaker does not not leak, a lower value of S/RVDL to wetwell wetwell pressure differential pressure differential is is calculated, which calculated, which results results in a longer in longer initial water leg in the initial water leg in the discharge line. discharge line.

• From the From obtained:

obtained:

the RVFOR04

• RVFOR04 analyses, analyses, the following the S/RVDL internal pressure transient S/RVDL following loads transient loads and response quantities were response quantities were

• S/RVDL pipe segment S/RVDL segment wave wave thrust transient transient

• S/RVDL water-clearing S/RVDL water-clearing thrust thrust transient transient

• Water-clearing Water-clearing time time

• water-clearing Water-clearing velocity velocity and acceleration acceleration

• T-Quencher T-Quencher internal internal pressure pressure

• S/RVDL wall S/RVDL wall temperature temperature Loads Loads were were obtained obtained for for all all 88 S/RVDLs S/RVDLs including including all all piping piping from the the S/RV in in the drywell the drywell through through the T-quencher discharge the T-quencher discharge device.device. S/RV discharge discharge Load Case Case A1.2 (actuation during A1.2 (actuation during IBA/SBA) lBA/SBA) was was identified identified as as the the bounding bounding load cases for caies for the S/RVD the S/RVD piping piping (both (both drywell drywell and and wetwell wetwell portions) portions) basedbased on aa study of the the longest longest S/RVDLS/RVDL for for allall S/RV S/RV loadload cases.

cases.

.

2.5.2 2.5.2 S/RVDL S/RVDL Reflood Reflood Transient Transient

• Following Following closure rapidly rapidly as' the sufficiently as s1,lfficiently low closure of the steam low steam of an an S/RV, steam flows S/RV, the flows out steam pressure, the steam out into steam pressure into the pressure, pool water 2-20 pressure in the pressure water reenters in the S/RVDL reenters the S/RVDL decreases suppression pool.

pressure suppression decreases pool. At a S/RVDL, causing the S/RVDL, causing a 04/16/02

• rapid depressurization of the line.

rapid depressurization S/RVDL to a level somewhat reestablished.

reestablished. The actual the S/RVDL vacuum some some minimum time interval occur.

actual reflood vacuum breakers line. The water may then rise through the somewhat above its initial reflood level depends breakers to allowallow a rapid interval after closure initial* level before equilibrium depends primarily on the ability occur. Loads are developed on the S/RVDL during this actuation.

(wave thrust, water-clearing water-clearing thrust, equilibrium is depressurization of the line. At rapid depressurization closure of the S/RV, S/RV, aa second thrust, and S/RVD pipe and T-quencher ability of second actuation actuation may actuation. These loads is of At may loads T-quencher pressures) depend depend on the waterwater level and/or the gas properties properties in in the line. line.

In the case In case of a consecutive actuation, the necessary consecutive S/RV actuation, necessary input data data for the line-clearing transient line-clearing transient load was obtained obtained from the computer code RVRIZO2, RVRIZ02, predicts the water reflood transient which predicts transient into the S/RVDL after the the, valve closure. This computer code closure. code was developed developed by GE and is is incorporated incorporated as partpart of the LDR load definition (Section 5.2.3) 5.2.3) for S/RVDL-clearing S/RVDL-clearing transienttransient loads (as described above). .

described above)

Sufficient sensitivity Sufficient sensitivity studies studies were conducted conducted to identify identify the highest water water heights, which reflood heights, which determine determine the maximum line-clearing line-clearing transients.

transients. A plant unique transient evaluation evaluation was also performedperformed to identify the minimum minimum time between actuations for both normal operating between S/RV actuations operating and LOCA conditions conditions (Reference 21).

(Reference 21) . This transient analysis is is based on the low-low set relief relief logic to be installed installed on the S/RVs. S/RVs.

For all anticipated anticipated operational operational transient events, transient events, the low-low set relief relief logic extends the minimum time between actuations actuations to approximately approximately 36 seconds, seconds, which which is is enough to pass pass all significant significant reflood peaks for Load Load Case C3.1.

Case C3.1. Therefore, Therefore, the loads associated associated with Load Load Case C3.1 were not were not

• governing for design.

governing design. If If there there is is no loss of off-siteoff-site power (LOOSP) (LOOSP) or early early' MSIV MSIV isolation during aa LOCA event, S/RV subsequent actuations isolation during. actuations would not not occur for any break size. If If LOOSP occurs,occurs, the low-low set relief logic extends the minimum time interval extends between two consecutive interval between consecutive actuations actuations to to approximately 31 seconds approximately seconds for breaks smaller than 0.2 ft breaks smaller ft 22 ,, which which will be enough enough to pass the first first peak water water reflood reflood for Load Case C3.3. C3. 3. Predicted second peak peak reflood levels are below the initial water level in in the line; therefore, therefore, line-clearing line-clearing loads associated associated with Load Case C3.3 C3. 3 were not, not, governing for for design.

design.

2.5.3 Thrust Loads on T-Quencher T-Quencher ArmsArms Following Following an S/RV actuation, actuation, the pressurization pressurization of the discharge discharge line causes causes the water initially in in the T-quencher and piping piping to be accelerated accelerated and expelled through through the T-quencher T-quencher arm holes holes into the suppression suppression pool. pool. The The redirection redirection of flow of the fluid in in the arms (90 (90 degrees degrees out the holes) and the internal internal pressure pressure of the arms results results in in thrust loads on the arm and endcaps.

endcaps. Since the T-quencher T-quencher discharge devices devices in in the Cooper Cooper Station suppression pool have suppression have endcap endcap holes holes on one arm only, only, and due to uneven water-clearing between the two arms of the T-quencher, water-clearing T-quencher, a net thrust load acts along along the axis of the T-quencher T-quencher device.

device. Following Following the water and air air clearing, clearing, there are net thrust loads along along the axis of the T-quencher T-quencher device device due to steam discharging. Uneven water clearing steam discharging. clearing between the two sides of an arm results in in a thrust load perpendicular perpendicular to the T-quencher T-quencher arms. arms. All of of these loadings loadings were calculated calculated for the S/RVDL S/RVDL were calculated calculated with the bounding loads.

bounding loads.

• The procedure procedure used to caiculatecalculate these thrust loads is is the procedure procedure specified in in Section 5.3.6 of the LDR. Water-clearing velocities LOR. Water-clearing velocities and accelerations fromfrom RVFORO4 RVFOR04 analyses analyses were used in in determining determining these loads. loads. Loads were defined defined forfor 2-21 04/16/02

• bounding S/RV the bounding (1)

(2)

(2)

S/RV Load Thrustt loads Thrus Load Case Case C3.1 for the following uneven thrust load cases were defined:

The following (1) Thrust loads along along axis loads perpendicular axis of the line with the highest thrust loads of the T-quencher T-quencher based on endcap perpendicular to the T-quencher water-clearing. The signs of the end water-clearing. end loads loads on endcap forces.

T-quencher arms due to uneven on each T-quencher arm loads..

forces.

arm were arrangedarranged to consider all all possible combinations, combinations, i.e.

i.e. to to result result in the in the maximum turning moment on the discharge device and the maximum bending moment .at at the center of the discharge discharge device.

2.5.4 Torus Shell Pressures Pressures When an

. When an S/RVS/RV actuates, actuates, the expulsion of water and then air air into the suppression pool through suppression pool through the discharge device the discharge device results in in pressure pressure loads on on the submerged the submerged portion portion of the torus shell and induces drag loads on submerged structures.

structures.

Prior to the initial Prior initial actuation of an S/RV, actuation S/RV, the S/RVDL contains air air and suppression pool suppression pool water water in in the the submerged submerged portion of the piping. piping. Following Following S/RV S/RV actuation, actuation, steam enters steam enters the S/RVDL, S/RVDL, compressing the air compressing air within the line, expelling the expelling the water slug, water slug, and discharging discharging the air air into the suppression suppression pool. pool.

The compressed The compressed air air bubbles bubbles expand, expand, resulting in resulting in an outward motion of the suppression pool suppression pool water. water. The outward momentum of the suppression suppression pool water water causes the causes the pressure pressure within the bubbles bubbles to drop below below the local hydrostatic pool pressure. The pool pressure. The negative negative bubble bubble pressure pressure slows slows and and reverses reverses the bubble bubble expansion, and expansion, and the suppressionthe suppression pool water begins to move inward. The inward inward.

momentum momentum of of the the water water results in in compression of the air a compression air bubbles to a pressure pressure above above the the local hydrostatic pool local hydrostatic pressure.

pool pressure. The expansion and and compression of compression of the the air air bubbles bubbles continues until until the bubbles bubbles rise rise and break through at through at the suppression pool water the suppression surface. The positive and negative water surface.

dynamic pressures dynamic pressures developed developed within these bubbles result in in an oscillatory oscillatory pressure pressure loading on the torus wall. wall.

The load

,The load definition definition used used to to analyze analyze the torus shell shell for S/RV discharge discharge pressures pressures is is based based on the the procedure procedure described described in in Section 5.2.2 of the LDR. LDR.

A computer A computer code (QBUBSO2),

code (QBUBS02), developed developed by GE, GE, was used for analytically analytically predicting predicting the the torus torus shell shell pressure distribution resulting pressure distribution resulting from an S/RV discharge discharge through through aa T-quencher T-quencher device. device. The The maximum maximum torus shell pressure pressure occurs occurs at at thethe torustorus bottom bottom dead-center, dead-center, and and remains remains constant approximatelyapproximately 6.5 ft.

6.5 ft. on on both both sides sides from from the discharge device the discharge device centerline centerline along along the torus torus longitudinal longi tudinal axis. axis. Then Then the the pressure pressure attenuates attenuates to a minimum minimum value value...'The The computer computer code code also also calculates calculates pressures pressures aU selected at' selected cross-sectional cross-sectional locations.

locations. These These pressures pressures attenuate attenuate from from the the bottom bottom dead-center dead-center to the water water surface.

surface.

The pressure The pressure waveformwaveform predicted predicted by by QBUBS02 QBUBS02 was also also used in all in all torus shell shell structural structural evaluations.

evaluations. AA typical typical pressure waveform, waveform, showing showing very very low low attenuation attenuation with with time, time, is is shown shown in in Figure Figure 2.24.2.24. All All assumptions assumptions described described in in LDR LDR Section Section 5.2.2 5.2.2 (with (with the the exception exception of of one)one) were were included included in in thethe load definition.

definition.

The The modifications modifications to to thethe S/RVDL S/RVDL air clearing shell air clearing shell pressure pressure loads loads required required in in Section Section 2.13.3 2.13.3 of of the the NRC NRC Acceptance Acceptance Criteria Criteria were also incorporated incorporated in in the

• torus torus shell shell load load definition.

definition. The The modifications modifications to to the LDRLDR procedure procedure required by the NRC by the NRC include: include:

2-22 2-22 04/16/02 04/16/02

• *

Limiting water leg length predicting bubble predicting Limiting bubble pressure.

Limiting line volumes Limiting torus shell pressures Limiting pressure.

volumes to 65 ft in in the ft 3 for prediction pressures to 1.65 S/RVDL to 13.5 prediction of bubble pressure.

1.65 times the peak ft.

ft.

pressure.

bubble for for bubble pressure pressure for multiple multiple valve actuation actuation cases. cases.

• • Use Use' of recommended uncertainty recommended uncertainty margins (25%

(25% for first first actuation; actuation; 40%

40% for subsequent subsequent actuation) on predicted predicted upper and lower lower frequency ranges. ranges.

• Use of first actuation first actuation pressure with subsequent subsequent actuation frequency for defining defining all all subsequent actuationactuation load load definitions.

definitions.

Two exceptions Two exceptions to the LDR and NRC Acceptance Criteria procedures Acceptance Crite~ia procedures were taken: taken:

(1)

(1) For For multiple mUltiple valve actuation events, valve actuation Acceptance Criteria events, the NRC Acceptance Criteria requires requires linear superposition linear superposition (ABSS method) of bubble bubble pressure spatial spatial distributions due to single valve valve actuations.

actuations. For CNS, CNS, a plant unique plant unique evaluation evaluation was performed to justify justify a modified square square root of the sum of the squares squares (SRSS) method for combining (SRSS) method spatial spatial pressure distributions.distributions. The modified SRSS procedure procedure was was developed by generating developed generating CNS plant unique unique Cumulative Cumulative Distribution Functions Functions (CDFs) (CDFs) for combined combined peak torus shell pressures. pressures. These These

,.

CDFs account account for variations variations in reactor pressure in reactor pressure rise rise rate, rate, S/RV S/RV set set point, point, and and S/RV S/RV opening time. The combined peak opening time. peak pressures in in these CDFs these CDFs were determined through algebraic were determined addition of the algebraic addition pressure waveforms pressure analytically predicted waveforms analytically predicted for each valve. valve. The The studies indicated studies indicated that a 1.2 multiplier on the SRSS SRSS combination of peak peak pressures provides provides an 84% 84% NEP on the CDF with a 90% 90%

confidence confidence level. level. This plant unique study is is described described in in Appendix A A to this report. report.

(2)

(2) The, LDR procedure The, procedure for defining def ining initial conditions ini tial condi tions for QBUBS02 QBUBS02 assumes that pure air air mass is is in in the S/RVDL prior to valve opening. As discussed opening. discussed by the NRC in in Section 3.10.2.6 of the SER, SER, this this' is is a conservative conservative assumption for LOCA events when an an air/steam mixture exists in air/steam in the drywell.

drywell. For load case A2.2 A2.2 onlyonly (ADS a,ctuation (ADS actuation during an lBA/SBA IBA/SBA event),event), torus torus shell shell pressure loads were defined using an initial initial 30% 30% relative relative humidity humidity in in the S/RVDL.

S/RVDL. Reduced torus Reduced torus- shell pressurespressures and increasedincreased pressure waveform frequencies result from this assumption.

waveform frequencies assumption. The design design ADS ADS actuation event occurs 300 seconds into an lBA IBA and 600 seconds seconds into an into an SBA.

SBA. SinceSince these these S/RVD S/RVD pressure pressure loads are to be combined combined with the with the high high wetwell pressure pressure obtained by assuming assuming all air all air in in drywell drywell is is purged purged into into wetwell before ADS actuation, the results results are still are still conservative.

conservative.

Torus shell loads Torus shell loads were calculatedcalculated using the above procedure for the following load cases:

cases:

• • A1.1 Al.l - NOC-SVA, NOC-SVA, First First Valve Valve Actuation

• • A1.3 Al.3 -- LOCA-DBA, LOCA-DBA, Single Valve Valve Actuation

• ** A2.2 - LOCA-IBA/SBA, LOCA-lBA/SBA, ADS Actuation 2-23 04/16/02

• Loads

Loads were defined shell pressures combined peak combined C3.1 - NOC-8MVA, NOC-8MVA, Subsequent C3.2 - LOCA-SBA/IBA pressures and the broadest pressure shell pressure for multiple peak pressure Subsequent Valve Actuation LOCA-SBA/IBA 8MVA, multiple valve cases pressure was 14.5 psi.

Subsequent Valve 8MVA, Subsequent defined for the S/RVDL configurations Valve Actuation configurations resulting pressure frequency ranges.

cases was psi. Frequency Actuation resulting in in the highest ranges. Peak combined was 20.5 psi; for the ADS event, Frequency ranges were highest combined event, the were 5.8 to 15.4 Hz for for subsequent actuation actuation cases,cases, and 4.5 to 9.4 Hz for first first actuation cases.

actuation cases.

program QBUBS03 was used to calculate The program calculate torus shell pressures for use in in the reanalysis reanalysis of the torus shell stresses stresses for development of a general general corrosion corrosion allowance.allowance. See See Sections Sections 1.2.2.2 1.2.2.2 and 3.2.5 for additional additional details.

details.

2.5.5 Loads on Submerged Loads Submerged Structures Structures All structures structures submerged submerged in in the suppression suppression pool pool are subjected subjected to loadings loadings following an S/RV discharge following event. These discharge event. These loadings loadings are are due to eithereither water water jets following jets following the water clearing clearing from the S/RVDL S/RVDL or drag loadings.due loadings due to the oscillating oscillating air air bubbles expelled bubbles expelled from the T-quencher. T-quencher.

2.5.5.1 2.5.5.1 T-Quencher Water T-Quencher Water Jet-Induced Jet-Induced Drag Loads Loads When an S/RV is When actuated, water is actuated, water initially initially contained contained in in the submerged submerged portion of the S/RV discharge discharge line line isis forced out of the T-Quencher T-Quencher arms throughthrough the arm holes.

holes. These These T-quencher T-quencher waterwater jets jets will induce drag loads on nearby will nearby submerged structures which are within the jet submerged jet path.

path. T-quencher T-quencher water jet jet loads were evaluated loads evaluated using a revised methodology methodology based upon the procedure procedure in in Section 5.2.4 Section 5.2.4 )of the LDR. LDR. The main differences differences betweenbetween LDR and the the revised methodology and the major assumptions methodology assumptions employed employed in in revised methodology methodology are:are:

(1)

(1) In In the LDR methodology, the LDR methodology, the the jetjet velocity velocity is is assumed assumed constant constant at at its its maximum maximum value throughout throughout the transient. transient. However,However, the jet jet reaches reaches its its maximum maximum velocity velocity towards towards the end of the transient. transient.

methodology defines The revised methodology defines the transient jet jet front location by taking taking into consideration consideration the transient transient behavior behavior of the jet jet velocity.

velocity.

(2)

(2) In methodology, In the revised methodology, velocity and position of each the velocity each particle particle leaving the T-quencher T-quencher arm are determined determined using steady jet jet characteristics.

characteristics. Actually, the decay decay of velocity velocity in in an an unsteady unsteady jet jet will be much faster than steady jet; jet; therefore, therefore, this assumption results assumption results in in conservative conservative jet jet penetration distances.

penetration distances.

(3)

(3 ) Conservatively, the loads are determined for the maximum Conservatively, maximum velocity and the maximum loads loads are are assumed to exist during during the entireentire transient.

transient.

For the structures intercepted by the jet, structures intercepted jet, the revisedrevised methodology gives gives higher loads. loads. However, However, using the revisedrevised methodology, methodology, fewer structures are intercepted intercepted by the jet jet than would be intercepted intercepted if if the LDR methodology methodology is is used. The loads on these used. these structures, structures, however, however, are very small in in magnitude magnitude and and are bounded bounded by the T-quencher T-quencher air air bubble-induced drag loads which bubble-induced which immediately immediately follow the T-quencherT-quencher water jet jet loads.

loads .

• \

2-24 2-24 04/16/02

\

comparison of various load A comparison load cases shows that S/RV S/RV Load Case Case C3.1 C3.1 results results in in the longest jet jet penetration distances distances and and highest highest jet jet velocities.

velocities. Therefore, Therefore, only Load Load Case C3.1 was analyzed analyzed to determinedetermine the T-quencher T-quencher water jet jet loads.

loads.

The T-quencher T-quencher water jet jet loads were determined loads determined using the revised revised methodology methodology structures intercepted for the structures intercepted by the jet, jet, which are tabulated tabulated in in Table 2.17. 2.17.

2.5.5.2 T-Quencher Air Bubble-Induced T-Quencher Bubble-Induced Drag Loads After actuation actuation of the S/RV, high-pressure steam from from the main steam line line enters the S/RVDL and and compresses compresses the air-water air-water vapor mixture mixture initially initially inside the line. This process expels the water column and the air-vapor air-vapor mixturemixture into into suppression pool.

the suppression pool. Once inside the pool, pool, the air-vapor mixture forms high-pressure bubbles which oscillate high-pressure oscillate and rise rise toward the pool surface. surface. The oscillation oscillation of these S/RV bubbles creates a three-dimensional three-dimensional flow field, field, and therefore induces standard standard and acceleration acceleration drag forces on the structures submerged in in the suppression suppression pool. pool.

The computer program TQFORBF was developed developed by GE to calculate calculate the drag forces induced by T-quencherT-quencher air air bubbles on submerg'ed submerged structures.

structures. The program program is is based upon the procedure procedure described described in in Section 5.2.5 of the LDR, LDR, and includes includes all all modifications modifications required by Section Section 2.14.4 of the NRC Acceptance Acceptance Criteria.

Criteria.

structure drag loads Submerged structure loads following S/RV actuations actuations were defined defined for all all structures listed structures listed in Table 2.8.

in 2.8. Loads were conservatively conservatively estimatedestimated for the

\

initial initial conditions producing producing the maximum drag load. These initial initial conditions conditions correspond correspond to 'first

'first valve actuation actuation during during an SBA (Load (Load Case A1.2). A1.2).

• Thermal-hydraulic Thermal-hydraulic parameters regardless regardless of correspond to an envelope correspond torus shell 2.5.5.3 parameters related to the longest S/RVDL (which results the highest drag loads) were used in location.

location. The frequency envelope of pressure shell loads (see Subsection in defining the loads for all frequency ranges pressure waveform Subsection 2.5.4).

T-Quencher Air Bubble Differential T-Quencher 2.5.4).

Differential Loads ranges for the load transients waveform frequencies Loads frequencies calculated all results structures structures transients calculated for in in To account account for uneven air-clearing ioads uneven air-clearing 'loads on'theon the T-quencher T-quencher arms supports, arms and supports, it is it is conservatively conservatively assumed that that only two bubbles bubbles in in phase are are active.

active.

To find the maximum maximum lateral lateral loads loads on ,the the T-quencher T-quencher arm and and supports, supports, itit is is assumed assumed that two two bubbles bubbles in in phase on one one side of of the T-quencher T-quencher arm are active active and there are are no no bubbles bubbles on the other side of the arm. arm. 2

)

To obtain obtain the maximum moment-producing moment-producing loading loading on the T-quencher T-quencher arm arm andand

) ..

supports, it supports, It is lS assumed assumed that there there are are two bubbles bubbles in in phase phase on one diagonal one diagonal side of the the arm, arm, and and there there are no bubbles bubbles on on the other other diagonal diagonal side. side.

With these assumptions, Wi th 'these assumptions, loads were were then determineddetermined' using the procedures procedures and and assumptions assumptions describeddescribed in in Subsection Subsection 2.5.5.2. 2.5.5.2.

J 2.5.5.4 2.5.5.4 Interference Interference Effects Effects Interference Interference effects effects were were included included in in all all S/RV S/RV discharge-related discharge-related submerged submerged structure structure loads loads as as multipliers multipliers on on the the loads. loads. Interference Interference factors factors for for structures are structures are tabulated tabulated in in Table 2.8. 2.8 .

• 2-25 2-25 04/16/02

• 2.6 OTHER LOADS OTHER original original hydrodynamic LOADS This section briefly design hydrodynamic load definitions.

2.6.1 2.6.1 Other Operating discusses additional load briefly discusses basis and definitions.

Operating LoadsLoads other other LOCA-related LOCA-related load cases not inc or S/RV included in the 1 uded in discharge-related In performing In performing the structural structural evaluations, evaluations, several several load conditions conditions not not identified identified above were included in the evaluations.

included in evaluations. These loads are thrust thrust forces at pipingpiping elbows due to momentum changes changes near discharge discharge outlets.

outlets.

Additionally, Additionally, for piping piping analysis ~-of of ECCS lines, lines, consideration consideration of design temperatures was included.

temperatures included.

2.6.2 2.6.2 Other Secondary Secondary Loads Loads A number number of suppression pool hydrodynamic-related hydrodynamic-related phenomenaphenomena which generate generate either secondary loads on the containment either secondary containment system and structures structures or otherother considerations considerations to the load definitions definitions were neglected.

neglected. This conclusion conclusion is is consistent consistent with the NRC position position in in the SER.

SER. These secondary secondary load considerations considerations are: are:

(1)

(1) Seismic slosh due to seismic motion motion of the suppression suppression pool pool water.

water.

(2)

(2) Pressure loads on the torus walls due to post-pool swell waves.

Pressure waves.

(3) )

(3 Asymmetric pool hydrodynamic Asymmetric hydrodynamic loading conditioncondition due to asymmetric asymmetric vent system flow. flow.

(4)

(4) Downcomer Downcomer air-clearing air-clearing lateral loads due to LOCA air-clearing through the vents.vents.

(5))

(5 Differential pressure loading on submerged Differential pressure submerged structures and the structures torus wall due to sonic and compression compression waves following a postulated LOCA-DBA.

postulated LOCA-DBA.

(6) )

(6 Drag loads*

loads. on submerged submerged structures structures produced produced during the period of of the S/RV steam dischargedischarge in in the suppression suppression pool through the T-quencher discharge device.

T-quencher discharge device.

(7)

(7) Effects Effects of suppression pool thermal stratification stratification for a minimum minimum downcomer submergence of 3 feet.

downcomer submergence 2.6.3 Steam Steam Discharge Discharge Condensation Condensation LoadsLoads discussed in As discussed in Section Section 2.3 of the SER, actuation at elevated SER, S/RV actuation elevated pool pool temperatures could result in temperatures in severe vibratory pressure loads.

vibratory pressure loads. To eliminate this concern, concern, the currentcurrent practice practice is is to limit the pool temperature temperature so thatthat the "threshold" temperature temperature for severe severe vibrations vibrations will not be achievedachieved during operational operational and upset modes; e. e.g.,

g., a stuck-qpen stuck-open S/RV event.event. Plant-unique Plant-unique transient evaluations of the Cooper transient evaluations Cooper Station suppression performed suppression pool were performed to demonstrate demonstrate that local pool temperatures temperatures remain below 200'F. 200°F. Section Section 77 of of

. this report describes describes this evaluation.

• evaluation. Since Since the pool temperature temperature limit is is satisfied, satisfied, S/RV discharge steam condensation condensation loads were not considered considered inin the requalification requalification of CNS containment containment and a~d piping systems.

systems.

2-26 2-26 04/16/02

• 2.7 This containment COMBINATIONS LOAD COMBINATIONS This subsection identifies identifies components containment components due this this section.

sequence is The timing sequence due the timing sequence to is illustrated illustrated sequence of the the hydrodynamic to the hydrodynamic phenomena the loading loading conditions conditions for described throughou~

phenomena described in figures which identify the hydrodynamic in throughout hydrodynamic loading conditions loading conditions resuJ. resultingting from from LOCA and from S/RV discharges. discharges. Seismic Seismic loadings, loadings, and structural and structural and and water water deadweight deadweight loads,loads, can act at any time during all all transients. The lengths of the bars in transients. in the figures indicate indicate the time periods during which a loading condition may exist. The loading conditions of CO and chugging were assumed to exist continually continually during the indicated time indicated time period.

period. For For S/RV discharge discharge loads, the duration of of the loading is is short, but the loads may, short, may. occur at at any time during the indicated indicated time period-. Loads are considered period*. considered to act simultaneously simultaneously on a structure structure at a specific time if specific if the loading condition bars overlap at that time. time.

2.7.1 Shell Torus Shell The torus The shell load torus shell load sequence sequence for LOCA-DBA, LOCA-DBA, -IBA,-IBA, and -SBA -SBA cases are shown in in Figures 2.25 through 2.27.

Figures 2.25 through 2.27. Durations of Durations of the LOCA-related LOCA-related loads were based on on the durations specified the durations specified in in thethe LDR with the exception containment pressure exception of containment and and temperature temperature transients which were based on plant unique transient transient evaluations (Subsection 2.4.1).

evaluations 2.4.1). Timing of S/RV discharge transients was also based on based plant unique on plant unique evaluations.

evaluations. In In assessing the torus shell response to to ADS actuations during ADS actuations during a LOCA, a containment pressures LOCA, containment pressures and temperatures temperatures at the time time of ADS initiation initiation were used in in the loadload combinations.

combinations. '

• The ring The 2.7.2 The vent The Vent girder is ring girder (Subsection 2.7.4).

(Subsection vent system 2.7.4).

vent System System is also also system load sequences subjected sequences for LOCA-DBA, to submerged LOCA-DBA, -IBA,

-IBA, structure structure and load sequences, sequences,

-SBA are shown and -SBA shown inin Figures 2.28 Figures 2.28 to 2.30. These to 2.30. These sequences sequences are obtained obtained from the LDR and plant plant unique transient evaluations unique transient evaluations of containmentcontainment pressure pressure and temperature.

temperature.

The submerged portion The submerged portion of of the downcomers, the downcomers, downcomer tiebars, downcomer tiebars, and and main main vent vent drain drain line line are are also also subjected subjected to submerged to submerged structure structure load load sequences sequences (Subsection (Subsection 2.7.4).

2.7.4).

2.7.3 Internal Internal Structures Structures Above Above PoolPool The load sequence The load sequence for for structures structures above above the suppression suppression pool high-water,high-water level level during LOCA-DBA is shown in Figure during LOCA-DBA is shown in Figure 2.31. Structures 2.31. Structures above the the pool surfacesurface are not subjected are not subjected to hydrodynamic loading to hydrodynamic loading during during either either an IBAor IBA or SBA event. event.

2.7.4 Submerged Structures Submerged Structures The The load load combinations combinations for for the the submerged submerged structures structures are shown shown in in Figures Figures 2.32 through through 2.342.34 forfor LOCA-DBA, LOCA-DBA, -IBA, -IBA, and and -SBA

-SBA events.

events. The The loads loads following following an an S/RV actuation actuation are are illustrated illustrated in in Figure Figure 2.35.2.35.

2.7.5 S/RVD Piping S/RVD \.j

• S/RVD S/RVD piping loads, piping lines loads, and lines are and above-pool are subjected above-pool loads.

subjected to loads. The to line transient The latter latter two 2-27 2-27 transient loads, two load loads, submerged submerged structure sequences are load sequences structure are discussed discussed in in 04/16/02 04/16/02

• Subsections 22.7.4 Subsections associated discharge

. 7 . 4 and 2.

associated with 'Load transients.

discharge transients.

2.7.6 Attached. Piping Torus Attached 7 . 3 respectively.

2.7.3 Load Case A1.a respectively. For line transient events, A1.2 were conservatively events, loads conservatively used for all S/RV Loadings on torus attached piping external to the torus shell are due to to accelerations. Therefore, torus shell accelerations. Therefore, load sequencing sequencing for the torus shell shell (Subsection 2.7.1) applies applies to attachedattached piping evaluations.

evaluations. Portions Portions of of attached piping attached piping systems inside the wetwell wetwell are also subject subject to submerged submerged structure and above-pool structure above-pool loads (Subsections 2.7.4 2.7.4 and 2.7.3).-

2.7.3).

2.7.7 2.7.7 Fatigue Fatigue Design. Basis Design Basis For components components requiring requiring evaluation evaluation for cyclic loads, a fatigue design basis cyclic loads, basis was developed.

developed. The design basis assumes assumes 40 years of plant operation with one plant operation one LOCA over the design life. The postulated postulated LOCA can be either either a DBA, DBA, IBA, IBA, or or event. Tables 2.18 and 2.19 give the design basis for 40 years SBA event. years of normal normal operation followed by a DBA event or IBA/SBA event. event. InIn accordance accordance with the PUAAG, pool swell is PUAAG, is not considered considered as part of the fatigue design basis. basis. For For the fatigue evaluation of the downcomer/ventdowncomer/vent header intersection, the design header intersection, basis for chugging is described in is described Subsection 2.4.5.3.

in Subsection 2.4.5.3.

In developing In developing the fatigue design basis, the number of cycles cycles for each load combination was estimated combination, estimated by multiplying multiplying the duration of the load load by the maximum significant maximum significant structural structural response frequency frequency (taken to be 30 Hz). Since Hz). Since the maximum stress for each load combination combination is is unlikely to occur with this this

• number of cycles, cycles, a reduced number of effective determined. This effective cycles was determined. This number of effective effective cycles cycles was based on Mark I program studies studies which which determined determined fatigue usage for actual response time histories. histories. Calculation Calculation of of fatigue fatigue usage assuming assuming the maximum maximum stress for the load combination combination applied over the number number of effective effective cycles cycles produces produces the same usage for the load combination combination as would be produced produced by considering the actual considering actual response response time histories.

histories.

In In determining the number of S/RV actuations actuations over the 40-year 40-year plant life, operating records operating records for CNS were reviewed. reviewed. This review indicated indicated that 63 S/RV S/RV actuations actuations at full reactor power power have occurred since start-upstart-up (i.e.,

(i.e., over-a over a period period of roughly seven seven years).

years). Therefore, Therefore, the fatigue design basis of 500 500 valve valve actuations actuations by each each S/RV ~or for a 40-year plant plant life is is considered conservative. .

conservative

• 2-28 2-28 04/16/02

• CONTAINMENT Table 2.1 Table 2.1 HYDRODYNAMIC DATA CONTAINMENT HYDRODYNAMIC DRYWELL DRYWELL Volume Free Air volume 132 , 465 cu.

132,465 cu. ft.ft.

Operating Operating Pressure (High)

Pressure (High) 1.1 1.1 psig (Low)

(Low) 0.9 psiq Operating Operating Bulk Temperature Temperature (Nominal)

(Nominal) 135 0 F Internal Internal Design Design Pressure 58 psig Design Temperature Temperature (FSAR)

(FSAR) 281°F VENT SYSTEM SYSTEM Free Air Volume volume 13,540 cu. cu. ft.ft.

Number of Downcomers Number Downcomers 80 80

• Submergence Downcomer Submergence Maximum (High Water Level) 3.33 ft ft. .

Minimum (Low Water Water Level) 3.00 3.00 ft. ft.

WETWELL (SUPPRESSION CHAMBER)

WETWELL (SUPPRESSION CHAMBER)

Pool Volume Volume Maximum (High Water Water Level)

Level) 91,100 cu. cu. ft.ft.

Minimum (Low (Low Water Level)

Level) 87,650 cu. cu. ft.ft.

Free Air Volume volume Maximum (Low Water Water Level)

Level) 112,240 112 , 240 cu.ft.

cu. ft .

Minimum (High Water Water Level)

Level) 106,850 cu.ft. cu.ft.

Water Water Level Distance to Torus Centerline Maximum (Low Water (Low Water Level)

Level) 1.79 ft.

ft.

Minimum (High Water Water Level) 1.46 ft.

ft.

Pool Surface Area Area 9,115 sq. sq. ft.ft.

Operating Operating pool Pool Temperature (Maximum)

Temperature (Maximum) 95 0 F Design Design Pressure 58 psig

/'

Design Temperature (FSAR)

Design Temperature (FSAR) 281°F

• 2-29 2-29 04/29/82

• Table 2.2 2.2 PROPOSED LOW-LOW SET SAFETY/RELIEF VALVE VALVE SYSTEM S/RV S/RV SYSTEM A

A B C C D D E E F F G G H_(_)

Hili Pressure Relief Relief Function x X x X x X x X x X x X x X x X

ADS Function x X x X x X - x X x X x X -

Low-Low Low-Low Set Set Relief Relief Function - - - X x X x

Valve Group III III III III III I I III I II II III II Steam Pilot pilot Opening Opening Set Point (psig)

(psig) 1125 1125 1115 1105 1115 1115 1115 1125 1105 Steam Pilot pilot Closing Set Point (psig)

(psig) 1091 1091 1082 1072 1082 1082 1091 1072 1072 Low-Low Low-Low Set Set Open Open (psig)

(psig) - 1045 1045 1075

- - - 1075 Low-Low Low-Low Set Set Close Close (psig)

(psig) - 945 - - - 975 975 Note:

Note:

(1) Valve (1) Valve H is is currently designated as an ADS valve.

currently designated valve. Since itit isis necessary necessary to to

-

f--- separate ADS valves from low-low set valves, separate valves, and since it since it isis desirable desirable to to use the lowest lowest group valves valves for low-low low-low set,set, the ADS function for valvevalve H will be assigned to valve valve FF. .

• 2-30 2-30 04/29/82

• 102%

102% Licensed Power (Mwt)

Licensed Power (Mwt)

Table 2.3 2.3 PLANT CONDITIONS AT INSTANT OF DBA PIPE BREAK 2429 2429 Temperature (OF)

Suppression Pool Temperature Initial Suppression Initial (OF) 78.5 78.5 Downcomer Submergence Submergence (ft) (ft) 3.333 3

Airspace Airspace Volume (ft 3 ))

Volume (ft Drywell Drywell 132,465 132,465 Wetwell /

106,850 106,850 Airspace Pressure (psig)

Airspace Pressure (psig)

Drywell 1.10 Wetwell Wetwell 0.1

• 2-31 2-31 04/29/82

• 102% Licensed 102%

PLANT Licensed Power Power (Mwt) (Mwt) 2.4 Table 2.4 PLANT CONDITIONS AT INSTANT OF IBA/SBA PIPE BREAK 2429 2429 Initial Suppression Pool Temperature Initial Suppression Temperature (OF)

(°F) 90 90 Submergence (ft)

Downcomer Submergence (ft) 3.333 Airspace Airspace Volume (ft (ft 3 ))

Drywell Drywell 132,465 132,465 Wetwell Wetwell 106,850 106,850 Airspace Pressure (psig)

Airspace (psig)

Drywell Drywell 1.10 1.10 Wetwell 0.1

• 2-32 04/29/82

Table 2.5 Table 2.5 STRUCTURES STRUCTURES SUBJECTED TO POOL POOL SWELL SWELL IMPACT, DRAG, IMPACT, DRAG, AND FALLBACK FALLBACK LOADS LOADS vent Vent System Components Components

- Main Vent Main Vent

- Downcomer tiebar Downcomer tiebar

- Vent deflector deflector support support struts struts

- Drywell-to-wetwell Drywell-to-wetwell vacuum vacuum breakers breakers

- Main vent Main vent drain drain line line S/RVDL Piping and Supports Supports S/RVD line line B B (long (long line) line) piping piping S/RVD line line B B supports supports in in airspace Internal Piping and Supports Supports

- test RHR pump test line and supports supports

- RCIC turbine RCIC turbine exhaust exhaust piping

- HPCI HPCI turbine exhaust piping

- Core spray Core spray pump test test line line

- RCIC condensate RCIC condensate pipingpiping

- HPCI condensate HPCI condensate pipingpiping

- Demineralized water inlet Demineralized inlet piping Non-Essential Structures Non-Essential Structures

- Platform Platform grating, grating, framing, and supports supports

(

2-33 2-33 04/29/82

Table 2.6 2.6 STRUCTURES STRUCTURES SUBJECTED TO FROTH IMPINGEMENT IMPINGEMENT

\ AND FROTH FALLBACK LOADS LOADS vent Vent System Components Components

- Main Main vent vent

- Vent Vent system support support columns columns

- Drywell-to-wetwell Drywell-to-wetwell vacuum breakersbreakers

- Main Main vent vent drain line line Piping and Supports S/RVD Piping Supports

- S/RVD line B S/RVD B support in in airspace airspace Internal Piping and Supports Internal Piping Supports

- test RHR pump test line line

- Containment Containment spray header header Non-Essential Structures Non-Essential Structures

- Platform Platform handrails handrails and ladderladder

- Monorail beam beam 2-34 04/29/82

Table 2.7 Table 2.7 i

J STRUCTURES STRUCTURES SUBJECTED TO LOCA WATER JET-INDUCED WATER JET-INDUCED DRAG LOADS LOADS Torus Shell Components Components

- Ring Ring girder girder

- Ring Ring girder gussets girder gussets S/RVD Supports S/RVD Piping and Supports

- S/RVD piping S/RVD T-quencher piping and T-quencher

- T-quencher T-quencher support pipe assembly pipe assembly

- 16" 16" support pipe support pipe for S/RVDL S/RVDL 10" stiffening stiffening pipe Internal Piping and Supports Internal Supports

- RHR RHR pump suction strainer pump suction strainer

- RCIC RCIC pump suction strainer pump suction strainer

- HPCI HPCI pump pump suction suction strainer strainer

- Core spray pump suction Core spray suction strainer strainer

- HPCI HPCI turbine exhaust piping and supports turbine exhaust supports

- RCIC RCIC turbine exhaust piping and supports turbine exhaust supports

• Non-Essential Structures Non-Essential Structures

- Platform support Platform support columns columns

• 2-35 2-35 04/29/82

Table 2.8 2.8 STRUCTURES SUBJECTED TO SUBMERGED STRUCTURES SUBMERGED STRUCTURE LOADS STRUCTURE DRAG LOADS AND INTERFERENCE INTERFERENCE FACTORS FACTORS Interference Interference Factors(l)

Factors(i)

Torus Shell Components Components

- Ring Ring girder girder 1.3 - 2.06

- Ring girder Ring girder gussets gussets 1.0 1.0 - 2.0 2.0 Vent System Components Components

- Downcomer tie-bars Downcomer tie-bars 2.0 2.0

- Main vent drain Main vent drain line line 1.0 1.0

- Downcomers Downcomers (2) (2) 1.0 1.0 S/RVC Piping and Supports Supports

- S/RVD line A A Piping and T-quencher T-quencher 1.0 1.0 -- 2.3 2.3

- S/RVD line S/RVD line B B piping and T-quencher T-quencher 1.0 1.0 - 2.3 2.3

- T-quencher T-quencher support support pipe assemblyassembly 1.2 1.2 - 2.2 2.2

- 16" 16" support support pipe for S/RVDL B 1.5 1.5 - 2.4 2.4

- 10" 10" stiffening stiffening pipe 1.1 1.1 - 2.1 2.1 0 Internal Piping Internal Piping and Supports Supports RHR pump pump suction suction strainer strainer 1.

1.35 35 RCIC pump pump suction suction strainer strainer 1.

1.35 35 HPCI pump pump suction suction strainer strainer 1.

1.35 35 Core spray spray pump suction strainer strainer 1.

1.35 35 HPCI turbine turbine exhaust exhaust piping and supports supports 1.71 1.71 RCIC turbine turbine exhaust exhaust piping and supports supports 1.

1.76 76 HPCI condensate condensate piping 1.0 1.0 RCIC condensate condensate piping 1.0 1.0 RHR pump test test lines 1.0 1.0 Core spray pump test test lines 1.2 - 2.0 2.0 Demineralized Demineralized water inlet inlet 1.0 1.0 Non-Essential Structures Non-Essential Structures

- Platform support columns columns 1.0 - 2.0 2.0 Notes:

Notes:

(1)

(1) several structures, For several interference factors depend structures, interference depend on location on the structure. Range of the factors is structure. is indicated indicated inin the table.

table.

(2) ) Submerged structure structure drag loads downcomers defined

(2 Submerged on downcomers are defined only for for T-quencher T-quencher bubble drag loads loads..

2-36 2-36 04/29/82

Table 2.9 2.9 CONDENSATION CONDENSATION OSCILLATION OSCILLATION BASELINE RIGID RIGID WALL PRESSURE AMPLITUDES ON TORUS SHELL SHELL BOTTOM DEAD CENTER CENTER Frequency Frequency Amplitudes Amplitudes (1) (1) Alternate Alternate Amplitudes Amplitudes Range Range to be Analyzed Analyzed To be Analyzed (1) (1)

(Hz)

(Hz) (PSI)

(PSI) (PSI)

(PSI) 1 2 3 0-1 \

1-2 1-2 0.29 0.25 i 2-3 2-3 0.32 NONE NONE 3-4 3-4 0.48 iI 4-5 4-5 1. 86 1.86 1.

12 1.20 l

20 0.24 0.24 5-6 5-6 05 1.05

1. 2.73 2 .73 0.48 0.48 6-7 6-7 E,

('-; rLI et:: rLI

• 0.42

[;3:<:('-;0 F4 U)

('-; [;3 U) 0.49 0.99 0.99 7-8 7-8 0O'~M *~(/]Z U) 0.59

0. 59 0.38 0.38 0.30 0.30 rLI ~ ~ r<) ~ U) rLI 00 8-9 8-9 et:: rLI rLI K) rLI rLI :> 0.. 0.59

0. 59 0.38 0.38 0.30 0.30 W B H(/]('-;('-;('-;('-;HUl H 9-10 >-=i ~ ~ >-=i 0 U)

('-; rLI wHQ rLI 0.59 0.59 0.38 0.38 0.30 0.30 10-11 10-i1 1J~~~~~:r:et:: E, B 0.34 0.34 0.79 0.79 0.18 0.18 11-12 11-12 ('-;~et::~rLlE-<8~ H u

0 0.15 0.45 0.45 0.12 u:>[;j>-=i~i;5~ U) 12-13 12-13 rLI I'.. ('-; ~ ~ >-=i H 0.17

0. 17 0.12 0.12 0.11

>-=i 00 H rLI:x:

U) 13-14 13-14 rLI

(/] rLI r l-U)

Ul ~ 0.12 0.08 0.08 0.08 0.08 14-15 14-15 0.06 00.07

.07 0 .03 0.03 15-16 15-16 16-17 0.04 1 0 0.10 0.10 0.10 0 .02 0.02 17-18 18-19 00.04

.04 0.04 0.-04 r 19-20 19-20 0.27 NONE NONE 20-21 20-21 0.20 21-22 21-22 22-23 22-23 23-24 23-24 0.30 0.30 0.34 0.34 0.33 1'

24-25 24-25 0.16 2-37 04/29/82

• AMPLITUDES ON Table 2.9 Table CONDENSATION OSCILLATION 2.9 (Continued)

ON TORUS Frequency Frequency (Continued)

OSCILLATION BASELINE BASELINE RIGID WALL TORUS SHELL WALL PRESSURE SHELL BOTTOM DEAD CENTER Amplitudes Amplitudes Range Range to be Analyzed (1)

Analyzed(l)

(Hz)

(Hz) (PSI)

(PSI) 25-26 0.25 26-27 0.58 27-28 0.13 28-29 0.19 29-30 0.14 30-31 30-31 0.08 31-32 0.03 32-33 0.03 33-34 33-34 0.03 34-35 0.05 35-36 0.08 36-37 0.10 0.10 37-38 0.07 38-39 38-39 0.06 39-40 39-40 0.09 40-41 0.33 41-42 0.33 42-43 0.33 43-44 0.33 44-45 0.33 45-46 0.33 46-47 0.33 47-48 47-48 0.33 48-49 48-49 0.33 49-50 49-50 0.33 NOTE NOTE (1)

(1) Half range range (=

(= 1/2 peak to peak 1/2 of peak peak amplitude) amplitude)

• 2-38 2-38 04/29/82 04/29/82

• CONDENSATION Table 2.10 Table CONDENSATION OSCILLATION 2.10 OSCILLATION ONSET Onset Onset ONSET AND AND DURATION DURATION Time Time Duration Duration Break Size Break Size After After Break Break After After Onset Onset DBA 55 seconds seconds 30 seconds 30 seconds IBA IBA 55 seconds seconds 900 seconds 900 seconds SBA SBA Not Applicable Applicable Not Applicable Applicable

• 2-39 2-39 04/29/82 04/29/ 82

• VENT SYSTEM Table 2.11 SYSTEM LOAD AMPLITUDES AND FREQUENCIES FOR CONDENSATION FREQUENCIES CONDENSATION OSCILLATION DBA IBA Forcing Function Forcing Sinusoidal Sinusoidal Sinusoidal Sinusoidal Spatial Distribution Spatial Uniform Uniform Uniform Uniform Frequency Range Frequency Range 4-8 Hz 4-8 6-10 Hz 6-10 Amplitude:

Amplitude:

Main Vent Vent and +/-2.5 psi psi +/-2.5 psi psi Vent Header Header DownComer Downcomer +/-5.5 psi psi +/-2.1 psi psi Note:

Note:

• These loads components .

components.

are used only to determine determine hoop stresses stresses in in vent system system

• 2-40 04/29/82

• VENT Table Table 2.12 VENT SYSTEM DOWNCOMER DUE TO 2.12 DOWNCOMER LATERAL LOAD TO CONDENSATION CONDENSATION OSCILLATION OSCILLATION Pressure Pressure (psi)

(psi) Frequency Frequency Range (Hz)

Range (Hz)

Amplitude Type DBA IBA

-BA DBA IBA IBA Internal Internal +/-3. 6

+/-3.6 +/-1.1

+/-1.1 4-8 4-8 6-10 6-10 Differential Differential +/-2. 85

+/-2.85 +/-0.2

+/-0.2 Internal Internal +/-1.3

+/-1.3 +/-0.8

+/-0.8 8-16 12-20 12-20 Differential Differential +/-2. 6

+/-2.6 +/-0.2

+/-0.2 Internal Internal +/-0.6

+/-0.6 +/-0.2

+/-0.2 12-24 12-24 18-30 18-30 Differential Differential +/-1.

+/-1. 22 +/-0.2

+/-0.2

• 2-41 2-41 04/29/82

• Table 2.13 ONSET AND DURATION CHUGGING ONSET CHUGGING Onset Onset Time Time Duration Break Size Size After Break After Onset Onset DBA 35 seconds seconds seconds 30 seconds IBA IBA seconds 5 seconds 900 seconds seconds SBA 300 seconds seconds 900 seconds seconds

• 2-42 04/29/82

• POST-CHUG RIGID POST-CHUG ON TORUS Table 2.14 RIGID WALL PRESSURE AMPLITUDES TORUS SHELL BOTTOM AMPLITUDES BOTTOM DEAD CENTER Frequency Frequency Ampli tude l11 Amplitude("' Frequency Frequency Amplitude l11 Amplitude(i)

Range (Hz)

Range (Hz) (PSI)

(PSI) Range (Hz)

(Hz) (PSI) 0-1 0.04 25-26 0.04 1-2 1-2 0.04 26-27 26-27 0.28 0.28 2-3 2-3 0.05 27-28 27-28 0.18 0.18 3-4 3-4 0.05 28-29 28-29 0.12

0. 12 4-5 4-5 0.06 29-30 29-30 0.09 5-6 5-6 0.05 30-31 0.03 6-7 6-7 0.1 0.1 31-32 0.02

0. 02 7-8 7-8 0.1 0.1 32-33 0.02

0. 02 8-9 8-9 0.1 0.1 33-34 0.02

0. 02 9-10 0.1 0.1 34-35 0 .02 0.02 10-11 10-11 0.06 35-36 0.03 0 .03 11-12 11-12 0.05 36-37 0.05 12-13 12-13 0.03

0. 03 37-38 37-38 00.03

.03 l3-14 13-14 0.03 38-39 38-39 00.04

.04 14-15 14-15 0.02

0. 02 39-40 00.04

.04 15-16 15-16 0.02

0. 02 40-41 0.15 0.15 16-17

• 0.01 41-42 0.15 17-18 17-18 0.01 0.01 42-43 0.15 18-19 0.01 0.01 43-44 0.15 19-20 19-20 00.04

.04 44-45 0.15 20-21 20~21 0.03

0. 03 45-46 0.15 0.15 21-22 0.05 46-47 0.15 0.15 22-23 0.05 0.05 47-48 0.15 0.15 23-24 23-24 0.05 48-49 0.15 0.15 24-25 0.04

0. 04 49-50 0.15 0.15 NOTE:

NOTE:

(1)

(1) Half range (= 1/2 peak to peak range (= peak amplitude) amplitude)

• 2-43 04/29/82

• Table 2.15 VENT SYSTEM LOAD AMPLITUDES AND FREQUENCIES AMPLITUDES FREQUENCIES FOR CHUGGING Arnpli tude (psi)

. Amplitude (psi)

Frequency Frequency Main Vent Vent Load Type Load Type (Hz)

(Hz) Vents Header Header Downcomers Downcomers Gross Vent vent System System Use wave form in in LDR +/-2.5

+/-2.5 +/-2. 5

+/-2.5 +/-5.0

+/-5.0 Pressure Figure 4.5.4-1 Oscillation (0.7 Hz)

(0.7 Hz)

Sinusoidal with Sinusoidal +/-2. 5

+/-2.5 +/-3.0

+/-3.0 +/-3.

+/-3.55 Acoustic Vent Acoustic Vent frequency varying frequency Pressure System Pressure between 6.9 to 9.5 between 9.5 Oscillation Hz Acoustic Downcomer Acoustic Downcomer Sinusoidal Sinu~;oidal with N/A N/A N/A N/A N/A N/A Pressure frequency varying Oscillation between 40 to 50 Hz between

• 2-44 04/29/82

• DISTRIBUTION OF DISTRIBUTION Table Table 2.16 OF DOWNCOMER 2.16 DOWNCOMER LATERAL LOAD REVERSALS DUE TOTO CHUGGING CHUGGING REVERSALS Maximum Percent of Maximum Load Range Range Group 1 Group 2 5-10 4,706 3,168 3,168 10-15 10-15 2,696 2, 696 1,104 1,104 15-20 15-20 1,399 709 20-25 676 676 452 25-30 380 255 30-35 30-35 209 139 139 35~40 35-40 157 86 86 40-45 113 48 48 45-50 45-50 83 83 32 32 50-55 65 65 14 14 55-60 55-60 51 51 11 60-65 60-65 44 44 5 65-70 65-70 32 32 7 70-75 19 19 11 75-80 26 26 4 80-85 80-85 12 12 2 85-90 85-90 11 0 90-95 90-95 9 2 95-100 7 2 Notes:

Notes:

(1)

(1). Group 1: Sectors Group 1: Sectors 1, 1, 2, 2, 7,7, && 8 Group Group 2: Sectors Sectors 3, 3, 4, 4, 5,5, && 6 (2)

(2) Refer Refer to to Figure Figure 2.23 2.23 forfor the the sectors sectors

/

• 2-45 04/29/82 04/29/82

Table 2.17 STRUCTURES SUBJECTED TO T-QUENCHER STRUCTURES WATER JET LOADS T-QUENCHER WATER LOADS Torus-Shell Torus-Shell Components Components

- Ring girder Ring girder S/RVD Piping Piping and Supports Supports

- 16" 16" support pipe for S/RVD support S/RVD Internal Piping Internal Piping and-Supports and Supports

- RCIC pump suction strainer RCIC pump strainer

- HPCI pump suction HPCI pump strainer suction strainer

• 2-46 2-46 04/29/82

• Combination Combination Number Number FATIGUE Load Load Combinations Combinations Table 2.18 FATIGUE DESIGN BASIS INCLUDING INCLUDING DBA EVENT Number of Effective Effective Cycles at Maximum Stress(l) 1 1 Containment DBA CO + Containment 1 Containment Temp + Containment 2 Pressure ++ SSE SSE((2 ))

2 DBA CO + SSE 9 3 CO DBA CO 80 80 44 Post-Chug 33))

Post-Chug( 32 32 (3

5 Pre-Chug Pre-Chug(3) ) 100 100 66 NOC S/RV Discharge(4)

Discharge (4 ) 50 50

+ OBE(5)

OBE (5 )

77 Discharge NOC S/RV Discharge 2950 2950 Notes:

Notes:

(1)

(1 ) Number Number of effective effective cycles cycles is is the equivalent equivalent number of of cycles at at maximum maximum stress contributing to fatigue usage. usage.

(2)

(2) One SSE over over 40 year plant life life assumed to occur during DBA event event significant load cycles/SSE)

(10 significant (10 cycles/SSE). .

(3)

(3) Chugging Chugging load duration duration divided divided into periods of Pre-chug and Pre-chug Post-chug as described described in in LDR Section Section 4.5.1.2.

4.5.1.2.

(4)

(4) 500 S/RV 500 S/RV discharges discharges during during normal normal operating conditions operating conditions (NOC)

(NOC) assumed assumed based on plant operating based operating data.data.

(5)

(5) Five Five OBE events events over 40 year plant life life assumed to occur assumed occur during S/RV S/RV discharge events discharge events (10 significant significant load cycles/OBE). cycles/OBE) .

9J (6)

(6) Cumulative Cumulati ve usage determined by calculating usage determined calculating usage for each each combination summing over and summing over all all combinations combinations. .

• 2-47 04/29/82

• Combination FATIGUE Load Table 2.19 FATIGUE DESIGN BASIS INCLUDING INCLUDING IBA/SBA EVENT Number of Effective Number Number Combinations Combinations Cycles at Maximum StressStress(i' (1) 1I Post-Chug + 6 ADS Post~Chug ADS 11 S/RV Discharge ++

Containment Containment Temp ++

Containment Containment 2

Pressure SSE((2 ))

+ SSE 22 Post-Chug + 6 ADS ADS 99 S/RV Discharge + SSE 3 Post-Chug(3) 960 960 (3

4 Pre-Chug Pre-Chug(3) ) 3040 3040 5 IBA COCO 3040 3040 6 Discharge(4)

NOC S/RV Discharge (4

) 50 50 (5

+ OBE OBE(5))

77 NOC S/RV Discharge(4)

Discharge (4 ) 2950 2950 Notes:

Notes:

(1)

(1) Number Number of of effective effective cycles cycles is is the equivalent the equivalent number of of cycles cycles at at maximum stress contributing maximum contributing to fatigue usage. usage.

(2)

(2) One One SSE over 40 SSE over 40 year year plant plant life life assumed assumed to occur during occur DBA event event (10 significant (10 significant load cycles/SSE).

load cycles/SSE) .

(3)

(3) Chugging Chugging load load duration duration divided divided into into periods periods of of Pre-chug Pre-chug and Post-chug as described described inin LDR SectionSection 4.5.1.2.

4.5.1.2.

(4)

(4) 500 discharges during normal 500 S/RV discharges normal operating conditions operating conditions (NOC)

(NOC) assumed assumed based on based on plant plant operating operating data. data.

(5) )

(5 Five Five OBE events over OBE events over 40 year plant 40 year plant life life assumed assumed to occur during S/RV discharge discharge events (10 (10 significant significant load cycles/OBE). .

load cycles/OBE)

(6)

(6) Cumulative Cumulati usage ve usage determined determined by calculating usage by calculating usage for each combination and summing and summing over over all all combinations.

combinations .

• 2-48 2-48 04/29/82

60

• *

• I--

6t.4

- Y

/"

-f--

-t

~ ,\l

,.. o ~Y\lIlELL. PAESSUf E - IH 0

.

f-f- "- ~ ~

40

" ,

.1-I II

"" "- .....

I1j I

~ ....... ..,;,..

J PRESSURE -psig WETWELL PRESSURE i - ~ WETWELL - IHIg -

, ./' ~

!4. 3 4.3 1-20

~ t--

'-- - ~

1.,,0' "".

'/ UII

/

.

f 1f-

! .~.

t-- 1--'

f- - - r- .-

f-o 0I 10 20 30 40 o 10 20 TIME (sec$

30 40 TIME bect FIGURE 2.1 FIGURE 2.1 DBA CONTAINMENT DBA PRESSURE RESPONSE CONTAINMENT PRESSURE RESPONSE 22-49

-49 04/29/82 04/29/82

• 400-450

-

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1m I

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-- - t - - I-I-I Ii.~.- * -

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-

-I-p-mm mp-~

I -.-- 1 .- I------f -4 -4.----- 4 ---

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• " * =--*-:-" "" --

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_.1-- I- - I--

0.

i 1- r- t-- f -

...

w

-- t--

" I - f-1- - I- 0 -12m - 12 15(

160 ,

WETWELL TEMPERATURE TEMPERATURE --O-F-V- '2' -

- - t-- I-- I - -- - - -- -,- - WETWELL of I,."

f - I-- -

zamm m,,," -

f-

~ I-- t-- i - i -

- f- - f- .'

m_.- - m .. m m_ - m -_ m m-. m m - m m m -,

- -

_. - -

- 1- - ~ '-

f- - - f-o0 10 20 30 40 40 o 10 TIME 20 (sac) 30 TIM!; hecl FIGURE 2.2 FIGURE 2.2 CONTAINMENT TEMPERATURE DBA CONTAINMENT DBA TEMPERATURE RESPONSE RESPONSE 2-50 04/29/82 04/29/82 2-50

- *

• I-I -

-

!- >-.

f- l-I-- >-.

- 312 -..

1\ I - i-

\

" OAYWEll 30 J.

"ii - -

lI-:  :-T I I IT

~WE1WEll I- t-

§ Au - i II' I I I

! .

w cc 22.0-=\ I II I I I -

II \ _L I I I

J . \ II .. .- 28.9

~ 22. "Ill I-u' UJ I m

a:::

-...

> I 4.

0- t- Il 2D II' I\"

i.ooo i-" T

- J I~

"-J.

.r \

_\

\ 1-= 20.1

~

.J. L ~-

1'1 IL'.J. 2---U

'-I-

~ L 10 - ~II'

"'~ -

~ .7

.J'

~7 L."IjIII' ~

f- i-.

.... ~

J o

.-

--

I-..:;; ,.....

L....II ~

L....."'"

- i- f-..

-I-I1 10 10 100 100 1000 1000 10000 10000 TIME Ioc)

TIME heel FIGURE 2.3 FIGURE 2.3 CONTAINMENT PRESSURE IBA CONTAINMENT IBA PRESSURE RESPONSERESPONSE 2-51 04/29/82 04/29/82 2-51

..a 61ff U -- I1 -- r

• 0- U -1

• 400 400

-

f-9- 300  :~ 216-, if if*

&l.

IL '-

w a:

~

w

- .j

, ~ DRYWELl a:

0(

-:-

--

• U I I _  ; , J'OF

~

a: ~262

- '-,

w CL w

CLl 2-

1 w 200

~ m-- -m - ,,, -U

• 167 I-.

\ Iu 100

, WETWElL

-

, -".

L 100

.-- - "

~110

-'

I- i - r- 1-'

..

- - -...

,- - ,....,

o ID -

I 10 100 100 1000 1000 10000 10000 TIME (sec)

'TIME hed FIGURE 2.4 FIGURE 2.4 CONTAINMENT TEMPERATURE IBA CONTAINMENT RESPONSE TEMPERATURE RESPONSE 2-52 04/29/82

Ah .m m

-

U

- -

-m m-

-

m-ml.mm mm

- '

mmm.

• - -.-. ,m- -

-

-m m Um Um Um

-

-m m- m mm

- " -- .. _- - -

40 =

40 30",

- 30

!

LU UJ

.- 23.2 Ir"' 23.2 a: 30 - -_ . ~ --- - 20. - mmDRYWELL I- I-

=> --

~ ,- i a-UJ a:

"WETWE I'\.

, "

!~

II 10-DRVWELL I-WETWElL A. 1fI".

20 20 I-

- iJ I

• ~ ~ -- 21.3 -7 r,

I/~ ~ rc=- 21.3 III

- --

--

- -

- L ILl L L

II to to -r-- -- ill"

"" I 1..01'"

~

-:7

.7

'" '"

7

./

-.,.... --~ ..

~

L..oII""

00 I

0 -- ... 1 10 10

..

I~Z= I - I

,..... ~jIII'"

L ! i 100 100

- I - i I i t I;i H

-

I 1000 1000 r(

LZ; I .-

L H7t 10000 10000 TIME Ibc)

TIME beet FIGURE 2.5 FIGURE 2.5 CONTAINMENT PRESSURE SBA CONTAINMENT SBA PRESSURE RESPONSE RESPONSE 2-53 2-53 04/29/82 04/29/82

• I

• WI - - - - U U - - -

• -

- - - - - - -

• r+-

400 400 -

- - 1-- - - - -

-f- f-

_____ - - - - - - -

- - - - - - - - - -t- - - - - - I- f-.

- -

-'-4--- - - -

- ----- 4-- - - - - -

-

- - - ---- 4-- - - - - -

- - - - -

- - - - -- 4--- - - - - -

-I .....

f-I I1-

____ - - - -

I- ELL-+- -- 4

- - I DRYWELL uM v VvI u.

IL 300 300

- - -

I . . ,

I I

- i -EITI-1-11,11- I- I-.

~ -

\AI a: -

~w c(

a:

\AI Cl..

t-w

~ -

'.

200 200

-

_- -'12 3 1r--'123

~

100--'*

• WETWELL- - -

100""'"\

- - ---

-.1 ~~ !--WETWEll L.-o" 100. ~

100

-_--

I- i-- .-

- I- f-.

- - '.

I - I- f-.

o 0 ~ ~ ~ ~ ~ ~ ~ , ~ - H m 100000 1I 10 1PO 100 1000 tO0000 10000 TIME (sac)

TIME hed FIGURE FIGURE 2.6 2.6 TEMPERATURE RESPONSE CONTAINMENT TEMPERATURE SBA CONTAINMENT RESPONSE 2-54 04/29/82

FIVI 2

P2'4 FIVI = VERTICAL FORCE FORCE ON ON MAIN VENT END CAP CAP FiHl FIHl =

= HORIZONTAL FORCE ON MAIN HORIZONTAL MAIN VENT END CAP CAP F2V

= VERTICAL FORCE ON ON VENT HEADER (PER MITRE HEADER (PER MITRE BEND)

BEND)

F2H =

= HORIZONTAL HORIZONTAL FORCE ON VENT HEADER (PER MITRE BEND) BEND)

F3V =

VERTICAL VERTICAL FORCE FORCE ON DOWNCOMER MITRE MITRE BEND F3H = HORIZONTAL HORIZONTAL FORCE ON DOWNCOMER MITRE BEND DOWNCOMER MITRE

• FIGURE FIGURE 2.7 2.7 VENT SYSTEM THRUST LOAD APPLICATION 2-55 2-55 04/29/82

~---------------------

F1Vl FII i

!

fJ ~-too

-tOO II:

0o II.

IL

-150

-1150

• -~O~-----------6L.----------~10------------'~5----------~~----------~----~I-----~~----------~35 0 5 10 15 20 25 30 TIME (so)

TIME'_'

2.8 FIGURE 2.8 SINGLE MAIN VENT SINGLE MAIN FORCES VENT FORCES (0-30 sec),

(0-30 sec), ZERO ZERO t,p AP 2-56 2-56 04/29/82

(

• 0 8

8 FORCE (k~s~

II 0

C a' - a a'

-4 m TIME hee) -

FIGURE 2.9 N N N) ~

VENT HEADER FORCES PER MITER BEND (0-30 sec), ZERO ~P Nz H)

N N

U N

N C) 0 N N U)

N N

N U) U 0 0 w () N N N

0 N 7

2-57 04/29/82 0 K)

U)

N)

.2~------------~*~----------------*~

ACC.

F3V 0

-1 j

III u

cr:

2 0

0 IL

-2 F3H C-

-3 C-.

~----------~----------

o 9-0 Ql 15 ..

10----------~----------~----------~------~

01 15 20 TIME (sec) oz 25* ----------~35

~ ..

FIGURE 2.10 SED'dOq EENODNMOa HIONIS OE-o) (Des SINGLE DOWNCOMER FORCES (0-30 sec), ZERO dV 0OdZ

~p 2-58 04/29/82

.~------------~.~-------------.~

U -

\

a FlVT

~FNIETV FNE'TV 0

400

-I F~t F.vn I

..----------..----------.. ..

0 5 is 20 25 30 35

~~----------

o 10 t6 FIGURE 2.11

---

~--

TIME foe?

TIME ,_,

20  :'

'

..

30--~------ 35 TOTAL AND NET VERTICAL FIGURE FORCES 2.11 (0-30 sec), ZERO AP TOTAL AND NET VERTICAL 2-59FORCES (0-30 sec), ZERO ~p 04/29/82 2-59 04/29/82

• . ~__________~e~____________~.

COOt'EFIL STATION COOPER sTATION DRYWELLIWETWE DRVWELUWETWELL LL PIEUURE

"'!aURE DIFFERENTIAL 0.0 Pd A 0.0 DIFFERENTIAL.1 pIId 3.33 ft 3.33 SUBMERGENCE. AP:

It SUBMERGENCE. 0.0 poid lAP: 0.0 pIId 44 1- 0 O~~~~---------t--------------------------------~~------;

-4

'!

I

'.

---

~----------~----------~----------~----------~------~,--

0o 200 400 600 eoo  !

BOO 1000 1000 ..--------...1400 120D 1400 TIME Immc)

TIME Imwcl FIGURE FIGURE 2.122.12 NET NET TORUS TORUS VERICAL VERICAL LOAD, LOAD, ZERO ZERO AP

~p 2-60 2-60 04/29/82 04/29/82

• 8

• Peak Peak Up Up 5.653 5.653

• 4 4-

,--,

-0 (J)

C,,

0

'-'

0.

-0

~

0 0 0-

..J

~

()

-'-

QJ

>0 I-- -4 QJ Z

(J)

...

J 0

I-

-8

-8

___ .P.eak Down -10.557

.Peak Down -10.557

-12

-12 ,i

~----------~--------~----------T----------'----------r----------r------~'d--r o

0 400 400 600 800 1000 1000 1200 1200 0

': 1400 200 200 (msec)

Time (msec)

FIGURE 2.13 CORRECTED TORUS NET VERTICAL LOADS (NRC),

(NRC), (ZERO ~P)

(ZERO AP) 2-61 2-61 04/29/82

• 50 50

• r 40 r-

~

33 C,,

CI) 0.c.

'-'

...

(1)

I-.

J r~

C,)

CI)

U)

CI)

...

(1)

I...

a.

0~

20 I10 0 4 0 6 0 800 1000 1200 0 Time (msec)

(msec)'

FIGURE FIGURE 2.14 2.14 CORRECTED CORRECTED AVERAGE AVERAGE SUBMERGED SUBMERGED PRESSURE PRESSURE DUE DUE TO POOL SWELL TO POOL SWELL (NRC),

(NRC), ZERO ZERO AP

~P -

2-62 2-62 04/29/82 04/29/82

050

• 40 40 30-30

,.....

(J) a.

-..J e-%

....Q) 2

l (J)

U)

(J) 0)

Q) 0-

....

a..

10-10 21 FIGRE 0

O'~----------~--------~~------~----------r----------r--------~~--------'

'0

'0 200 200 400 400 600 600 .801000

.800 1000 1200 1 20~)

Time Time (msec)

(msec)

FIGURE 2.15 FIGURE 2.15 AP CORRECTED TORUS AIRSPACE CORRECTED.TORUS PRESSURE DUE AIRSPACE PRESSURE POOL SWELL TO POOL DUE TO (NRC), ZERO SWELL (NRC), ZERO ~P 2-63 04/29/82 2-63 04/29/82

• eA BaC c cc aa A BCD 8 C D C B B A BCD 8 C D

• 0

! !, ~ ~ ~ ! J IV iIC A

~ JJ~ J ~ U~

1 11C A 1C I I

• I I

I I

I

, , '!IJ

~

, 1.I I

I ,

I

~. 1.5~

I, I I

I

,

I I 11.56,

, I I

I I I

- 2.47 I I

I U',\'J' I* , .- - . -

1.5& I I

~

I 2.47 1 2.47 I 2.47 r 1"1 2.47 i

,,

I

, I I

'-

I I I I I I *

~

.. - I --

r I I I r I .I I~

Ze - 1.0 lIt* 1.0 3.150 ALL DIMENSIONS

+ + *1- +

3.eo DIMENSIONS ARE IN 3.12 3.12 3.&0

• 1-3.1SO

~

Zit*

Z/9 - 0 IN FEET FIET

...

fit

- ..

...... ...6 {!,.:. ~ ...N 1ft f'I TRANSIeNTS T A -* TRANSIENTS A T,1

~

-

... ...~

tv - ... ....-

...- 8 -* TRANSIENTS TRANSIENTS T T2. To. T, 2 . T4.... Te. T9 ,'J

• j

J 0)q.,

cC *- TRANSIENTS TRANSIENTS T7. T7 , T10.

T10 . T Tn 12 I.,'

o0 *a TRANSIENTS TRANSIENTS T3. T&"To, T3 , T50 Te. T T11 11 FIGURE FIGURE 2.16 LOCATION OF OF IMPACT/DRAG IMPACT/DRAG PRESSURE PRESSURE TRANSIENTS TRANSIENTS ON VENT HEADER HEADER 2-64 2-64 04129/82 04/29/82

TORUS EL. 876'-7'2" IVACUUM BREAKER 1340

'340 4124 Ib/ft 4'24 'bItt fl., =

AP = 0.0 0.0 M9O 3'0 042 Ib/ft 942 Iblll I---+_~_ _ _ _..J-_ _ _ _ _ _.(aec . ,Cue}

0.604 .623 0.7223 (v.,.t DBA Start) 0.415 0.463 0.604 .523 0.7223 C** I.t. DBA St.,tI 0.4 ff 0.4'3 0.678 0.618 Timeo(ac) impact and Drag Load on Vacuum Breaker Volvo Impact ."d Dr.g Lo.d 0" Vacuum Br....r Velft Tlm.Cue}

Impact and Drag Load on Main Vent Impact and Dlag Load on Main Ve"t

• FIGURE 2.17 FIGURE 2.17 POOL SWELL IMPACT/DRAG LOAD TRANSIENTS POOL SWELL IMPACT/DRAG LOAD TRANSIENTS ON MAIN VENT, AP = 1.0 psid ON MAIN VENT, 2-65

~P 2-65

= 1.0 psid 04/29/82 04/29/82

7100

~ r------------------------------------------------------------------.

COOPER STATION DEFLECTOR FUll SCALE LOADS 6000 8000

h. ZJL A ZJl* -o.o 0.0 5o o Z/L 0 ZJl* - 0.5 0.5 E0

[J Z/LZJl* - 1.0 1.0

\

J 16 16 in.

in. DIAMETER DIAMETER PIPE PIPE WITH WITH ANGLES ANGLES CLEARANCE CLEARANCE TO TO WATER WATER SURFACE SURFACE 4.3 4.3 in.

in.

DOWNCOMER DOWNCOMER SUBMERGENCE SUBMERGENCE 3.333 3.333 tth 4000 -,,AP: 4P: 00 Pei PI; 4000

-

w U

~UI

(,)

I0a:

-

0

~ 300

J:)OO 3O0 1000 1000 06.

Oha--------~~3-C---~--------~--------~--------~----~~~

190 110 230 230 270 270 310 310 350 3&0 390 430 430 TIME TIME (misc)

(INK'

• VENT FIGURE FIGURE 2.18 VENT HEADER 2.18 HEADER DEFLECTOR DEFLECTOR LOADS 2-66 2-66 LOADS

\

04/29/82 04/29/82

FROTH REGION I jTYP OF BOTH SIDES OF HEADER)

HEADER) w;...._ _ _- - \_ _TYPICAL

-TYPICAL STRUCTURE STRUCTURE

-:----.- :". -

- - - - - - t - - n I R-DIRECTION ECTION OF OF LOAD LOAD APPLICATION APPLICATION Region I REGION REGION J--.R

-yoR14.375 14.375 Ft.----1 Ft.

ll1\ .6R--. l

~O.6R--i

• ..-..--,.--

POOL

-POOL SWELL PROFILE PROFILE Region II Region II

• DEFINITION FIGURE 2.19 DEFINITION OF FROTH FROTH IMPINGEMENT 2-67 IMPINGEMENT REGIONS 04/29/82

DIRECTION OF LOAD

• LOAD APPLICATION FROTH FROTH ITYP (TV? OF REGION R~GION II SIDES Of BOTH SIDES OF H(ADEn)

HEADER)

_0 TRANSIENT TRANSIENT

~

w I-

-TYPICAL

'-~~===l-TYPICAl ~TRUCTuRE STRUCTURE 0 a:

00 80 msec UHIIFCTIO:I OI11[Cfl():' (),

r}r QAI) tI0 lO,\{) APVLII ":.'

"P"L A riot, flolI TIME OF TIME TIME liME (m.eel tmisec)

VENT HEADER VENT IMPACT

(

Froth Impingemenl Frolh Impingement Region II POSSIBl( STRUCTURE STRUCTUnE DIRECTIONS OF lOAn~ 90 O ~/'\' cc v [N T I u0J TORUS TORUS c:

HEAD[R 2 o :00 rnsoC

~-~~----------~-

TIME liME OF MAXIMUM -.l TIME liME (msec)

(mscc)

POOL SWELL SWEll VELOCITY VELOCITY Froth Impingemelit Frolh Region It Impingement Region"

/

TRUCTURE v (III

"""'U w u

0 0

~

a:

....

0 I-

¶000 W~3CC TORUS TORUS TIME OF TIME OF FROTH IMPACT--1 FROTH

~

IMPACT.

I TIME TIME (reseL)

(msf"C)

I Froth Fallback Froth

• DEFINITION DEFINITION OF OF FROTH FIGURE FIGURE 2.20 FROTH LOAD APPLICATIONS 2.20 APPLICATIONS AND 2-68 2-68 AND TRANSIENTS TRANSIENTS 04/29/82 04/29/82

A . LOCAL rRIESSU-4f OSCILLATION AUPLITUDE WET WEll AMAK - AXIMLUM "R(SSURE OSCILLATION AIR S'ACE A...... * "A.)(U,.V~ 'RlSSURE OSClllATIO .... AUPLITUDE A..... Ut'UO(

BAT TORUS BOTTOM D0 AD CENT R IAT TORUS BOTlOM Of AD CENT' At A

A,144

, RH SURFACE SUPPRESSION

. ,OOL 3 -t 3

o* All All 5050 frequencies frequencies assumedassumed Ininphase phase

• Frequency set to any torus natural frequency within

• Frequency set to any torus natural frequency within the theband band (ring (ring girder girder saddle saddle torus torus frequencies frequenciesin-In-a dicat-ed on frequency axis)

0. dlca~d on frequency axis) 2- *

• Envelope Envelope3 3alternative alternativeamplitudes amplltudea inin4-16 4-16HzHzrange range

-O It 2 a

I-.

...,".. 1 -

1

.,..

4, I.'

'"

01 0

o II I I I I S 10 15 2020 2525 3030 35 40 4545 5050 o 35 40 Frequency (Hz)

Frequency (Hz)

• FIGURE FIGURE2.21 2.21 TORUS PRESSUREAMPLITUDE TORUSPRESSURE DISTRIBUTIONFOR AMPLITUDEDISTRIBUTION FORCONDENSATION CONDENSATIONOSCILLATION OSCILLATION 2-69 2-69 04/29/82 04/29/82

• I00 100

• 270 90 90 NOTE: THE AMPLITUDE NOTE: THE HERE REPRESENTS SHOWN HERE AMPLITUDESHOWN REPRESENTS ONE*HALF OF ONE-HALF OF THE PEAK*TO*PEAK AMPLITUDE THE PEAK-TO-PEAK AMPLITUDE

-

~ 3 3 ~------------------------------------------------------------------------------------------,

o w

• o NOTE: HIGHEST VALue IN BAY SHOULD BE w

...-

J APPLIED oveR THE ENTIRE BAY

...J

~

~ 22 c{

w

.:J a:

w

~

UJ a:

~

1 1

cc a:

...w zwZ w

o

~

o 0o 0t:o en (I)

>

cc a: -1~ ________________. .________________~__________________________________~

o. -1

...

0.

o 360 90 180 270 360 08 Idegree)

Idllgree)

FIGURE 2.22 FIGURE 2.22 TORUS ASYMMETRIC TORUS DISTRIBUTION FOR CIRCUMFERENTIAL DISTRIBUTION ASYMMETRIC CIRCUMFERENTIAL FOR PRE-CHUG PRESSURE AMPLITUDE PRE-CHUG PRESSURE AMPLITUDE 2-70 2-70 04/29/82 04/29/82

\N 00 292.

• 67.50 2700 12900 E 2700r-----------------~~~-----------------J E 247.50 112.5° 1800 FIGURE 2.23 SECTORS USED TO DEFINE DIRECTIONSFIGUR E 2.23 LOADS OF LATERAL ON DOWNCOMER END

• SECTORS USED TO DEFINE DIRECTIONS OF LATERAL LOADS 2-71 2-71 ON DOWNCOMER END 04/29/82 04/29 /82

-15 Tlme(!>>

• FIGURE FIGURE 2.24 TYPICAL TORUS SHELL S/RV PRESSURE PRESSURE TIME HISTORIES GENERATED USING QBUBS02 AND QBUBS03 GENERATED 2-72 2-72 QBUBS03 04/16/02

• LOGA-DBA LOCA-DBA PRESSURE AND TEMPERATURE TRANSIENT

• TRANSIENT

~---------------1 SINGLE -S SNG-LE S/RV RV ACTUATION ATUATI ON

,TORUS TORUS SHELL LOADS

~~--- ......... ----------~--

0 TORUS SHELL PRESS. PRESS.

DUE TO POOL SWELL 0 \

L)

~/o C/O TORUS SHELL LOADS 0

CHUGGING TORUS HUGGING TORUS SHELL LOADS HELL LOADS A ,I II 1 I

0.0 vy 5 35 35 65 65 0.0 Time After Time After LOCA (sec)

FIGURE 2.25 FIGURE 2.25 TORUS SHELL SHELL LOAD LOAD COMBINATIONS COMBINATIONS FOR FOR LOCA-DBA LOCA-DBA 2-73 2-73 04/29/82 04/29/82

• LOCA-IBA PRESSURE AND TEMPERATURE TRANSIENT LOGA-IBA PRESSURE AND TEMPERATURE TRANSIENT

• J.

}

-

~----------

SINGLE 5/RV SINGLE

- - - -- -(S/RV S/RV ACTUATION*

ACTUATION* (S/RV

--

- - - EVENT- CASE EVENT CASE Al

-

- -A1.2)

- - --------------_..:._------)

21 TORUS SHELL LOADS LOADS

• _

.... _. - - - ... _-- - - ------------ - - - - - ..... - - ---------------

MULTIPLE S/RV ACT.ACT.

0 ON SET POINT TORUS SHEll SHELL LOADS (S/RV A3.2, C3.2)

(S/RV EVENTS A3.2, ADS ACTUATION ACTUATION ,--

(S/RV (S/RV EVENT A2. 2)

A2.2)I TORUS SHELL LOADS 0

I C/O TORUS SHELL SHELL LOADS**j ,

0-I 1 LOADS**I CHUGGING TORUS SHELL LOADS

"

CHUGGING TORUS SHELL LOADS

.

A

".

V m6 L~I

- -. -" _I-N f

J I A v

v I

I

-

55 13.

13.5 S tADS tAOS 300 300 900 900 Time After Time After LOCA (sec) (sec)

• Loading does

• Loading does 'not not combine combine with wi th other S/RV cas,es.

other S/RV cases.

• • Bounded by chugging loads.

• • Bounded loads. ~'

FIGURE 2.26 FIGURE TORUS TORUS SHELL SHELL LOAD LOAD COMBINATIONS COMBINATIONS FOR LOCA-IBA 2-74 2-74 04/29/82

• LOCA-SBA PRESSURE AND TEMPERATURE TRANSIENT TRANSIENT onion

~z

• mpMW 0ý-Ww - 0 -...

SINGLE SjRV

- -0 S/RV ACTUATION m

---

m -

-

Al .2)

(S/RV ,EVENT CASE Al.2)

(S/RV,EVENT TORUS SHELL LOADS* LOADS*

~-----------

-ý 0000mw -0ofi mno fm ý dONW -

I m ACTUATION TORUS ADS ACTUATION TORUS MULTI PLE MULTIPLE SHELL LOADS S/RV SjRV (S/RV EVENT A2.2)

ACTUATION U)

ON SET POINT 0

od S/RV EVENT S/RV EVENT 0

u A3.2, C3.2 A3.2, C3.2 I CHUGGING TORUS CHUGGING TORUS SHELL LOADS LOADS ]

3.5 3.5

-,-1 100 100 300 I1 610 I;I.

900

.-

Time After LOCA LOCA (Sec) does not

• Loading does

• Loading combine with not combine with other S/RV cases.

other S/RV cases.

FIGURE 2.27 FIGURE 2.27 TORUS SHELL TORUS SHELL LOADLOAD COMBINATIONS COMBINATIONS FOR LOCA-SBA 2-75 2-75 04/29/82

• LOCA-DBA PRESSURE PRESSURE AND VENT_ SYSTEM PRESSURE VENT AND TEMPERATURE TRANSIENT AND PRESSURE TRANSIENT

~----------------~.

TEMPERATURE. TRANSIENT TRANSIENT THRUST LOADS AND THRUST LOADS

~

POOL SWELL

-.POOL SWELL

_

_I IMPACT IMPACT & DRAG

&

O'J C

I FROTH IMPINGEMENT ** f FROTH IMPINGEMENT AJ o

.....

0

.....

.....

"'C U

C 0o I~~~~Ov.'NCOMER C0 LOADS DOWNCOMER LATERAL LATERAL, I

"'C

.0CIl o IC/O VENT SYSTEM LOADSI

...:I C/O VENT SYSTEM LODS1

~HUGGING HUGGING DOWN COMER DOWNCOMER

~ATERAL LOADS SA TERAL LOADS CHUGGING CUGGING VENT VENT SYSTEM SSE tLOADS fLOADS SS~r 0o 5 35 35 65 After LOCA T~e After Time (sec)

(sec)

• For main vent main vent only.

only.

• • For submerged

• • For submerged portion portion of downcomers see of downcomers see also Figure also Figure 2.32 FIGURE 2.28 VENT SYSTEM LOAD LOAD COMBINATIONS COMBINATIONS FOR LOCA-DBA**

FOR LOCA-DBA**

2-76 04/29/82

0 LOCA-IBA LOCA-IBA PRESSURE AND TEMPERATURE I

TEMPERATURE TRANSIENT 0

d DWNOOER LTERA

,-[_~_~_~_WN_C_OME_R_LA_T_E_RAL C/O DOWNCOMER LATERAL LOADS _ _---,I

• J*

U) 0 0

r. .

C/O VENT SYSTEM LOADS

_'_O_V_E_N_T_SY_S_T_EM_L_O_AD_S_---'I

• 0.

IACHUGGING

[CHUGGING DOWNCOMER LATERAL LOADS LOADS DOWNCOMER LATERAL I ICHUGGING VENT SYSTEM LOADS]

I CHUGGING VENT SYSTEM LOADS I

.-

• .1 k k&

I

,

0o 5 900 Time After After LOCA (sec)

• Bounded by chugging.

chugging.

• • For submerged portion of downcomers

• • Forsubmerged portion downcomers see also Figure 2.33. 2.33.

FIGURE 2.29 FIGURE 2.29 VENT SYSTEM LOAD COMBINATIONS COMBINATIONS FOR LOCA-IBA**

LOCA-IBA**

2 -77 2-77 04/29/82

• V w

LOCA-SBA PRESSU'RE LOCA-SBA w

AND TEMPERATUJRE TRANSIENT PRESSu~E AND TEMPERATURE TRANSIENT

• 0 rHUGGING DOWNCOMER LATERAL LOAD~

0

'0 FUGGIN~ VENT SYSTEM LOADS ]

0 9w4 II A A

y II -

o 0 300 900 Time After LOCA (sec)

'9

"

• • For submerged portion of downcomers see also Figure 2.34. 2.34. ,

Ii FIGURE 2.30 FIGURE 2.30 VENT SYSTEM VENT SYSTEM LOAD LOAD COMBINATIONS COMBINATIONS FOR FOR LOCA-SBA**

LOCA-SBA**

2-78 2-78 04/29/82 04/29/82

• LOCA-DBA LOCA-DBA PRESSURE PRESSURE AND AND TEMERATURE 0

TEMPERATURE TRANSIENT TRANSIENT

• POOL SWELL POOL SWELL IMPACT IMPACT &

& DRAG DRAG 0

0 fOOL FALLBACK I

P4*

0

[FROTH IMPINGEMENT & FALLBACK

• I Io ,-

j 0

Time Time After After LOCA LoeA (sec)

(sec)

• Froth

• Froth fallback fallback loads loads on on structures structures in in Region Region II II only.

only.

FIGURE FIGURE 2.31 2.31 LOAD LOAD COMBINATIONS COMBINATIONS FOR FOR STRUCTURES STRUCTURES ABOVE ABOVE HWL HWL FOR FOR LOCA-DBA LOCA-DBA 2-79 2-79 04/29/82 04/29/82

• LOCA-DBA PRESSURE AND TEMPERATURE TEMPERATURE TRANSIENT

• TRANSIENT

---

J SINGLE SINGLERGES/RV SUBMERGED SRAACTUATION CTUA LATISON SUBM{ERGED STRUCTURE LOADS

---

LOADS 0

0 D

IL I LOCA JET LOCA JET LOADS LOADS 0

0 LiIZI~

[_~_ _ _ _] LOCALOCA BUBBLE LOADS BUBBLE LOADS C/O SUBHERGED SUBIERGED STRUCTURE LOADS STRUCTURE LOADS

[,HUGGING

• 1

~HUGGING SUBMERGED SUBMERGED STRUCTURE TRUCTURE LOADS LOADS o

0 5 35 65 6S 35 After LOGA Time After LOCA (sec)

(sec)

FIGURE 2:32 FIGURE 2:32 SUBMERGED SUBMERGED STRUCTURES STRUCTURES LOAD LOAD COMBINATIONS COMBINATIONS FOR LOCA-DBA 2-80 04/29/82

")

e)

• LOCA-IBA tOCA-IBA PRESSURE PRESSURE AND AND TEMPERATURE TEMPERATURE TRANSIENT

• TRANSIENT

• S INGLE S/RV ACTUATION (S/RV EVENT A22 SUBMERGED STRUCTURE LOADS* A1 )...

0 W.4 MULTIPLE MULTIPLE S/RV S/RV ACTUATION ACTUATION LOADS LOADS ADS (S/RVACTUATION ADS ACTUATION S/RV EVENT S/RV LOADS LOADS 0

(S/RV (S/RV EVENT EVENT A3.2, A3.2, C3.2, C3.2, C3.3)

C3.3) (S/RV EVENT A2.2)A2.2) 0

[U~~UBMERGED 0 C/O SUBMERGED STRUCTURE*

MADS STRUCTURE*j CHUGGING SUBMERGED STRUCTURE k OADS

~OADS CHUGGING SUMERGED STRUCTURE A- A 2

m A 049 4pW 11 V 55 tADS 300 tADS 300 §00 900 Time Time After After LOCA.(sec) tOCA (sec)

• Loading does

/

• Loading does not not combine combine withwith otherother S/RV S/RV events.

events.

• • Bounded

• • Bounded by by chugging chugging loads.

loads.

,i FIGURE FIGURE 2.33 2.33 SUBMERGED SUBMERGED STRUCTURES STRUCTURES LOAD LOAD COMBINATIONS COMBINATIONS FORFOR LOCA-IBA LOCA-IBA 22-81

-81 04/29/82 04/29/82

• IDCA-SBA PRESSURE LOCA-SBA

• PRESSURE AND TEMPERATURE TEMPERATURE TRANSIENT TRANSIENT

~-----

mwo 0-os" 6-Ms dwt ft 0i -mm On-a -swfw 40x ds dvfm 40w 6

---

~--.-

SINGLE SINGLE S/RV S/RV ACTUATION ACTUATION (S/RV EVENT Al.2)

---

N SUBMERGED SUBMERGED STRUCTURE STRUCTURE LOADS* LOADS* '

s-

~-----

n oonf -- w ww - nm oww x - wo- - mdwmný I

ACTUATION S/RV LOADS ADS ACTUATION LOADS MULTIPLE MULTIPLE (S/RV EVENT A2.2) A2.2)

S/RV S/RV ACTUATION' ACTUATION en s::0, LOADS WADS '\

0

'M

~

0

.,.-j 4 ro S/RV EVENT '"

s:: /

I 0

u A3.2, A3.2, C3.2 C3.2 "

u ro 1\1 CHUGGING SUBMERGED CHUGGING SUBMERGED STRUCTURE STRUCTURE LOADS I'

S J 3.5 3.5 ' 100 100 II I 300 300 600 600

,

6 L iV 900 900

,

.- '---she

-

Time After LOCA (sec)

FIGURE FIGURE 2.34 2.34 STRUCTURES LOAD SUBMERGED STRUCTURES COMBINATIONS FOR LOCA-SBA LOAD COMBINATIONS 2-82 04/29/82

P *

• 0 4-WATER JET LOADS I T/Q WATER JET LOADS I I

r.

0 cc IT/Q T/Q AIRAIR BUBBLE BUBBLE INDUCED INDUCED LOADSI LOADS]

s to ti tl

>

Time Time After After S/RV S/RV Actuation Actuation (se.c)(se.c) to to == S/RV S/RV actuation actuation time time tl == S/RVDL tj S/RVDL water water clearing clearing time time t2 == time t2 time at at which which S/RV S/RV bubbles bubbles reach reach pool pool surface surface FIGURE FIGURE 2.35 2.35 S/RV S/RV DISCHARGE DISCHARGE LOADS LOADS ON ON SUBMERGED SUBMERGED STRUCTURES STRUCTURES 2-83 2-83 04/29/82 04/29/82

COOPER NUCLEAR STATION COOPER PLANT UNIQUE ANALYSIS REPORT PLANT REPORT SECTION 33 SECTION TORUS SHELL SHELL AND SUPPORTS SUPPORTS

• 3.1

• 31INTRODUCTION INTRODUCTION This section section describes the results of the structural structural evaluations evaluations of the CNS torus shell and support support structures.

structures. Components included Components included in in these evaluations evaluations are the torus shell, shell, the torus support system, the internal internal ring girder, girder, and all attachments penetrations on the torus shell pressure attachments and penetrations boundary.

boundary.

Descriptions Descriptions of these components and modifications modifications made to these components components are provided provided in in Section 1 of this report. thermal-hydraulic report. The thermal-hydraulic load definitions defini tions and load combinations combinations are described in Section 2.

in Section 2. This section provides provides a description description of the design load combinations, allowables, combinations, design .allowab1es, analysis analysis methods and results, results, and code evaluations evaluations for all structural structural components listed above. above.

3.2 TORUS TORUS SHELL SHELL This subsection discusses discusses the results of the structuralstructural evaluations evaluations of the

,pressure boundary away from penetrations torus shell pressure penetrations and attachments.

attachments.

Penetrations and attachments Penetrations attachments are addressed addressed inin Subsection Subsection 3.5.

3.5.

3.2,1 3.2.1 Design Load Combinations Combinations Table 3.1 shows shows the 27 design load combinations combinations applied to the torus shell. shell.

This table is is taken directly directly from the Mark II Containment Program PUAAG.

Containment Program PUAAG.

ASME Code Service Service level assignments for each event combination combination are also also indicated indicated inin the table.

table.

Of these 27 load combinations, combinations, potentially potentially bounding bounding load combinations combinations were were identified identified for the torus shell shell evaluations.

evaluations. These These bounding combinations are bounding combinations shown inin Table Table 3.2.3.2. Torus shell stresses compared against allowables for stresses were compared for these load combinations.

load combinations.

3.2,2 3.2.2 Allowables Design Allowables The torus shell is classified as a Class MC vessel.

is classified vessel. Design allowables are taken from Subsection Subsection NE-3000 NE-3000 of the ASME Code (referred to as the Code). Code) .

3.2.2.1 Shell Stress Allowables Stress Intensity Allowables Torus shell stress intensityintensity values values are calculated calculated using the procedure procedure in in Subsection NE-3215 of the Code. Code. Combined stress intensity values were Combined were required required to satisfy the :requirements

requirements of Subsection NE-3221 for all load combinations.

combipations. The fatigue evaluationevaluation of the torus shell was also performed performed as required by Subsection required 'by Subsection NE-3221.5.

NE-3221.5.

Stress intensity allowables are summarized summarized in in Table Table 3.3 for Level A, B, and C Service load combinations.

Service combinations. Allowables Allowables are based on SA-516 material SA-516 Grade 70 material properties properties at 200°F 200OF (design torus temperature temperature for Mark I containment containment loadings).

loadings) 3.2.2.2 3.2.2.2 Allowables Buckling Allowables The LOCA and S/RV S/RV discharge-related discharge-related loads loads are dynamic in nature.

in nature. The The

• ASME Code methods,Section III of the load and the inertial analysis inertial aspects requirements requirements for buckling apply methods, using standard charts and equations that ignore aspects of the structural 3-1 3-1 ignore the non-uniformity structural response.

static non-uniformity response. This code 04/29/82

solution solution indicates indicates the typical typical Mark I containment containment torus shell does not meet meet the ASME buckling buckling criteria criteria of either Subsection NE-3133 either Subsection NE-3133 or Code Case N-284 for the defined hydrodynamic hydrodynamic loads. loads. Therefore, Therefore, the stability of the Mark I torus under these dynamic dynamic loads was demonstrated demonstrated using both in-plant in-plant data data and nonlinear dynamic analyses.

nonlinear analyses.

The potential potential torus instability investigated were the buckling instability cases investigated buckling of the bottom of the shell due to negative negative pressure, pressure, the buckling of the upper upper crown region region due to beam-like beam-like bending, bending, and the buckling of the inner inner equator region due to positive pressure.

pressure.

The first first two of these cases have have been extensively been extensively evaluated using evaluated experimental experimental data, and the last one has been eliminated eliminated as a design concern based on geometric geometric considerations.

considerations. The following conclusions conclusions were drawn from from the evaluations evaluations of the experimental experimental data data (Reference 29): 29) :

(1)

(1) The upper crown crown region region of the torus will not experience experience any instability instabili ty under the most unfavorableunfavorable loading loading condition, which which is combined is combined LOCA and S/RV actuation.actuation.

(2)

(2) The most unfavorable unfavorable loading condition for the stability of the bottom of the shell is is caused by S/RV actuation actuation alone.

alone.

(3)

(3) With the exception exception of Oyster Creek, Creek, the torus shells shells did notnot exhibit any instabilities instabilities in in the eighteight in-plant S/RV discharge test results examined.

examined. The 'Oyster Oyster Creek torus was unstable for a short period of time during the tests, but it subsequently it subsequently regained regained its its stability without without any damage.damage. The Oyster Creek torus has has thethe thinnest shell wall of all the Mark Mark I plants plants and is is nearly nearly half half as thick as the CNS torus shell. shell.

(4)

(4) S/RV discharge discharge tests at Monticello, Monticello, with pressurepressure waveforms waveforms having having frequencies frequencies nearly in in resonance resonance with torus shell shell frequencies, frequencies, did not result in in any instabilities.

instabilities.

(5)

(5) Installation of T-quenchers Installation T-quenchers provides provides aa safety factor of 2.0 to to 2.5 2.5 forfor the design' conditions over the worst ramshead test case design' conditions case which was examined examined in in the test data review.review.

To confirm confirm the stability of a typical Mark I containment containment torus shell for for bounding bounding S/RV discharge discharge transient transient loads, nonlinear dynamic analysis was loads, a nonlinear was performed (Reference performed (Reference 29). 29) . For the design design load case, a factor of safety safety ofof approximately approximately seven against instability instability was observed:

observed: These conclusions can These conclusions be directly applied to the CNS torus shell configuration configuration for the following reasons:

reasons:

(a) The Cooper Station torus shell has a lower lower diameter/thickness diameter/thickness ratio than the torus shell considered considered in in the generic generic study.

(b)

(b) The design torus shell S/RV discharge discharge pressure Cooper pressure for Cooper Station has a peak pressure pressure value which is is 70%

70% of the peak pressure used in in the generic generic study. The pressure waveformswaveforms used in in both the CNS torus analysis and the generic generic study

• are are both described described in based on in Section 2.5.4.

3-2 3-2 the GE computer 2.5.4.

code QBUBS02, code QBUBS02, as as 04/29/82

In summary, In summary, an adequate margin of safety safety against against in?tability instability of the CNS CNS torus shell exists for all shell all design load combinations combinations and the provisions of of Code Code Subsection NE-3222 are are satisfied.

satisfied. Therefore, Therefore, torus shell bucklingbuckling was was not not considered as aa design limitation. limitation.

3.2.3 Analysis Methods and Results This subsection subsection describes the analyses and. and .key key results of of the torus shell shell evaluations.

evaluations. Analysis results from this subsection were also used in in the evaluations of the torus support system, ring girder, penetrations, evaluations penetrations, and attachments.

attachments.

,

The reanalysis of the lower half of the torus shell to develop general The general corrosion allowances allowances was was-based based on a 1/16 section finite element element model using the program the program ANSYS where the water was explicitly modeled. modeled. See Section 3.2.53.2.5 additional details.

for additional details.

3.2.3.1 3.2.3.1 Torus Mathematical Torus Mathematical ModelsModels 3.2.3.1.1 3.2.3.1.1 Shell Models Models Two finite Two finite element element models models of the torus shell and its support support system were used in in the structural evaluations:

evaluations:

(1)

(1 ) Primary evaluations Primary evaluations were were performed performed using aa coupled shell-fluid model representing model representing a 1/32 section of the torus. torus. This section extended from the centerlinecenterline of a vent bay to the plane of the

• ring girder.

ring girder. The finite element The finite elemen~ model representing the torus representing torus is is shown shown in in Figure 3.1. 3.1. The general general purpose program EDS-SNAP EDS-SNAP (described in in Appendix Appendix B) B) was used to develop develop this model. model.

Three-dimensional Three-dimensional shell elements with mid-side mid-side nodes were used to to represent the represent the torus shell shell and ring girder girder web.web. These shell shell elements elements can accurately accurately model model a quadratic quadratic variation variation in in displacement and displacement and allow allow the use of a coarser coarser finite element mesh element mesh to represent a section of the torus.

to represent torus. Linear Linear beambeam elements were were used used to to represent represent the torus support support columns and ring girder girder flange.

flange. Modeling Modeling of fluid effects effects are discussed in in Subsection 3.2.3.1.2.

Subsection 3.2.3.1.2.

(2)

(2 ) Torus Torus response response to horizontal horizontal seismicseismic loads loads was evaluated evaluated using using a plate plate element element model of a 902 90 section Q section of the torus (Figure 3.2). 3.2) .

Program Program EDSGAP EDSGAP (described (described in in Appendix Appendix B) B) was used to develop this this model.

model. Fluid effects were Fluid effects were included included usingusing the tributary mass the tributary mass method, method, assuming 100% 100% of the fluid inertia inertia is is effective effective during horizontal horizontal seismic seismic loading.

loading.

3.2.3.1.2 3.2.3.1.2 Fluid-Structure Interaction Fluid-Structure Interaction Model Model A

A three-dimensional three-dimensional consistent consistent massmass matrix matrix formulation formulation was used to model model the structural structural and and fluid mass characteristics fluid mass characteristics of of the 1/32 1/32 section section torus model model described described above. above. The The mass mass effects effects of of the the enclosed enclosed fluid were were modeled modeled by the added added mass formulation, formulation, which uses a pressure-based pressure-based fluid element element to modelmodel the the incompressible incompressible fluid and condenses condenses the fluid inertia inertia and fluid-structure interaction interaction (FSI) (FSI) effects effects intointo the the structural structural consistent consistent mass matrix. matrix. It It has has been demonstrated been demonstrated that added mass formulation formulation producesproduces a more accurate more accurate representation representation of of the the actual actual FSIFSI effects effects (Reference (Reference 30) 30) than provided provided by the conventional conventional tributarytributary mass methods.

methods. Appendix Appendix C describes describes this this approach approach andand 3-3 3-3 04/16/02 04/16/02

• its its implementation.

implementation. The fluid model used represent represent the enclosed Figure Figure 3.1.

which is A second A

developed developed enclosed fluid in 3.1. This model was developed used in in a 1/32 segment in the evaluations approximately 1-1/2 feet below the torus centerline.

is approximately second fluid model for representing only 40%

model representing performing performing the 40% 'ef pool evaluations was developed segment of the torus, developed based upon the high water centerline.

',of the enclosed fluid was also swell swell dynamic developed to torus, as shown shown in water elevation, elevation, to in analysis analysis (Subsection 3.2.3.2.2).

3.2.3.2.2).

3.2.3.2 Analysis Analysis Procedures Procedures and Results Results The analyses analyses described in in this subsection subsection were used in qualification of in the qualification of the shell.

shell. All dynamic analyses analyses were performedperformed using the coupled shell-fluid shell-fluid model of 1/32-section 1/32-section of the torus described described in in Subsection Subsection 3.2.3.1.1.

3.2.3.1.1. Damping Da~ping was taken to be 2% of critical critical for allall dynamic analyses.

dynamic analyses.

3.2.3.2.1 3.2.3.2.1 Static Static Analyses Analyses Static analyses of the torus shell were performed performed using using the 1/32 section torus torus model described described in Subsection 3.2.3.1.1.

in Subsection 3.2.3.1.1. The horizontal horizontal seismic analysis analysis was performed performed using using the 90 9022 section section model.

model.

The following static following static load cases were were analyzed:

analyzed:

(1)

(1) Containment Pressure Containment Analysis for a uniform uniform internal internal pressure pressure of 1 psi was performed. performed.

Results Resul ts for other internal internal pressure values values were determined determined by by scaling scaling these results by the ratio ratio of the containment containment pressurepressure toto 1 psi.

psi.

(2)

(2) Containment Temperature Containment Temperature An An analysis analysis was performedperformed for the worst worst case condition condition of the torus torus at maximummaximum design design temperature temperature (200°F) (200 0 F) and the reactorreactor building at minimum minimum design design temperature temperature (50°F). (50 0 F) . The torus support support structure structure was assumed assumed to be at the reactor building building temperature temperature except except near the shell, shell, where steady-state steady-state heat conduction conduction methods methods were were used to predict predict the temperature distribution.

temperature distribution.

(3)

(3) Gravity An analysis was performed performed including including the weight weight of the torus shell, shell, enclosed enclosed suppression pool, pool, and internal internal equipment equipment (including vent system, T-quencher T-quencher assembly,assembly, etc.). etc.). The saddle saddle support was assumed assumed to be inactive inactive since installation installation of the saddle was performed saddle performed while the torus was filled filled water.

with water.

(4) )

(4 Seismic Seismic An An equivalent, static equivalent static analysis was performed performed using design accelerations taken from the FSAR response spectra accelerations spectra (Reference (Reference 16)16) using using the lowest torus natural frequency. frequency. A A separate analysis was separate analysis was done for vertical

• vertical (using the 1/32 1/32 section section model) model) and. horizontal and.horizontal (using the 90 9022 section section model) seismic input. input. The anl:tlyses analyses were were performed performed for for OBE OBE loading loading and the SSE results were were taken as twice results. Combined the OBE results. Combined stress intensities stress intensities for seismic seismic loading 3-4 3-4 04/16/02 04/16/02 1

• (5)

(5 )

were computed computed by taking the maximum the torus resulting analyses analyses accordance and combining accordance with NRC Regulatory stress intensity maximum stress intensity anywhere on resulting from both the vertical them vertical 'nd using Regulatory Guide 1.92).

intensity was then used Penetration and Attachment Penetration the horizontal seismic

~nd horizontal SRSS technique 1.92). The maximum combined used for all torus shell Attachment Reactions Reactions locations.

shell locations.

on seismic (in (in combined Subsection 3.5.3.

See Subsection 3.5.3.

3.2.3.2.2 3.2.3.2.2 Torus Shell Dynamic Properties Properties Torus Torus shell dynamic analyses analyses were performed using torus natural natural frequencies frequencies determined through an eigensolution.

and mode shapes determined eigensolution. The subspace iteration method method was used for the eigensolution eigensolution (Reference 31). 31) . The eigensolution eigensolution was was performed performed using the coupled coupled shell-fluid shell-fluid 1/32 1/32 section section model described described in in Subsection 3.2.3.1.1.

Subsection 3.2.3.1.1. All torus model static degrees of freedom freedom were retained as dynamic degrees degrees ~fof freedom in in the eigensolution.

eigensolution.

Eigensolutions Eigensolutions were were performed using two boundary boundary conditions on the 1/32 1/32 section torus model: model:

(1)

(1) Symmetric boundary Symmetric boundary conditions conditions at both the ring girder plane and and the midbay.

midbay.

(2)

(2) Anti-symmetric Anti-symmetric boundary boundary conditions at the ring girder girder plane and symmetric boundary conditions symmetric conditions at the midbay.midbay.

Consideration symmetric and anti-symmetric Consideration of both symmetric anti-symmetric boundary conditions conditions allows allows.

representation representation of the 1/16 section *behavior behavior under S/RV discharge loading.

discharge loading.

Torus mode shapes up to 50 Hz for the symmetric symmetric model and 40 Hz for the anti-symmetric model were computed.

anti-symmetric computed. There are 50 torus natural natural frequencies frequencies in in this range.

range. The lowest torus natural natural frequencies are 9.8 Hz (anti-symmetric (anti-symmetric model) and 12.8 12.8 Hz (symmetric model).model).

eigensoluion used 1n The eigensoluion in the reanalysis reanalysis' of the torus shell to develop a C

corrosion corrosion allowance allowance was performed performed using the LANCZOS method with only only symmetric symmetric boundary boundary conditions.

conditions. See Section Section 3.2.5 for additional. details. details.

3.2.3.2.3 3.2.3.2.3 Analysis Pool Swell Dynamic Analysis A

A time history analysis history analysis for pool swell swell loads performed on the was performed 1/32 section 1/32 section coupled shell-fluid shell-fluid model of the torus shell with symmetric symmetric boundary boundary conditions.

conditions. The pool swell load load definition definition described described in in Subsection 2.4.3.2 was represented Subsection represented as a set of pressure surfaces surfaces which which were were directly applied to the finite element model.

directly applied model. Direct time integration integration using the Newmark Newmark method method was employed employed 'in in the analysis.

analysis. To model the water in in flight flight during the upload portion portion of the pool 'pool swell event, event, the analysis analysis was carried out to the start start of the upload phase using aa fluid model representing representing 100% 100% of of the enclosed enclosed pool volume.

volume. A restart r-estart analysis was then. performed performed for the second half of the analysis, analysis, using a 40% 40% fluid model to properly include include the dynamic effects of the reduced dynamic effects reduced pool mass (60% (60% of the pool mass is is in in flight flight as discussed discussed in in Subsection Subsection 2.4.3.1).

2.4.3.1). For the upload phase of the analysis, analysis, the intermediate supports on the saddle saddle were assumed to be inactive. inactive. Results

• intermediate supports Results from these these two analyses were were then sequencedsequenced to produce a time-history analysis of the entire entire pool swell swell event.

event.

3-5 3-5 04/16/02

• Only the bounding differential shell bounding load case case of zero initial considered in differential was considered in the torus shell shell stress intensities due to pool swell 9.5 ksi (surface).

3.2.3.2.4 (surface).

DBA CO Frequency Frequency Domain Domain Analysis Analysis initial drywell-to-wetwell drywell-to-wetwell pressure evaluation. Maximum torus shell evaluation.

swell were 7.~ 7.1u ksi (membrane)

(membrane) and and For the DBA CO load load case, case, a frequency frequency domaindomain analysis analysis was performed performed on the 1/32 section shell-fluid model of the torus shell with symmetric section coupled shell-fluid symmetric boundary conditions. In boundary conditions. In the frequency domain analysis procedure, procedure, torus shell shell response response (stresses, accelerations, displacements, etc.)

accelerations, displacements, etc.) are determined for for each of the 50 load harmonics in in the DBA CO load 'definition

' definition (Subsection 2.4.4.1) assuming (Subsection steady-state response.

assuming steady-state response. The responses responses to each load harmonic are then combined combined to obtain the total response response to the load definition.

definition. The combination combination method used recognizes the random phasing of the individual individual load harmonics observed in harmonics observed in the Full Scale Test Facility (FSTF)

Facility (FSTF) data.

data. combination method involves The combination determination involves the determination of structural structural response to each of the individual load components, components, followed by the combination of these responses combination responses using the absolute absolute sum of the four highest highest responses added added to a SRSS combination combination of the remaining remaining 46 responses.

responses.

Statistical Statistical studies have shown shown that this design design rule providesprovides an 84% 84%

Non-Exceedence Probability (NEP)

Non-Exceedence Probability (NEP) on Cumulative Cumulative Distribution Functions (CDFs) (CDFs) generated using random phase generated phase angles angles for the 50 load harmonics. harmonics. These design rules were also used to analyticallyanalytically predict the response of the FSTF to to DBA CO loading.

loading. Predicted Predicted results results stillstill conservatively bound the responses conservatively responses measured measured in in all FSTF tests. These studies studies are documented in in Reference

• Reference 32.

32 .

For the DBA CO analysis, analysis, the envelope of the three three LDR alternative alternative load cases cases in in the the 4 to 16 Hz range was used. used. The load frequency frequency for each each harmonic harmonic band was set to the midpoint of the frequency frequency band, except except whenwhen a structural structural natural frequency frequency fell within a band. band. In In this case,case, the structural natural natural frequency frequency was assigned assigned to the pressure component.

pressure component. AlISO All 50 load harmonics were harmonics were used inin the analysis.

analysis. All torus natural frequencies frequencies below 50 Hz were used to to calculate calculate the torus response.

response. Maximum Maximum torus shell stress stress intensities intensities due to to DBA CO were 8.4 ksi (membrane)

(membrane) and 10.6 10.6 ksi (surface).

(surface).

Analyses Analyses were were performed performed onlyonly for DBA CO loading. IBA CO results results were bounded bounded by pre-chug loads (see below) below). .

3.2.3.2.5 3.2.3.2.5 Chugging Frequency Frequency Domain Analysis Analysis The chugging chugging frequency domain analysis was performed performed in in aa similar manner to to the DBA CO analysis (described above). above). For chugging, chugging, no statistical studies studies on phasing phasing of load components components were available available prior to preparation preparation of this this hence, responses report; hence, responses to load harmonics harmonics were conservatively combined using conservatively combined absolute summation.

absolute summation.

For post-chug loads, alISO post-chug loads, all 50 load harmonics harmonics (Subsection 2.4.5.1) were were used in in the analysis.

analysis. All torus natural frequencies frequencies below 50 Hz were used to to calculate the torus response.

calculate response. The load frequency frequency for each harmonic harmonic band was was set to the midpoint midpoint of the frequency band except when a structural structural natural natural frequency frequency fell within a band. band. In In this case, the structuralstructural natural natural frequency frequency was assigned to this load component. component. Maximum Maximum torus shellshell stress intensities

• intensities due to post-chug post-chug werewere 3.6 3.6 ksi (membrane)

(membrane) and 4.6 ksi (surface) (surface). .

3-6 3-6 304/16/02

'04116/02

Evaluation of the torus for pre-chug Evaluation pre-chug loads loads indicated indicated that all responses responses werewere bounded bounded by post-chug responses.

responses. Therefore, Therefore, post-chug post-chug results were were conservatively used for all load combinations conservatively combinations involving chugging. chugging. Pre-chug results were used for all load combinations combinations involvinginvolving IBA CO. CO.

3.2.3.2.6 3.2.3.2.6 S/V Discharge Dynamic Analyses Analys,es discharge load cases, For S/RV discharge cases, time historyhistory analyses were performed performed 'on on the 1/32 section coupled shell-fluid section coupled shell-fluid model of the torus shell. shell. Since the spatial spatial load distribution distribution for S/RV discharge pressures pressures is is symmetric symmetric over a 1/16 section section of the torus, torus, the following following analysis analysis steps steps were employed:

employed:

((1)

1) The spatial spatial load distribution for a 1/16 section 1/16 (Subsection 2.5.4)

(Subsection was divided divided into two distributions:

distributions: one one symmetric about about the th~e ring girder plane and one anti-symmetric anti-symmetric i

about .thethe ring girder girder plane.plane. The algebraic algebraic sum of these these two distributions was equivalent equivalent to the S/RV discharge discharge load definition definition for aa 1/16 1/16 section.

section.

(2)

(2) The peak torus shell pressure pressure waveform waveform was identified identified by by selecting selecting the frequency of the waveform waveform to be the value wi within thin the specified specified S/RV discharge frequency frequency range range which maximizes the torus response.

response. This transient was extended significant extended over six significant load cycles, cycles, which was sufficientsufficient to generate generate the maximum maximum torus response.

response.

(3)

(3) The 1/32 section coupled coupled shell-fluid shell-fluid model with symmetric symmetric boundary boundary conditions conditions was analyzed analyzed for the symmetric load distribution and pressure distribution pressure waveform waveform specified specified in in step (2). Modal (2). Modal superposition time history analysis was performed superposition performed with all, symmetric torus modes up to 50 Hz included.

symmetric included.

(4)

(4) The 1/32 1/32 coupled coupled shell-fluid shell-fluid model with anti-symmetric anti-symmetric boundary conditions was analyzed conditions analyzed for the anti-symmetric anti-symmetric load load distribution and pressure pressure waveform in in step (2) (2). Modal Modal superposition time-history time-history analysis was performed performed with all anti-symmetric anti-symmetric torus torus modes up to 40 40HzHz included.

included.

(5)

(5 ) To evaluate evaluate torus response response in in a, ~\ typical vent bay, bay, the results from steps (3) (3) and (4) (4) were were algebraically algebraically added at each time step.

(6)

(6 ) To evaluate evaluate torus response in in a typical non-vent non-vent bay, results from step (4) (4) were algebraically algebraically subtracted subtracted from the results of of step (3) ~t at each time-step.

time-step.

Torus analyses were performed in in this manner for _S/RV discharge Load S/RV discharge Load Cases A2.

A2.22 'and

'and AI.

AI.I.

1. Torus response to all other other S/RV dischargedischarge load cases cases were obtained by scaling scaling the results from these these two analyses.

analyses. See See Subsection 2.5 Subsection for a discussion discussion of S/RV discharge discharge load cases cases and corresponding load definitions.

corresponding definitions.

The SRV shell pressure pressure loads used for the reanalysis reanalysis of the torus shell to to restore restore aa corrosion allowance

• generated using the computer allowance were generated computer code QBUBS03.

QBUBS03.

The shell was analyzed analyzed using time histories on a 1/16 1/16 section model for SRV load cases A1.1, A2.2 and C3.2.

cases Al.l, C3.2. See Section Section 3.2.5 for additional additional details.

details.

3-7 3-7 04/16/02

• 3.2.4 design Code Evaluation This subsection subsection describes describes the code evaluation combinations summarized design load combinations The results upper results presented presented in upper half of the torus shell.

summarized in shell.

evaluation of in Table 3.2.3.2.

the in the two sections below are only applicable The stresses and fatigue.'usage torus shell for applicable for the fatigue usage factor for the the stresses in stresses in the lower half half of the shell have have been revised due to reanalysis reanalysis of the torus.

torus. See Section Section 3.2.5 3.2.5 for additional details. details.

3.2.4.1, 3.2.4.1 Shell Stress Intensities Torus intensities for the design load combinations Torus shell stress intensities combinations were computed were computed for all points on the torus shell. shell. Absolute Absolute summation of the stress intensities intensities from each load case case inin a combination was performed. performed. For time history analyses, the maximum stress history analyses, intensity over all time steps stress intensity steps inin the transient transient was used for the load combination.

combination.

combined state of stress for all design load combinations The combined' combinations meets the allowables of Table allowables 3.3. Maximum Table 3.3. Maximum combined combined stress intensities intensities are 21.4 21.4 ksi ksi (membrane) and 28.5 ksi (surface) for the Level B Service load combination combination IBA/SBA IBA/SBA chugging plus S/RV discharge discharge following ADS actuation. actuation. The combined combined membrane membrane stress stress intensity intensity is is classified classified as a local primary membrane stress primary membrane stress intensity according to the criteria intensity according criteria of Code Subsection NE-3213.10.

Code Subsection NE-3213.10. The The maximum maximum combined combined stress intensities intensities are therefore therefore 74% 74% and 98%,

98%, respectively, respectively, of the corresponding corresponding allowables.

allowables. All other other general primaryprimary membrane and and membrane membrane plus primary primary bending stress intensities intensities are below allowablesallowables at all all

• torus locations for all design load combinations.

3.2.4.2 3.2.4.2 Fatigue stress Fatigue Fatigue Evaluation Fatigue usage was checked intensity anywhere stress intensity combinations .

checked at critical torus shell shell locations.

locations. The maximum anywhere on the torus for each load case was conservatively used as the stress for each fatigue check.

maximum conservatively check. The fatigue design basis described in Subsection 2.7.7 was used~for in Subsection used, for this evaluation.

evaluation. The highesthighest torus shell shell usage factor was 0.51 at the butt weld between the torus shell shell plates of of unequal thickness thickness at the torus equator.

equator.

3.2.5 Torus Re-Analysis Re-Analysis to Establish Establish Corrosion Allowance Corrosion Allowance In 1996/1997 the eNS In 1996/1997 CNS torus was reanalyzed reanalyzed in establish .a in order to establish .a corrosion allowance in allowance in support of evaluations evaluations to justify continued operations justify continued operations as a result of significant significant pitting corrosion corrosion prevalent prevalent on the* the, torus shell.

shell. This This analysis only evaluates evaluates the stresses stresses in in the lower half of the torus shell. shell.

Upper Upper half shell stresses, stresses, ring girder stresses,stresses, saddle & column loads, loads, seismic ties and torus response response spectra spectra for attached attached piping are are not affected by this reanalysis.

reanalysis. The details of this analysis and those methodologies methodologies used which differ differ from those used previously previously are are described below.

described below.

3.2.5.1 Mathematical Models Torus Mathematical Models The reanalysis reanalysis of the CNS torus shell was performed performed using a 1/16 section model of the torus using the computer code ANSYS. ANSYS. The model extends from mid

.

mid bay of a vent line bay to mid bay ofa of a non vent line bay. bay. The model was was

• constructed from 2154 thin shell constructed the shell shell and ring girders.

girders.

circumferentially with additional circumferentially shell plate plate elements The (ANSYS element SHELL63) elements (ANSYS general node spacing refinement near the shell to ring girder additional refinement 3-8 3-8 is SHELL63) for 8

for degrees is 8 degrees girder 04/16/02

• junction and near the support column connections.

junction quencher quencher support pipes the water the water in the water.

water.

element pipes were were modeled in the torus was considered modeled using 16 The water model consisted of 1408 FLUID30) coupled element FLUID30) coupled to the shell elements.

to the high water line of 17.5" included a corrosion allowance included connections.

considered via explicit elements.

17.5 H below the centerline allowance of 1/16 16 pipe elements.

explicit finite 1/16"H subtracted finite Additionally Additionally the T-elements.

element 1408 acoustic fluid elements (ANSYS The water The effect element modeling modeling of water volume corresponds centerline of the torus. torus.

subtracted from the nominal thickness T-effect of of of (ANSYS corresponds model The model thickness of the lower shell, however however the mass of the model model corresponds corresponds to the full full uncorroded thickness of the shell.

uncorroded shell.

In general symmetric In symmetric boundary boundary conditions conditions were used as follows: follows:

" midmid baybay shell shell andand T-Quencher T-Quencher supports have symmetric plane constraints constraints

" support support columns fixed for vertical columns fixed vertical displacements displacements only only

" saddle saddle base plates fixed for vertical vertical displacements displacements only

• fluid free surface pressure pressure set to zero

• fluid symmetry symmetry planes at mid bay bay normal normal pressure pressure set to zero The eigensolution eigensolution of the shell was performed performed using using the LANCZOS method method since use of the the' FLUID30 elementselements results in in unsymmetric stiffness and mass unsymmetric stiffness mass matrices.

matrices.

3.2.5.2 Combinations Load Combinations The The re-evaluation re-evaluation of of the the lower lower half half of the torus' torus- shell shell was performed performed using the controlling the controlling load combination combination as defined defined previously previously in Table 3-2.

in 3-2. The The combination of any two LOCA or SRV loads combination performed by loads was performed the 1.1'SRSS method I.I'SRSS method

• in accordance in accordance with Appendix 3.2.5.3 The Seismic, SRV Seismic, Loads Loads The torus shell SRV PS, Appendix D shell was analyzed D..

analyzed for Normal PS, CO and Chugging Chugging Loads.

Loads.

(deadweight, (deadweight, thermal, thermal, pressure),

pressure)

Normal Loads Normal Loads The torus The torus is is subjected subjected to to internal internal pressure pressure and thermal thermal expansion associated associated with the postulated postulated SBA, SBA, IBA,IBA, and DBA LOCA events. events. The The maximum pressures maximum pressures and temperatures temperatures for each controlling controlling event event (Reference (Reference

22) at

22) at thethe times corresponding to the LOCA/SRV loads times corresponding loads were includedincluded inin each combination.

each combination.

Seismic Loads Loads Seismic stresses Seismic stresses were calculated calculated by static static equivalent methods methods for both the vertical vertical and horizontal portions of the load. vertical seismic The vertical

.OBE

,OBE loads loads were scaled using using the deadweight deadweight results results and the peak horizontal stresses horizontal stresses taken taken from the 1/4 1/4 beam modelmodel of the torus were used for horizontal horizontal seismic stresses.

seismic stresses.

Pool Swell LoadsLoads Since Since PoolPool Swell Loads were Swell Loads were notnot controlling controlling in in the original original analysis, analysis,

• Pool Pool the Swell Pool Swell Loads Loads

'Swell analysis Pool 'Swell the re-evaluation.

re-evaluation.

were analysis of not run on this Section 3.2.3.2.3 of Section 3-9 3-9 model model and the 3.2.3.2.3 were conservatively results results from the conservatively used in in 04/16/02

• SRV Loads Loads SRV Air Bubble pressure GE computer pressure loads on the torus shell computer code QBUBS03.

QBUBS03.

the SRV loads generated generated in in Section 2.5.4.

Section 2.5.4.

shell were developed The load was developed developed in developed using the in the same manner manner as as CO and Chugging Loads Chugging Loads condensation oscillation The condensation oscillation and chugging evaluated using the chugging loads were evaluated general methodology same general methodology as performed performed previously previously in in Sections 3.2.3.2.4 3.2.3.2.4 and 3.2.3.2.5.

3.2.3.2.5.

3.2.5.4 3.2.5.4 Analysis Results Analysis Results The maximum maximum combined stresses for the combinations combined stresses combinations from Table 3.2 meet the allowables allowables of Table 3.3 and include include a corrosion allowance of 3/32" corrosion allowance 3/32" for the lower half half of the torus shell.

torus shell. The maximum General Primary Membrance Stress Membrance Stress is 19.27 ksi, maximum is maximum Local Local Primary Membrance Stress is Primary Membrance is 28.81 ksi and the maximum primary primary + local stress range range is ksi.

is 62.21 ksi. These These stresses are a maximum of 99.8%

99.8% of the allowables.

allowables. The cumulative cumulative usage factor is is 0.947 calculated using the conservative calculated conservative and limiting ASME code fatigue strength reduction reduction factor of 5 for the entire shell. shell.

3.3 TORUS TORUS SUPPORT SYSTEM SUPPORT SYSTEM This section describes describes the results of the structural evaluations of the torus structural evaluations consisting of the support shell support system, consisting columns, saddle structure, support columns, structure, and anchorage anchorage (tie-down) located at each each of the sixteen miter joints. joints. Also included as part of the support system are the four seismic ties designed designed toto restrain net torus lateral lateral movement.

movement.

3.3.1 3.3.1 Design Design Load Combinations Combinations The 27 design load combinations combinations for the torus support support system system and the corresponding service corresponding service limit assignments are shown shown inin Table 3.1.

3.1. An envelope envelope of the load load combinations producing producing the maximum net vertical reactions reactions and bending moments bending moments was used in in the evaluation of the torus support columns. columns. The The enveloping summarized in enveloping load cases are summarized in Table 3.4.

3.4. InIn the saddle saddle evaluation, evaluation, the load combination producing combination producing the maximum maximum net upload and download, download, summarized in summarized in Table 3.5, were used.

Table 3.5, used. For the seismic tie evaluation, evaluation, the load combination combination horizontal SSE plus 8MVA S/RV discharge discharge produces produces the maximum net net lateral lateral loads.

loads.

3.3.2 Design Design Allowables Allowables The torus support support system system ds (is classified integral Class MC component classified as an integral component support.

support. Design allowables allowables are taken from Subsection Subsection NF-3000 NF-3000 of the Code, Code, except except for the portion portion. of the. supports wi within the limits of reinforcement thin the' reinforcement from the torus shell (NE) (NE) boundary boundary and the welds directly on the pressure boundary. These exceptions boundary. exceptions to the NF classification classification have design allowablesallowables specified specified inin Section Section NE.NE .

• 3-10 3-10 04/16/02

3.3.2.1 3.3.2.1 Support Columns Support Columns I

The torus The torus support columns support columns are considered linear-type considered linear-type supports.

supports. Evaluation for Evaluation for axial and and bending bending loads loads was performed performed inin accordance accordance with wi th the procedure in the procedure in

/

~'

3-11 3-11 04/16/02 04/16/02

' Appendix XVII of the Code. Material allowables (based on a design temperature 200 0 F) XVII of 200°F)

Appendix 3.3.2.2 are 20.2 of the Anchorage Anchorage Assembly The torus anchorage connected in ksiCode.

in compression Assembly and 22.0 Material allowables

\

22.0 ksi in (based anchorage (tie-down) consists of four anchor bolts per column, connected to either a box beam or bracket bending.

in bending.

on a design temperature bracket assembly designed column, transfer designed to transfer upload upload from the columns to the bolts. bolts. The box beam assemblies assemblies are considered considered linear linear type supports and have the same design allowables allowables as the support support columns. The bracket assembly is columns. is considered considered a plate-and-shell plate-and-shell type supportsupport and isis evaluated evaluated using the procedure procedure in in Subsection Subsection NF-3320.

NF-3320. The allowable allowable stress value for the bracket bracket assembly is is 13.9 ksi.

ksi.

The anchor allowables are based on the bolt material anchor bolt allowables material allowable allowable and the pullout pullout load for the bolt. bolt. The pullout pullout load is is based on the shear strength strength ofof the grout grout and the total shear area. The shear shear area. shear strength of the grout was based upon tests to determine determine the bond stress where the measured measured bond stress was was divided by a factor of safety safety of 4. 4. Based Based on the minimum of these these allowables, the allowable two allowables, allowable force per anchor anchor bolt is is 103 kibs kips and 135 kips for the inner and outer columns, respectively.

columns, respectively.

3.3.2.3 3.3.2.3 Seismic Seismic Ties Ties Seismic ties were considered considered as, as' linear-type component supports since they linear-type component act they act under a single component component of direct stress. stress. Material allowables are 12 ksi in Material allowables in shear shear and 18 ksi in bending. The welds connecting in bending. connecting the seismic ties to the torus shell is is within the NE jurisdiction jurisdiction and has an allowable force per unit unit O length length of 3.3 kip/in.

3.3.2.4 3.3.2.4 Saddle Ring Girder Saddle The ring girder saddle web is is considered considered a plate-and-shell plate-and-shell type supportsupport and is is evaluated evaluated using the procedureprocedure in in Subsection Subsection NF-3320.

NF-3320. The allowable stress value value is ksi.

is 20.6 ksi.

Stiffeners and flanges on the saddle Stiffeners saddle web are considered linear-type component considered linear-type component supports. 'The supports. 'The design allowable is design allowable is 21.7 ksi in in tension.

The portion portion of the ring girder saddle web within the NE limit of of reinforcement (1-1/2")

reinforcement (1-1/2") has the same design allowable stress intensities design allowable intensities as as the torus shell Subsection 3.2.2.1).

shell (see Subsection 3.2.2.1).

The weld attaching the saddle saddle web to the torus boundary boundary is is also within the NE jurisdiction.

jurisdiction. The allowable allowable force/unit length length on this weld is is 5.8 5.8 kip/in.

kip/in.

3.3.3 3.3.3 Analysis Analysis Methods and Results Results Subsection describes This Subsection describes analysis procedure the analysis procedure used to qualify the components components of the torus support system. Results Results from the torus shell analysesanalyses (Subsection (Subsection 3.2) 3.2) are are used in in these evaluations.

evaluations.

3.3.3.1 3.3.3.1 Column Anchorage Evaluation Column and Anchorage Design downloads downloads on the torus support columns 'and anchorage assembly were and the anchorage were determined direct'ly determined directly from the finite element analyses of the 1/32 element analyses 1/32 section torus model (Subsection 3.2.3).

3.2.3). In determining In determining the design uploads, uploads, the results of the 1/32 section section torus model analyses analyses required modification. The required modification. The 3-12 04/16/02

• intermediate supports on the saddle are not tied down.

intermediate modeled with these supports transferred to the column anchorages.

transferred the inner anchorages. In inner column and inner intermediate column.

column. A similar anchorage, similar adjustment In these cases, down. However, intermediate support were assigned adjustment was performed anchorage, the load per bolt was determined reaction reaction among the four anchor bolts. bolts.

However, the torus supports fixed. Any upload at these supports must be cases, the uploads torus is carried by uploads carried assigned to the inner performed for the outer column.

determined by uniformly column. At the uniformly dividing the tensile is be by inner Tensile Tensile and compressive compressive reactions reactions were determined determined in in this fashion for all all load cases.

cases. The weight of the torus and suppression pool is is carried carried solely solely by the columns columns since the saddle was installed installed with the torus filled with water. water.

For the S/RV discharge discharge load cases,cases, a knockdown factor of 0.6 was applied to to the predicted reactions. This knockdown factor is predicted column reactions. is based, based, on the factor factor used to bound global pressurepressure loads on the torus from the Monticello Monticello in-plant in-plant test as specified specified by Section Section 2.13.3.2 2.13.3.2 of the NRC Acceptance Acceptance Criteria.

Criteria.

Maximum Maximum combined uploads were 347 kips kips' on the inner column and 494 kips on on the outer column for the bounding Level Level B Service Service load combination.

Service Service combination.

Maximum Maximum downloads were 407 kips (inner) and 460 kips (outer) (outer) for the bounding bounding Level Level B Service Service Service load combinations combinations (Table 3.4). 3.4). In determining the In determining column reactions reactions for the chuggingchugging plus S/RV discharge combination, the discharge load combination, 1.1 SRSS combination 1.1 combination method (Appendix D) D) was used to determinedetermine the combined combined reaction due to these two dynamic loads. loads.

Evaluation of the column-to-shell Evaluation column-to-shell connection, connection, support column, column, anchor bolts, and and box beam anchorage beam anchorage assemblies assemblies were performed using the procedures were performed procedures in in Appendix Appendix XVII of the Code and the AISC manual (Reference 15)

(Reference 15). . The The

• bracket-type bracket-type anchorage 3.3.3.2 3.3.3.2 Reactions Seismic assembly was evaluated anchorage assembly this assembly (using program program EDSGAP).,

Seismic Tie Evaluations EDSGAP)

Evaluations evaluated using a finite element Reactions at the seismic ties are a result of net torus from the following load cases: cases:

element model of torus lateral loads arising loads arising of (1)

(1) Horizontal Horizontal Seismic Seismic Reactions Reactions were determined determined directly directly from the SSE analysis of the analysis 902 section 90 section Q torus torus model model for for horizontal; horizontal; seismic seismic loads loads (Subsection 3.2.3.2.1).

3.2.3.2.1).

(2)

(2) Non-symmetric Non-syffimetric S/RV Discharges Discharges S/RV discharge S/RV discharge devices devices are located in in alternate alternate bays of the tDe torus. If torus. If the torus is is divided into two 1802 180 2 segments, segments, there there will will discharge devices be four discharge devices located in in each segment.

segment. The bounding bounding net net lateral load on the torus due to non-symmetric non-symmetric S/RV discharge is calculated is calculated assuming that the torus shell pressure pressure waveforms waveforms acting acting on one 1802 180 segment Q

segment arean~ out-of-phase out-of-phase with the pressure pressure waveforms acting waveforms acting on the other other 180 18022 segment.

segment. The lateral lateral load magnitude was determined magnitude determined by first first calculating the horizontal calculating horizontal reaction reaction at one miter joint joint due to an 8MVA 8MVA S/RV discharge discharge event.

event.

The column column load knockdown factor of 0.6 for S/RV discharge events discharge events was applied to this reaction. reaction. Then, Then, this reaction was applied applied in in an outward direction an outward direction at eight consecutive consecutive miter joints and then applied in applied in an inward direction at the remaining eight miter miter 3-13 3-13 04/16/02 o04/16/02

• (3)

(3 )

joints.

joints. This force distribution around to give a conservative Asymmetric Reactions previous conservative estimate Asymmetric Pre-Chug Pre-Chug around the torus was integrated estimate of the net lateral load.

Reactions from this load case are considered previous two postulated postulated load cases.

considered bounded cases. This observation b1ounded by the observation isis based on on the very low torus response response to pre-chug pre-chug loads as discussed in in Subsection 3.2.3.2.5.

Subsection 3.2.3.2.5.

Lateral loads were divided equally Lateral equally among two of the four seismic ties. ties. For For combination of load cases (1) the combination (1) and (2) (2) above, the design reaction reaction on on*

one seismic tie is is 300 kips.

kips. The procedure procedure in in Appendix XVII of the Code and and AISC manual was used to evaluate evaluate the ties for this reaction.

reaction.

3.3.3.3 3.3.3.3 Ring Girder Saddle Saddle Evaluation The ring girder girder saddle structure evaluated using a finite element structure was evaluated element representation representation of the saddle and performingperforming a series of static static analyses, analyses, as described described below.

below.

3.3.3.3.1 3.3.3.3.1 Saddle Model Saddle Model A detailed model model of the ring girder saddle support was developed developed for for evaluating evaluating this component.

component. The model was developed by modifying develope,d modifying the 1/32 section shell model model described described in in Subsection Subsection 3.2.2.2.1 to include a detailed detailed representation representation of the saddle and its stiffeners and flanges.

its stiffeners flanges.

• Figure Figure 3.3 shows the basic saddle model. Program EDS-SNAP was used to develop saddle model.

model. A this model. A second version of this saddlesaddle model was developed to evaluate the critical saddle saddle cut-out (for piping) configuration.

configuration.

3.3.3.3.2 3.3.3.3.2 Static Static Analyses Analyses A series of static static analyses performed on the saddle analyses were performed saddle models to determine determine stresses stresses and forces in in the saddle elements.

elements. On' On- both the basic saddle model saddle model and the cut-out configuration, configuration, the following static static analyses were performed:

were performed:

(1)

(1) Design Download Download Maximum design download of 1600 1600 kips for the Level Level C Service Service load case DBA pool swell plus SVA S/RV discharge (determined from the torus shell analyses and correcting correcting for torus and suppression pool weight) was applied applied to the support support system.

system. This load was was specifying a hydrostatic pressure distribution applied by specifying distribution overover the wetted wetted portion portion of the torus shell as shown shown in in Figure 3.4.3.4. The The distribution was determined peak pressure for this distribution determined to produce produce the download. For the download, design download. analysis, download. analysis, the intermediate intermediate saddle saddle supports are modeled as active. active.

(2) )

(2 Design Upload Upload Maximum design upload of 1250 1250 kips for the load case IBA/SBA IBA/SBA chugging chugging plus ADS S/RV dischargedischarge (determined from the torus shell analyses and correcting correcting for torus and suppression

• pool pool weight) was applied applied as a negative wetted applied to the support negative hydrostatic 3-14 support system.

hydrostatic pressure system. This load was pressure distribution.

wetted portion of the torus shell (Figure 3.4).

distribution, over the 3.4). The peak pressure was 04/16/02 04/16/02 1

• (3)

(3 )

for this for the modeled Uniform A

this distribution upload distribution was selected analysis, analysis, inactive.

modeled as inactive.

Uniform Pressure Pressure A uniform 30 psi positive the selected to give the intermediate saddle intermediate positive pressure th~ design pressure was applied over design upload.

saddle supports upload. For supports were over the torus For were shell to predict predict saddle stresses stresses due to con'tainment containment pressurization. Intermediate pressurization. Intermediate saddle supports supports were were modeled as as active.

active.

(4)

(4) Design Temperature Design Temperature The The design design uniform uniform temperature distribution of the saddle temperature distribution saddle at 50°F50°F with the torus shell at 200°F 200OF was applied to the saddle saddle model.

model. ToTo maximize maximize the saddle saddle stresses, intermediate .saddlesupports stresses, the intermediate saddle supports were modeled active.

modeled as active.

Combined Combined stresses and forces were were determined for the cases cases of design down load load plus pressure pressure and design upload plus pressure pressure (Figure 3.4). 3.4). Each of of these these two cases were two cases were considered considered with design temperature. Stresses design temperature. Stresses and forces forces were were combined algebraically.

combined algebraically.

From From these these combinedcombined stresses stresses and forces, forces, all saddle all saddle components components were were evaluated. These evaluated. These evaluations evaluations included design stresses in in the saddle saddle web,web, axial forces and bending bending moments in in the stiffeners stiffeners and flanges,flanges, forces per per unitt length along welds, uni welds, and base plate pI-ate stresses at the intermediate intermediate saddle saddle

• supports.

supports. For either For either thethe cut-out cut-out configurations configurations not explicitly explicitly modeled modeled oror variations variations in in stiffener stiffener designs, designs, evaluations evaluations were performed performed by hand calculations using the basic saddle load distributions predicted

.calculations predicted by these analyses.

analyses.

3.3.3.4 3.3.3.4 Nonlinear Support Assessment Nonlinear Assessment For. dynamic For. dynamic loading loading resulting in in net tension tension on the intermediate intermediate saddle saddle supports, supports, the response response of the torus support support system ~ill be nonlinear.

system will nonlinear. This This nonlinearity is nonlineari-ty is due due to to the lack lack of anchorage anchorage at these intermediate intermediate locations.

locations.

To assess To assess this this effect, a one-dimensional effect, one-dimensional nonlinear nonlinear model was developed, developed, as as discussed in in Section Section 6.4 (c) (c) of the PUAAG. Nonlinear time history analyses PUAAG. Nonlinear analyses confirmed that for all confirmed all combinations, design combinations, the linear analysis techniques techniques provide provide aa conservative conservative estimateestimate of torus shell and support response. response. NoteNote that that for for poolpool swell swell loading, loading, the nonlinear support the nonlinear support behavior behavior is is included explicitly explicitly in the torus shell in shell analysis (Subsection (Subsection 3.2.3.2.3) 3.2.3.2.3).

3.3.4 3.3.4 Code Evaluation Evaluation This subsection describes This subsection describes the code evaluation evaluation of the torus torus shell shell support support system for the design load combinations summarized in combinations summarized in Table 3.4. 3.4.

3.3.4.1 Column and Anchorage Anchorage The column-to-shell connection, The column-to-shell connection, support columns, anchor bolts, support columns, bolts, and anchorage anchorage assemblies assemblies all all meet meet design allowables allowables for the design combinations. Torus design load combinations. Torus tie-down capacity tie-down capacity is is 320 kips (inner column) and 430 kips (outer column) for for

• the limiting anchorage assemblies.

the limiting anchorage assemblies. Design uploads Design uploads are 97%

97% (inner column) and and 100% (outer column) 100% column) of these capacities.

capacities.

3-15 3-15 04/16/02 1

• 3.3.4.2 3.3.4.2 The lateral which which is is Seismic Ties lateral load (Subsection 3.3.3.2).

(Subsection greater greater capacity of a seismic tie load capacity 3.3.3.2). Thus, than the torus shell meet design allowables.

the design lateral Thus, the seismicseismic ties allowables.

tie lateral ties determined to be 660 kips, was determined load predicted by analysis predicted and their welded welded connections kips, analysis connections to to 3.3.4.3 3.3.4.3 Ring Girder Saddles Saddles Code evaluation evaluation of the ring girder saddle indicates girder saddle indicates that all all components components satisfy satisfy code allowables for the design load cases. cases. This conclusion conclusion was was determined for all determined all saddle configurations.

configurations. combined saddle web The maximum combined web stress stress was was 10.410.4 ksi (54% (54% of allowable).

allowable) . The maximum force per length in in the torus-to torus-to saddle saddle web weld is is 4.6 kips/in kips/in (79% of allowable).

allowable).

3.3.4.4 3.3.4.4 Fatigue Evaluation Fatigue Fatigue usage was checked checked at the welds connecting connecting the torus to the columns, columns, saddle saddle web, web, and and seismic seismic ties. ties. For the fatigue design design basis described described in in Subsection Subsection 2.7.7, 2.7.7, the cumulative cumulative usage at the torus to column intersection was was 0.29.0.29. The cumulative usage The cumulative usage at the other two locations locations was less than percent. Therefore, one percent: Therefore, all all fatigue usage factors are within within allowables.

allowables.

3.4 RING GIRDER

,

This section This section discusses discusses the results of the structural structural evaluations evaluations of the torus shell shell ring girder. girder. The ring girder includes the ring girder girder web and and flange,

• 3.4.1 The ring The same same 27 stiffeners, gusset stiffeners, Design Design Load ring girder 27 design the submerged girder is design load attachment to the torus shell and attachment Combinations Load Combinations load combinations combinations as the torus shell submerged portion of the ring girder girder is shell..

is an integral part of the torus shell and therefore shell (Table 3.1).

is subjected subjected to submerged therefore has the 3.1). In addition, In addition, submerged structure drag loads.loads. Concentrated C'oncentrated reactionsreactions are are also also present present at several attachment attachment points on the ring girder.

points girder.

Table 3.6 Table 3.6 shows shows the bounding load cases considered considered in in the evaluation evaluation of the ring girder.

ring girder. Where reactions reactions at component attachment attachment points are indicated, indicated, loads loads from from these components were taken these components taken from the analysis results results for these components.

components.

3.4.2 Allowables Design Allowables The ring The ring girdergirder is considered as an integral is c'onsidered int,egral Class MC component component support.

support.

Design allowables Design allowables are taken from Subsection Subsection NF-3000 of the Code, Code, except except for for the the portion of the ring girder girder within the limits of reinforcement reinforcement from the torus shell (NE) (NE) boundary.

boundary. These These exceptions exceptions to the NF classification classification have design allowables allowables specified specified in SubsectionNE.

in Subsection NE.

3.4.2.1 3.4.2.1 Ring Girder Web and Flange The The ring girder girder web is is considered considered a plate-and-shell plate-and-shell type support support and is is evaluated evaluated. using the procedure procedure in Subsection NF-3320.

in Subsection NF-3320. The allowable stress

• stress value value is is 19.3 ksi ksi..

3-16 3-16 04/16/02 04/16/02 I

• The ring girder flange and the gusset plates considered linear-type considered tension and 13.5 specified linear-type component 13.5 ksi in component supports.

in shear.

she1r.

plates attached to the web are supports. Design The portions of the ring girder web within the NE limits of reinforcement (1-1/2" from the torus shell) have the same allowable specified for the torus shell (see Subsection allowables are 20.2 ksi in Design allowables reinforcement allowable stress intensities 3.2.2.1).

Subsection 3.2.2.1).

intensities as in as 3.4.2.2 3.4.2.2 Ring-Girder-to-Shell Ring-Girder-to-Shell Weld Weld The double 5/16" fillet fillet weld weld connecting connecting the ring girder girder to the torus shell is is within the NE jurisdiction.

jurisdiction. The allowable allowable force/unit force/unit length on this weld is is 3.3 3.3 kip/in.

kip/ in. In In the vicinity of the platform attachments (where the platform support attachments weld isis reinforced reinforced to 3/4" on each side), side), the allowable allowable force/unit force/unit length length isis 8.9 kip/in.

kip/in.

3.4.3 Analysis Analysis Methods Methods and ResultsResults subsection describes This subsection describes the analysis procedures analysis procedures used to qualify qualify the components components of the ring girder. girder. Results from the torus shell shell analyses analyses (Subsection (Subsection 3.2) 3.2) are used in in these evaluations.

evaluations.

3.4.3.1 In-Plane Loading Ring Girder In-Plane Loading Stresses in in the ring girder girder web and flange were were taken taken from the results of the 1/32 section section coupled shell-fluid shell-fluid model analyses analyses (Subsection 3.2.3.2). These (Subsection 3.2.3.2). These results results were also used to estimate estimate the force/unit length on the ring ring

• girder-to-shell girder-to-shell weld.

in these analyses.

in discussed discussed in 3.4.3.2 Stresses in weld. The ring girder analyses. These analyses in Subsection 3.2.3.2.

Ring Girder Lateral 3.2.3.2.

Lateral Load girder web and flange were explicitly analyses provided Load in the ring girder web and flange and reactions explicitly modeled provided stress results for all load cases reactions along the ring cases ring girder girder weldweld due to submerged structure drag loads were determined.

submerged structure determined. The The procedures described procedures described in Subsection 6.3.3.2 in Subsection 6.3.3.2 were used for these evaluations.

evaluations.

A finite element element model of the longest submerged section section of the web betweenbetween gusset stiffeners was developed using program gusset stiffeners EDS-SNAP. Equivalent static program EDS-SNAP.

analyses analyses were then performed performed for all drag loadings loadings acting acting on this section.

section.

The largest lateral load on any submerged largest lateral submerged section was uniformlyuniformly applied applied to to this model to conservatively consider the worst case conservatively consider loading. Stresses case ,loading. Stresses inin the web and reactions at the weld weld were then taken from this model. model. Forces in in the ring girder girder gussets were also evaluated from this model. model. For the chugging plus discharge S/RV discharge load combination, load combination, the 1.1 SRSS combination method combination method (Appendix D) D) was used to determine determine the combined combined reaction reaction on the ring girder girder weld due to these two dynamic loads.

dynamic lateral loads.

3.4.3.3 3.4.3.3 Ring Girder Attachments Attachments In addition to in-plane In in-plane loading loading and lateral lateral loads due to submergedsubmerged structure drag, drag, the ring girder girder was also analyzed for local local reactions reactions from torus internal structures structures and piping supports. supports.

The local reactions considered were due to the following structures:

reactions considered structures:

(1)

(1) supports Vent system supports 3-17 3-17 04/16/02 04/16/02 1

(

6

• (2) )

(2 (3)

(3)

(4)

(4) 24-inch diameter 16-inch diameter T-quencher 16-inch diameter T-quencher support pipe diameter S/RVDL BB support pipe 10-inch diameter T-quencher bracing 10-inch bracing pipe (5)

(5) S/RVDL B supports supports in In the torus airspace airspace (6)

(6) HPCI turbine turbine exhaust sparger supports exhaust sparger supports (7)

(7) RCIC turbine turbine exhaust exhaust sparger sparger supports supports (8)

(8) Containment Containment spray header header supports supports (9)

(9) Platform supports supports The The maximum reactions from each each of these structures structures for all all load cases~were cases'were statically statically applied applied to calculate calculate the ring girder girder and ring girder-to-shell girder-to-shell weld weld.

stresses.

stresses. These reactions were determined determined from the individual individual analyses analyses of of each structure structure described described throughout throughout this report.

report. Local stresses from the ring ring girder attachments attachments were combined combined with the in-planein-plane and lateral lateral load-induced load-induced stresses stresses prior to the code evaluation. evaluation.

3.4.4 Code Evaluation Evaluation

. This This describes the code evaluation subsection describes evaluation for the Cooper Cooper Station ring Station

• girder for the design load combinations 3.4.4.1 3.4.4.1 Stresses in Stresses maximum maximum web stress due to pool swell dU'e Ring Girder Girder Web and Flange in the ring girder stress is swell plus S/RV discharge Flange summarized in combinations summarized girder web are below allowables discharge loads.

in Table Table 3.63.6..

allowables at all locations.

is 16.1 ksi (56% of allowable) away from any attachments loads. At all attachments, locations. The The attachments attachments, local web web stresses are also below the allowable.

stresses allowable. Loads Loads on the ring girder girder flange and stiffeners are all within allowables.

gusset stiffeners allowables.

3.4.4.2 Girder-to-Shell Weld Ring Girder-to-Shell Weld The maximum maximum force/length force/length in in the unreinforced unreinforced ring girder-to-shell girder-to-shell weld away away from any ring girder attachments attachments is is 2.6 kip/in (79% (79% of allowable).

allowable). In the In reinforced portion of the weld reinforced weld near the platform platform support attachments, the support attachments, maximum maximum force/length force/length is is 7.8 kip/in (97% of allowable).

allowable). All ring ring girder-to-shell girder-to-shell weld weld*'stresses stresses at ring girder attachments are also within girder attachments allowables.

allowables.

3.4.4.3 3.4.4.3 Fatigue Fatigue Evaluation Fatigue Fatigue usage was checked checked at the ring girder-to-shell girder- to-shell weld for the fatigue design basis described in in Subsection Subsection 2.7.7.

2.7.7. All cumulative cumulative fatigue usage usage factors at the critical critical locations were locations were below below one.

one.

.

3.5 TORUS SHELL PENETRATIONS AND ATTACHMENTS SHELL PENETRATIONS ATTACHMENTS

• This subsection piping girder sub~ection describes the results of the torus shell evaluations penetrations and other attachments piping penetrations girder and saddle support).

attachments (with the exception support). Piping penetrations penetrations are associated 3-18 3-18 evaluations at both exception of the ring associated with the torus ring 04/16/02 04/16/02 I1

• attached attached piping covered covered in 3.5.1 3.5.1 piping systems.

in Section 6.

Evaluation systems. Other 6.

Combinations Design Load Combinations Evaluation of the torus shell penetrations attachments include Other attachments beam and ECCS piping inside the wetwell.

include supports for the monorail wetwell. Evaluations Evaluations of these systems penetrations and attachments involves the monorail systems are determination determination of local local torus shell stresses. Therefore, shell stresses. Therefore, the '27 design load combinations for the torus shell (Table 3.1) apply for these evaluations.

combinations evaluations.

Table 3.7 shows the bounding combinations for which the penetrations bounding load combinations penetrations and attachments evaluated.

attachments were evaluated.

3.5.2 3.5.2 Design Allowables Design Allowables Local stress intensities intensities due to reactions at penetrations penetrations and attachments attachments are determined determined using the procedure in Subsection NE-3215 of the Code.

in Subsection Code. Since the torus shell shell is is being evaluated, evaluated, stress intensity limits established established inin Table 3.3 must be satisfied.

Local stress intensities due to penetrations stress intensities penetrations and attachments attachments are classified as primary local stresses for the membrane local stresses component and as secondary membrane component secondary stresses for the surfacesurface stress intensity intensity (see Code Subsection Subsection NE-3213)

NE-3213).. In In comparison with comparison allowables, stress withallowables, stress intensities intensities due to primaryprimary loads on the torus shell must also be included. included. Absolute Absolute summation of the local and primary stress intensities was performed. performed. The combined combined stress intensity summarized in limits were summarized Subsection 3.2.2.1.

in Subsection 3.2.2.1.

3.5.3 3.5.3 Analysis Analysis Methods and Results Results This subsection describes describes the analysis procedures procedures used to determine determine local local stress intensities intensities at torus shell penetrationspenetrations and attachments.

attachments.

3.5.3.1 Torus Attached PipingPiping Penetrations Penetrations Torus shell attached attached piping penetrations penetrations are summarizedsummarized in in Table 1.2.

Table 1.2.

Reactions Reactions at each penetration (3 forces and 3 moments) penetration moments) were obtained obtained from the results results of the torus attached attached piping analyses analyses (Section 6). 6). Where a piping system had both an internal and external portion portion (relative to the wetwell),wetwell),

reactions reactions for a load case from each portion of the piping were conservatively conservatively summed absolutely absolutely to obtain the design design reactions.

reactions. Additionally, for dynamic dynamic load cases, load cases, the maximum maximum reactions in in all 6 directions are assumed to act on on the penetration penetration at the same time. time. Thus, Thus, the combined combined reaction reaction load on each penetration was conservatively torus shell penetration conservatively defined.

defined.

Combined reactions due to mul multiple tiple dynamic dynamic load cases cases were determined by by using a modified modified SRSS procedure.

procedure. The reactionsreactions (in (in a given direction) from from the two the two most most significant dynamic dynamic load cases cases were combined combined by SRSS with a multiplier mUltiplier of 1.1 1.1 on the combination.

combination. Remaining dynamic and static static load cases cases were then added absolutely to this combination. combination. The modified modified SRSS method method was was justified justified for this application application through the study summarized summarized in in Appendix D.

Local shell stresses at -each *each nozzle were determined determined using the procedure in in Welding Welding Research Research Council (WRC) (WRC) Bulletin Bulletin No. No. 107 (Reference 33). 33). several For several 1 inch and 2 inch penetrations, penetrations, the WRC procedure was not applicable. applicable.

Stresses Stresses at these small-bore penetrations penetrations were calculated calculated through through modeling 3-19 04/16/02

penetration insert plate the penetration plate as a simply supported supported annular annular plate plate with concentrated concentrated forces and moments applied at the penetration. penetration.

Local shell stresses stresses at the edge edge of each penetration penetration insert plate plate were were determined considering the attenuation determined by consid~ring attenuation of the bending moment away from the nozzle.

nozzle. This attenuation was taken to be the same as that for a cylindrical cylindrical concentrated radial ring load (Reference 34).

shell under a concentrated 34). A reduced bending moment was calculated calculated at the end of the insert plate; plate; then shell stresses were calculated calculated considering considering the reduction reduction in in shell shell thickness thickness going from the insert plate to the clean clean shell.

shell.

3.5.3.2 3.5.3.2 Monorail Supports Supports Local Local torus shell stresses stresses at the three three monorail monorail beam beam. supports in in each bay were computed computed using the WRC 107 107 method.

method. Reactions from the monorail beam monorail beam (resulting only from froth impingement impingement loads) were determined determined using the procedure procedure in in Subsection Subsection 6.4.3.2.

6.4.3.2.

3.5.3.3 3.5.3.3 ECCS Piping Supports Supports Local torus shell stresses were computed computed at the torus shell attachmentattachment of of several pipe supports several supports for ECCS piping in in the wetwell.

wetwell. These pipe supports are on the RHR pump test, HPCI condensate condensate drain, drain, and RCIC condensate condensate drain lines.lines.

The WRC 107 method was *used used for these evaluations.

evaluations. Reaction loads on the determined from the evaluations shell were determined evaluations described in in Subsection Subsection 6.3 and and include include both pipe reactions reactions and hydrodynamic hydrodynamic loads on the supports themselves.

themselves.

S

~ 3.5.4 3.5.4 Code Evaluation This subsection describes describes the code evaluation evaluation for the torus shell shell penetrations and attachments penetrations attachments for the design load combinationscombinations summarized summarized inin 3.7.

Table 3.7.

3.5.4.1 3.5.4.1 Torus Attached Attached Piping Piping Penetrations Penetrations The combined combined local and general torus shell stress intensities were compared compared allowables for each against allowables each penetration combination. Stress penetration and each load combination. Stress intensities intensities were checked checked at both the nozzle and the edge of the insert plate. plate.

All stress intensities intensities primary local (both primary local and secondary) were were within allowables for all design load combinations.

allowables combinations. Table 3.8 3.8 shows the local stress intensity intensity and the percentage percentage of allowable for each penetration.

penetration. The The percentage percentage of allowable allowable is is based on the combinedcombined local and generalgeneral stress intensities.

intensities.

3.5.4.2 3.5.4.2 Stress Intensities Torus Shell Stress Intensities at Attachments Attachments Local torus shellshell stress stress intensities intensi ties at all attachments attachments (monorail supports supports and ECCS piping supports) are within the allowable allowable reserve reserve stresses stresses for allall load combinations.

load combinations.

3.5.4.3 3.5.4.3 Fatigue Fatigue Evaluation Fatigue usage was checked at all penetrations penetrations (both at the nozzles and the edge of the insert plate), plate), and at all attachments attachments using the fatigue design

~ basis in subjected in Subsection 2.7.7.

Subsection 2.7.7.

subjected to reactions In evaluating In evaluating fatigue usage reactions due to chugging loads from both internal usage at penetrations penetrations internal and external external 3-20 3-20 04/16/02 1

• piping, the piping, external For reactions reactions the local stress external reactions.

summation of summation For fatigue unnecessarily unnecessarily add add fatigue evaluation fatigue stress intensity was reactions. For of internal For consideration internal and fatigue evaiuation, and external evaluation, absolutely absolutely conservative.

conservative.

evaluation only is the was based consideration of throughout throughout based on an of local external reactions is the assumption assumption that an an SRSS combination of SRSS is therefore therefore justifiable.

justifiable.

IBA, IBA, an SRSS SRSS of local stress SBA, SBA, of these of the is aa potential that the or or the internal stress intensity, potential design the internal these reactions internal and intensity, absolute absolute design concern'.

internal and concern'.

and external external DBA event reactions event for the is is the The The cumulative usage cumulative usage factors factors atat all all torus shell torus shell penetrations penetrations andand attachments attachments are are with~n allowables .

with'in allowables.

\

• 3-21 3-21 04116/02 04/16/02

EVENT COMBINATIONS

• EVENT C0/1BINATIONS DESIGN SRV SRV COMBINATIONS AND SERVICE DESIGN LOAD COMBINATIONS SRV SRV

+

+

SBA SBA IBA IBA SERVICE LEVEL LIMITS FOR SBA SBA ++ EQ IBA EQ IBA ++ EQ EQ SBA IBA TABL*.

TABL SBA ++ SRV SRV I3A ++ SRV SRV

• . 11 FOR CLASS MC COMPONENTS SBA IBA SRV + EQ SBA + SRV IBA ++ SRV SRV ý T EQ EQ EQ COMPONENTS AND INTERNAL DBA DBA INTERNAL STRUCTURES DBA ++ EQ DBA EQ STRUCTURES DBA +

DBA + SRV SRV

• DBA ++ EQ DBA EQ +- SRV SRV EQCO, CO, CO, CO, PS CO, CO, CO, EQ CH CO,CH CH COCH (i) CH PS COCH CH CO,Cr! CH CO,Cr! (1) CH PS CO,CH PS PS CH CH PS COCH CO,CH EARTHQUAKE TYPE OF Kl\RTHQUAKE 0 S 0 S S 0 S 0 S 0 SS 0 S 0 S 0 S 0 SS COMBINATION NUMBER COMBINATION Nu'"MBER 1 ° 22 3 44 55 ° 6 7 ° 8 99 10 10 11 11 ° 12 13 ° 14 14 15 15 16 17 ° 18 19 ° 20 21 22 23 ° 24 25 ° 26 2, 27 LOADS LOADS Normal (2) (2) N N x X X X x X x X xX x X xX x X xX x X x X x X x X xX xX xX xX Xx xX xX x X xX xX xX x X xX XX Earthquake Earthquake EQ X X X X X X X X X X XX X X X X XX X X X X XX X X X X X X X X X X X

SRV Discharge Discharge .SRV

• SRV X X X X X X X X X X XX X X XX XX ,

x X X X X X X X X X X

Thermal LOCA Thermal TA TA X X X X X X X X X X X X X X X X XX X X X X X X X X X H X X X X X X X LOCA Reactions Reactions RH RA X X XX X X X X X X X XX X XX XX X X X X XX X X X X X X X X X X X X X

LOCA Quasi-Static Quasi-Static Pressure Pressure PA P A xX x X x X H X H X H X X xX xX X X xX xX XX X X X xX xX X x X X X XX x X Xx X LOCA Pool Swell Pms Pes X X X X X X X X X X

LOCA Condensation Condensation Oscillation Oscillation Pco p(:o XX X X XX X X XX XX X X X X X X X XX X LOCA Chugging Chugging PC.

P CH XX X X XX X X XX XX XX X X X X X ZX X STRUCTURAL ELEMENT' STRUCTURAL ELEMENT ROW External External Class MC MC Torus, External Torus, External Pipe, Vent Pipe, Bellows, Drywell Bellows, Dryw.ell 11 A A BB C C A A AA B B C C B B C C AA AA B B C C BB CC A A A A BB CC BB C C CC CC C C C C C C C C

(at Vent),

(at Vent) ,

Attachment Welds, Welds, Torus Supports, Supports, Seismic Restraints Internal Vent Internal Vent Pipe General and 2 A A B B C C A A A B B C C B C C A A A B B C B C A A A A BB C C B C C C C C C C C C C C Attachment Melds Attachment Welds At Penetrations Penetrations 3 A A B B C C A A A B B C C B B C C A

.l\ A A B C C BB C C A A A A BB C C B C C C C C C C C C C C C C (e.g. , Header)

(e.g., Header)

Vent Header Header General and 4 A B B C C A A A B B C C B C C A A A A B C BB C C A A AA BB C C B C C C C C C C C C C C C Attachment Welds Attachment I'lelds At Penetrations At Penetrations 55 A B C A A B C C B C C A A A A B C C BB C C A A A B C C B C C C C C C C C C C (e.g.

(e.g.,, Downcomers)

Downcomers)

Downcomers Downcomers General General and 66 A A' BB C C A A AA B B C C B C A A A A B C B C C A A A A BB C C B C C C C C C C C C C C C Attachment Attachment Welds Welds Internal Supports Supports 77 A A BB C C A A AA B B C C B C C A A A A B B C C BB C C A A A A BB C C B C C C C C C C C C C C Internal Structures Structures General General 88 A A BB C C A AA C D D C D D C C D E DD E E E E E EE E E E E E E E E E .E E

Vent Deflector Deflector 9 A A B B C C A AA C C D D C DD C C C C D 0 D DD D D D D D D D D D D D D D D D D D D DD 3-22 I

• BOUNDING Combination Load Combination TORUS Table Table 3.2 TORUS SHELL 3.2 BOUNDING LOAD COMBINATIONS COMBINATIONS 'FOR SHELL EVALUATIONS EVALUATIONS

FOR Service Service Level Level Chugging ++ 66 ADS IBA/SBA Chugging ADS S/RV + B B

Gravity + Pressure ++ Thermal Thermal + OBE OBE CO + Gravity ++ Pressure + OBE DBA CO OBE B B

Gravity ++ OBE DBA PS + Gravity B B

NOC 8MVA S/RV + IBA IBA CO ++ B B

Gravity + Pressure ++ OBE DBA CO + Gravity + C Pressure + SSE IBA/SBA Chugging Chugging + 6 6 ADS S/RV + C Pressure + SSE Gravity + Pressure SSE S/RV + IBA CO +

NOC 8MVA S/RV+ C Gravity + Pressure + SSE DBA PS + SVA S/RV +

• C Gravity + Pressure Pressure + SSE SSE 3-23 3-23 04/16/02 04/16/02 I

• TABLE 3.3 3.3 STRESS INTENSITIES FOR' ALLOWABLE STRESS THE TORUS SHELL Stress FORý Stress Intensity Intensity (ksi)

(ksi)

Type of Stress Service Level Service Level Level Intensity Intensity A/B AlB C Pm 19.3 33.7 33.7 PL 29.0 50.6 50.6 P1, + Pb 29.0 50.6 50.6 PL, + Pb + Q 67.5 67.5 Notes:

Notes:

(1)

(1) Allowables are Allowables are for for SA-516 SA-516 Grade, Grade. 70 steel at 2002002Q design temperature temperature. .

• 3-24 3-24 04/16/02 04/16/02 I

• Load Combination Table Table 3.4 BOUNDING LOAD 3.4 LOAD COMBINATIONS COMBINATIONS FOR TORUS SUPPORT COLUMN EVALUATIONS TORUS EVALUATIONS Service Level Level DBA CO ++ Gravity ++

Pressure ++ OBE B B

DBA PS ++ Gravity ++ OBE OBE B NOC 88 MVA S/RV S/RV + IBA CO ++

Gravity ++ OBE OBE BB

• 3-25 04/16/02 04/16/02 I

• Load BOUNDING BOUNDING LOAD Load Combination Combination Table Table 3.5 LOAD COMBINATIONS COMBINATIONS FOR 3.5 FOR TORUS TORUS SADDLE SADDLE EVALUATIONS EVALUATIONS Service Service Level Level IBA/SBA IBA/SBA Chugging Chugging ++ 66 ADS ADS S/RV S/RV

++ Gravity Gravity ++ Pressure Pressure ++ OBE OBE BB IBA/SBA IBA/SBA Chugging Chugging ++ 66 ADS ADS S/RV S/RV

++ Gravity Gravity ++ Pressure Pressure ++ Thermal Thermal ++ OBE OBE BB DBA DBA PSPS ++ SVA SVA S/RV S/RV ++ Gravity Gravity ++

Pressure Pressure ++ SSE SSE CC 0

• 3-26 3-26 04/16/02 04/16/02 II

• Load Combination, Table 3.6 Table 3.6 COMBINATIONS FOR BOUNDING LOAD COMBINATIONS Combination, RING GIRDER EVALUATION FOR Level Service Level Chugging + 6 ADS S/RV +

IBA/SBA Chugging Gravity + Pressure + OBE B B

IBA/SBA Chugging + 8 MVA S/RV +

Gravity + Pressure + OBE OBE B B

DBA CO + Gravity + Pressure + OBE B B

DBA PS + Gravity Gravity + OBE OBE B B

DBA PS.+

PS.+ SVA S/RV + Gravity +

Pressure + SSE SSE C 3-27 3-27 04/16/02

• Load Combination Table 3.7 3.7 BOUNDING LOAD COMBINATIONS BOUNDING TORUS SHELL COMBINATIONS FOR SHELL PENETRATIONS PENETRATIONS AND AND ATTACHMENTS ATTACHMENTS Level Service Level Service IBA/SBA Chugging + 66 ADS S/RV +

Gravity + Pressure Pressure ++ OBE B B

NOC 88 MVA S/RV + Gravity IBA CO + NoC

++ Pressure +

+ OBE B B

DBA CO + Gravity + Pressure Pressure + OBE B B

3-28 3-28 04/16/02 04/16/02 I1

!

• +/- +

Table 3.8 ATTACHED PIPING QNOZZLE NOZZLE 3.8 LOCAL STRESS INTENSITIES TORUS ATTACHED INTENSITIES OF PIPING PENETRATIONS OF PENETRATIONS EDGE OF INSERT PLATE PPI,L + PDPb + QQ Percent of Percent of P P,L + P

+ b +

Pb + Q Percent of Percent of PENETRATION PENETRATION (ksi) Allowable Allowable (ksi)

(ksi) Allowable Allowable NOZZLE 210A 210A 66.2 66.2 98 98 59.6 88 88 210B 57.3 57.3 85 85 59.6 88 88 211A 12.4 12.4 92 92 (1)

(1) (1)

(1) 211B 56.3 56.3 83 83 (1)

(1) (1)

(1) 212 58.8 58.8 87 87 62.5 62.5 93 93 214 214 50.0 50.0 74 74 63.2 63.2 94 94 223A N/A N/A N/A N/A 60.6 60.6 90 90 223B N/A N/A N/A N/A 60.6 60.6 90 90

• 224 224 57.5 57.5 85 85 (1)

(1) (1)

(9) 225A 65.0 65.0 96 96 (1)

(1) (1)

(1) 225B 59.8 59.8 89 89 (1)

(1) (1)

(1) 225C 65.6 65.6 97 97 )(l)

J( 1) (1)

(1) 225D 64.3 64.3 95 95 (1)

(1) (1)

(1) 226 226 63.9 63.9 95 95 (1)

(1 ) (1)

(1) 227A 67.5 67.5 100 100 (1)

(1) (1)

(1) 227B N/A N/A N/A N/A 66.6 66.6 98.

98, Notes:

Notes:

(1)

(1) secondary stress intensities Primary and secondary intensities at the edge of the insert insert plate plate were calculated calculated to be less than those those at the nozzle.

nozzle.

(2)

(2) For penetrations 223A, For penetrations 223B, and 227B maximum local stress 223A, 223B, stress intensities intensities were determined determined at the edge of penetration reinforcement rather than at penetration reinforcement at the nozzle.

nozzle .

• 3-29 3-29 04/16/02 I1

• TABLE 3.8 (Cont'd)

LOCAL STRESS (Cont'd)

STRESS INTENSITIES INTENSITIES OF PIPING PENETRATIONS TORUS ATTACHED PIPING PENETRATIONS

+/- + NOZZLE EDGE OF INSERT PLATE PL + Pb PL Pb + Q Percent of Percent of P PLL + Pb + Q Pb Q Percent of Percent of PENETRATION PENETRATION (ksi) Allowable Allowable (ksi) Allowable Allowable 203A 36.9 36.9 55 55 34.9 52 52 203B 36.9 36.9 55 55 34.9 52 52 205 205 51.

51.5 5 76 76 58.3 52 52 206A 36'.9 36'.9 55 55 34.9 52 52 206B 36.9 36.9 55 55 34.9 52 52 206C 36.9 36.9 55 55 34.9 52 52 206D 36.9 36.9 55 55 34.9 52 52 209A -

209A D 36.9 36.9 55 55 34.9 34.9. 52 52 215 215 36.9 36.9 55 55 34.9 52 52 220 220 48.5 48.5 72 72 66.5 98 98 221 221 48.8 48.8 72 72 38.9 58 58 222 222 48.8 48.8 72 72 38.9 58 58 228 228 60.0 60.0 89 89 65.0 96

.96 229A - K 36.9 36.9 55 55 34.9 52 52 229L - M 36.9 36.9 55 55 34.9 52 52 213A 45.5 45.5 67 67 55.5 82 82 213B 45.5 45.5 67 67 55.5 82 82 3-30 3-30 04/16/02 I1

• Torus Shell Torus Midside Node Midside Node locations Locations (Typ) Ring Girder Ring Girder Typical Element Outside Support Column Column P,

• Ring Girder Saddle Support Column Inside Support Inside Structure Structure Fluid Fluid Building Plan Reactor Building Reactor Plan View View

• 1/32 FIGURE FIGURE 3.1 SECTION TORUS 1/32 SECTION 3-31 3-31 3.1 TORUS MODEL MODEL 04/16/02 04/16/02 I

• j' FIGURE 3.2 FIGURE 3.2

• 90° SECTION TORUS MODEL 900 SECTION 3-32 MODEL 04/16/02

.04/16/02 I

• *0

• iI~o;!!l!d~ H'Od1!! .

L<<'.II!t*~~31~TYl'. )

• .Ain Girder Ratctor Rc-b*CrteJt' Bfi ilh SullClln'il Pl&sn H 4i:fI View V16k' 7rypithal 1eI ~oti

ý-Va"Il support C'ellu'e' FIGURE 3.3 FIGURE 3.3 1/32 1/32 SECTION SECTION TORUS TORUS MODEL MODEL WITH WITH DETAILED DETAILED RING RING GIRDER GIRDER SADDLE SADDLE 3-33 3-33 I 04/16/02 1 04/16/02

-

~.

-u 4

30 ps1 l

Design Download Design Download

-

+ 30 psi Design Upload Desin Upload

• FIGURE FIGURE 3.4 3.4 LOAD COMBINATIONS USED LOAD COMBINATIONS SADDLE EVALUATION IN SADDLE USED IN EVALUATION 3-34 3-34 04/16/02 1 04/16/02 I

• !

S.2 -.

~YS S.?2 SYS AR*2S 1996 MAR2S 1996 15:06:52 15:06:52 1' ELEMENTS EfLEMENTS TYPE TYPE HUM xv

'XN -1.1

,e Yv YV -1 ZV ..1

-1 "N .1 DIST.317.9 0IS1..317.9 XF XF ,149.878

..149.878 YF YF -- 11.471

.. -11.471 ZF -593.842 ZF -593.842 CENTRO10 CENTROID HIXDDEN HIODEN

• 0 Torus Torus Finite Finite Element Element Model Model -- 1/16 1/16 Model Model FIGURE FIGURE3.5 3.5 1/ 16 TH TH ANSYS MODEL FOR TORUS REANALYSIS 1/16 ANSYS MODEL FOR TORUS REANALYSIS 0

3-34 3-34 04/16/02 04/16/02

..ANSYS SYS 5.2 MAR 25 1996 R*A 1996 15:08:13 ElEMENTS ELEMENTS TYPE lYPE HUM HUH

';:oJ -1 xv W ..-11 YV

'1:'1 ZV -1 .1

,OI5T-317.9 DIST-317.9 XF .149.878 XF .149.878 YF --

YF a-11.471 11.471

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• 3 -35 3-35 04/16/02

• SYS2S1996 15:10:36 ELEMENTS TYPEH* -

XV xv -1.1 wW .1 .1 ZI/ -1 ZV .1 DIST.317.9 DIST*317.9 XFXF -149.878

-149.878 YF YF ----11.471 11.471 zFZF -593.842

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• Torus Gi rder and A!~!!.Girder TOrus Ring and Support Support FIGURE 3.7

/ 7T f1GURE3.7 1 16 mANSYS MODEL RING GIRDER AND SUPPORT ELEMENTS FOR TORUS

!116 ANSYS MODEL RlNG GIRDER AND SUPPORT ELEMENTS FOR TORUS REANALYSIS REANALYSIS

• 3-36 3-36 04/16/02 04/16/02

COOPER NUCLEAR COOPER NUCLEAR STATION PLANT UNIQUE ANALYSIS ANALYSIS REPORT

) SECTION SECTION 4 VENT SYSTEM SYSTEM AND SUPPORTS SUPPORTS

• 4.1 IN'rRODUCTION p

4.1 INTRODUCTION

This section section describes describes the results of the structuralstructural evaluations evaluations of the vent vent system and associated associated support structures.

structures. The components included in components included in this evaluation are the vent header, evaluation header, main vent, vent, downcomers, downcomers, vent header header deflector, deflector, vent 'header support support system, downcomer tiebars, main vent bellows, downcomer tiebars, bellows, vent drain line, and associated associated penetrations penetrations and intersections intersections on the vent system.

Descriptions Descriptions of these components and modifications these components modifications are provided provided in in Section 1. 1.

The The thermal-hydraulic thermal-hydraulic load definitions and load combinations combinations are described in in Section 2. 2. This section section describes describes the design design load combinations, combinations, design allowables, allowables, analysis methods methods and results, and code evaluations for all code evaluations all structural components structural components listed above.

listed above.,

4.2 VENT HEADER HEADER AND MAIN VENT VENT subsection discusses the results of the structural evaluations This subsection evaluations of the vent header, main vent, vent header, vent, vent header and main vent penetrationspenetrations (i.e. vacuumvacuum breaker breaker and main vent drain line penetrations), penetrations), the drywell penetration, penetration, and the main vent bellows.

bellows. Structural Structural evaluations evaluations of the downcomers, downcomers, downcomer/vent downcomer intersection, and downcomer

/vent header intersection, downcomer tiebars are discussed in in Subsection 4.3.

Subsection 4.3.

4.2.1 Design Combinations Design Load Combinations The 27 design load combinations combinations for the vent header and main vent are are shown in in Table 3.1 of Section Section 3. 3. This table is is taken from the PUAAG (Reference 19).

(Reference 19).

ASME Code Service Limit assignments assignments for each load combination combination are also indicated indicated In in the table. Of the 27 load combinations, potentially bounding combinations, potentially load combinations combinations were identified for the vent header and main vent vent evaluations. These evaluations. Th~se bounding bounding combinations are shown in in Table 4.1. Combined 4.1. Combined vent vent system system stresses were compared compared against against allowables for these load combinations.

combinations.

4.2.2 'Design Allowables "Design Allowables The The vent vent header and main vent are classified classified as Class MC components.

components. Design allowables are are taken from Subsection Subsection NE-3000 NE-3000 of the ASME Code.Code.

4.2.2.1 4.2.2.1 Header and Main Vent Header Main Vent Vent Stress intensity intensity values are calculated calculated using the procedure procedure in in Subsection NE-3215 Subsection of the Code. Code. Combined Combined stress intensity values values were were required required to satisfy satisfy the requirements requirements of Subsection Subsection NE-3221 for all load combinations. Fatigue evaluation combinations. evaluation of the vent system was also performed performed as as required by Subsection Subsection NE-322 NE-3221.5.

f .5. /

)

Stress intensity allowables for the vent system Class MC components intensity allowables components are shown shown in in Table 4.2. 4.2. allowables are based These allowables based upon material material allowables allowables for for SA-516 Grade 70 steel at a design temperature corresponding to the temperature of 289°F corresponding maximum maximum LOCA temperature temperature along the main vent. vent.

4.2.2.2 Header and Main Vent Penetrations Vent Header Penetrations

.

• The The vent header breaker intensity allowables shown in intensity allowables penetrations (i.e.,

header and main vent penetrations breaker and the main main vent drain line) are evaluated in Table 4.2. In Table 4.2.

4-1 4-1 (i.e., penetrations penetrations at the vacuum evaluated against the stress accordance with the procedure In accordance vacuum stress procedure in 04/29/82 in

• Reference Reference 19, membrane membrane plus at at all all vent allowables allowab1es for was was not 19, allowable vent header allowable stresses plus primary primary bending for vent not required, loads.

loads.

required, as vent header stresses for primary bending (PL+Pb) header penetrations header stresses as Level stresses due Level A/BA/B Service primary local (PL+P b ) stress due to Service Limits to local local membrane stress intensities penetrations for LOCA-related local pool Limits were membrane (PL) intensities are LOCA-related loadings.

pool swell were satisfied (P L) and are increased loadings. Use Use of swell impact satisfied for and primary increased by primary by 30%

of increased for pool 30%

increased impact pressures pressures pool swell swell 4.2.2.3 4.2.2.3 Drywell Drywe11 Penetration Penetration The The drywell drywell penetration penetration was was evaluated evaluated against against the the stress stress intensity intensity allowables allowables shown in Table shown in Table 4.2. 4.2.

4.2.2.4 4.2.2.4 Main Main Vent Vent Bellows Bellows The The stress stress allowable allowable for for the the bellows bellows material material (A240 (A240 TP304 TP304 stainless stainless steel) is is 16.6 ksi 0 at 16.6 ksi at 300 300°F.F.

4.2.3 4.2.3 Analysis Analysis MethodsMethods andand Results Results This This subsection subsection describes describes the the analyses analyses and and keykey results results ofof the the vent vent header header and and main main vent vent evaluations.

evaluations.

The The vent vent system system structural structural response response to to thethe loads loads described described in in Section Section 22 waswas evaluated to demonstrate compliance evaluated to demonstrate compliance with the Structural with the Structural Acceptance Acceptance Criteria.

Criteria.

The The vent vent system system response response was was determined determined throughthrough the the use use of of several several analytical analytical techniques-techniques', which which were were selected selected based based upon upon the the nature nature ofof the the loads loads andand the the expected expected response.

response.

To To evaluate evaluate the the ventvent system system shell shell response response to to most most static static and and dynamic dynamic loads, loads, aa 1/16 1/16 segment segment of of the the vent vent system system was was modeled modeled using using shell shell elements.

elements. This This model model waswas developed developed to to predict predict overall overall vent vent system system dynamic dynamic behavior, behavior, generalgeneral shell shell membrane membrane and and bending bending stresses, stresses, 'and and support support reactions.

reaction's. Stresses Stresses in in the the region region of of thethe downcomer/vent downcomer /vent headerheader intersection intersection were were determined determined using using aa detailed detailed modelmodel of of the the intersection intersection region region (Subsection (Subsection 4.3.3.1.1).

4.3.3.1.1). This This model model provides a more accurate representation provides a more accurate representation of of local local stresses stresses than than provided provided by by the the 1/16 1/16 segment segment model.model.

For For overall overall vent vent system system response response to to non-symmetric non-symmetric load load cases cases (e.g. (e. g. seismic seismic and and chug chug synchronization),

synchronization), aa beam beam model model representing representing aa 1800 180 segment 0

segment of of the the vent vent system system was was used.

used. Scale Scale factors factors were were thenthen used used to to translate translate the the responses responses from from the the 180'180 0 beam beam model model into into stresses stresses in in the the 1/16 1/16 shell shell model.

model.

For For several.

several, components, components, such such asas the the ventvent header header penetrations penetrations and and downcomer downcomer tie-bars tie-bars (Subsection (Subsection 4.3.3.3.1),

4.3.3.3.1), hand hand calculations calculations were were sufficient sufficient to to predict predict component component stresses.

stresses.

This This subsection subsection describes describes both both the the analysis analysis methodsmethods and and results results for for all all vent vent system system loadload cases.

cases. AfterAfter aa discussion discussion of of thethe mathematical mathematical modelsmodels used used in in the the analyses analyses -and and thethe predicted predicted ventvent system system dynamic dynamic properties, properties, the the analyses analyses for for each each load load casecase identified identified in in Section Section 22 are are described.

described. The The application application of of the the loads loads to to thethe structural structural model, model, the the analysis analysis methodsmethods and and procedures, procedures, and and the the important results are summarized. Finally, important results are summarized. Finally, the simplified calculations the simplified calculations of of miscellaneous miscellaneous vent vent system system components components are are reviewed.

reviewed .

• 4-2 4-2 04/29/82 04/29/82

• 4.2.3.1 4.2.3.1 other (2) aa beam (2)

Vent System Mathematical Mathematical Models other load cases required three structural 1/16 segment beam model to represent detailed model detailed Models The analysis of the vent system for LOCA-related, represent non-symmetric model of the downcomer/vent downcomer/vent LOCA-related, S/RV discharge-related structural models: (1) segment of the vent system for consideration discharge-related and (1) a shell model of a consideration of vent system dynamics, non-symmetric vent system, response, intersection region.

header intersection and dynamics, response, and (3) a region. This This subsection describes subsection describes the first first two modelsmodels used to evaluate evaluate the vent system. system.

The detailed detailed model of the downcomer/vent downcomer/vent header intersection intersection region is is described described in in Subsection Subsection 4.3.3.1.1.

4.3.3.1.1.

The vent system has eight vertical The planes of symmetry which divide vertical planes divide the vent vent system into sixteen repeti repetitive structural segments.

ti ve ,structural segments.**

Almost all vent system load cases' cases (e.g. pool swell, swell, thrust load, etc.)

load, et~.)

exhibit the sam~same symmetry.

symmetry. Therefore, Therefore, the primary primary finite element element model of the vent system is is a shell model representing representing a 1/16 1/16 segment segment spanning spanning from the centerline of aa vent bay to the centerline centerline centerline of an adjacent adjacent non-vent bay.

Figure 4.1 shows the shall shell model used in in the structural evaluations.

structural evaluations.

This 1/16 segment shell model employed eight node, node, isoparametric isoparametric shell shell elements to represent represent the main vent and vent header. header. Equivalent spring stiffnesses were computed stiffnesses computed for the main vent penetration penetration at the drywell drywell liner.

The The program program EDS-SNAP described described in in Appendix B was used to develop develop this model.

model.

Since the downcomers Since downcomers have aa relatively relatively stiff stiff cross-section cross-section when compared compared with the vent header cross-sectional cross-sectional properties, properties, beam elements were used to to represent the downcomers in represent in the shell shell model.

model. Beam elements were were also used to to model the vent header support columns, columns, downcomer tiebars, tiebars, and vent header header deflector.

deflector. Constraint equations equations were were specified specified for nodes around the downcomer/vent header junction downcomer/vent junction to prevent distortion of the downcomer downcomer pipe.

pipe.

These constraints were intended These constraints intended to model the stiffening stiffening effect effect that the relatively rigid downcomer relatively downcomer cross-section cross-section has on the vent header. header.

The axial and lateral stiffnesses stiffnesses of the bellows are insignificant insignificant relative to the main vent stiffness stiffness and were were not included included in in this model.

model. However, However, the covering on the bellows was expected to significantly covering significantly stiffen stiffen the main vent vent in in the hoop direction direction and was modeled using stiff stiff elements.

truss elements.

A consistent consistent mass matrix matrix formulation formulation was employedLfor employedLfor the vent system shell shell model. inertial effects model. The inertial effects of the suppression pool were considered considered by takingtaking the mass of the fluid displaced displaced by the submerged submerged portionportion of the downcomer downcomer and downcomer tiebars tiebars and "lumping" "lumping" this mass ~ass on the nodes at the downcomer tips and on the tiebars.

tiebars. Additionally, Additionally, the downcomer downcomer submerged portions were were assumed assumed to be filled with water for all load cases. cases. Although Although there there is is some some question question as to whetherwhether this assumption assumption is is valid during CO, CO, itit provides provides a conservative estimate conservative estimate of vent system system CO response.

response. The full water mass inside the downcomer downcomer was assumedassumed to be effective. effective. The increased mass on the submerged downcomer submerged downcomer portions portions due to the combined effects effects of the suppression pool and the downcomer downcomer water leg is is twice twice the mass of the water contained contained in in the downcomer.

downcomer. The mass of the vacuum breaker breaker was included in in the model by by its mass to the nodal mass of nearby nodes.

adding its nodes.

• Asymmetry presence of vacuum breakers Asymmetry due to the presence penetrations on breakers and S/RVDL penetrations on some of the segments, segments, is is not considered significant.

significant.

4-3 4-3 04/29/82

• asymmetric load cases, For asynunetric predict the overall structural predict utilized to utilized 1/16 segment A 180 A

segment shell model cases, aa larger portion structural response.

to evaluate asynunetric model were 180'0 segment of the vent system elements for for the were then portion of the vent response. Beam models asymmetric load cases.

then modified vent system was modeled models of the modified to include asynunetric modeled to the vent system cases. The results obtained system were obtained using the asymmetric effects.

system was modeled using three-dimensional the main vent lines and the vent header (Figure 4.2).

effects.

three-dimensional beam to were the beam elements 4.2) . By specifying either synunetric specifying symmetric or antisynunetric antisymmetric conditions conditions at the boundaries of of the model, model, the response of the full 360 36000 vent system was predicted.

predicted. A 1/16 segment beam model with synunetric symmetric boundary conditions was also developed determine scale factors relating the 1/16 to determine 1/16 segment shell model stresses to to the actual the actual 360 360'0 vent system stresses. stresses. The program EDSGAP described in in Appendix B was used for these beam models. models.

The two beam models were used to modify shell stresses stresses predicted by the 1/16 segment shell model to account for asynunetries 1116 asymmetries in in loads.

loads. Both the 1800 segment beam 180 segment beam model 0 model and the 1/16 beam model were analyzed for the same loads.

loads. The 180 18000 segment beam model incorporated incorporated the true boundary conditions, boundary conditions, while while thethe 1/16 segment beam model had the same boundary boundary conditions as the 1/16 segment 1/16 segment shell model. model. By comparing comparing beam forces and moments moments between between the two beam models, two beam models, scale factors were developed to correct correct the results from the 1/16 segment 1/16 segment shell model. model. These same factors were then applied to the shell shell stress results for the asynunetric asymmetric load case considered. considered. The modified shell shell stresses were stresses were then then used in evaluations. This procedure in subsequent Code evaluations. procedure waswas required required for for horizontal horizontal seismic seismic (Subsection 4.2.3.2.1) and for chug synchronization (Subsection synchronization (Subsection 4.2.3.2.5) analyses analyses. .

• 4.2.3.2 4.2.3.2 This system Vent Header and Main Vent This subsection subsection describes system shell analyses.

analyses. Vent system at the downcomer/vent at reactions Vent describes the analysis methods system shell downcomer/vent header intersection were determined reactions were determined using methods and results from the vent shell stresses stresses (except (except for local stresses intersection and penetrations) and support the 1/16 segment shell model. model. Analyses vent stresses support Analyses forfor all load all load cases cases described described in in Section 2 were perfor~edperformed using either dynamic or or equivalent static solution equivalent solution methods.

methods. Damping Damping was taken to be 2% 2% of critical critical for all dynamic analyses.

dynamic analyses.

4.2.3.2.1 4.2.3.2.1 Static Analyses Static Analyses Vent Vent system analyses analyses for static static design loads loads are described described in in this subsection.

subsection. Analysis procedures procedures are described for gravity, are described gravity, seismic, seismic, internal internal pressure, pressure, thermal and thrust thrust loads.

loads.

(1)

(1) Gravity Gravity and Seismic Seismic The The gravity and seismic seismic loadload cases were evaluated evaluated by performing performing static analyses analyses using both the 1/16 1/16 segment shell shell and 180 0 segment 1800 segment beam beam models.

models. The vent system system response response to vertical vertical seismic seismic loads loads was determined determined by scaling scaling the gravity analysis analysis results from from the 1/16 segment 1/16 segment shell shell model by the peak peak vertical vertical acceleration acceleration during an an SSE.

SSE.

The 18000 segment segment beambeam model was

• The 180 analyzed to was analyzed to determine determine vent system system response response to horizontalhorizontal seismicseismic motion.

motion. The resulting resulting peak horizontal horizontal acceleration acceleration was used used to develop develop scale scale factors whichwhich were then applied were then applied to the the 1/16 segment segment shell shell model.

model. The procedure procedure 4-4 4-4 04/29/82 04/29/82

• that performing this horizontal for performing described described (Subsection 4.2.3.2.5).

(Subs.ection horizontal 4.2.3.2.5).

horizontal seismic for the Combined horizontal seismic motions were conservatively absolutely absolutely adding the individual input motion.

seismic analysis chug Combined responses analysis is synchronization synchronization is the same as responses due to vertical and conservatively individual responses analysis analysis evaluated by evaluated responses to each direction motion. Results from the SSE analysis were used in cases involving involving seismic loads.

seismic loads.

and direction of by of in all load (2)

(2 ) Pressure Pressure Load Analysis Analysis Following a LOCA, LOCA, the vent system internal pressure pressure increases increases toto its its maximum value value within one second gradually decreases second and then gradually decreases (Figure 4.3).

4.3) The dynamic load factor (DLF) (DLF) for a single degree degree of freedom (SDOF) (SDOF) system subjsubjected ected to such a transient transient depends upon the ratio of the rise time of the load to the period of the SDOF system.

system.

Conservatively Conservati vely taking the rise time ,as as the vent clearing clearing time (0.2561 sec),

(0.2561 sec), a DLF of less than 1.1 was obtained obtained for all vent vent system periods.

periods. Therefore, Therefore, peak pressures were statically peak pressures statically applied to the 1/16 1/16 segment segment shell shell to evaluate evaluate vent systemsystem response to to pressure loads. Concentrated pressure loads. Concentrated loads were applied applied at the downcomer downcomer miter bends to miter bends to account account for pressures in in the downcomers.

downcomers.

The resulting resulting stresses from the pressure pressure load analysis are directly combined with stresses stresses induced induced by pool swell impact impact and drag on the. vent header on the assumption assumption that they occur

• occur simultaneously. The pressure load analysis simultaneously. analysis stress results for for subsequent times are scaled in subsequent in accordance accordance with the variations variations in in Figure 4.3 Figure 4.3 to determine determine stresses to be combined combined with other other LOCA LOCA event stres~

stress results.

results.

(3)

(3) Thermal Analysi~

Analysis temperatures shown The vent system temperatures shown inin Table 4.3 were were applied at at the appropriate appropriate nodal points of the shell. shell. These temperatures temperatures correspond to the saturated correspond saturated steamsteam and water water temperatures temperatures at the vent vent system system pressures occurring occurring 2.9 seconds after the vent vent clearing during a DBA.

clearing Temperatures at the edges of the collar DBA. Temperatures collar plate plate and Y-stiffeners, Y-stiffeners, support columns, columns, vent deflector, deflector, and downcomer tie-bars tie-bars were assumed assumed to be at 80'F, 80°F, the wetwell wetwell temperature temperature at the initiation of a DBA. DBA. A linear linear temperature temperature distribution was conservatively conservatively assumedassumed between the vent header header and the edges edges of the collar collar plate plate and Y-stiffener.

Y-stiffener.

Maximum stresses were Maximum stresses observed at the vent header miter joint and observed and in in the main vent/vent vent/vent header intersection.

intersection. These These stresses are due due to the constraint constraint of expansion by the collar vent header expansion collar plates Y-stiffeners.

and Y-stiffeners.

(4)

(4 ) Analysis Thrust Load Analysis Vent Vent system thrust loads loads (Figure 4.4) have a time variation

• similar to that, of the pressure similar pressure loads (Figure 4.3). 4.3). Therefore, Therefore, a static analysis of the vent system system for maximum thrust loads was was performed, performed assuming a DLF of 1.0. concentrated thrust 1.0. The concentrated thrust forces defined In in Subsection Subsection 2.4.2 were converted to pressure loads 4-5 4-5 04/29/82

• 4.2.3.2.2 4.2.3.2.2 along the outboard Vent outboard side of the vent header.

were applied at the downcomer downcomer miter bends.

Vent system stresses due to thrust loads were stresses for other tOCA-related than stresses Vent System System Dynamic Properties bends.

LOCA-related load cases.

Properties header.

cases.

Concentrated Concentrated loads typically typically loads lower lower The frequencies The frequencies and mode shapes of the vent system system were determined by were determined performing performing an eigensolution eigensolution of the 1/16 1/16 segment shell model using the computer program EDS-SNAP.

computer EDS-SNAP. The subspace subspace iteration iteration methodmethod was used .for for this eigensolution (Reference eigensolution (Reference 31). 31).

Eighteen natural natural frequencies below a 50 Hz cutoff were calculated calculated for the vent vent system.

system. The modes corresponding corresponding to the first first 13 13 frequencies frequencies are summarized in summarized Table 4.4.

in Table 4.4. The first The first seven seven modes modes are downcomer modes.

are downcomer modes. TheThe 88 th and the 114th through th th th 4 th through 18 1 8 th modes are are vent header modes.

header modes. The The 99 th,, 10l 0 th,, and and 13 th modes l3th modes are are vent deflector modes, vent header deflector modes, and the 11th iith and 12th 1 2 th modes are main main vent modes.

modes.

The first The first seven downcomer sway modes predicted seven downcomer predicted by the 1/16 1/16 segment segment shell shell model do not appropriately appropriately reflect the stiffness stiffness of the reinforced downcomer/vent downcomer /vent header intersection. intersection. Recognizing Recognizing that the swing mode of the downcomers downcomers is is similar similar to that of a spring-supported spring-supported pendulum, frequencies pendulum, frequencies representative representative of the reinforced reinforced intersection intersection were obtained obtained by mUltiplying multiplying the downcomer frequencies frequencies for the unreinforced unreinforced intersection intersection by a scale factor. This scale scale factor is is the square square root of the ratio of the stiffness of of the reinforced intersection the reinforced intersection to to that of the unreinforced unreinforced intersection.

intersection. The The stiffnesses stiffnesses of the reinforced reinforced and unreinforced intersections were determined unreinforced intersections determined using the using the detailed detailed downcomer/vent downcomer/vent header i~tersection model both with and header intersection

-without reinforcement.

-without reinforcement. Scale Scale factors factors were determined using both in-plane were determined in-plane and and out-of-plane out-of-plane unit loads applied applled at the bottom bottom of the down downcomer.

comer . The scale scale factors and downcomer downcomer sway mode frequencies frequencies obtainedobtained in in this manner are summarized summarized in in Table 4.5. 4.5.

4.2.3.2.3 4.2.3.2.3 Pool Swell Swell Dynamic Analysis Dynamic Analysis A dynamic A dynamic time history analysis analysis was performed on the 1/16 1/16 shell model to to evaluate evaluate the the vent system response to pool swell loads. loads. The time history analysis included analysi? included loadings loadings on all vent vent system components due to pool swell system components swell impact, impact, drag, froth impingement, impingement, and froth froth' fallback.

fallback. Figure 4.5 shows the sequence sequence and duration of pool swell loads used in in the analysis analysis of the vent vent system.

system. Pool fallback loads on the downcomer downcomer tiebarstiebars occur occur after the major major dynamic loads and were not expected expected to. contribute significantly to vent contribute significantly vent system response.

response. Pool swell impact impact and drag loads loads on the downcomer/vent downcomer/vent header reinforcing gussets and froth loads header reinforcing loads on the support columns are insignificant insignificant relative relative to other pool swell swell loads.

loads.

Vent header header impact impact and drag loads were applied applied as pressure pressure loads on the shell shell surface. All surface. All other other loadsloads were applied as concentrated concentrated forces. forces. ImpactImpact and drag loads loads on on the vacuum breaker the vacuum breaker valves valves were converted converted to equivalent equivalent forces and and moments at the penetration penetration and were applied directly to the were applied the shell model.model.

. A mode superposition using frequencies superposition analysis using the program analysis of the 1/16 segment shell EDS-SNAP.

program EDS-SNAP.

frequencies up to 50 Hz were used in The previously previously determined in the analysis.

shell model was performed determined mode shapes analysis. The analysis was started performed shapes and at the time of initial initial impact on the vent header header deflector deflector and was carried 4-6 4-6 04/29/82

. out for 0.65 sec .. to span the significant part of the pool swell transient.

The analysis required a time step analysis required step size of 0.00185 sec. and 350 time steps.

0.00185 sec.

out for 0.65 sec. to span the significant part of the pool swell transient.

A review of the resultingresulting response time histories indicated indicated that the peak steps.

vent vent system response was obtained during during the 0.65 0.65 sec.

sec. analysis duration. duration.

Figure 4.6 shows the displacement time history response at an Figure 4.6 shows the displacement time history response at an S/RVDL S/RVDL penetration penetration on the main vent. vent. Figure 4.7 shows shows an acceleration response response spectrum at the vacuum breaker penetration. Maximum compressive breaker penetration. compressive membrane stresses observed membrane stresses observed in in the vent system summarized in system are summarized in Table Table 4.6.

4.6.

4.2.3.2.4 4.2.3.2.4 Analysis CO Analysis As discussed discussed in in Subsection 2.4.4, Subsection 2.4.4, vent system system CO loads consist of of two components:

components: (1) (1) an oscillating oscillating internal pressure pressure used to determine determine hoophoop stresses stresses inin the main vent, vent, vent header, header, and downcomers, downcomers, and (2) lateral loads (2) lateral on the downcomers.

downcomers.

For determination determination of hoop stresses stresses in in the vent system system during CO, CO, the oscillatory oscillatory pressures statically applied and stresses pressures were statically stresses computed by hand. hand.

Static application of the loads is Static application is justifiable justifiable since the' the~ventvent system system modes modes expansion are involving radial expansion are close close to or over 1000 Hz. Hz. The frequencies frequencies of of the oscillating pressures pressures were all below below 50 Hz, Hz, resulting resulting in in a DLF of 1.0. 1.0.

calculated hoop stresses are 0.4 ksi for the main vent and 0.3 ksi for The calculated for the vent header.

header.

The CO lateral loads on the downcomer downcomer pairs pairs are consideredconsidered as the superposition superposition of an oscillating oscillating uniform pressure pressure in in both both downcomers downcomers and an oscillating oscillating pressure differentialdifferential between between the downcomers.

downcomers. The uniform uniform pressure component component results in in a net vertical vertical force on the vent header, header, while while the differential differential pressure pressure component imposes lateral lateral loads on the downcomers downcomers and the remainder remainder of the vent system. system. Table 4.7 summarizes summarizes these pressure pressure loads. From a review of the pressure loads: pressure magnitudes, magnitudes, DBA *CO *CO loads bounded bounded IBA lBA COCO conservatively used to estimate both DBA and lBA loads and were conservatively IBA responses.

responses.

Since the CO load definition for downcomer downcomer lateral loads loads specifies differential differential pressures pressures between downcomers down6omers in in a pair, it it is necessary to is necessary to determine determine which application application of pressure differential on the three downcomer, pressure differential pairs within a 1/16 segment of the vent system produces produces the maximum structural response. illustrates the eight possible response. Figure 4.8 illustrates possible configurations configurations of downcomer downcomer pressure pressure differential.

differential. The beam beam model representing representing a 1/16 section of the vent system was subjected subjected to all eight downcomer downcomer load configurations.

configurations. From aa review of these results, configuration 7 in resulis, configuration in Figure 4.8 Figure 4.8 identified as the controlling was identified controlling load case.case.

downcomer pressure The downcomer pressure loads were converted converted to equivalent equivalent concentrated concentrated loads wer~ applied to the 1/16 segment vent system and were system shell model. model. Loads on the downcomer tie bars were not considered significant downcomer significant and, therefore, were not and, therefore, not included included in in this analysis.

analysis. Load magnitudes were adjusted, adjusted, since higher since the higher downcomer sway frequencies downcomer frequencies were not includedincluded in in the shellshell model.

model. Loads Loads were were specified specified in in the frequency frequency domain with the frequencies frequencies selectedselected to maximize maximize the structural structural response.

response. A frequency frequency domain analysisanalysis .was was then performed using the 1/16 segment segment shell model to evaluate evaluate the overall overall vent system response to to the downcomer downcomer CO loads.loads.

• B Stresses Stresses in in the vent system due to chugging-induced chugging-induced stresses,stresses, justifying 4-7 4-7 the use of typically bounded CO are typically bounded by DBA CO results the for for 04/29/82

IBA CO response.

lEA Stresses at the downcomer/vent response. Stresses downcomer Ivent header intersection intersection due to to CO loads are discussed discussed in in Subsection Subsection 4.3.4.1.

4.3.4.1.

4.2.3.2.5 4.2.3.2.5 Chugging Analysis Chugging Analysis As wi withth the CO load case, case, chugging chugging loads consist of two components: components: (1) (1) an an oscillating internal pressure used for determining determining main vent, vent, vent header and downcomer stresses, downcomer stresses, and (2) (2) lateral lateral loads on the downcomers. downcomers. The chuggingchugging analysis methods and results for the downcomers are discussed discussed in in Subsections 4.3.3.1.4 and 4.3.3.2.4.

Subsections 4.3.3.1.4 4.3.3.2.4.

\

Oscillating Oscillating internal internal chugging chugging pressures in in the vent system occur occur at at sufficiently sufficiently frequencies that static analysis for these loads is low frequencies is justified. The calculated justified. calculated hoop stresses stresses are 0.4 ksi for the main vent and 0.3 ksi for the vent header. header.

Lateral loads on downcomers downcomers due to chugging chugging are assumed to be a result of of random pressure pressure fluctuations in in thedowncomer the downcomer legs. legs. Due to the random nature loads, the net lateral forces must be considered of the loads, considered to act in in any any direction on the downcomer downcomer leg. leg. It It isis possible possible that, that, at a given time during the chugging chugging event, event, a number number of downcomers downcomers will be loaded in in the samesame direction. This phenomenon is direction. is termed chug synchronization.

synchronization. As the number of of downcomers subjected downcomers subjected to chugging loads in in the same directiondirection increases, increases, the probability of these loads being the maximum possible magnitude decreases.

possible magnit'ude decreases.

This behavior behavior is is shown in in Figure 4.9. 4.9. It It can be seen that, that, for a given probability probability of occurrence, occurrence, as the number of downcomers chugging chugging in in synchronization increases, the forces on each synchronization increases, each of those downcomers downcomers decrease.

decrease.

• Therefore, two separate Therefore, the downcomer/vent Subsection Subsection 4.3.3.1.4.

separate situations net load on the entire downcomer/vent situations must be considered:

the maximum load on aa single downcomer, and 2) entire vent system. The first header intersection intersection 4.3.3.1.4. The second situation is of the vent system system components as described described below.

considered: 1) first situation situation is stresses and is used to evaluate below.

1) one situation with

2) one situation with the maximum is maximum is used to evaluate discussed is discussed evaluate the remainder remainder in in Acceptance Criteria recommends The NRC Acceptance recommends aa non-exceedance probability of non-exceedance probability of 10-4 10- 4 determining for determining the maximum maximum force per downcomer. downcomer. This non-exceedance non-exceedance probability results in' probability in , a maximum resultant resultant for:ce' force on each each downcomer of of 0.6 kips when all 80 downcomers downcomers chug synchronously.

synchronous'ly. This 0.6 kip force is is based upon FSTF data and is is adjusted adjusted using the procedure procedure in in Reference Reference 27 to to equivalent static plant unique loads for CNS.

develop equivalent CNS.

Accordingly, Accordingly, the forces acting in in the plane plane of a downcomer pair were were multiplied multiplied by the factor 7.55, 7.55, and the forces acting normal normal to the plane of a downcomer pair were multiplied downcomer multiplied by the factor 1.66. 1.66. For forces acting in other in other directions, directions, the load was divided into an in-plane in-plane and an out-of-planeout-of-plane component component and then scaled by the factors ,mentioned mentioned above.

above. Loads on the tiebars tiebars were were not considered significant for this analysis.

considered significant analysis.

The chug synchronization synchronization load is is asymmetric asymmetric and, and cannot cannot be directly directly considered considered using a 1/16 segment model of the vent vent system. To allow use of the shell shell model for Code evaluation, evaluation, scale factors were developed developed to account for the effect effect of the boundary conditions conditions on the 1/16 segment model. These segment model. These scale factors were were determined determined by applying applying the actual actual chug synchronization synchronization loads loads toto

.

• 18000 segment a 180 seg~ent beam beam model of the vent system (Figure 4.10). 4.10) . A beam model model of a 1/16 segment with the same 1/16 segment same boundary conditionsconditions as the shell shell model was then developed.

developed.

4-8 4-8 04/29/82

From the 180 18000 segment model model results, it it was was observed that that the net net load resisted by each of resisted of the main vents was not the same. same. TheThe loads loads applied applied to the 1/16 segment beam model were therefore further 1/16 further amplified by aa factor of of 1.87, 1.87, so that the main vent modeled in so in the 1/16 segment model carried the the appropriate resultant loads (Figure (Figure 4.10).

4.10).

The 1/16 The 1/16 segment segment beam model was then analyze,d analyzed for for these scaled scaled loads.

loads. The The differences differences in in the beam forcesforces and moments between the 180 180' segment beam model 0

model and the 1/16 1/16 segment beam model are then the effects of the 1/16 segment segment boundary conditions boundary conditions on the actual response. response. The ratio of the 180 180'0 segment segment model results to the 1/16 segment results are the scaling factors which vary from component component to component.

component. The The loads applied applied to the 1/16 1/16 segment segment shellshell model are also the same model same loads applied to the 1/16'segment 1/16'segment beam model. model.

Resulting stresses from the shell model are then modified by the scale scale factors to obtain the the, final vent system stresses. stresses.

Chug synchronization synchronization stress results are high in in many local regions along the vent header.

header. Treatment of these high stresses is is discussed in in Subsection 4.2.4.2.

Subsection 4.2.4.2.

4.2.3.2.6 4.2.3.2.6 S/RV Discharge Discharge Load Analysis Analysis The vent system is is loaded at the downcomer ends due to T-quencher T-quencher bubble drag loads following loads following an S/RV discharge. discharge. A review of the time histories of these loads (Figure 4.11),

loads 4.11), indicates that the forcing function can be approximated by a simple harmonic function. An equivalent static load on the downcomers downcomers was then was then determined determined by calculating calculating a DLF based on the downcomer downcomer sway mode mode frequencies and scaling the maximum applied frequencies applied load by this DLF. DLF. Using the load magnitudes and magnitudes frequency ranges and frequency ranges in in Table Table 4.8, 4.8, the equivalent equivalent static,static. loads on loads on the the downcomers downcomers were obtained obtained for three S/RV discharge discharge load cases. cases. These are summarized summarized in in Table 4.9. 4.9.

S/RV discharge bubble S/RV discharge bubble dragdrag loads loads are defined defined for the downcomersdowncomers in in the vent vent bay. Since bay. Since the T-quencher discharge T-quencher discharge device is is located in in this bay, loads on on the non-vent bay downcomers will be lower. lower. Because Because the loads loads are proportional proportional to the square of the distance between the S/RV discharge discharge bubble bubble and the downcomer, reduced loads were applied downcomer, applied to the non-vent non-vent bay downcomers.

downcomers.

Equivalent Equivalent static static analyses analyses of the vent vent system system for T-quencher T-quencher drag drag loads loads on on the downcomers downcomers were performed performed using the 1/16 segment shell model.

segment shell model. Drag Drag loads on the on the tie-bars tie-bars werewere not considered considered in in thethe analysis.

analysis. WhereWhere asymmetric asymmetric loading of of the vent vent system occurred occurred due to a single single valve discharge, discharge, the 180 180'0 segment segment beam beam model was used to develop develop scale scale factors to account for the asymmetry. asymmetry.

The The development development of these scale factors is is similar to the procedure procedure described in in Subsection Subsection 4.2.3.2.5 4.2.3.2.5 for chug chug synchronization synchronization loads. loads.

4.2.3.3 4.2.3.3 Vent Header Header and Main Vent Penetrations Penetrations Local stresses at Local stresses at vent vent system system penetrations penetrations were were evaluated evaluated using the Bijlaard method method for determining determining stresses stresses at at rectangular rectangular and circular circular attachments attachments on on cylindrical cylindrical shellsshells (Reference 33). 33) . The penetrations penetrations analyzed analyzed with this this method method were were the the S/RVDL S/RVDL penetrations penetrations on the main main vent,vent, thethe drywell-to-wetwell drywell-to-wetwell vacuum vacuum bre~ker and breaker and ventvent drain line line penetrations penetrations on the tne main main vent/vent vent/vent headerheader intersection, intersection, and and the the main vent penetration penetration on on the the drywell drywell liner liner

~ (Subsection 4.2.3.4).

(Subsection 4.2.3.4).

4-9 4-9 04/29/82

(1)

(1) S/RVDL Penetration Penetration Forces and moments at the main vent S/RVDL penetrations were were obtained from from the S/RVDL S/RVDL piping analyses.analyses. These These reactions included the effects of thrust loads loads on on the piping, wetwell wetwell hydrodynamic loads on the S/RVDLs, S/RVDLs, and main vent anchor motions. motions.

(2)

(2) Vacuum Breaker Vacuum Breaker Penetration For evaluation evaluation of the drywell-to-wetwell drywell-to-wetwell vacuum breaker breaker penetration, the vacuum breaker valve body reactions at the main penetration, vent/vent header intersectionintersection shell were determined for the governing case case of pool swell swell loads.

loads. The pool swell acceleration response spectra at the penetration,penetration, shown in shown in 4.7, Figure 4.7, includes reactions includes reactions at at the shell due to impact and drag loads on the vacuum breaker valve body. body.

The natural frequency of the vacuum breaker valve was estimated and the and corresponding spectral the corresponding spectral acceleration acceleration was used to calculatecalculate forces and forces and moments acting on the penetration. penetration. A A shear force of of 25 kips and a bending bending moment of 490 kip-in. were predicted predicted at at each penetration penetration due to pool swell loads. loads. Stresses in in the main main vent/vent header vent/vent header intersection intersection shell were calculated calculated by modeling the reinforcing reinforcing pads as rectangular rectangular attachments attachments and using the Bijlaard Bij laard procedure.

procedure. Maximum membrane membrane plus bending stress intensity intensity due to pool swell was 53 ksi. ksi.

(3)

(3) Vent Drain Line Penetration The vent The drain line vent drain line penetration penetration loads were were estimated estimated from the analysis of the drain line2 (Subsection drain line) (Subsection 4.4.3).

4.4.3).

In all penetration In all penetration analyses, analyses, vent system stresses determined determined fromfrom the previously described the previously described vent system system analyses were added to the local stresses prior to performing local stresses performing Code evaluations.

evaluations.

4.2.3.4 4.2.3.4 Drywell Penetration Drywell Penetration Local stresses Local stresses on on the main vent penetration the main penetration at the the drywell drywell were were determined determined using reactions using obtained directly reactions obtained directly from the vent vent system system analyses, analyses, using results results from from both both the 1/16 segment shell the 1/16 shell model and the the 1800 180 0 segment segment beam beam model.

model. TheThe Bijlaard method for Bij laard method for circular attachments on cylindrical circular attachments cylindrical shells shells (Reference (Reference 33) 33) was was used to evaluate evaluate the local stresses.

local stresses.

4.2.3.5 4.2.3.5 Main Vent Bellows Bellows Main Main vent bellows stresses vent bellows stresses werewere determined determined from the maximum wetwell wetwell pressure pressure using using the the procedure procedure in in Reference 35.

Reference 35. This procedure procedure calculates calculates circumferential circumferential and and meridional meridional membrane membrane stresses stresses and and meridional meridional bending bending stresses stresses due due toto design design pressures.

pressures. The maximummaximum membrane membrane stress stress inin the bellows bellows for for the the peak peak wetwell wetwell pressure pressure of 29 psi psi is is 4.7 ksi.

ksi.

Stresses in Stresses in the the bellows bellows due due to to the the relative relative displacements displacements of of thethe torus torus and and

. vent vent system system were also also calculated calculated using the procedure

• procedure in in Reference Reference 35.35. These These stresses stresses are are used used only for calculating calculating fatigue usage usage of the the bellows.

bellows. TheThe maximum maximum relative relative axial displacement displacement is is 0.35 0.35 in.

in. primarily primarily duedue to the the vent vent system system thermal thermal expansion.

expansion.

4-10 4-10 04/29/82 04/29/82

• 4 4.2.4 Code Code Evaluation This subsection subsection summarizes the Code evaluations vent structural Program structural components components required Structural Acceptance Program Structural combinations and corresponding combinations main main vent components Acceptance CriteriaCriteria evaluations of the vent header and main required to demonstrate demonstrate compliance (Reference compliance with the Mark (Reference 19)19).

corresponding service level limits for the vent header and components are summarized summarized in in Table 4.1.4.1.

The design design load main Mark I In reviewing the shell stresses, In reviewing stresses, distinction is distinction is made between general shell between general shell membrane membrane and bending stresses stresses and local local shell stresses near discontinuitiesdiscontinuities penetrations. Also, and penetrations. Also, checks checks for shell shell buckling buckling and fatigue are are discussed.

The primary prima.ry membrane (Pm) (Pm) and primary membrane plus primary bending bending (PL (P L ++ PPb) b)

stress stress intensities intensities

)

for design load combinations combinations were calculated calculated by combining combining the stress intensities from the vent system shell model analyses described stress intensities described in in Subsection Subsection 4.2.3. intensities 4.2.3. Stress interisi ties from separate separate load cases were were added by absolute summation in absolute in these combinations.

combinations. This procedure procedure is is more more conservative than the algebraic algebraic addition of stress components, components, followed followed by the computation computation of stress intensities intensities from combined stress components.

components. Also, Also,' stress intensities from several several dynamic load combinations combinations were conservatively conservatively combined combined using absolute summation. summation. The combined combined stresses stresses for the vent vent header header and main vent were evaluated evaluated away from from, any local local discontinuities, discontinuities, such as as penetrations penetrations or reinforcing reinforcing collars.

collars.

The Code compliance compliance checks indicate indicate that all vent header header and main vent vent components satisfysatisfy the requirements requirements of the Mark I Program Program for the design load

• combinations combinations. .

S 4.2.4.1 4.2.4.1 Main VentVent The maximum combinedcombined stress in in the main main vent occurs at bottom dead center of of the 1/4"-thick 1/4"-thick sectionsection near near the bellows location. location. The controlling controlling Level Level B Service Load Service Load case is is pool swell plus OBE, OBE, which produces a Pm of 9.4 ksi (49%

which produces (49%

of allowable) allowable) and a PL PL + PbPb of 10 ksi (34% allowable) . For the Level C (34% of allowable).

Service load case, Service case, where stressesstresses due to S/RV discharge drag loads are combined combined with pool swell swell and SSE loads, loads, a Pm P,,of 10.7 ksi (32% of allowable) and a P PLL + P Pbb of i1.3 11.3 ksi (22% of allowable) are observed. observed. Thermal Thermal stresses stresses in in the main vent are low, and the secondary secondary stresses stresses are therefore therefore less than 20%20%

of allowable.

allowable.

4.2.4.2 4.2.4.2 Vent Header Header The vent header stress intensities away from the downcomer intersections are downcomer intersections highest at the top dead center of the header at the midpoint of the non-vent non-vent bay span.

span. For the bounding load case case of chugging plus S/RV discharge discharge plus plus OBE OBE loads, loads, the Pm is 12.5 ksi (65% of allowable) and the P is 12.5 PLL + PbPb is is 20.8 ksi (72% (72%

of allowable).

allowable). Both are within Level B Service allowables.

Service Limit allowables.

Local stresses near the vent header miter miter joint joint are high, high, due.due. to the constraint of the collar constraint collar plate) platesin in this region.

region. For the bounding load load case case of of chug synchronization synchronization and S/RV discharge, discharge, the combined combined stresses were.slightly were slightly above allowable.

allowable. Maximum Maximum PLL P is is 30.3 ksi (104%), ,

(104%) and and P PLL + PPbb + Q is is 69.1 69.1 ksi (102%).

(102%). Numerous conservatisms conservatisms are included included in in these numbers.

numbers. The The

• collar collar plate temperature distribution is is assumed to be linear, decreasing decreasing to S wetwell somewhat somewhat plate temperature wetwell temperature temperature at the outer edge.

artificially artificially constricts constricts edge. This temperature vent header distribution effect temperature distribution expansion.

expansion. The effect stress to intensities intensi ties due to S/RV discha'rge discharge and chug synchronization synchronization are are combined using 4-11 04/29/82

• absolute absolute sum, associated associated wi sum, with these observations, which is is observations, the reported Vent header expansion of the collar.

of the allowable allowable value.

value.

conservative conservative th chug synchronization reported miter collar plate stresses header collar considering considering the low probabilities synchronization loads (Subsection (Subsection 4.2.3.2.5).

miter joint stress levels are acceptable.

stresses are induced induced by the differential collar. These stresses are not critical critical and reach probabilities 4.2.3.2.5). Based on acceptable.

differential thermal thermal reach only 50%

on 50%

4.2.4.3 Main Vent/Vent Vent/Vent Header Intersection The highest highest local local stresses in in this area are in in the vicinity of the Y-shaped Y-shaped reinforcing collar and along the reducer reinforcing section. Local membrane stresses reducer section. stresses due due to chugging chugging and S!RV S/RV discharge discharge loads in in these two areas areas reach 19.1 ksi (66%

of allowable) and 27.6 27.6 ksi (95% (95% of allowable),

allowable), respectively. Primary plus respectively.

secondary secondary bending approximately 50%

bending stresses are approximately 50% of allowable.

allowable. Stresses in in the Y-shaped Y-shaped collar differential thermal expansion collar due to differential expansion are are also within allowables.

allowables.

4.2.4.4 4.2.4.4 Penetrations Vent Header and Main Vent Penetrations 4.2.4.4.1 4.2.4.4.1 S/RVDL Penetration Evaluating the reactions Evaluating reactions at the main vent S/RVDL penetrations penetrations required the combination combination of reactions reactions from the dr"ywell drywell and wetwell portions of the S/RVDL.

wetwellportions S/RVDL.

These reactions reactions were combined by absolute absolute summation, summation, except except for cases where cases where directions could be clearly clearly combined algebraically algebraically (e.g. thermal thermal anchor anchor motions). The eighteight drywell drywell S/RVDL configurations configurations were reviewed reviewed to determine

• motions). determine reactions.

maximum reactions. These reactions were combined with the appropriate appropriate reactions reactions from the wetwell wetwell portion portion of the line. line. Typically, Typically, shorter the shorter wetwell S/RVDL S/RVDL lines produced the bounding reactions. reactions. The short wetwell wetwell lineline reactions reactions were combined combined only with the reaction from the four drywell lines which which connect to the short lines. lines.

Maximum combined local stresses are due to the S/RV discharge Maximum combined discharge thrust thrust reactions reactions during during an IBA/SBA event. These stresses were IBA/ SBA event. were combined combined with the general membrane and bending general bending stresses in in the main vent. vent. These maximummaximum combined local stresses stresses are below allowableallowable limits.

limits.

4.2.4.4.2 4.2.4.4.2 Vacuum Vacuum Breaker Breaker Penetration Pool swell impact impact and drag loads on the vacuum vacuum breaker breaker body contributed to body contributed to nearly nearly 90%90% of the stress at the vent header header penetration.

penetration. The remaining stresses are due to seismic stresses seismic and dead weight reactions reactions at the vent header. header.

After reinforcement reinforcement of the intersection, intersection, maximum P P,L is is 21.4 ksi (57% of of allowable) and PL PL ++ Ph Pb ++ Q is is 63.7 ksi (94% (94% of allowable) at a location location on the vent header nearnear the edge edge of the reinforcing reinforcing pad. pad.

4.2.4.4.3 4.2.4.4.3 Vent Drain Line Penetration Pool swell and S/RV discharge discharge loads on the main vent drain drain line produce produce maximum stresses in maximum in the header at the main vent/vent vent/vent header header intersection.

intersection.

When combined with generalgeneral membrane and bending stresses stresses in in the header for for these cases, the maximum P these load cases, is 17.1 PLL is 17.1 ksi (45% (45% of allowable) and PL PL ++ PPbb + Q Q is is 32.0 32.0 ksi (47% of allowable) allowable). .

• 4-12 04/29/82

4.2.4.5 Drywell Penetration Maximum drywell drywell shell stresses stresses at the main vent vent penetration penetration are caused by reactions from reactions from thethe main main vent vent due to pool swell swell and S/RV discharge discharge loads. The loads. The membrane plus bending combined membrane bending stress intensity is is 28 ksi (41%(41% of allowable) in the in the reinforcing reinforcing pad pad around around the intersection, intersection, and and 12 ksi J18% (18% of allowable) in the drywell in drywell shell away from reinforcement.reinforcement.

4.2.4.6 Main Vent Beilows Bellows Bellows stresses Bellows stresses were determined for relative relative torus-to-vent system combined combined displacements at displacements at the torus penetration, penetration, and for wetwell internal internal pressure.

Stresses due to relative displacements displacements are used only for fatigue evaluations evaluations (Subsection 4.2.4.7).

(Subsection 4.2.4.7). The wetwell peak pressure results in in aa circumferential circumferential membrane stress membrane stress of of 4.7 4.7 ksi and aa meridiona~

meridional bending stress stress of of 7.3 ksi. TheseThese stresses are 28%

stresses 28% and 44% 44% of the allowable for the bellows material. material.

4.2.4.7 Assessment Shell Buckling Assessment Compressive membrane stresses in Compressive in the vent system shell components were checked against checked against ASME ASME Code limits for buckling.

buckling. The maximum compressivecompressive stresses were stresses were compared compared with allowables for both hoop and axial compressive compressive stress.

stress. The The allowables allowables were were determined determined using the procedure procedure in in Subsection NE-3133 Subsection NE-3133 of of the the ASME ASME Code.

Code. In determining In determining the allowables, allowables, the presence presence of of shell shell reinforcement reinforcement at at thethe downcomer/vent downcomer/vent header intersection and at the collar plate at the collar plate near near the miter joint was accounted accounted for in in reducing reducing the effective span of the vent header effective header. .

• The compressive The compressive stresses localized localized stresses were regions regions stresses were determined in not, not, however, In In addition, which which have stresses are determined (near the (near general membrane however, general addition, these these stresses have aa peak in generally within allowables except at very are generally the downcomer/vent excess downcomer/vent of buckling stresses are induced primarily peak load durationduration of only 5 msec.

header header intersection) allowables.

intersection) buckling allowables. These stresses are membrane stresses for which the allowables allowables are defined.

chugging lateral primarily by chugging msec. As determined in where where defined.

lateral loads in the evaluation of evaluation of torus torus shell buckling buckling under dynamic dynamic loads (Reference (Reference 29),29), such a short short duration duration of compressive stress does not allow gross shell deformations of compressive deformations.

(associated with buckling (associated with buckling at at thethe static buckling stress limits) to occur.

static buckling occur. ForFor these reasons, this local exceedence of static these reasons, this local exceedence of static buckling allowables is buckling allowables is not not considered considered aa design design deficiency deficiency and and the current vent header configuration the current configuration is is acceptable with regard to shell acceptable buckling.

shell buckling.

4.2.4.8 4.2.4.8 Fatigue Fatigue Evaluation Vent Vent system system shellshell components components were checked checked against against fatigue as required required by by ASME Code rules ASME Coqe rules for for MC MC Components.

Components. Only the critical critical stress stress regions regions werewere evaluated for evaluated for fatigue. These These regions were generally generally areas of high local local stresses around stresses around penetrations penetrations or the miter miter joint.

joint. Stress concentration factors Stress concentration factors were developed to were developed calculate peak to calculate peak stresses stresses from the primary primary plus secondary secondary stress ranges determined stress ranges determined in in the analyses.

analyses. The fatigue design design basis basis is is described in Subsection described in Subsection 2.7.7. 2.7.7.

4.2.4.8.1 4.2.4.8.1 Main Main Vent/Vent Vent/Vent HeaderHeader Intersection Fatigue Fatigue usageusage at at thethe connection connection of of the vent headerheader and main main vent shellsshells around the Y-collar around the Y-collar is 0.15. is 0.15. Since pool pool swell swell loads are not considered considered in in evaluating evaluating fatigue (Reference 12), 12), thethe vacuum breaker/vent breaker/vent header header penetration penetration has has insignificant insignificant fatigue fatigue usage.

usage.

4-13 04/29/82 04/29/82

4.2.4.8.2 Vent Header Miter Joint Vent Joint Local stresses stresses in in the vicinity of the vent header miter miter joint and reinforcing collar produce a fatigue usage of 0.34.

fatigue 0.34. Chugging loads account for for 83%

83% of of this total usage.

4.2.4.8.3 4.2.4.8.3 Main Vent BellowsBellows Reference 35 Reference details the procedureprocedure used in in evaluating evaluating expansion bellows for for fatigue. The fatigue. main vent bellows has a very low fatigue usage. The cumulative cumulative usage for all stress cycles is stress is less than 0.01.0.01.

4.2.4.8.4 4.2.4.8.4 Main Vent S/RVDL S/RVDL Penetration In evaluating fatigue usage at the main vent S/RVDL penetration, In penetration, the fatigue assumes 250 S/RV actuations during normal plant operation.

design basis assumes operation. This This assumption is assumption is justifiable justifiable since the design number number of 500 S/RV actuationsactuations is is based on based on extrapolating extrapolating the the total total number of actuations actuations for all eight valves valves atat CNS. The number of actuations CNS. actuations by a particular particular S/RV, S/RV isis substantially substantially lower. lower.

Plant operating data show that each S/RV has approximately Plant operating approximately the same number of of actuations to actuations to date. date. For the S/RVDL penetration, penetration, the primary contributor to to fatigue usage fatigue usage is is from from stresses stresses induced by reactions of the S/RVDL. S/RVDL. Therefore, Therefore, the the design design basisbasis of of 250250 actuations actuations still still represents aa conservative represents conservative estimate estimate of the of the total total number number of of actuations actuations by anyoneany one S/RV for the 250 S/RV actuations actuations assumed, the assumed, the fatigue fatigue usageusage at the penetration penetration is is below 1.0.

1.0. Three-quarters Three-quarters of of this usage comes from S/RV discharge-related discharge-related load cases. cases.

• 4.3 This DOWNCOMERS AND TIEBARS DOWNCOMERS This subsection subsection discusses downcomer/vent downcomer/vent tiebars.

tiebars.

4.3.1 Design header TIEBARS discusses the results of the structural header intersection, intersection, Combinations Design Load Combinations structural evaluations the downcomers, downcomers, evaluations of the and the downcomer downcomer The The 2727 design design loadload combinations combinations for the downcomer/vent downcomer/vent header intersection, intersection, downcomers, and tiebar downcomers, and tiebar are are shown shown in in Table 3.1 of Section Section 3.3. Also indicated indicated in in Table 3.1 are the ASME Table 3.1 are the ASME Code Service Code Service Level assignments assignments for each each load combination.

combination. Of these 27 load combinations, combinations, potentially potentially bounding load combinations are shown combinations shown in in Table Table 4.10.

4.10. Actual downcomer and tiebar stresses stresses I

were compared compared against allowablesallowables for these these load combinations.

combinations.

4.3.2 Design Allowables Design Allowables The The ASME ASME Code Code design design classifications classifications for the downcomer/vent downcomer/vent header header intersection, intersection, the the downcomers downcomers and the downcomer downcomer tiebarstiebars are provided provided in in this this subsection.

subsection.

4.3.2.1 4.3.2.1 Downcomer/Vent Header Downcomer/Vent Header Intersection The The downcomer/vent downcomer/vent header header intersection intersection is is evaluated evaluated against against the stress stress intensity intensity allowables allowables shown shown in in Table Table 4.2.

4.2. In In accordance accordance with the .procedureprocedure in in Reference Reference 19, 19, allowable allowable stresses stresses for primaryprimary local local membrane membrane (PL)

(P L ) and primary primary membrane membrane plusplus primary primary bending (Pi, +

+ Pb)

Pb ) stress stress intensities

• bending (Pj intensities areare increased increased by by 30%

30% for LOCA-related LOCA-related loadings.

loadings .

4-14 04/29/82 04/29/82

• 4.3.2.2 Downcomers Downcomers The downcomers downcomers are classified allowables are taken allowables stress intensity allowables classified by the ASME Code as Class MC Components.

taken from Subsection NE-3000 of the Code.

values against which the downcomers intensity values allowables are based upon material material allowables downcomers are allowables for SA-516 Components. Design Code. Table 4.2 shows the are evaluated.

SA-516 ~rade These evaluated. These Grade 70 steel at a design temperature temperature of 289'F.289°F. Use Us.e of increased increased allowables allowables .duedue to local impact impact pressures pressures was not required, required, as Level A/B Service Service Limits were satisfied for for pool swell loads.

loads.

4.3.2.3 4.3.2.3 Downcomer Downcomer Tiebar Tiebar downcomer The downcomer tiebar is classified as a linear is classified linear component component and design allowables are taken from Subsection allowables Subsection NF-3300 NF-3300 of the Code. Code. Design stress stress intensity allowables intensity allowables for the downcomer downcomer tiebars tiebars are shown in in Table 4.11. These 4.11. These allowables are based upon material allowables allowables for SA-53, material allowables SA-53, Grade Grade B steel at a temperature of 200'F design temperature (corresponding to the maximum 200°F (corresponding suppression pool maximum suppression pool temperat\.1re) .

temperature).

4.3.3 4.3.3 Analysis Analysis Methods and ResultsResults subsection describes 'the This subsection analyses and key results of the downcomer

,the analyses downcomer evaluations. downcomer structural response evaluations. The downcomer response to the loads describeddescribed inin Section Section 2 is is evaluated evaluated to demonstrate compliance with demonstrate compliance the Structural Structural Acceptance Criteria.

Acceptance Criteria. This response was determined determined through through the use of several several analytical techniques described analytical described in in this subsection subsection which were selected selected based upon the nature nature of the loads and the expected response.

expected response.

4.3.3.1 4.3.3.1 Downcomer/Vent Header Intersection Downcomer/Vent Header The finite element element model developed developed to evaluate evaluate the downcomer/vent downcomer/vent header header intersection is intersection is described described in in this subsection, subsection, as well as the evaluations evaluations for for the bounding bounding LOCA and S/RV discharge loads. loads.

4.3.3.1.1 4.3.3.1.1 Mathematical Model Mathematical.Model I geometric complexity The geometric complexity of the downcomer/vent downcomer/vent header intersection region header intersection after reinforcement reinforcement by the gusset plate arrangement arrangement (Figure 4.12) required a more detailed model than the 1/16 segment segment shell shell model to predict predict the local local stresses.

stresses. This level of )detail ,detail inin the shell model would have substantially substantially increased increased the model size and made the shell model impractically impractically large for use use in analyses. Therefore, in dynamic analyses. Therefore, a separate, detailed detailed model of this region was was developed to qualify developed qualify the intersection.

intersection. The model was constructedconstructed using plate elements program EDSGAP.

elements and the program EDSGAP.

The gusset plate reinforcement reinforcement and weldingwelding pads on the vent header header and and downcomer are included in downcomer in the detailed model shown in in Figure 4.13.

4.13. The model model is symmetric about the vertical is symmetric vertical plane containing containing the vent headerheader centerline.

centerline.

Symmetric or anti-symmetric Symmetric anti-symmetric boundary boundary conditions conditions are used at the nodes on the vertical plane, vertical plane, depending upon the load case case being considered.

considered. The nodes at at the boundaries boundaries of the planes normal to the vent header header are fixed. The length of the model along the vent vent header header was selected selected so that the end fixity would would not affect affect the intersection intersection stresses.

stresses.

.

• Static Static analyses analyses of this model were performed the intersection performed to calculate intersection for unit loads at the downcomer 4-15 calculate local stresses in local stresses downcomer tips (three forces and in 04/29/82

three moments) . These results are scaled three moments). scaled by actual actual downcomer downcomer loads either either specified in specified in the load definitions definitions or predicted predicted by the 1/16 segment shell shell model to calculate calculate intersection stresses for actual intersection actual load cases.

load cases. This This procedure procedure allows predictionprediction of local stresses stresses at the intersection, intersection, without without substantial substantial refinement refinement of the detailed 1/16 1/16 segment shellshell model.

model.

Maximum Maximum stresses in in the intersection intersection were summarizedsummarized for unit loads in in directions. Table 4.12 summarizes six directions. summarizes the unit load analysis results. results. The The highest stresses occurred highest stresses occurred on the vent header header between the gusset welding welding pads in circumferential and longitudinal in the cir2umferential longitudinal directions:

directions.

These unit load analysis results results were scaled by the actual dynamic dynamic loads resulting from the previously previously performed vent system analyses. analyses. Table 4.13 summarizes summarizes these loads for load cases cases resulting in in downcomer lateral loads.

lateral loads.

The tabulated tabulated loads are the loads on one downcomer, downcomer, and do not include include tie-b~r tie-bar loads.

loads. For chugging, chugging, two cases of lateral loads are considered: (1) considered: (1) the load is is acting in in the planeplane of the downcomer downcomer pair, pair, and (2) the load (2) load is is acting acting normal to the plane of the downcomer down comer pair.

pair. These loads were were determined determined using the procedure procedure in in Reference Reference 27. 27.

The local stresses due to'pressure, to pressure, thrust,thrust, gravity, gravity, and seismic loads were were taken taken to be the same same as the stressesstresses on the "clean" vent header (2 downcomer downcomer diameters away from intersection).

diameters intersection). During vent system system heat-up, heat-up, it it isis assumed assumed that the gusset plates around the intersection intersection have the same*! same' temperature temperature as the vent header downcomers, thereby producing header and downcomers, producing the same thermal thermal stresses as predicted predicted for the clean vent header. header.

.

• 4.3.3.1.2 4.3.3.1.2 downcomer Pool Swell Analysis Table 4.13 includes Analysis includes the equivalent static static design loads on a single downcomer resulting from pool swell impact and drag on the down design load was derived by applying the impact and drag loads on the inclined portion of the downcomer.

model described above downcomer. The detailed above was then analyzed detailed downcomer downcomer/vent/vent header analyzed for this design pool swell single untied downcomer.

comer . The header intersection load.

swell load.

The 4.3.3.1.3 CO Lateral Lateral LoadsLoads

.CO lateral lateral loads on the downcomers downcomers are produced produced by uneven uneven pressure oscillations oscillations in in the two downcomers downcomers in in a pair pair as described described in in Subsection Subsection 4.2.3.2.4.

4.2.3.2.4. The maximum net downcomer downcomer lateral lateral load due to CO was was 4.3 kips in in-plane direction.

in the in-plane direction. The maximum maximum vertical vertical load on a downcomer downcomer pair pair was 0.7 kips. kips. Since these loads loads were bounded chugging lateral bounded by the chugging lateral and vertical loads no further evaluation evaluation was required.

required.

4.3.3.1.4 4.3.3.1.4 Chugging Lateral Lateral LoadsLoads Two separate conditions were evaluated separate design conditions evaluated for chugging lateral lateral loads on on the downcomers:

downcomers: (1) (1) the maximum chug design load occurs in in the critical critical direction on a single down direction downcomer, comer , and (2) (2) the maximum probable probable net load occurs occurs on the entire vent system. system. The first first situation situation is is used to evaluateevaluate the downcomer/vent header downcomer/vent header intersection intersection as discussed discussed in in subsection.

this subsection. The The second situation is second situation is evaluate the remainder used to evaluate remainder of the vent system system components as discussed in components in Subsection 4.2.3.2.5.

4.2.3.2.5.

.

• As shown in 9.7 kips.

intersection in Table 4.13, kips. This load is intersection as discussed 4.13, the maximum is used in discussed in downcomer lateral maximum downcomer in the qualification lateral load due to chugging is qualification of the downcomer/vent in Subsection 4.3.4.1.

4-16 4.3.4.1.

downcomer/vent header is header 04/29/82

• 4.3 .3 .1.5 4.3.3.1.5 S/RV discharge downcomer/vent the downcomer previously Discharqe Drag S/RV Discharg~

discharge bubble bubble drag loads

/vent header previously discussed in Draq Loads Loads loads on the downcomer downcomer ends result In intersection. The application header intersection.

in Subsection 4.2.3.2.6.

4.2.3.2.6.

application of these in stresses in these loads was in was As shown in in Table 4.13, 4.13, the maximum verticalvertical downcomer S/RV dischargedischarge lateral lateral load load isis 2.2 kips and the maximum out-of-planeout-of-plane load is is 7.5 kips.

kips. These loads were converted to stresses were converted stresses in in the downcomer downcomer/vent

/vent header header intersection intersection using the scale factors for the detailed detailed downcomer/vent downcomer /vent header intersection model header, intersection model previously previously discussed in in Subsection 4.3.3.1.1.

4.3.3.1.1.

4.3.3.2 4.3.3.2 Downcomers Downcomers The mathematical mathematical model and analysis procedures procedures used to qualify downcomers qualify the downcomers for pool swell loads and internal internal pressure loads due to CO and chugging chugging are described described in subsection.

in this subsection.

4.3.3.2.1 Mathematical Model Mathematical Model For evaluation evaluation of the down downcomer stresses due to downcomer comer stresses lateral loads, downcomer lateral loads, the detailed downcomer/vent header intersection detailed downcomer/vent intersection model was utilized, as previously previously described described in in Subsection 4.3.3.1.1.

4.3.3.1.1. Hoop stresses stresses in in the downcomers downcomers resulting from internal internal pressures pressures during the CO and chugging phases were computed computed by hand calculations.

calculations.

• 4.3.3.2.2 An equivalent 4.3.3.2.3 Pool Swell Analysis Analysis CO Analysis Analysis equivalent static analysis of the downcomer swell drag loads shown in in Table 4.13.

The maximum membrane plus bending downcomer arm was performed 4.13. A DLF of two was used in bending stress intensity was 17.5 performed for the pool pool in this analysis.

17.5 ksi.

ksi.

analysis.

The CO internal pressure pressure loads for the downcomers are defined as oscillating internal pressure loads as shown in in Table 4.14. determination of hoop 4.14. For determination hoop stresses stresses in in the downcomers during tC, 'CO, the oscillatory oscillatory pressures pressures were were statically statically applied and stresses stresses computed by hand. application of the hand. Static application co CO loads is is justifiable justifiable since the vent system umodes modes involving involving radial radial expansion expansion have frequencies over over 1000 Hz. Hz. The frequencies frequencies of the oscillating pressures pressures are all below below 50 Hz, Hz, resulting in in a DLF of 1.0. 1.0. The calculated calculated hoop stress is is 0.6 ksi in in the downcomer.

downcomer.

4.3.3.2.4 4.3.3.2.4 Analysis Chugging Analysis As with the co CO case, case, the chugging chugging internal internal pressure pressure loads for the downcomers downcomers consist of an oscillating oscillating internal pressure. pressure. oscillating The oscillating internal internal chugging pressure pressure occurs occurs at aa sufficientfY sufficiently low frequency frequency that static analysis static analysis is is justified justified for this load case. case. Similar Similar to the CO internal pressure, a DLF internal pressure, of 1.0 was used.

used. The resulting resulting hoop stress is is 0.6 ksi in in the downcomer.

downcomer.

membrane and membrane plus bending stress intensities Maximum membrane intensities due to chugging chugging lateral

• lateral loads were 3.4 ksi and 5.4 ksi, respectively. These stresses are at a ksi, respectively.

location location on the downcomer away from the downcomer downcomer/vent

/vent header intersection which which was discussed in in Subsection 4.3.3.1.

4.3.3~1.

4-17 04/29/82

--

4.3.3.2.5 4.3.3.2.5 Maximum downcomer S/RV Discharge Discharae Analysis Analysis Maximum membrane and membrane plus bendirg lateral loads following an S/RV discharge downcomer lateral respectively.

respectively. Again, bending stress intensities discharge are 3.3 Again, these stresses are at a location on the downcomer from the downcomer/vent downcomer/vent header header intersection.

intersection.

intensities 3.3 ksi and 5.2 due 5.2 ksi, downcomer away to to ksi, away 4.3.3.3 4.3.3.3 Downcomer Tiebar Downcomei Tiebar The mathematical mathematical analysis procedures model and analysis procedures used to qualify qualify the downcomer downcomer tiebars for QO, tiebars CO, chugging, chugging, S/RV discharge, discharge, and pool swell drag loads are described described in in this this subsection.

subsection.

4.3.3.3.1 4.3.3.3.1 Mathematical Model Mathematical Model Downcomer Downcomer tiebar tiebar forces and moments moments were determined from both the vent system vent system shell model model response response and a separate beam model model of- the tiebar.

tiebar. The beam beam model model was used to determine determine tiebar stresses stresses resulting