ML20023D717

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Inservice Insp Program, Technical Evaluation Rept
ML20023D717
Person / Time
Site: Cooper Entergy icon.png
Issue date: 09/02/1982
From:
SCIENCE APPLICATIONS INTERNATIONAL CORP. (FORMERLY
To:
NRC
Shared Package
ML20023D711 List:
References
CON-NRC-03-82-096, CON-NRC-3-82-96 186-028-04, 186-28-4, TAC-08295, TAC-8295, NUDOCS 8306020583
Download: ML20023D717 (36)
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SAI Report flo. 186-028-04 s

COOPER NUCLEAR STATION INSERVICE INSPECTION PROGRAM TECHNICAL EVALUATION REPORT 1

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Submitted to:

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U.S. Nuclear Regulatory Commission Contract No. 03-82-096 i

Science Applications, Inc.

McLean, Virginia 22102 i

September 2, 1982 l

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CONTENTS 1

INTRODUCTION..............................

I.

CLASS 1 C0HPONENTS..............

4 A.

Reactor Vessel........................

1.

Relief Requests C.I.B-A and C.1.B-B; Pressure-Retaining Welds, Categories B-A and B-8, Items B1.1 4

r and B1.2.........................

2.

Relief Request No. 7; Reactor Pressure Vessel Top 7

Head Nozzle Inner Radii, Category B-D, Item Bl.4.....

3.

Relief Request No. 10; Reactor Pressure Vessel Nuts.

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Category B-G-1, Item Bl.8 B.

Pressurizer (does not apply to BWRs)

C.

Heat Exchangers and Steam Generators (no relief requests) 11 D.

Piping Pressure Bounda ry...................

1.

Relief Request No. 6; Inaccessible Welds Inside Flued 11 Heads, Category B-J, Item B4.5..............

2.

Relief Request No. 2; Support Fillet Welds, 13 Category B-K-1, Item B4.9 15 E.

Pump Pressure Boundary...................

1.

P.elief Request No. 2; Support Fillet Welds, 15 4

Category B-K-1, Item B5.4

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2.

Relief Request No. 8; Internal Surfaces of Pumps, 15 Category B-L-2, Item B5.7 18 F.

Valve Pressure. Boundary...................

1.

Relief Request No. 2; Support Fillet Welds, 18 Category B-K-1, Item B6.4 2.

Relief Request Nc. 9; Internal Surfaces of Valves, 18 Category B-M-2, Item B6.7 21 II. CLASS 2 COMP 0NENTS........................

21 A.

Pressure Vessels.......................

1.

Relief Request No. 4; Residual Heat Removal Nozzle-21 to-Vessel Welds, Category C-B, Item C1.2.........

2.

Relief Request No. 3; Class 2 Bolting, Category C-D 23 (all items) t

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25 B.

Piping 1.

Relief Request No. 5; Inaccessible Weld Inside Floor Penetration, Category C-F, Item C2.1...........

25 2.

Relief Request No. 11; Pressure-Retaining Fillet 27 Welds, Category C-F, Item C2.1..............

28 3.

Bolting.........................

29 C.

Pumps 29 1.

Bolting.........................

29 D.

Valves............................

29 1.

Bolting

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III. CLASS 3 COMPONENTS (no relief requests) 29 IV. PRESSURE TESTS..........................

30 V.

GENERAL.............................

30 A.

Ultrasonic Examinatior. Tectrique...........

1.

Relief Request No.1; Ultrasotiic Recording Sensiti vity, 30 Class 1 and Class 2 33 B.

Exen.pted Components.....................

1.

Category B-0, Pressure-sttaining Welds in Control 33 Rod Ortve Housings..........,.........

C.

Other (no relief requests)

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35 REFERENCES..............................

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s TECHNICAL EVALUATION REPORT COOPER NUCLEAR STATION INSERVICE INSPECTION PROGRAM INTRODUCTION The revision to 10 CFR 50.55a, published in February 1976, required that r

Inservice Inspection (ISI) Programs be updated to meet the requirements (to the extent practical) of the Edition and Addenda of Section XI of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code

  • incorporated in the Regulation by reference in paragraph (b). This updating of the programs i

was required to be done every 40 months to reflect the new requirements of the later editions of Section XI.

As specified in the February 1976 revision, for clants with Operating i

Licensas issued prior to March 1,1976, the regulations became effective af ter September 1,1976,at the start of the next regular 40-month inspection period.

The initial inservice examinations conducted during the first 40-month period were to comply with the requirements in editions of Section XI and addenda in effect na more than six months prior to the date of start of facility commercial cperatica.

The Regulation recognized that the requirements of the later editions and addenda of the Section XI might not be practical to implement at facilities be-cause of lirnitations of design, geometry, and materials of construction of components and systems.

It therefore permitted determinations of impractical examination or testing requirements to be evaluated. Relief from these require-ments could be granted provided health and safety of the public were not endan-gered giving due consideration to the burden placed on the licensee if the requirements were imposed.

This report provides evaluations of the various requests for relief by the licensee, Nebraska Public Power District (NPPD),

of Cooper Nuclear Station.

It deals only with inservice examinations of com-ponents and with system pressure tests.

Inservice tests of pumps and valves (IST programs) are beinq evaluated separately.

The revision to 10 CFR 50.55a, effective November 1, 1979, modified the

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time interval for updatinq ISI programs and incorporated by reference a later l

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s edition and addenda of Sectidn XI. The updating intervals were extended,

from 40 months to 120 months to be consistent *with intervals as defined in Section XI.

i For plants with Operating Licenses issued prior to March 1,1976, the provisions of the November 1,1979, revision are effective after September 1, 1976, at the start of the next one-third of the 120-month interval.

During the one-third of an interval and throughout the remainder of the interval, r

inservice examinations shall comply with the latest edition and addenda of Section XI, incorporated by reference in the Regulation, on the date 12 months prior to the start of that one-third of an interval.

For Cooper Nuclear

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Station, the ISI program and the relief requests evaluated in this report, cover the last 60 months of the current 120-month inspection interval, i.e.,

from November 1, 1977, to July 1, 1984 This program was based upon the 1974 Edition of Section XI of the ASME Boiler ar.d Pressure Vessel Code with Addenda throtgh the Sumer of 1975.

r The November 1979 revision of the Regulation also provides that ISI programs may meet the reqairements of subsequent code editions and addenda, incorporated by reference in paragraph (b) and subject to Nuclear Regulatory Comission (HRC) approval. Portior:s of such editions or addenda ray be used provided that all related requirements of the respective editicns or addenda are met.

These instances are addressed on a case-by-case basis in the body of this report.

1 Finally,Section XI of the Code provides for certain components and systems to be exempted from its requirements.

In some instances, these exemptions are not acceptable to NRC or are only acceptable with restrictions.

As appropriate, these instances are also discussed in this report.

References (1) to (13) listed at the end of this report. pertain to previous information transmittals on ISI between the licensee and the Com-mission. By letters of April 28 and November 24,1976,(1,3) the Commission

!s provided general ISI guidance to all licensees. Submittals in response to that guidance were made by the licensee on June 2,1976,(2) and July 29,1977.(5)

The licensee submitted proposed technical specification changes on May 16, 1977.(4) On December 29,1977,(6) the Comission granted interim approval j

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of the ISI program, pending detailed review. By letters of February 24, l.1978,I7) and March 14,1982,(12) the Commission requested additional informa-tion to complete this review. This infomation ecs furnished by the licensee 29,1982,(13) respectively.

23,1978,(8) July 18,1978,(9) and liarch on March Additional relief requests were submitted by the licensee on December 18, 1983.(10) Additional guidance was furnished by the Comission to the licensee

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on February 23,1982.(I1)

From these submittals, a total of 14 requests (a) for relief from code requirements (b) for updating to a later code, and (c) for exemptions not t

necessarily acceptable to the Comission were identified. These requests are evaluated in the following sections of this report.

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CLASS 1 COMPONENTS ex A.

Reactor Vessel 1.

Rel.ief Requests C.1.B-A and C.I.B-B; Pressure-Retaining Welds, Categories B-A and B-B, Items Bl.1 and Bl.2 i

Code Requirement Category B-A (In Reactor Vessel Beltline Region):

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examination of the shell longitudinal and circumferential welds during each inspection interval shall cover at least IOC of the length of each longitudinal weld, and 5% of the length of each cir-cumferential weld, with the minimum length of weld of each circumfer-ential weld examined equal to one wall thickness. The examination may be performed at or near the end of each inspection interval.

c CategorLB-B (In Vessels): Volumetric examinations shall be performec during each inspection interval and shall cover at least 10% of the length of each longitudinal shell weld and meridional head weld and 5% of the length of each circumferential shell weld and head weld.

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Code Relief Request Relief is requested from the volumetric examination of the following reactor pressure vessel welds:

r Category B-A Welds Category B-B Welds VCB-BA-2 VCB-BB-1, 3 VLA-BA-1, 2, 3 VLC-BB-1, 2, 3 VLB-BA-1, 2, 3 HMB-BB-1, 2, 3, 4, 5, 6 Proposed Alternative Examination None. -

Licensee's Basis for Requesting Relief (a) Category B-A Welds:

Access to the reactor beltline region is not possible. The reactor vessel is insulated with permanent reflective insulation and surrounded by a concrete biological shield. The annular 1

space between the inside diameter of the insulation and the out-l side diameter of the reactor vessel is a nominal 2 inches. There 1

is no working space to remove the insulation panels from the 6

vessel, which precludes both direct and remote examination of the outside surface. The interior surface is clad and the vessel J

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internals, shroud and jet pumps make an internal volumetric examination of these welds impractical for a meaningful ex-amination. The reactor vessel is monitored for radiation damage in the beltline region. This program, reference NED0-10115 and APED-5490, 67A PE2 May 1967 Class I and Station Surveillance Procedure 7.4.9 meet the intent of 10 CFR Part 50, Appendix H.

This program will provide data to monitor radiation damage to the vessel beltline materials throughout the vessel's service life.

The vessel was designed and fabricated in accordance with the i

rules of Section III,1965 Edition of the ASME Boiler and Pres-sure Yessel Code.

Parts of the longitudinal seams VLA-BA-1, 2 and 3 appear to be accessible from openings around the recirculation riser nozzles N2A, N2E, and N2H respectively. These welds are only accessible for an examination for a few inches closest to the nozzles. When the nozzle welds (Category B-D) are examined, these few inches shall be scanned to the extent possible.

Additionally, the vessel flange weld, VCB-BC-5, a more highly

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stressed weld, shall be 100% examined volumetrically once during each inspection interval. Also the areas of these welds shall be inspected visually from the reactor vessel inside surface to the extent practical using a remote television camera during the inspection required for Categories B-N-1 and B-N-2.

(b) Category B-B Welds :

r The biological shield prohibits access to these welds. The clearance between the shield wall ar.d the reactor pressure vessel varies from approximately 14-1/4" to 12-3/4".

Insulation is in-stalled between the shield wall and the vessel. The clearance between the insulation and the reactor pressure vessel varies from 7/8" to 1-7/8".

The insulation is only removable in the area of the nozzles.

These welds are not accessible from the inside of the re-actor pressure vessel. Welds VLC-BB-1, 2, 3 may be partially accessible from the outside. Meridional welds HMB-BB-1, 2, 3, 4, 5, 6 are only accessible for examination from the outside for a distance of approximately six inches between the support skirt to vessel weld and the bottom head circumferential weld HMC-BB-1.

These welds will be examined to the extent possible.

Evaluation l

l Imposition of the Code requirenents would necessitate l

removing portions of the concrete biological shield and the l

permanently installed insulation to perform the required i

examination from the vessel exterior of the listed welds.

The vessel internals, shroud, and jet pumps preclude volu-metric examination of almost all the beltline weld volume from the vessel interior.

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i The reactor vessel is presently monitored for radiation damage in the beltline region by an acceptable surveillance program and hence, confonns to the intent of 10 CFR 50, Appen-dix H.

In addition, the vessel was designed and fabricated in accordance with the rules of Section III of the 1965 Edition of the ASME Boiler and Pressure Vessel Code.

This examination requirement is impractical due to the existing design and geometry for the above welds.

To maintain the extent of examination, an alternative inservice inspection program of both volumetric and visual examination is needed. Certain longitudinal and circumfer-ential welds, not in the core region, are partially or wholly accessible for inservice examination. The volumetric exami-nation of accessible Category B-B welds could be increased to achieve (1) an examination sample whose total weld length is i

equal to that required for the Category B-A and B-B welds for which relief was requested or (2) 100% of the length of each accessible Category B-B weld, whichever is less.

In addition, visual examination for gross leakage could be performed during each system pressure test in accordance with IWB-1220(c).

Such examinations should furnish sufficient information to

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evaluate the structural reliability of the welds.

Conclusions and Recocynendations Based on the above evaluation, it is concluded that for the welds discussed above, the code requirements are impractical.

It is further concluded that the alternative examination discussed above will provide necessary added assurance of structural reli-a bility. Therefore, the following is recommended:

Relief should be granted from volumetric examination of the identified welds for the 10-year inspection interval with

' c the following provisions:

(a) The examination of the accessible Category B-B welds should be increased to achieve (1) an examination sample whose total weld length is equal to that required for thd Category B-A and B-B welds for which relief was requested or (2) 100% of the length of each accessible Category B-B weld, whichever is less.

(b) General visual examinations per IWB-1220(c) should be made during each system pressure test for evidence of l

leakage in the areas of the lower head and the shield annulus below the vessel.

References References 5, 8 and 9.

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Relief Request No. 7; Reactor Pressure Vessel Top Head Nozzle Inner Radii, Category B-D, Item Bl.4 Code Requirement The extent of the volumetric examination of each nozzle shall cover 100% of the volume to be inspected as shown in Figure IWB-2500D, which includes the primary nozzle-to-vessel welds and inside radiused sections. All nozzles shall be examined 4

during each inspection interval.

Code Relief Request Relief is requested from the volumetric examination of the nozzle inner radius (NIR) for the following nozzles on the Reactor Pressure Vessel (RPV) Closure Head:

N6A NIR Head Spray Nozzle N6B NIR Instrumentation Nozzle N7 NIR Head Vent Nozzle Proposed Alternative Examination Surface examination of the inner radius of the three identi-fied nozzles would be performed.

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licensee's Basis for Requesting Relief During refueling activities, the RPV Closure Head is removed j

allowing access to RPV Closure Head NIR.

A surface examination is more sensitive in detecting surface defects at the NIR, than the volumetric examination performed from the outside surface.

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In addition, this would shorten the time of examination and sub-sequent evaluation.

Evaluation.

Volumetric examination of the nozzle-to-vessel weld is required, and would be performed ultrasonically, independently of the NIR examination. Because of the geometry of the joint, UT examination of the NIR sections is not feasible.

If the i

l entire joint were radiographed, an extra set of exposures l

would be required for the NIR sections. The proposed surface examination, however, would be more sensitive than a volumetric examination in detecting surface defects at the NIR.

In addition, surface examination of the NIR at the three nozzles as proposed l

f for the alternative examination would effect radiation exposure savings.

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Conclusions and Recommendations Based on the above evaluation, it is concluded that for the welds discussed above, some of the code requirements are impractical.

It is further concluded that the alternative examination discussed above will provide necessary added assur-ance of structural reliability. Therefore, the following is recommended:

c Relief should be granted from the volumetric examination of the nozzle inner radius of the three identified nozzles during the inspection interval, provided that the proposed alternative surface exanination is carried out.

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Relief Request No. 10; Reactor Pressure Vessel Nuts, Category B-G-1. Item Bl.8 Code Requirement The areas shall include bolts, studs, nuts, bushings, washers, and threads in base material and flange ligaments between threaded stud holes.

The examinations performed during each inspection in-t, terval shall cover 100% of the bolts, stud:, nuts, bushings, and threads in base material and flange ligaments between threaded stud holes.

Bushings, threads, and ligaments in base material of flanges are required to be examined only when the connection f

is disassembled.

Bolting may be examined either in place under tension, when the connection is disassembled, or when the bolting is removed.

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The methods of examination for the closure studs and nuts, when removed, shall be volumetric and surface.

Code Relief Request Relief is requested from the volumetric examination of the Reactor Pressure Vessel nuts PRB-BG-1 through PRB-BG1-52 Prcposed Alternative Examination r2 Only a surface examination would be performed.

Licensee's Basis for Requesting Relief The surface examination is more sensitive in detecting discontinuities that would occur in the more highly stressed i

threaded region. The surface examination will detect the discontinuity before it reaches a size detectable by volumetric examination. Therefore, the surface examination alone is a reliable method for examining and accepting the RPV nuts for service. The later editions of Section XI (Summer 1979 and Winter 1980) recognize that the surface examination alone is sufficient for the detection of unacceptable discontinuties and only require that the surface examination be performed.

Evaluation (4

The 1977 Edition of Section XI has been referenced in 10 CFR l

50.55a and inservice examinations may meet the requirements of this edition in lieu of those from previous editions with following provisions:

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(a) Commission approval is required to update to the more recent edition (pursuant to 10 CFR 50.55a(g)(4)(iv));

(b) When applying the 1977 Edition, all of the addenda through Summer 1978 Addenda must be used; (c) Any requirement of the more recent edition which is related to the one(s) under consideration must also be met.

The requirements for volumetrically examining closure head nuts on the reactor pressure vessel are deleted from the 1977 Edition with addenda through Summer 1978. Surface examination requirements are substituted.

Recommendations Pursuant to 10 CFR 50.55a(g)(4)(iv), approval should be t

granted to update to the requirements of the 1977 Edition of Section XI, through Summer 1978 Addenda, for Category B-G-1 items. This approval would permit the proposed alternative surface examination of the closure head nuts on the reactor pressure vessel.

Reference Reference 13.

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Pressurizer Does not apply to BWRs.

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Heat Exchangers and Steam Generators No relief requests.

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Piping Pressure Boundary 1.

Relief Request No. 6; Inaccessible Welds Inside Flued Heads, Category B-J, Item B4.5 i

Code Requirement Volumetric weld examinations shall be performed during each inspection interval and shall cover all of the area of 25% of the circunferential joints including the adjoining 1 ft. sections of longitudinal joints and 25% of the pipe branch connection joints.

Code Relief Request

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Relief is requested from the volumetric examination of one pressure-retaining piping weld in each primary containment penetration assembly.

Proposed Alternative Examination C2 A visual inspection for evidence of leakage will be con-ducted during the system hydrostatic pressure test of IWB-5000.

Licensee's Basis for Requesting Relief r,

Due to its design, the primary containment penetration assembly leaves one pressure retaining piping weld inaccessible for examination by either surface or volumetric methods.

i Evaluation l'

The identified welds are completely inaccessible for volu-L metric or surface examination because the welds are located inside a contair. ment penetration.

Each primary containment penetration assembly, due to its design, leaves one pressure-retaining piping weld inaccessible for examination by either surface or volumetric means. The welds can only be examined by inspecting for evidence l'

of leakage during system hydrostatic pressure tests.

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The initial design of the assemblies did not provide for accessibility for inservice examinations.

If, however, the work-manship and quality ssurance of the welding as well as the preservice examinations are assumed adequate, then an examination of the first. pressure boundary weld outside the containment should c

reflect service-induced failures for that particular piping sec-tion. Thus, the first pressure boundary weld outside the contain-ment on each of these process pipes would be volumetrically examined, where practical, over 1000 of its length during each inspection interval.

Such an examination would maintain sample size. The licensee could also conduct visual exaninations at i

these penetrations as proposed.

Conclusions and Recommendations Based on the above evaluation, it is concluded that for the r

welds discussed above, the code requirements are impractical.

It is further concluded that the alternative examination discussed above will provide necessary added assurance of structural reli-ability. Therefore, the following is recommended:

Relief should be granted from the volumetric examination of the identified welds,with the following previsions:

e The first pressure boundary weld outside the containment on each of these process pipes should be volumetrically examined, where practical, over 100% of its length during each inspection interval.

e The proposed visual examinations should be performed on the containment penetration assemblies when leakage and hydrostatic tests are conducted in accordance with IWB-1220(c).

c Reference Reference 13.

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Relief Request No. 2; Support Fillet Welds, Category B-K-1 Item B4.9 Code Requirement The volumetric examination performed during each inspection interval shall cover 25% of the integrally welded supports. The areas shall include the integrally welded external support at-i<

tachments. This includes the welds to the pressure-retaining l

boundary and the base metal beneath the weld zone and along the l

support attachment member for a distance of two support thick-nesses.

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Code Relief Request Relief is requested from the volumetric examination of all integrally welded external support attachments for piping, valves and pumps.

Proposed Alternative Examination Integrally welded support attachments will be liquid pene-trant examined in place of ultrasonic examinations.

Licensee's Basis for Requesting Relief The geometric reflectors that are recordable from fillet type welds are impossible to distinguish from relevant indica-tions, hence an ultrasonic examination is impractical.

Evaluation Because of the weld design, i.e., fillet welds, ultrasonic examination required by the Code is impractical. As an alterna-tive examination the licensee has committed to subject these

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welds to surface examination. Based on the loading conditions

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of these types of welds, flaws would most likely be generated at the weld surface and thus be detectable by surface examination.

Conclusions and Reconsnendations

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Based on the above evaluation, it is concluded that for the welds discussed above, the Code requirements are impractical.

It is further concluded that the alternative examination discussed above will provide necessary added assurance of structural reli-ability. Therefore, the following is recommended:

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i Relief should be granted from the volumetric examination of all integrally welded external support attachments for piping, valves, and pumps, provided that the welds are liquid penetrant r

examined and that such exami.iations cover 25% of the integrally welded support attachments during each inspection interval.

Reference Reference 13.

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Pump Pressure Boundary 1.

Relief Request No. 2: Support Fillet Welds, Category B-K-1,_

Item B5.4 The request for relief from volumetric examination of integrally welded external support attachments for pumps (I.D.2 of this report) applies here. Therefore, the following is reconnended:

Relief should be granted from the volumetric examination of all integrally welded external support attachments for piping, valves, and pumps,provided that the welds are liquid penetrant examined and that such examinations cover 25% of the integrally welded support attachments during each inspection interval.

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Relief Request No. 8: Internal Surfaces of _P_umas. Catenary B-t-2, Item B5.7 Code Requirement 7

Pump internal pressure boundary surfaces shall be visually examined.

One pump in each of the group of pumps performing similar functions in the system shall be examined during each inspection O

interval. The examinations may be performed at or near the end of the inspection interval.

Code Relief Request y'

Relief is requested from the visual examination of the in-ternal surfaces of the reactor recirculation pump at the pres-sure boundary.

Proposed Alternative Examination f

The internal surfaces of the recirculation pump casing will be visually examined whenever the surfaces are made accessible when a pump is disassembled for maintenance purposes.

Licensee's Basis for Requesting Relief The recirculation pump casing material is cast stainless steel. This material type has performed very well in nuclear serviceandhasdemonstratedsubstantialresistancetosuc se.nc. Appeauons,inc.

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c chemical processes as pitting, corrosion, and stress corrosion cracking which would decrease the structural integrity of the pump. To do the required visual inspection of this pump's in-ternal surfaces, large amounts of radiation exposure and time would be required. This was demonstrated at a similar nuclear statign, where an expenditure of approximately 1000 man-hours and 50 man-rem was requirtd to complete the visual inspection of a similar designed pump. The large expenditure of man-rem and man-hours to complete the visual inspection of a perfectly good pump solely for the purpose of inspection is impractical and not comensurate to the increased safety achieved by the inspec-tion. Cooper Nuclear Station believes that adequate safety margins are inherent in the basic pump design and that the health l

and safety of the public will not be adversely affected by not l

performing the visual examination of the pump casing internal surfaces solely for the purpose of inspection.

If, however, a pump requires disassembly for maintenance, then a visual inspec-tion, to the extent practical, will be performed.

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Evaluation The visual examination is to determine whether unariticipated severe cracking or erosion of the casing are occurring. However, previous experience during examinations of pumps at other plants has not shown any significant degradation of casings.

The disassembly of the reactor recirculation pumps to the degree necessary to inspect the internal pressure retaining sur-faces is a major effort, involving large personnel exposures and the generation of large amounts of radioactive waste.

In view of the effort required to disassemble a pump, the information returned from visual examination of its internal surfaces would be marginal.

The licensee has comitted to the concept of visual examina-(~

tion if the pump is disassembled for maintenance. Meanwhile, pressure and flow are monitored during pump operatica to assess perfonnance.

The visual examination of the internal pressure boundary I'

may be performed at or near the end of the 10-year inspection interval. Therefore, relief from examination requirements is not necessary until then because the licensee will be in compliance with the Regulation up to that time. The Code committee and the Electric Power Research Institute (EPRI) are undertaking a program to assemble and evaluate results

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of visual examinations of internal pump casing surfaces.

Within the next two years, this program should provide a more definitive basis for the Code comittee and NRC for upholding or modifying this Code requirement. Since so many licensees consider this requirement impractical and an undue burden, it is reasonable to postpone a decision to grant relief until that program is completed. The v

licensee could submit a new relief request at that time.

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Conclusions and Recommendations Based on the above evaluation, it is concluded that for the Code-required internal visual examination discussed above, e

I a more definitive technical basis is needed. Therefore, the following is recommended:

(a) Relief should not be granted at this time from the visual examination of the internal surfaces of the reactor recirculation pump at the pressure boundary.

(b) The licensee's proposal to perform a visual exami-nation whenever the surfaces are made accessible because a pump is disassembled for maintenance purposes should be accepted.

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References References 5 and 13.

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Valve Pressure Boundary 1.

Relief Request No. 2: Support Fillet Welds, Category B-K-1, Item B6.4 The request for relief from volumetric examination of inte-grally welded external support attachments for valves (I.D.2 of this report) applies here. Therefore, the following is e

recommended:

Relief should be granted from the volumetric examination of all integrally welded external support attachments for piping, valves, and pumps, provided that the welds are liquid penetrant examined and that such examinations cover 25% of the integrally welded support attachments during each inspection interval, n

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Relief Reques: No. 9; Internal Surfaces of Valves, Category B-M-2, Item B6.7 f

Code Requirement Visual examination of the internal pressure boundary surfaces, on valves exceeding 4-in. nominal pipe size.

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One valve in each group of valves of the same constructional design, e. g., globe, gate, or check valve, manufacturing method and manufacturer that performs similar functions in the system shall be examined during each inspection interval.

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The examinations may be performed at or near the end of the inspection interval.

Code Relief Request Relief is requested from the visual examination of the internal

'O surfaces at the pressure bour.dary of the Class 1 valves exceeding 4-in. diameter nominal pipe size.

Proposed Alternative Examination A visual inspection of a valve (1 per group per interval) in-ternal surfaces will be performed when the valve is disassembled for maintenance.

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C Licensee's Basis for Requesting Relief In the Class 1 system, there are 54 valves in 16 groups which are greater than four inches nominal pipe size. The requirement to disassemble an operable valve for the sole purpose of performing a visual examination of the internal pressure boundary is imprac-tical and not commensurate to the increased safety achieved by the inspection and has only a very small potential of increasing plant safety margins with a very disproportionate impact on expenditures of plant manpower and radiation exposure.

Perfoming these visual examinations under such adverse conditions as high dose rate (10 R/Hr) and poor as-cast surface condition, provides little additional in-formation as to the valve casing integrity. The performance of both carbon and stainless cast valve bodies has been excellent in all BWR applications. Cooper Nuclear Station believes that adequate safety margins are inherent in the basic valve design and that the health and safety of the public will not be adversely affected by

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not performing the visual inspections of the valve body internal surfaces solely for the purpose of inspection.

If, however, a valve requires disassembly for maintenance, then a visual inspection, to the extent practical, will be performed.

Evaluation The disassembly of large valves to the degree necessary to inspect the internal pressure-retaining surfaces (bodies) is a major effort, involving large personnel exposures. To do this disassembly solely to perfom a visual examination of the internal C

casing is impractical.

The licensee has comitted to the concept of visual exami-nation if the valve is disassembled for maintenance. The visual examination specified is to detemine whether unanticipated severe degradation of tne casing is occurring due to phenomena such as erosion or corrosion.

The visual examination of the internal pressure boundary may be perfonned at or near the end of the 10-year inspection interval. Therefore, relief from examination reauirements is not necessary until then because the licensee will be in n

compliance with the regulation up to that time. Since so many licensees consider this requirement impractical and an undue burden, it is reasonable to postpone a decision to grant relief until near the end of the inspection inter-val when additional relevant infonnation from this plant and from the industry in general will be available.

g The licensee could submit a new relief request at that time for each valve classification for which a valve has not been disassembled and examined. Submitting such relief requests as soon as possible after the next-to-last sched-uled outage of the inspection interval and at least six months before the scheduled start of the last outage would minimize delays and outage time.

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For those inspection periods when valve maintenance does not occur, visual examinations could be perfonned when the system pressure tests (IWA-5000) are conducted in accord-ance with the requirements for Category B-P.

These visual examinations will eerve to develop an experience record to be considered if specific relief requests' are submitted near the end of the inspection interval.

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Conclusions and Reconrnendations Based on the above evaluation, it is concluded that for the valves discussed above, there is not presently enough justification for granting relief from the impractical Code requirements. Therefore, the following is recocinended:

(a) Relief should not be granted at this time from visual examination of the internal pressure boundary surfaces on valves exceeding 4-in. nominal pipe size.

(b) The licensee's proposal to perform the Code-required examinations whenever the valves are opened because

.c of maintenance should be accepted.

(c) During other inspection periods, the licensee should perfonn visual examinations for leakage when the system pressure tests (IWA-5000) are conducted in accordance with the requirements for Category B-P.

r (d) The licensee should submit specific relief requests as the end of the inspection interval approaches for each valve classification for which a valve has not been disassembled and examined in each unit.

c References References 5 and 13.

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II. CLASS 2 COMP 0NEtiTS A.

Pressure Vessels 1.

Relief Request No. 4; Residual Heat Removal Nozzle-to-Vessel Welds, Category C-B, Item C1.2 Code Requirement Volumetric examination of 100% of the nozzle-to-vessel attachment welds for the equivalent of one Residual Heat Removal (RHR) Heat Exchanger shall be performed over the 40-year inspection interval.

Code Relief Request Relief is requested from the volumetric examination of welds RHR-CB-2A and RHR-CB-2B, the N4 nozzle to-vessel weld on each of two RHR Heat Exchangers, IA and 13.

O Proposed Alternative Examination There is one reinforcement ring weld on each of two RHR Heat Exchangers. These welds are accessible and will be given a liquid penetrant surface examination.

O Licensee's Basis for Requestinq Relief The joint configuration has a reinforcing pad covering up the nozzle-to-vessel weld.

O Evaluation The welds required to be examined are completely covered by a thick reinforcing ring that prevents a volumetric examination as required by the Code. The ring is welded to the shell and to the nozzle with fillet welds. The licensee pro-O poses to perform a surface examination on the reinforcing ring welds which are completely accessible. Weld cracking would be detected by the surface examination.

Visual examination of the welds during periodic hydrostatic testing would provide additional assurance that an adequate level O

of safety will be maintained.

Conclusions and Recomendations Based on the above evaluation, it is concluded that for the welds discussed above, the code requirements are impractical.

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is further concluded that the alternative examination discussed above will provide necessary added assurance of structural reli-ability. Therefore, the following is recommended:

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Conclusions and Recommendations Based on the above evaluation, it is concluded that for the welds discussed above, the Code requirements are imprac-tical.

It is further concluded that the alternative examination discussed above will provide necessary added assurance of struc-tural reliabi~.ity. Therefore, the following is recommended:

Relief should be granted from performing volumetric examina-tion of identified welds, provided that:

(a) The proposed alternative liquid penetrant examination is performed.

(b) Visual examination of the welds for leakage is performed during periodic hydrostatic testing in accordance with IWC-5000.

c References Reference 13.

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Relief Request ilo. 3: Class 2 Bolting, Category C-D (all items)

Code Requirement For pressure-retaining bolting exceeding 1-in. in diameter, the areas shall include bolts, studs, nuts, bushings, washers, and threads in base material and flange ligaments between threaded stud holes.

Visual examinations perfonned during each inspection interval shall cover 100% of the bolts, studs, nuts, bushings, and threads in base material and flange ligaments between threaded stud holes.

Nondestructive examinations shall be performed on 10~. of the bolting in each joint, but not less than two bolts or studs per joint.

Bushings, threads, and ligaments in base material of flanges are required to be examined only when the connection is disassembled.

Bolting may be examined either in place under tension, when the connection is disassembled, or when the bolting is removed.

I Item Examination ilo.

Components and Parts to be Exa_ mined Method C1.4 Pressure vessels pressure-retaining bolting Visual and r

C2.4 Piping pressure-retaining bolting s

ce C3.2 Pumps pressure-retaining bolting or volu etric C4.2 Valves pressure-retaining boltir.g t

Code Relief Request Licensee requests permission to use the 1977 Edition, Summer 1978 Addenda of Section XI for Category C-D.

Proposed Alternative Examination Licensee would comply with the more recent edition of the Code.

Licensee's Basis for Requesting Relief The intent of the ASME Code is to have Class 2 areas l

subject to examination the same or less than those of Class 1.

l (Reference IWB-2500, Category B-G-1).

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l Evaluation The 1977 Edition of Section XI has been referenced in 10 CFR 50.55a and inservice examinatio,ns n;ay meet the requirements of this edition in lieu of those from previous editions with the fol-lowing provisions:

(a) Commission approval is required to update to the more recent edition (pursuant to 10 CFR 50.55a(g)(4)(iv));

(b) When applying the 1977 Edition, all the addenda through Summer 1978 Addenda must be used; (c) Any requirement of the more recent edition which is related to the one(s) under consideration must also be met.

The requirements for examining Class 2 bolting 2-inch in diameter and less are deleted from the 1977 Edition with addenda through Summer 1978.

7 Recommendations Pursuant to 10 CFR 50.55a(g)(4)(iv), approval should be granted to update to the requirements of the 1977 Edition, Summer 1978 Addenda for Category C-D items. This approval r

would delete the requirement to examine Class 2 bolting, 2-in. diameter and less.

References

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Reference 13.

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Piping 1.

Relief Request No. 5: Inaccessible Weld Inside Floor Penetration, Category C-F, Iten C2.1 Code Requirement For pressure-retaining welds in piping which circulates reactor coolant, vclumetric weld examinations shall cover 100" of the welds. These examinations shall be scheduled over the r

lifetime of the plant (four intervals with three periods within each interval).

Code Relief Request Relief is requested from the volumetric examination of the pressure-retaining weld RHD-CF-9.

Proposed Alternative Exanination A visual inspection for evidence of leakage will be conducted r

during the system hydrostatic test of IWC-5000.

Licensee's Basis for Requesting Relief The location of this weld inside the floor penetratica

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makes it inaccessible for volumetric or surface examination.

Evaluation The weld for which relief is requested is located in the t-6-in. RHR Head Spray Vent System. This system contains 31 Class 2 Category C-F welds scheduled for exanination over the lifetime of the plant; i.e., four intervals or 40 years.

Because.of its inaccessible location, the weld cannot be examined by volumetric or surface methods. Visual examinations could, however, be performed during system leakage and hydrostatic tests.

Conclusions and Reconnendations Based on the above evaluation, it is concluded that for the welds discussed above, the code requirements are impractical.

It is further concluded that the alternative examination discussed above will provide necessary added assurance of structural reli-ability. Therefore, the following is recommended:

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Code relief from the volumetric examination of the identified weld should be granted, provided that visual l

examinations are performed during system hydrostatic pres-sure tests in accordance with IWC-5000.

Reference Reference 13.

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Relief Request No. 11; Pressure-Retaining Fillet Welds, Category C-F, Item C2.1 Code Requirement For pressure-retaining welds in piping which circulate reactor coolant, volumetric weld examinations shall cover 100~

of the welds. These examinations shall be scheduled over the lifetime of the plant (four intervals with three periods within each interval).

Code Relief Request Relief is requested from the volumetric examination of the following pressure-retaining fillet welds:

PNC-CG-20 PNC-CG-21 PNC-CG-23 PNC-CG-24 t

Proposed Alternative Examination A surface examination of the fillet welds would be performed.

Licensee's Basis for Requesting Relief r

The geometry of these pressure-retaining fillet welds

  • a makes a meaningful ultrasonic examination impossible. A surface examination of these fillet welds and the surrounding base material will provide a more sensitive and reliable means of detecting defects in these welds.

,c Evaluation The welds for which relief is requested are located in the Nitrogen Primary Containment Isolation System. This system contains 36 Class 2, Category C-F welds scheduled for examina-tion over the lifetime of the plant; i.e., four intervals or 40 years.

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For the purpose of inservice inspection, however, these welds were placed in AS!1E Section XI Examination Category C-F.

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  • Because of tne weld design, i.e., fillet welds, ultra-sonic examination required by the Code is impractical. As an i

al.ernative examination, the licensee has conmitted to subject these welds to surface examination.

Surface examination of fillet welds is an acceptable alternative examination.

Conclusions and Recommendations Based on the above evaluation, it is concluded that for the welds discussed above, the code requirements are impractical.

It is further concluded that the alternative examination discussed above will provide necessary added assurance of structural reli-ability. Therefore, the following is recommended:

Relief from the volumetric examination of the identified welds should be granted.provided that a surface examination of the welds is performed, f

Reference Reference 13.

3.

Bolting

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The relief request pertaining to all Category C-D items (II.A.2 of this report) applies here. Therefore, the following is recommended:

Pursuant to 10 CFR 50.55a(g)(4)(iv), approval should be

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granted to update to the requirements of the 1977 Edition, Summer 1978 Addenda for Category C-D items. This approval would delete the requirement to examine Class 2 bolting, 2-in.

in diameter and less.

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Pumps 1.

Bolting l

The relief request pertaining to all Category C-D items (II.A.2 of this report) applies here. Therefore, the following is recommended:

Pursuant to 10 CFR 50.55a(g)(4)(iv), approval should be granted to update to the requirements of the 1977 Edition, Sumer 1978 Addenda for Category C-D items. This approval muld delete the requirement to examine Class 2 bolting, 2-in.

In diameter and less.

D.

Valves 1.

Bolting The relief request pertaining to all Category C-D itens (II.A.2 of this report) applies here. Therefore, the following is recommended:

Pursuant to 10 CFR 50.55a(g)(4)(iv), approval should be granted to update to the requirements of the 1977 Edition, Sumer 1978 Addenda for Category C-D items. This approval would delete the requirement to examine Class 2 bolting, 2-in.

in diameter and less.

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III. CLASS 3 COMPONENTS (No relief requests)

IV. PRESSURE TESTS The licensee plans to submit additional relief requests relating to the System Pressure Testing Program presently under development (Ref. 13). Consequently a review of the system pressure tests of Reference 5 is delayed pending an updating of the System Pressure Testing Program. Thus, these tests are not evaluated in this report.

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GENERAL A.

Ultrasonic Examination Technique 1.

,Ralief Request No.1; Ultrasonic Recording Sensitivity, Class 1 a'nd Class 2 Code Requirement ASME Code Section XI (1974 Edition), Paragraph IWA-2232 Ultrasonic Examination:

" Ultrasonic examination shall be con-ducted in accordance with the provisions of Appendix 1.

Where Appendix I (I-1200) is not applicable, the provisions of Article 5 of Section V shall apply."

ASME Code Section V (1974 Edition), Paragraph T-537 i

Evaluation of Indications:

"All indications which produce a response greater than 20% of the reference level shall be in-vestigated to the extent that the operator can evaluate the shape, identity, and location of all such reflectors in terms of the acceptance-rejection standards of the referencing Code

- r Section."

Code Relief Request Relief is requested from recording all responses greater than 20% of the reference level when ultrasonically examining all pressure-retaining welds in piping and vessels for the following categories and item numbers:

Category Item Numbers B-F Bl.6, B4.1

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B-J B4.5, B4.6 C-F C2.1, C2.2 C2.3 C-G C2.1, C2.2 C2.3 1

Proposed Alternative Examination When ultrasonically examining the identified pressure-retaining welds, all responses greater than 50% of reference level shall be recorded.

Licensee's Basis for Requesting Relief Geometric type indications or weld interface noise is often times just greater than 20% of the reference level, making these indications recordable. The intent of the ASME Code is to record at 50% of the reference level.

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Evali.ation Recording and evaluating indications at 20% of the s

reference level is impractical for the foliowing reasons:

(a) The welded joints in nuclear piping frequently contain Code-allowable wall thickness differences (12% of nominal thickness) as wall as some weld drop-through, counterbore taper, crown height, etc. These conditions generate an extremely large number of geometric reflectors which produce UT indications greater than 20% of the reference level.

(b)deldmetalinstainlesssteelpipingcontainsreflec--

tors due to the metallurgical structure that produce a 11arge number of UT indications.

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(c) ATl examination personnel experience radiation exposure during inservice examinations. The s

Section V requirement to record and evaluate UT indications at the 20% level places an unnecessary s

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burden on the limited number of experienced and qualified examiners available to the licensee.

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The'k977 Edition of Section XI has been referenced in il 10 CFR 50.55a and inservice examinations may meet the require-y q

ments of this edition in lieu of those from previous editions with the following provisions:

0 (a) Comission approval is required to update to the more

. c-recent-edition (pursuant to 10 CFR 50.55a(g)(4)(iv));

(b).-When~ applying the 1977 Edition, all of the addenda through Sumer 1978 Addenda must be used; (c)'Any requirement of the more recent edition which is related to the one(s) under consideration must also

.r be met.

Appendix III was incorporated into Paragraph IWA-2232 of the >1977 Editica through Summer 1978 Addenda of Section XI. To meet the requirements of (c) above, the entire Paragraph IWA-2232 a

3 in the Summer 1978 Addenda should be adopted by the licensee.

-This paragraph includes the following:

(a) For examination of welds, reflectors triht produce a respons6 greater than 50% of the reference level shall be recorded. (IWA-2232(c)(1))

x (b).For examination of welds, all reflectors which produce a l response greater than 100% of the reference level 3

shall be investigated to the extent that the operator can determine the shape, identity, and location of all s

'such reflectors in terms of~the acceptance-rejection Ii standards of IWA-3100(b).

(IWA-2232(c)(2)) '

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(c) The size of reflectors shall be measured between points which give amplitudes equal to 100% of the reference level.

(IWA-2232(c)(3))

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In addition, indications of 20% of reference level or greater which are interpreted to be a crack must be identified 1

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and evaluated according to the rules of Section XI.

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Recommendations Pursuant to 10 CFR 50.55a(g)(4)(iv), approval should be granted to update to the requirements of the 1977 Edition of l

Section XI, through Summer 1978 Addenda, for Paragraph IWA-2232, provided that indications 20% or greater of reference level that are interpreted to be a crack are identified and evaluated according to the rules of Section XI.

References References 9 and 13.

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Is B.

Exempted Components 1.

Category B-0, Pressure-Retaining Welds in Control Rod Drive Housings Code Requirement Category B-0:

Volumetric examinations shall be performed during each inspection interval and shall include 100% of the welds in 10% of the peripheral control rod drive housings. The ex-

c aminations may be performed at or near the end of the in-spection interval.

IWB-1220(b)(1) (Summer 1975):

Components may be exempted from examination if under the postulated conditions of loss of coolant from the component

I during normal reactor operation, the reactor can be shut down and cooled down in an orderly manner assuming makeup is pro-vided by the reactor coolant makeup system only.

However, in no instance may the size exemption be more than three-inch nominal pipe size.

Exemption Exemption from volumetric examination of control rod drive housings per IWB-1220(b)(1).

Licensee's Position Analysis shows that the reactor can be cooled down in an orderly manner using only the reactor coolant makeup system when there is a complete break in a two-inch water line.

Evaluation The control rod drive housings are 6-in. nominal pipe size but due to the internal mechanism the area unobstructed L

to flow is equivalent to a 1.8 in. nominal pipe diameter.

Each housing has a stop to prevent it and the mechanism from being separated completely from the vessel in the event of the complete failure of a circumferential weld. Therefore, the requirements of IWB-1220(b)(1) have been met and the Code re-l quirements to exempt these components satisfied, t

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.r Conclusions and Recommendations Based on the above evaluation, it is concluded that for the t

welds discussed above, the exemption from code requirements has been demonstrated. Therefore, the following is recommended:

Exemption from volumetric examination of control rod drive housings per IW8-1220(b)(1) should be allowed.

References References 5 and 9.

C.

Other r

(No relief requests)

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s.; \\ s REFERENCES 1.

Dennis L. Ziemann (NRC) to J. M. Pilant (NPPD), Cooper Nuclear Station, April 28, 1976.

2.

J. M. Pilant (NPPD) to Dennis L. Ziemann(NRC), Inservice Inspection Testing Requirements for ASME Code Class 1, 2 and 3 Components, Cooper Nuclear Station, June 2,1976.

3.

Dennis I.. Ziemann (NRC) to J. M. Pilant (NPPD), Cooper Nuclear Station License No. DPR-46, November 24, 1976.

4.

J. M. Pilant (NPPD) to D. L. Ziemann (NRC), Proposed Changes to Radiological Technical Specifications, Cooper Nuclear Station, Docket No. 50-298, May 16, 1977.

5.

Jay M. Pilant (NPPD) to Don K. Davis (NRC), Updated 40 Month Inservice Inspection and Testing Programs, Cooper Nuclear Station, July 29, 1977.

6.

Don K. Davis (NRC) to J. M. Pilant (NPPD), Cooper Nuclear Station, December 29, 1977.

i 7.

George Lear (NRC) to J. M. Pilant (NPPD), Request for Additional Informa-tion, Cooper Nuclear Station Inservice Inspection and Testing Program, Feb uary 24, 1978.

8.

J. M. Pilant (NPPD) to George Lear (NRC), Request for Additional Informa-tion, Cooper Nuclear Station, Inservice Inspection Program, March 23, 1978.

9.

Jay M. Pilant (NPPD) to Thomas A. Ippolito (NRC). Inservice Inspection and Testing Submittal of July 1977, July 18,1978.

10.

J. M. Pilant (NPPD) to Thomas A. Ippolito (NRC), ISI and IST Additional Relief Requests, December 18, 1980.

11.

Domenic B. Vassallo (NRC) to J. M. Pilant (NPPD), Guidance on ISI Cooper Nuclear Station, February 23, 1982.

12.

Domenic B. Vassallo (NRC) to J. M. Pflant (NPPD), Request for Additional Information on Relief Requests for Cooper Nuclear Station, March 14, 1982.

13.

J. M. Pilant (NPPD) to Domenic B. Vassallo (NRC), ISI and IST Relief Requests, March 29, 1982.

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