ML18038B886
| ML18038B886 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 06/04/1997 |
| From: | Abney T TENNESSEE VALLEY AUTHORITY |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9706110162 | |
| Download: ML18038B886 (44) | |
Text
CATEGORY 1 REGULATOR INFORMATION DISTRIBUTION STEM (RIDS)
ACCESSION NBR:9706110162 DOC.DATE: 97/06/04 NOTARIZED:
NO DOCKET FACIL:5g-260 Browns Ferry Nuclear Power Station, Unit 2, Tennessee 05000260 AUTH.'NAM AUTHOR AFFILIATION'BNEY,.T.E.
Tennessee Valley Authority-RECIP.NAME RECIPIENT AFFILIATION Document Control Branch (Document Control Desk)
SUBJECT:
Forwards request for relief from specified Section XI ISI sys pressure testing requirements of 1986 edition of ASME BaPV code.
DISTRIBUTION CODE: A047D COPIES RECEIVED:LTR ENCL SIZE:
TITLE: OR Submittal: Inservice/Testing/Relief from ASME Code GL-89-04 NOTES:
E RECIPIENT ID CODE/NAME PD2-3 WILLIAMS,J.
COPIES LTTR ENCL 1
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1 RECIPIENT ID CODE/NAME
- PD2-3-PD COPIES LTTR ENCL 1
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INTERNAL:
FILE CENTER 898 RES/DET/EIB CT 1
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1 AEOD/SPD/RAB NRR/DE/EMEB OGC/HDS3 RES/DET/EMMEB 1
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1 EXTERNAL: LITCO ANDERSON NRC PDR 1
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N NOTE TO ALL "RIDS" RECIPIENTS:
PLEASE HELP US TO REDUCE WASTE. TO HAVE YOUR NAME OR ORGANIZATION REMOVED FROM DISTRIBUTION LISTS OR REDUCE THE NUMBER OF COPIES RECEIVED BY YOU OR YOUR ORGANIZATION, CONTACT THE DOCUMENT, CONTROL DESK (DCD)
ON EXTENSION 415-2083 TOTAL NUMBER OF COPIES REQUIRED:
LTTR 14 ENCL 13
IQ'I E'I k
(
Tennessee Valley Authority, Post Office Box 2000, Decatur, Alabama 35609-2000 June 4, 1997 10 CFR 50.55a(a)
(3) (i and ii)
U.S. Nuclear Regulatory Commission ATTN:
Document Control Desk Washington, D.C.
20555 Gentlemen:
In the Matter of
)
Tennessee Valley Authority
)
Docket No. 50-260
- --=
BROWNS FERRY NUCLEAR PLANT (BFN)
UNIT 2 AMERICAN SOCIETY OF MECHANICAL ENGINEERS (ASME)
SECTION XI, INSERVICE INSPECTION AND SYSTEM PRESSURE TEST PROGRAMS RELIEF REQUESTS TO SUPPORT THE CYCLE 9 REFUELING OUTAGE In accordance with 10 CFR 50.55a(a)(3)(i and ii), the enclosures to this letter contain requests for relief from specified Section XI inservice inspection and system pressure testing requirements of the 1986 Edition (no addenda) of the ASME Boiler and Pressure Vessel Code.
I In Enclosure 1,
TVA is submitting four permanent relief requests to the Unit 2 ASME Section XI system pressure test requirements.
Each of these relief requests seeks to invoke an ASME Code Case as an alternative to the existing Code requirement(s).
The ASME Code Committee has approved each of the proposed Code Cases,
- however, NRC has not accepted the Code Cases for use in Regulatory Guide 1.147, Revision 11, "Inservice Inspection Code Case Acceptability ASME Section XI, Division 1," dated October 1,
1994.
However, provisions stated in footnote six to 10 CFR 50.55a provide for use of other Code Cases upon request, if approved by the Director of the Office of Nuclear Reactor Regulation pursuant to 10 CFR 50.55a(a)(3).
TVA considers that each of the Code Cases,
,9706iiOi62 970604
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U.S. Nuclear Regulatory Commission Page 2
June 4, 1997 submitted as proposed ASME Code alternatives, in the relief requests provide an acceptable level of quality and safety.
- Further, compliance with the specified Code requirements would result in a hardship or unusual difficultywithout a compensating increase in the level of quality or safety.
The requests for relief are listed and briefly described below:
2-SPT-9 Requests relief from the 10-year system hydrostatic testing for Class 1,
2, and 3 systems.
TVA will instead utilize the requirements of ASME Code Case N-498-2, "Alternative Requirements for 10-Year Syst: em Hydrostatic Testing for Class 1,
2, and 3 Systems,Section XI, Division 1," which allows the use of an inservice leakage test in lieu of a hydrostatic pressure test.
This relief request is a
revision to one previously submitted for Unit 2 by TVA, invoking Code Case N-498-1, by letter dated March 9,
- 1995, and accepted by NRC letter dated August 18, 1995.
Code Case N-498-2 removes the holding time (a minimum of four hours for insulated systems and ten minutes for noninsulated systems) at nominal operating pressure before performing the VT-2 visual examination.
Relief request 2-SPT-9 (revised) is similar to one submitted for BFN Unit 3 (3-SPT-2) by letter dated January 22,
- 1997, as part of the ASME Section XI, second inspection interval, program.
Notwithstanding the different ASME Section XI Codes of record (1986 Edition for Unit 2 and 1989 for Unit 3) staff review of the two relief requests could be performed concurrently.
'2-SPT-10 Requests relief from ASME Section XI, Subsection IWA-2300, which requires that personnel performing VT-2 visual examinations be qualified and certified using a written approved procedure prepared in accordance with SNT-TC-1A and the additional requirements of Division 1 of ASME Section XI.
TVA will instead utilize the requirements of ASME Code Case N-546, "Alternative Requirements for Qualification of VT-2 Examination Personnel,"
which permits experienced plant personnel to perform VT-2 examinations during the performance of system pressure tests.
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U.S. Nuclear Regulatory Commission Page 3
June 4, 1997 TVA submitted a similar relief request (3-SPT-3) for BFN Unit 3 by letter dated January 22, 1997.
Staff review of the two relief requests could be performed concurrently.
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2-SPT-11 Requests relief from ASME Section XI, Subsection IWA-5250 (a)(2) that states if leakage occurs at a bolted connection, the bolting shall be removed, VT-3 visually examined for corrosion, and evaluated in accordance with Subsection IWA-3100.
As an alternative, TVA will use the provisions of ASME Code Case N-566 which states:
- 1) the leakage shall be stopped and the bolting and component material shall be reviewed for joint integrity,
- 2) if the leakage is not stopped, the joint shall be evaluated in accordance with IWB-3142.4 for joint integrity.
TVA submitted a similar relief request for BFN Unit 3 (3-SPT-4) by letter dated January 22, 1997.
Staff review of the two relief requests could be performed concurrently.
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2-SPT-12 Requests relief from ASME Section XI, Table IWC-2500-1, Category C-H (all pressure retaining components) that requires VT-2 visual examinations
- during, 1)
IWC-5221, System Pressure Test During System Functional and System Inservice Tests, and 2)
IWC-5222, System Hydrostatic Tests.
TVA will instead use ASME Code Case N-522 which states the results of the containment testing program as required by 10 CFR 50 Appendix J may be used for Class 2 piping and isolation valves penetrating primary containment for systems outside the scope of ASME Section XI.
TVA submitted a similar relief request for BFN Unit 3 (3-SPT-5) by letter dated January 22, 1997.
Staff review of the two relief requests could be performed concurrently.
In Enclosure 2,
TVA is submitting one permanent request for relief (2-ISI-7 revised) to the BFN Unit 2 ASME Section XI inservice inspection program.
TVA is requesting relief from ASME Section XI, Table IWB-2500-1, Examination Category
I pt
U.S. Nuclear Regulatory Commission Page 4
June 4,
1997 B-K-1, integrally welded attachments for Class 1 components (Figure IWB-2500-15) and Table IWC-2500-1, Examination Category C-C, integrally welded attachments for Class 2
components (Figure IWC-2500-5).
As an alternative, TVA proposes to perform the required examination on the accessible volume/area of the support integral attachment without removal of the support.
TVA considers that the proposed alternative provides an acceptable level of quality and safety.
- Further, compliance with the specified-Code requirement would result in a hardship or unusual difficulty without a compensating increase in the level. of quality or safety.
In addition, the ASME Section XI, 1995 Addenda provides for examination of the accessible areas of integral attachm'ents without removal of support members.
This relief request was originally submitted for Unit 2 by 'TVA letter dated November 12,
- 1996, and is being revised to include Class 2 components.
A similar relief request for Unit 3 (3-ISI-4) was submitted by TVA letter dated January 22, 1997.
Staff review of the two relief requests could be performed concurrently.
Review of this submittal is requested prior to the Unit 2 Cycle 9 refueling outage (except 2-SPT-9) to support scheduled ASME Section XI outage activities.
The outage is currently scheduled to begin September 26, 1997.
TVA will inform the NRC Project Manager of any changes to the outage schedule.
For 2-SPT-9, TVA is requesting review prior to the Unit 2 Cycle 10 refueling outage scheduled to begin in March 1999.
There are no commitments contained in this letter.
If you have any questions, please telephone me at (205) 729-2636.
cerely T. E. Abn y Manager of Lic sin and Industr Affai s Enclosures cc:
See page 5
I
. U.S. Nuclear Regulatory Commission Page 5
June 4, 1997 Enclosures cc:
(Enclosures):
Mr. Mark S. Lesser, Branch Chief U.S. Nuclear Regulatory Commission Region II 61 Forsyth Street, S.W.
Suite 23T85
- Atlanta, Georgia 30303 NRC Resident Inspector Browns Ferry Nuclear Plant 10833 Shaw Road
- Athens, Alabama 35611 Mr. J.
F. Williams, Project Manager U.S. Nuclear Regulatory Commission One White Flint, North 11555 Rockville Pike Rockville, Maryland 20852
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ENCLOSURE 1
TENNESSEE VALLEY AUTHORITY BROWNS FERRY NUCLEAR PLANT (BFN)
UNIT 2 AMERICAN SOCIETY OF MECHANICAL ENGINEERS (ASME)
SECTION XI SYSTEM PRESSURE TEST (SPT)
PROGRAM (SECOND INSPECTION INTERVAL)
REQUESTS FOR RELIEF TO SUPPORT THE CYCLE 9 REFUELING OUTAGE (See Attached)
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TENNESSEE VALLEY AUTHORITY BROWNS FERRY NUCLEAR PLANT (BFN)
UNIT 2 ASME SECTION XII 'SYSTEM PRESSURE TEST PROGRAM (SECOND INSPECTION INTERVAL)
REVISION TO REQUEST FOR REL'IEF 2-SPT-9 (CODE CASE N-498-2)
SYSTEMS
- Various, American Society of Mechanical Engineers (ASME)Section XI DRAWINGS COMPONENTS Various Class 1,
2, and 3 pressure retaining components CODE CLASS FUNCTION 1,
2, and 3
Pressure retaining boundary ASME CODE REQUIREMENT (S)
ASME Section XI, 1986 Edition (no Addenda),
10-Year System Hydrostatic Testing for Class 1,
2, and 3
Systems.
Table IWB-2500-1, Category B-P; Table IWC-2500-1, Category C-H; and Table IWD-2500-1, Categories D-A, D-B, and D-C.
BASIS FOR RELIEF In accordance with 10 CFR 50.55a(a)(3)(i and ii) TVA proposes to use ASME Code Case N-498-2, "Alternative Rules for 10-Year System Hydrostatic 'Testing for Class 1,
2, and 3 Systems,Section XI, Division 1," as an alternative to the ASME Section XI requirements specified above.
ASME Code Case N-498 has been accepted by NRC as listed in Regulatory Guide 1.147, Revision 11, "Inservice Inspection Code Case
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Acceptability ASME Section XI Division 1," dat:ed October 1,
1994.
This Code Case allows the use of an inservice leakage test instead of a hydrostatic pressure test when performing the required 10-year pressure
.test. for Class 1 and 2
systems.
ASME Code Case N-498-1 extends the use of this alternate test method to Class 3 systems and N-498-2, removes the hold time (a
minimum of four hours for insulated systems and ten minutes for
.noninsulated systems) at nominal operating pressure before performing the VT-2 visual examination.
ASME Code Case N-498-1 has been authorized for use for BFN Units 1, 2,
and 3 by NRC letter from F. J.
Hebdon to O.
D. Kingsley dated August 18, 1995.
ASME Code Case N-498-2 removes the holding time requirements, before performing the VT-2 visual examination.
Operating experience has shown that:
most leaks are discovered during normal system operation.
Any apparent leakage will, in most cases, have already been identified. It is unlikely that any service induced leakage would be generated in this additional operating time.
Also, system startup evolution requires time to atta'in and stabilize system conditions at nominal operating
,pressure and time is required to initiate and perform the system walkdown.
Some amount of elapsed time is inherent in this process thereby allowing any existing leakage to occur.
This is particularly true for primary (Class
- 1) piping systems.
The Class 1
systems will have been under pressure for several hours.prior to reaching full test pressure.
Therefore, additional hold times would provide li;ttle or no added benef'its.
The probability of identification of additional leakage is considered small
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and the benefits, if any, are not commensurate with the cost and plant operational delays imposed by the additional hold times.
The revision of Code Case N-498-1 (resulting in N-498-2,)
was intended to provide agreement with recent editions of the ASME Code.
The hold.times in question were removed in the 1995 Addenda to the 1995 Edition of the ASME Section XI Code.
Code Case N-498-2 was issued to remove the unnecessary hold times after the applicable ASME Section XI Code paragraph had been revised.
TVA considers that the proposed alternative (Code Case N-498-2) provides an acceptable level of quality and safety.
- Further, compliance with the specified ASME Section XI Code requirements would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety.
ALTERNATIVE TESTING As an alternative to the existing ASME Section XI requirements, BFN will utilize the provisions of ASME Code Case N-498-2.
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TENNESSEE VALLEY AUTHORITY BROWNS FERRY NUCLEAR PLANT (BFN)
UNIT 2 ASME SECT'ION XII SYSTEM PRESSURE TEST PROGRAM (SECOND INSPECTION INTERVAL)
REQUEST 'FOR RELIEF 2-SPT-10 (CODE CASE N-54 6)
SYSTEMS DRAWINGS COMPONENTS CODE CLASS FUNCTION ASME CODE REQUIREMENT (S)
Various. American Society of Mechanical Engineers (ASME)Section XI Various Class 1,
2, and 3 pressure retaining components 1.,
2, and 3
Pressure retaining boundary ASME Section XI, 1986 Edition (no Addenda),
Subsection IWA-2300 requires that personnel performing VT-2 visual examinations be qualified and certified using a written, approved procedure prepared in accordance with SNT-TC-1A and.the additional requirements of Division 1 of ASME Section XI.
BASIS FOR RELIEF In accordance with 10 CFR 50.55a(a)(3)
(i and ii) TVA proposes to use an alternative to the ASME Section XI Code requirement specified above.
The use of Code Case N-546 will allow experienced plant personnel to perform VT-2 visual examinations during the performance of system pressure tests and provide an acceptable level of qual'ity and safety.
Experienced plant personnel are knowledgeable of the plant systems and routinely perform walkdowns of plant systems looking for abnormalities such as leaks in
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piping systems.
They are more familiar with the location of piping systems and can therefore perform VT-2 examinations in a more timely manner.
Using experienced plant personnel will also eliminate the need for hiring additional personnel fully certified to IWA-2300.
This is especially prevalent during refueling outages when pressure tests are performed and the number of IWA-2300 certified personnel are limited.
Since the VT-2 examination is a check for the evidence of leakage, the use of plant personnel certified to the N-546 alternative requirements, and who typically perform this type of examination during their daily activities, will not compromise the quality or safety of the systems examined.
Compliance with the specified ASME Code requirements would result in an undue hardship without a compensating increase in the level of quality and safety.
TVA considers the ASME Code Case N-546 requirements to be an acceptable alternative to the qualification and certification of VT-2 (visual examination personnel) using a
written, approved procedure prepared in accordance with SNT-TC-1A and the additional requirements of ASME Section XI, Division 1.
ALTERNATIVE TESTING As an alternative to the existing ASME Section XI requirements, BFN will utilize the provisions of ASME Code Case N-546.
Personnel must have at least 40 hours4.62963e-4 days <br />0.0111 hours <br />6.613757e-5 weeks <br />1.522e-5 months <br /> plant walkdown experience, such as that gained by licensed and non-licensed plant operators, local leak rate personnel, system engineers, and inspection and non-destructive examination personnel.
Individuals must have at least four hours of training in Section XI requirements and plant specific procedures for visual examinations.
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Each.person must meet (annual) vision test requirements in accordance with the 1995 Edition of the ASME Section XI Code, Paragraph IWA-2321.
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TENNESSEE VALLEY AUTHORITY BROWNS FERRY NUCLEAR PLANT (BFN)
UNIT 2 ASME SECTION XI.,;SYSTEM PRESSURE TEST PROGRAM (SECOND INSPECTION. INTERVAL)
REQUEST FOR RELIEF 2-SPT-11 (CODE'ASE, N-566)
'SYSTEMS Various, American Society of Mechanical Engineers (ASME)Section XI DRAWINGS
'COMPONENTS Various Class 1,
2, and 3 pressure retaining bolted connections CODE CLASS FUNCTION 1,
2, and 3
Pressure retaining boundary ASME CODE'EQUIREMENT (S)
ASME'ection XI, 1986 Edition (no Addenda),,
IWA-5250 (a)(2) states, if leakage occurs at a bolted connection, the bolting shall be
- removed, VT-3 visually examined for corrosion, and evaluated in accordance with IWA-3100.
BASIS FOR RELIEF In accordance with 10 CFR 50.55a,(a)
(3) (i and ii) TVA proposes to use ASME Code Case N-566 as an alternative to the ASME Section XI requirements specified above.
ASME Section XI inservice pressure tests
- are, as a rule, performed with the system in service.
In particular, the Code Class 1 leakage tests are performed as the unit is returning to service following each refueling outage.
The requirement to remove bolting from a mechanical connection when evidence of leakage is detected can create significant hardship on the plant which is not commensurate with the increase i.'n the level of quality and safety that is provided.
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For systems that are aligned to normal plant operating configuration during testing, paragraph IWA-5250 (a)(2) may require the system be taken out of service and depressurized to permit removal of one of the bolts prior to any type of engineering analysis of the connection.
Stoppage of the leakage and/or an engineering evaluation of the leak and the affected mechanical connection may be able to determine that sufficient structural integrity exists in the connection.
ALTERNATIVE TESTING As an alternative to the existing ASME Section XI requirements, BFN will utilize the provisions of ASME Code Case N-566 which states that one of the following requirements shall be me't for leakage at bolted'onnections:
a)The leakage shall be.stopped and the bolting and component material shall be reviewed for joint integrity.
b)If the leakage is not stopped, the joint shall be evaluated in accordance with IWB-3142.4 for. joint integrity.
This evaluation shall include consideration of the number and condition of bolts, leaking medium, bolt and component
- material, system function, and leakage monitoring.
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TENNESSEE VALLEY AUTHORITY BROWNS FERRY NUCLEAR PLANT (BFN)
UNIT 2 ASME SECTION XI, SYSTEM PRESSURE TEST PROGRAM (SECOND INSPECTION INTERVAL)
REQUEST FOR RELIEF 2-SPT-12 (CODE CASE N-522)
SYSTEMS DRAWINGS Systems outside the scope of ASME Section XI except for their Class 2 piping, and isolation valves that penetrate containment.
2-47E822-1 2-47E852-1 2-47E852-2 2-47E856-2 COMPONENTS CODE CLA'SS FUNCTION" Piping That Penetrates a Containment Vessel Pressure Retaining Boundary ASME CODE REQUIREMENT (S)
ASME Section XI, 1986 Edition (no Addenda),
Table IWC-2500-1, Category C-H, requires visual VT-2 examinations
- during, a)
IWC-
- 5221, System Pressure Test During System Functional and'ystem Inservice Tests and b)
IWC-5222, System Hydrostatic Tests.
BASIS FOR RELIEF In accordance with 10 CFR 50.55a.(a)(3)(i and'i)
TVA proposes to use ASME Code Case N-522 as an alternative to the ASME 'Section XI requirements specified above.
The 10 CFR 50, Appendix J program tests the primary containment pressure boundary and verifies the boundary integrity.
All piping and penetrations of primary containment are tested.
This includes
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systems outside the scope of ASME Section XI, where their Class 2 piping and isolation valves penetrate containment.
Portions of the subject systems are classified as Class 2 since they are a
piping system that penetrates primary containment.
Therefore, for primary containment integrity purposes, the penetration piping and valves are important to nuclear safety.
The actual system process functions are not s'afety-related and are not important to nuclear safety.
Code Case N-522 acknowledges this and allows verification of the penetration piping and valve integrity per the containment testing
- program, as required by 10 CFR 50 Appendix J, instead of the IWC-5221/5222 pressure tests.
Leak rate testing for Unit 2 is performed in accordance with 10 CFR 50 Appendix J, Option B (performance based) at a minimum pressure of 49.6 psig (accident pressure).
Implementation of Code Case N-522 will eliminate the need for approval and maintenance of eight surveillance procedures.
It will also eliminate craft, inspector, operations, and engineering manhours and the radiation exposure associated with performance of the tests (estimated at 400 man-hours and 1 manrem, respectively).
The pressure retaining function of these lines and valves are verified by the Appendix J program.
Redundant testing provides little additional benefit in quality or safety while expending significant resources and additional radiation exposures.
ALTERNATIVE TESTING As an alternative to the existing Section XI, Table IWC-2500-1, Category C-H requirements, BFN will utilize the provisions of ASME Code Case N-522 which states that 10 CFR 50, Appendix J test results may be used.
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ENCLOSURE 2 TENNESSEE VALLEY AUTHORITY BROWNS FERRY NUCLEAR PLANT (BFN)
UNIT 2 AMERICAN SOCIETY OF MECHANICAL ENGINEERS ASME SECTION XI INSERVICE INSPECTION (ISI)
PROGRAM (SECOND INSPECTION INTERVAL),
REQUEST FOR RELIEF TO SUPPORT THE CYCLE 9 REFUELING OUTAGE (See Attached)
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Tennessee Valley Authority Browns Ferry Nuclear Plant (BFN)
Unit 2 ASME 'SECTION XI INSERVICE INSPECTION PROGRAM (SECOND INSPECTION INTERVAL)
REQUEST FOR'ELIEF 2-ISI-7 (REVISED)
UNIT COMPONENTS ASME CODE CLASS EXAMINATION CATEGORY ITEM NUMBER BFN Unit 2 Class 1 and 2 Integral Welded Attachments 1 and 2
B-K-1 and C-C B10.10, C3.20 ASME CODE REQUIREMENT (S)
ASME Section XI, 1986 Edition (no addenda),
'Table IWB-2500-1, Examination Category B-K-1 integrally welded attachments greater than or equal to 5/8 inch thickness, Figure IWB-2500-1'5.
ASME Section XI, 1986 Edition (no addenda),
Table IWC-2500-1, Examination. Category C-C integrally welded, attachments greater than or equal to 3/4-inch thickness, Figure IWC-2500-5.
BASIS FOR RELIEF In accordance with 10 CFR 50.55a (a)(3)(i and ii) TVA proposes to use an alternative to the ASME Code requirements specified above.
Relief is, requested from:
(1)
ASME Section XI, Table IWB-2500-1, requirement
.to perform a volumetric or surface examination, as applicable, of essentially 100 percent of the examination volume/area.
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(2)
ASME Section XI, Table IWC-2500-1, requirement to perform a surface examination of 100 percent of required areas of each welded attachment.
TVA is requesting relief from ASME Section XI, 1986 Edition (no addenda) requirements related to the 100 percent examination of the required weld and base material volume required by Figure IWB-2500-15 for Examination Category B-K-1 integrally welded supports.
The supports shall be identified after'each outage in which examinations are performed, and an updated list of integrally welded supports shall be prepared each inspection period and incorporated into this request for relief.
Examination of the accessible areas of the integral attachment welds with out removal of support members would result in estimated savings of approximately
$ 110,000 for personnel and materials, and approximately 150 man-rems of exposure, which equates to
$ 1, 500, 000 during the remaining BFN Unit 2 inservice inspection intervals for a total savings of $ 1.6 million dollars.
ASME Section XI, 1986 Edition (no Addenda),
Table IWB-2500-1, Examination Category B-K-1, Item Number B10.10, requires examination of essentially 100- percent of the weld and base material for integrally welded at tachments and Table IWC-2500-1, Examination Category C-C, Item Number C3.20, requires examination of 100 percent of required areas of each welded attachment.
In some cases this examination would require the removal of support members to achieve the coverage required by the ASME Code.
Estimated duration for activities associated with the temporary removal of these ASME Class 1 and 2,supports for the examination of integrally welded attachments with an estimate to perform the Code required examination, and associated man-hours,
- dose, and overall costs are listed below:
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A~ctivit Duration (man-hrs)
Engineering evaluation of temporary support 20 Craft time for support member removal, installation of temporary support, and support reinstallation 1'00 Quality Control verification of activity An average man hour cost of $35/hour was utilized for the estimate along with approximately 25 supports requiring temporary removal for the current inspection interval.
An average drywell exposure rate of 50 mrem/hr was utilized for the man-rem exposure estimate.
These values result in estimated savings of approximately
$ 110,000 for personnel and materials.
A cost of $ 10,000 per man-rem for the 150 man-rems of exposure estimated during
.the remaining inservice inspection intervals for Unit.2 would result in a savings of
$ 1, 500, 000.
The Code of record requires examination of 100 percent of the Class 1 integrally welded attachments subject to-examination which precludes selection of alternate integrally welded. attachments without interferences to meet ASME Code requirements.
n The 25 Class 1 supports estimated as requiring disassembly to conduct the examination of the integrally welded attachments represent approximately 45 percent of the total number of integrally welded supports in this Code category subject,to examination.
The Class 2 integrally welded attachment supports are those examined in accordance with Examination Categories C-F and C-G.
The Class 2 supports that would require disassembly to conduct the examination will be evaluated during each inspection period E2-4
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for Code coverage achieved on all accessible areas and the areas that cannot be examined, without disassembly.
Integral attachments where examinations could not be performed and reduction in coverage would be greater than 10 percent would become a part of this request for relief with relevant information identified as an attachment to this request for relief.
The limitations encountered during performance of the surface examination are caused by component configuration.
Based on a construction permit date issued prior to January 1,
1971, for BFN Unit 2 and as required by 10 CFR 50.55a(g)(1) and 10 CFR 50.55a(g)(4),
BFN must meet the requirements of ASME Section XI, except design and access provisions, to the extent practical within the limitations of design,
- geometry, and materials of construction of the components.
BFN Unit 2 was not designed to provide access for ASME Section XI examinations.
ALTERNATE EXAMINATIONS The surface examinations of the subject integral attachments from the accessible surfaces provide an effective assessment of the integral attachment's structural integrity.
Perform the required examination method from Table IWB-2500-1, Examination Category B-K-1, Item Number B10.10 on the accessible examination volume/area of the support integral attachment without removal of support members.
Perform the required surface examination from Table IWC-2500-1, Examination Category C-C, Item Number C3.20, on the accessible areas of the support integral attachment without removal of support members.
The examination of the accessible areas without removal of support members was approved for a future Code revision by the ASME Section XI committee during their March 1995 meeting and incorporated into the 1995 ASME Section XI Addenda.
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