ML18039A387
| ML18039A387 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 06/12/1998 |
| From: | Abney T TENNESSEE VALLEY AUTHORITY |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| TAC-M97805, TAC-M99004, NUDOCS 9806190118 | |
| Download: ML18039A387 (54) | |
Text
CATEGORY 1 REGULATO~
INFORMATION DISTRIBUTION STEM (RIDS)
ACCESSION NBR:9806190118 DOC.DATE: 98/06/12 NOTARIZED: NO DOCKET ¹ FACIL:50-.260 Browns Ferry Nuclear Power Station, Unit 2, Tennessee 05000260 50-'296 Browns Ferry Nuclear Power Station, Unit 3, Tennessee 05000296 AUTH.NAME AUTHOR AFFILIAT1ON ABNEY,T.E.
Tennessee Valley Authority RECIP.NAME RECIPIENT AFFILIATION Document Control Branch (Document Control Desk)
SUBJECT:
Provides two revised requests for relief,3-SPT-3
& 3-SPT-2, for BFN,Unit 3,ASME Section ZI,Sys Pressure Test Program.
Revised request for relief,2-SPT-ll,encl.
DISTRIBUTION CODE: A047D COPIES RECEIVED:LTR ENCL SIZE:
TITLE: OR Submittal: Inservice/Testing/Relief from ASME Code GL-89-04 NOTES:
RECIPIENT ID CODE/NAME PD2-3 DEAGAZ10,A COPIES RECIPIENT LTTR ENCL
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INTERNAL: ACRS
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1 EXTERNAL: LITCO ANDERSON NRC.PDR 1
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NOTE TO ALL nRIDS" 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
- a l
Tennessee Valley Authority, Post Of(ice Box 2000. Decatur. Alabama 35609 June 12, 1998 10 CFR 50. 55a U.S. Nuclear Regulatory Commission ATTN:
Document Control Desk Washington, D.C.
20555 Gentlemen; In the Matter of Tennessee Valley Authority Docket Nos.
50-260 50-296 BROWNS FERRY NUCLEAR PLANT (BFN)
UNITS 2 AND 3 AMERICAN SOCIETY OF MECHANICAL ENGINEERS (ASME )
SECTION XIr SYSTEM PRESSURE TEST PROGRAM REQUESTS FOR RELIEF 3 SPT 3 r 3 SPT 4
AND 2-SPT-11 (TAC NOS.
M97805 AND M99004)
This letter provides two revised requests for relief (3-SPT-3 and 3-SPT-4) for the BFN Unit 3, ASME Section XI, System Pressure Test Program.
TVA is also submitting a revised request for relief (2-SPT-11) for the BFN Unit 2, ASME Section XI, System Pressure Test Program.
The Unit 3 requests for relief were originally submitted by TVA letter dated January 22,
- 1997, as part of the BFN Unit 3 ASME Section XI Inservice Inspection and System Pressure Test Programs for the second inspection interval.
In response, NRC issued a request for additional information (RAI) by letter dated October 6,
1997.
The Unit 2 request for relief was initially submitted by TVA letter dated June 4,
1997.
NRC responded by letter dated August 11, 1997, stating that ASME Code Case N-566, on which the relief was based, had not been reviewed and approved by the NRC staff and that relief would not be granted.
980bi'sfOii8 980bi2 PDR ADOCK 050002b0 P
II C
U.S. Nuclear Regulatory Commission Page 2.
June 12, 1998 Enclosure 1 to this letter provides TVA's response to NRC's RAI regarding requests for relief 3-SPT-3 and 3-SPT-4.
Enclosure 2 provides revisions to the BFN Unit 3 requests for relief, 3-SPT-3 and 3-SPT-4, that address NRC's questions.
TVA will submit a response to the other issues identified in the NRC request for additional information in a separate response.
Enclosure 3 contains the BFN Unit 2 revised request for relief 2-SPT-11.
TVA requests review of the enclosed Unit 3 requests for relief by August 14, 1998, to support the Unit 3 Cycle 8
refueling outage scheduled to begin September 20, 1998.
- Also, TVA requests review of the enclosed Unit 2 request for relief by March 1,
- 1999, to support the Unit 2 -Cycle 10 refueling outage scheduled to begin on April 11, 1999.
There are no commitments contained in this letter.
If you have any questions, please telephone me at (256) 729-2636.
ce ly T. E. Abney Manager of Li ensing and Industry Affai s Enclosures cc:
See page 3
U.S. Nuclear Regulatory Commission Page 3,
June 12, 1998 Enclosures cc (Enclosures):
Mr. Michael T. Anderson INEL Research Center 2151 North Boulevard P.O.
Box 1625 Idaho Falls, Idaho 83415-2209 Mr. Harold O. Christensen, Branch Chief U.S. Nuclear Regul'atory 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. Albert W.
De Agazio, Project Manager U.S. Nuclear Regulatory Commission One White Flint, North 11555 Rockville Pike Rockville, Maryland 20852
Ii IO C
I
ENCLOSURE 1
TENNESSEE VALLEY AUTHORITY BROWNS FERRY NUCLEAR PLANT (BFN)
UNIT 3 AMERICAN SOC IETY OF MECHANICAL ENGINEERS (ASME)
SECT ION XI SYSTEM PRESSURE TEST (SPT)
PROGRAM (SECOND INSPECTION INTERVAL)
RESPONSE
TO REQUEST FOR ADDITIONAL INFORMATION FOR REQUESTS FOR RELIEF 3 SPT 3 ~
AND 3 SPT 4
Introduction By letter dated January 22,
- 1997, TVA submitted the BFN Unit 3 ASME Section XI Inservice Inspection and System Pressure Test Programs for the second inspection interval.
TVA also included requests for relief that had been identified as needed for the second inspection interval.
For the System Pressure Test Program, requests for relief 3-SPT-3 and 3-SPT-4 were included in this submittal.
In response, NRC issued a
request for additional information (RAI) by letter dated October 6,
1997.
Listed below are the specific NRC questions regarding 3-SPT-3 and 3-SPT-4 and TVA's response.
TVA is responding to the other issues identified in the subject RAI in a separate response.
For Code Case N-546, Alternative Requirements for Qualification of VT-2 Visual Examination Personnel, the NRC staff finds this alternative to Code requirements acceptable only if the licensee commits to:
(1) Developing procedural guidelines for obtaining consistent, quality VT-2 examinations; (2) document and maintain records to verify the qualification of persons selected to perform VT-2 visual examinations; and (3) implement independent review and evaluation of leakage by persons other than those that performed the VT-2 visual examinations.
TVA Res onse TVA agrees to the additional conditions to Code Case N-546 as stated above.
A revision to 3-SPT-3 is included in Enclosure 2.
This request for relief is consistent with
F
request for relief 2-SPT-10 submitted by TVA letter dated September 9,
- 1997, and accepted by the staff in NRC letter dated October 16, 1997.
The licensee has requested approval for the use of Code Cases N-498-2, N-547, and N-566.
These Code cases are currently being reviewed by the NRC and have not been approved for use as written.
As such, their use is not endorsed.
Therefore, the licensee should review the current submittals associated with these Code cases and consider withdrawal.
Describe
.the action the licensee proposes regarding the use of the subject Code cases.
TVA Res onse TVA is submitting a revised request for relief (3-SPT-4) that is site specific, yet is similar to Code Case N-566.
Request for relief 3-SPT-4 seeks relief from ASME Section XI, Subarticle IWA-5250(a)(2) which, in all cases, requires removal of bolting from leaking bolted connections which are identified in the course of an IWA-5000 pressure test.
The BFN Unit 3 request for relief is more prescriptive and more conservative than the code case.
It also addresses many of the implementation and radiological hardships associated with IWA-5250(a)(2); and maintains the conclusion of the ASME Code Committee by assuring that a proper evaluation of the connection and/or the bolting is performed.
The bolted connection evaluation will consider factors, which if indicative of degradation, must be dispositioned in accordance with ASME Section XI, Subsection IWB-3140.
The alternate bolted connection evaluation is more comprehensive than the simple bolt inspection currently required by IWA-5250.
The alternative requirements of this request for relief ensures structural integrity is maintained, reduces the operational, maintenance, and radiological hardships of the current requirements, and provides an acceptable level of quality and safety.
TVA considers this request for relief as an acceptable alternative in accordance with 10 CFR 50.55a(a)(3)(i).
TVA is also submitting a similar request for relief (2-SPT-11) for BFN Unit 2.
TVA initially submitted 2-SPT-11, which was based on ASME Code Case N-566, by letter dated June 4,
1997.
NRC responded by letter dated August 11, 1997, stating that
O~
~5
ASME Code Case N-566 had not been reviewed and approved by the NRC staff and that relief would not be granted.
TVA subsequently withdrew request for relief 2'-SPT-11 by letter dated September 9,
1997.
- However, TVA stated that it may resubmit 2-SPT-11 at a later date
~
The BFN Unit 2 request for relief (2-SPT-11) considers the same evaluation attributes discussed above for the BFN Unit 3 (3-SPT-4) request for relief.
The BFN Units 2 and 3 requests for relief are consistent with requests for relief previously accepted by. the NRC staff for Oyster Creek and V. C.
Summer generating stations by letters dated October 3,
- 1996, and September 22, 1997.
TVA will respond to the NRC staff's request for additional information regarding ASME Code Cases N-498-2 and N-547 in a separate response.
E1-3
i~
ENCLOSURE. 2 TENNESSEE VALLEY AUTHORITY BROWNS FERRY NUCLEAR PLANT (BFN)
UNIT 3 AMERICAN SOC IETY OF 'MECHANICAL ENGINEERS (ASME )
SECTION XI SYSTEM PRESSURE TEST (SPT)
PROGRAM (SECOND INSPECTION INTERVAL)
REVISED REQUESTS FOR RELIEF 3-SPT-3 AND 3-SPT-4 (See Attached)
II ii
TENNESSEE VALL'EY AUTHORITY BROWNS FERRY NUCLEAR PLANT (BFN)
UNIT 3'SME SECTION X'II,SYSTEM PRESSURE TEST (SPT)
PROGRAM (SECOND INSPECTION INTERVAL' REQUEST FOR RELI'EF 3 SPT 3 I REVIS ION 1
.(ASME CODE'ASE N-54 6)
EXECUTIVE
SUMMARY
As a proposed alternative, in accordance with. 10 CFR 50.55a(a)(3)(i),
to the VT-2 visual inspection qualification requirements (ASME Code Section XI, Subarticle IWA-2300)'t is requested that trained experienced plant personnel that meet specific vision requirements be qualified to perform the required ASME Section XI leakage inspections.
ASME Code Case N-546 (Attachment A) specifies alternate requirements for VT-2 inspectors.
TVA previously submitted a request for relief for BFN Unit 3 identified as 3-SPT-3 for NRC review by letter dated January 22, 1997.
Following TVA's submittal, NRC responded by letter dated October 6,
- 1997, with additional requirements.
TVA has incorporated the additional requirements requested by NRC into this revised relief request (3-SPT-3, Revision 1).
This request for relief is consistent with one previously accepted for BFN Unit 2 by NRC letter dated October 16,,
1997.
UNIT:
Second ASME Section XI ISI/SPT Interval, (Start Date:
November 19, 1996),
SYSTEMS Various American Society of Mechanical Engineers (ASME) Section.XI Systems E2-2
II i>
Re uest For Relief 3-SPT-3, Revision 1,
(Continued)
COMPONENTS'lass 1,
2, and 3 Pressure Retaining Components CODE CLASS:
FUNCTION 1,
2, and 3
Pressure Retaining Boundary ASME CODE REQUIREMENT (S):
ASME Section XI, 1989 Edition.(no Addenda),
Subarticle 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-lA and the additional requirements of Division 1 of ASME Section XI.
ASME CODE REQUIREMENT FROM WHICH RELIEF IS REQUESTED'elief is requested from the inspector qualification requirements stipulated in ASME Section XI, 'Subsection IWA-2300.
BASIS FOR RELIEF:
In accordance with 10 CFR 50.55a(a)(3)(i)
TVA proposes to use an alternative to the ASME Section XI Code requirement specified above.
The use of Code Case N-546, "Alternative Requirements for Qualification of VT-2 Examination Personnel,
" will allow experienced plant personnel to perform VT-2 visual examinations during the performance of system pressure tests and provide an acceptable level of quality 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 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 E2-3
i+i
Re uest For Relief 3-SPT-3, Revision 1, (Continued) to IWA-2300.
This is especially pertinent 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 qualified 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.
TVA considers the ASME Code Case N-546 requirements to be an acceptable alternative to the qualification 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 REQUIREMENTS's an alternative to the existing ASME Section XI requirements, BFN will utilize the provisions of ASME Code Case N-546 and add'itional criteria.
ASME Code Case N-546 states:
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.
2.
Individuals must have at least four hours of training in Section XI requirement:s and plant specific procedures for visual examinations.
3.
Each person must meet (annual) vision test requirements in accordance with the 1995 Edition of t:he ASME Section XI
- Code, Paragraph IWA-2321.
E24
Re uest For Relief 3-SPT-3, Revision 1,
(Continued)
In addition to the requirements of ASME Code Case N-546, TVA will also:
Develop procedural guidelines for obtaining consistent quality VT-2 visual examinations.
2.
Document and maintain records to verify the qualifications of personnel selected to perform VT-2 visual examinations.
3.
Implement independent review and evaluation of leakage by persons other than those that performed the VT-2 visual examinations.
JUSTIFICATION FOR GRANTING RELIEF The use of Code Case N-546, with TVA's additional requirements, will allow experienced plant personnel to perform VT-2 visual examinations following maintenance, modifications, and during the performance of system pressure tests.
Experienced plant personnel are knowledgeable of the plant systems and routinely perform walkdowns of plant systems looking for abnormalities such as leaks in 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, especially, during refueling outages when pressure tests are performed and the number of IWA-2300 certified personnel are limited.
Since the VT-2 examination is an examination for the evidence of
- leakage, the use of plant personnel qualified to the N-546 alternate E2-5
Re uest For Relief 3-SPT-3, Revision 1,
(Continued) requirements, and who typically perform this type of examination during their daily activities, will not compromise the quality or safety of the systems examined.
TVA considers the ASME Code Case N-546 requirements to be an acceptable alternative to the qualification 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.
IMPLEMENTATION SCHEDULE:.
The request for relief is applicable to the BFN Unit 3, ASME Section XI Program, second inspection interval.
ATTACHMENT:
Attachment A (ASME Code Case N-546)
E2-6
0
~i
Case N-546 3 y Revision I Attachment A
,tive Requizeaents for:Quailfication of VT-2 Examination Personnel Section XI, Divf.lion 1 Inquiry'hat altexnative to the requirements of IMA-2300 may be used for qualification of VT-2 visual examination personnel?
reply~
It, is the opxnzon of the Committee that VT-2 visual examination personnel need not be quoiified nor certified to comparable levels of competence in accordance with the referenced standar4
( I ~ e
~
ANSl Ni5.2. 6, ASNT SNT-TC-1A, or ASST CP" 189 )
.p<<<<4~
t,he examination personne) are qualified. in accordance with the foll<wing requirements.
At least 40 hours4.62963e-4 days <br />0.0111 hours <br />6.613757e-5 weeks <br />1.522e-5 months <br /> plant valkdovn experience, such as t.hat gained by licensed and nonl lcensed.operators, local lea)c ra te personnel, sys tea eng ineers, and ins pect ion and nondestructive examination personnel.
1eact four hours of training on Section XI xequiroaent s and plant speci fic procedures for vT-2 visual examination.
3
~
Vision test requirements of ISA-2321, 1995 Editior..
cabilit From the 1977 Edition up to and including the 1995 edition.
II I '
TENNESSEE VALLEY AUTHORITY BROWNS FERRY NUCLEAR PLANT (BFN)
UNIT 3 ASME SECTION XI~
SYSTEM" PRESSURE TEST (SPT)
PROGRAM (SECOND INSPECTION INTERVAL)
REQUEST FOR RELIEF 3 SPT 4 ~ REVISION 1 EXECUTIVE
SUMMARY
As a,proposed alternative, in accordance with 10 CFR 50.55(a)(3)(i),
to the mandatory removal of bolting from leaking bolted connections
'(ASME Code Section XI, Subarticle IWA-5250(a)(2)) it is requested that a corrective action plan should be allowed following a specific evaluation of the bolted connection structural integrity and susceptibility of the bolting to corrosion and potential failure.
The corrective action plan may or may not require removal of bolting.
TVA previously submitted BFN Unit 3 request for relief 3-SPT-4, based on ASME Code Case N-566, for NRC review by letter dated January 22, 1997.
NRC responded by letter dated October 6,
1997, stating that ASME Code Case N-566 had not been reviewed and approved by the NRC staff and that relief would not be granted.
Code Case N-566 does not prescribe or reference any specific variables or conditions which should be part of the bolted connection evaluation.
Subsequent review by TVA of NRC accepted relief requests from Oyster Creek and V.C.
Summer (NRC letters dated October 3,
- 1996, and September 22, 1997) indicate that an evaluation option may be acceptable to the staff provided a
similar minimum set of evaluation.
variables and corrective actions are prescribed in the request for relief.
E2-7
0 i(
Re uest For Relief 3-SPT-4, Revision 1
(Continued)
UNIT:,
Second ASME Section XI ISI/SPT Interval, (Start Date:
November 19, 1996)
SYSTEMS'arious American Society of Mechanical Engineers (ASME)Section XI Systems COMPONENT:
Class 1,
2, and 3 bolted connections that have leakage identified in the course of an IWA-5000 pressure test.
CODE REQUIREMENT:
ASME -Section XI, 1989 Edition (no Addenda),
Subarticle IWA 5250(a),(2) requires that the source of leakage detected during the conduct of a system pressure test shall be located and evaluated by the Owner for corrective measures.
If leakage occurs at a bolted connection,
.the bolting shall:
(1) be
- removed, (2) VT-3 visually examined for corrosion,,and (3) evaluated in accordance with IWA-3100.
CODE.
REQUIREMENT FROM WHICH RELIEF IS REQUESTED'elief is requested from the requirement in ASME Section XI, Subarticle IWA-5250(a)(2) which, in all cases, requires removal of bolting from leaking bolted connections (which were identified in the course of an IWA-5000 pressure test).
'BASIS FOR RELIEF Relief from the bolt removal requirements of IWA-5250(a)(2) is requested under 10 CFR 50..55(a)-(3)(i), in which the proposed alternative provides an acceptable level of quality and safety.
Some of the problems associated with the current requirements of IWA-5250 (a) (2) are summarized's follows:
E2-8
Re uest For Relief 3-SPT-4, Revision 1
(Continued)
~
IWA-3100 does not provide an acceptance standard for a VT-3 bolt inspection.
~
The requirement calls for bolt removal without regard to the size of the leakage.
~
The requirement increases the radiological dose to workers for leaks that are often not a challenge to operational or structural limits.
~
Bolts sometimes cannot be removed without damaging the bolt or cannot be removed due to component:configuration.
~ It is not a requirement of the Code that the licensee must stop the leakage, and inspection of the bolting is not necessarily going to stop the leak.
~
Removing one bolt at a time,. if allowed by system conditions, may actually increase the leakage.
~
In many cases, implementation of the requirement may cause the plant an unnecessary transient or delay startup.
In addition to the problems associated with the requirements of IWA-5250(a)(2), the ASME Working Group-Pressure Testing concluded that the system integrity of a bolted connection is not necessarily compromised by leakage and recommended the approval of Code Case N-566.
This relief request is essentially a
conservative subset of the Code Case.
E2-9
Re uest For Relief 3-SPT-4, Revision 1
(Continued)
ALTERNATIVE EXAMINATIONS As an alternative to the existing Section XI requirements, the source of all leakage at bolted connections detected by VT-2 examinati'on during a system pressure test shall be evaluated to determine the susceptibility of the bolting to corrosion and potential failure.
This evaluation will consider the following variables at a
minimum:
~
Location of leakage
~
History of leakage
~
Fastener materials
~
Evidence of corrosion, with the connection assembled
~
Corrosiveness of the process fluid
~ History and'tudies of similar fastener material in.a similar environment
~
Other components in the vicinity that may be degraded due to the leakage When the evaluation of the above variables is concluded, and if the evaluation determines that the.leaking condi'tion has not degraded the fasteners, then no further action is required.
- However, reasonable attempts to stop the leakage shall be taken.
If the bolted connection evaluation, using the variables
- above, indicates the need for further evaluation, or no evaluation is performed, then a bolt closest to the source of leakage shall be removed.
The bolt will receive a VT-1 examination and be evaluated for corrosion in accordance with IWA-3100(a) and dispositioned in accordance with IWB-3140.
If the information from the bolted connection evaluation is supportive, the removal of the bolt for VT-1 examination may be deferred to the next refueling outage.
When the removed bolting shows evidence of rejectable degradation,, all E2-10
0 l
Re uest For Relief 3-SPT-4, Revision 1
(Continued) remaining bolts, in the connection, shall be removed and receive a VT-1 examination and evaluation in accordance with IWB-3140.
JUSTIFICATION FOR GRANTING RELIEF This relief request is more prescriptive and more conservative than the Code Case.
It also addresses many of the implementation and radiological hardships associated with IWA-5250(a)(2) and maintains the conclusions of the ASME Committee by assuring that a proper evaluation of the connection and/or the bolting is performed.
The bolted connection evaluation must consider specific factors which, if indicative of degradation, must be dispositioned in accordance with IWB-3140.of ASME Section XI.
Due to the fact that the bolted connection evaluation is more comprehensive than the simple bolt inspection currently required by IWA-5250, coupled with the benefit that these alternative requirements ensure structural integrity is maintained, and reduce the operational, maintenance, and radiological hardships of the current requirements, this relief request provides an acceptable level of quality and safety and should be considered as an acceptable alternative in accordance with 10 CFR 50.55a(a)(3)(i).
This conclusion is further supported by the fact that the ASME has approved Code Case N-566 and this relief request is essentially a
conservative subset of the Code Case.
IMPLEMENTATION SCHEDULE:
This request for relief is applicable to the BFN Unit 3, ASME Section XI Program, second inspection interval.
ATTACHMENT:
Attachment A
0 ig(
031< 1x oc950QS66 02-21-97 1
16' APPtovll Oats August 9. 4990 Sw Humorioal Index for acpiration and any roaNrma4'on data+
CASE N-666 Case
<V-566 Correcdve Action for Leakage Ideatitied at Bolted ConnectionsSection XI, INvision '1 3-SPT-4, Revision 1
Attachment A
Inqulryr What alternative to tbe requirements of IWA-5250(aX2) may be used when leakage is detected at bolted coanectioas?
Raplyr lt is tbe opinion of tbe Committee that, as an alternative to the rcquircaxuts of iWA-5250(al(2),
one of the followiug requircr~ts shaO be met for leakage at, bolted connecnons:
(a) The leakage shall be stopped.
and the boltbrg and component material shall be reviewed for joint integrity.
fb) lf the leakage is not stopped.
tbe joint shall be evaluated In accocdaax whh IWB-3142.4 for joht integrit. This evaluanon shall Include consideration of tbe number and condition of bolts, btaking medium.
bolt and component
- matcdal, system
- function, and leakage monitoring.
ii
ENCLOSURE 3
TENNESSEE VALLEY AUTHORITY BROWNS FERRY,NUCLEAR PLANT (BFN)
UNIT 2 ASME'ECTION XI ~
SYSTEM PRESSURE TEST (SPT)
PROGRAM (SECOND INSPECTION INTERVAL)
REQUEST FOR RELIEF 2 SPT 1 1 ~ REVIS ION 1 (See Attached)
0 ig~
TENNESSEE VALLEY AUTHORITY BROWNS FERRY NUCLEAR PLANT (BFN)
UNIT 2 ASME SECTION XI ~
SYSTEM PRESSURE TEST (SPT)
PROGRAM (SECOND INSPECTION INTERVAL)
REQUEST FOR RELIEF 2 SPT 1 1 I REVISION 1 EXECUTIVE
SUMMARY
As a proposed alternative, in accordance with 10 CFR 50.55(a)(3)(i),
to the mandatory removal of bolting from leaking bolted connections (ASME Code Section XI, Subarticle IWA-5250(a)(2)) it is requested that a corrective action plan should be allowed following a specific evaluation of the bolted connection structural integrity and susceptibility of the bolting to corrosion and potential failure.
The corrective action plan may or may not require removal'f bolting.
TVA previously submitted BFN Unit 2 request for relief 2-SPT-11, based on ASME Code Case N-566, for NRC review by letter dated June 4,
1997.
NRC responded by letter dated August 11, 1997, stating that ASME Code Case N-566 had not been reviewed and approved by the NRC staff, and that relief would not be granted.
Code Case N-566 does not prescribe or reference any specific variables or conditions which should be part of the bolted connection evaluation.
Subsequent review by TVA of NRC accepted relief requests for Oyster Creek and V.C.
Summer (NRC letters dated October 3,
- 1996, and September 22, 1997) indicate that an evaluation option may be acceptable to the staff provided a similar minimum set of evaluation variables and corrective actions are prescribed in the request for relief.
E3-2
II
Re uest For Relief 2-SPT-11, Revision 1'Continued)
UNIT:
BFN Unit 2 IS I INTERVAL:
SYSTEMS Second ASME Section XI ISI/SPT Interval, (Start Date:
May 24, 1992)
Various American Society of Mechanical Engineers (ASME)Section XI Systems COMPONENTS:
Class 1,
2, and 3 bolted connection that have leakage identified in the course of an IWA-5000 pressure test.
CODE REQUIREMENT:
ASME Code 1986 Edition (no Addenda),
Section XI, Subarticle IWA-5250(a)(2) requires that the source of leakage detected during the conduct of a system pressure test shall be located and evaluated by the Owner for corrective measures.
If leakage occurs at a bolted connection, the bolting shall be:
(1)
- removed, (2) VT-3 visually examined for corrosion, and (3) evaluated in accordance
.with IWA-3100.
CODE REQUIREMENT FROM WHICH RELIEF IS REQUESTED:
Relief is requested from the requirement in ASME Section XI, Subarticle IWA-5250(a)(2) which, in all cases, requires removal of bolting from leaking bolted connections (which were identified in the
,course of an IWA-5000 pressure test)
BASIS FOR RELIEF Relief from the bolt removal requirements of IWA-5250(a) (2.) is requested under 10 CFR 50.55(a) (3) (i), in which the proposed alternative provides an acceptable level of quality and safety.
Some of the problems associated with the current requirements of'WA-5250(a)(2) are summarized as follows:
'E3-3
0
<i
Re uest For Relief 2-SPT-11, Revision 1
(Continued)
~
IWA-3100 does not provide an acceptance standard for a VT-3 bolt inspection.
~
The requirement calls for bolt removal without regard to the size of the leakage.
~
The requirement increases the radiological dose to workers for leaks that are often not a challenge to operational or structural limits.
~
Bolts sometimes cannot be removed without damaging the bolt or cannot be removed due to component configuration.
~ It is not a requirement of the Code that the licensee must stop the leakage, and inspection of.the bolting is not necessarily going to stop the leak.
~
Removing one bolt at a time, if allowed by system conditions, may actually increase the leakage.
~
In many cases, implementation of the requirement may cause the plant an unnecessary transient or delay startup.
In addition to the problems associated with the requirements of IWA-5250(a)(2), the ASHE Working Group-Pressure Testing concluded that the system integrity of a bolted connection is not necessarily compromised by leakage and recommended the approval of Code Case N-566.
This relief request is essentially a
conservative subset of the Code Case.
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~ '
Re uest For Relief 2-SPT-11, Revision 1
(Continued)
ALTERNATIVE EXAMINATIONS:
As an alternative to the existing Section XI requirements, the source of all leakage at bolted connections detected by VT-2 examination during a system pressure test shall be evaluated to determine the susceptibility of the bolting to corrosion and potential failure.
This evaluation, will consider the following variables at a
minimum:
~
Location of leakage
~ History of leakage
~
Fastener materials
~
Evidence of corrosion, with the connection assembled
~
Corrosiveness of the process fluid
~
History and studies of similar fastener material in a.similar environment
~
Other components in the vicinity that may be degraded due to the leakage When the evaluation of the above variables is concluded and if the evaluation determines that the leaking condition has not degraded the fasteners, then no further action is required.
- However, reasonable attempts to stop the leakage shall be taken.
If the bolted connection evaluation, using the variables
- above, indicates the need for further evaluation, or no evaluation is performed, then a bolt closest to the source of leakage shall be removed.
The bolt will receive a VT-1 examination and be evaluated for corrosion in accordance with IWA-3100(a) and dispositioned in accordance with IWB-3140. If the information from the bolted connection evaluation is supportive, the removal of the bolt for VT-1 examination may be deferred to the next refueling outage.
When the removed bolting shows evidence of rejectable E3-5
)Q
Re uest For Relief 2-SPT-11, Revision 1
(Continued) degradation, all remaining bolts, in the connection, shall be removed and receive a VT-1 examination and evaluation in accordance with IWB-3140.
JUSTIFICATION'OR GRANTING RELIEF This relief request is more prescriptive and more conservative than the Code Case.
It also addresses many of the implementation and radiological hardships associated with IWA-5250(a)(2) and maintains the conclusions of the ASME Committee by assuring that a proper evaluation of the connection and/or the bolting is performed.
The bolted connection evaluation must consider specific factors which, if indicative of degradation, must be dispositioned in accordance with IWB-3140 of ASME Section XI'ue to the fact that the bolted connection evaluation is more comprehensive than the simple bolt inspection currently required by IWA-5250, coupled with the benefit that these alternative requirements ensure structural integrity is maintained, and reduce the operational, maintenance, and radiological hardships of the current requirements, this relief request provides an acceptable level of quality and safety and should be considered as an acceptable alternative in accordance with 10 CFR 50.55a(a)(3)(i).
This conclusion is further supported by the fact that the ASME has approved Code Case N-566 and this relief request is essentially a
conservative subset of the Code Case.
IMPLEMENTATION SCHEDULE:
The request for relief is applicable to the BFN Unit 2, ASME Section XI Program, second inspection interval.
ATTACHMENT:
Attachment A
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CASE N-666 Case iV-566 Core ective,hction foe Leakage IdeetNed at Bolted ConnectionsSection XI, INvisloa I 2-SPT-1'1, Revision 1
Attachment A
Inquiry: What.alternative to the requirements of IWA-5250(a){2) may be used when leakage is dctcctcd
',at bolted connccdoos7
,Rrpiyr It.is the opinion of, the Commlnee that, as an alternative to the requirements of IWh-5250(a)t2),
one of the followiug aqulrements shall be met for leakage at bolted connections:
,(a) Tbe leakage shall be stopped.
and, the bolting and component material shall be reviewed for joint integrity.
(b) If the, leakage ls not stopped, the joint shall be evaluated ln accordance whh IWB-3142.4 for Joint integrity. This evaluanon shal1 include consideration of the number iand condition of bolts, lbaklng mediutne bolt and component matcrbtl.
system function, and leakage monitoring.
it