ML17278B168
| ML17278B168 | |
| Person / Time | |
|---|---|
| Site: | Columbia  |
| Issue date: | 01/09/1987 |
| From: | Sorensen G WASHINGTON PUBLIC POWER SUPPLY SYSTEM |
| To: | Adensam E Office of Nuclear Reactor Regulation |
| References | |
| GO2-87-004, GO2-87-4, TAC-60740, NUDOCS 8701160164 | |
| Download: ML17278B168 (10) | |
Text
ACCESSION NBR:
FAC IL:50-397 AUTH. NAI'tE BQRENSENp 0. C.
RECXP. NANE ADENSAN> E. C.
REQU ORY INFORNATION DISTRIBUT SYSTEM <RIDS) 8701160164 DOC. DATE: B7/01/09 NOT*RIZED:
NQ WPPBS Nuclear Prospect.
Unit 2i Washington Public Pove AUTHOR AFFILIATION Washington Public Power SupplM System RECIPXENT AFFILIATION BWR Prospect Directorate 3
DOCKET ¹ 05000397
SUBJECT:
Forwards addi info re proposed MNP-2 Tgpe C testing progYam per telecon.
DISTRIBUTION CODE:
A017D COPXES RECEIVED: LTR ENCL SIZE:
TXTLE:
OR Submittal:
Append J Containment Leak Rate Testing NOTES'ECIPIENT ID CODE/NAt'tE BWR ADTB BWR EICBB BWR PD3 LA BRADFUTE, J
'BWR RBB INTERNAL ACRB 07 ELD/HDB2 08 NRR PWR-A ADTS B
EIB 0 FIL 04 COPIES LTTR ENCL 1
1 2
2 0
1 1
1 10 10 1
1 1
REC IP IENT ID CODE/NANE BWR EB BMR FQB BWR PD3 PD 01 BMR PSB
5 5
1 0
1 1
1 EXTERNAL: LPDR NBIC 03 05 1
1 1
1 NRC PDR 02 1
1 TOTAL NUNBER QF COPIES REQUIRED:
LTTR 35 ENCL 33
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Washington Public Power Supply System P.O. Box 968 3000 George Washington Way Richland, Washington 99352 (509) 372-5000 8701160164 87010'P PDR ADOCK 05000397 P
PDR January 9,
1987 G02-87-004 Docket No.
50-397 Director of Nuclear Reactor Regulation Attn:
Ms.
E.
G.
- Adensam, Project Director BWR Project Directorate No.
3 Division of BWR Licensing U.S.
Nuclear Regulatory Commission Washington, D.C.
20555 Dear Ms.
Adensam:
Subject:
Reference:
NUCLEAR PLANT NO.
2 OPERATING LICENSE NPF-21 REQUEST FOR EXEMPTION/TECHNICAL SPECIFICATION CHANGE (APPENDIX J AND SECTION 4.6.1.2.d) 1)
Letter.
G02-86-338, G.C.
Sorensen (SS) to E.G.
Adensam (NRC),
same subject, dated 1/31/86 2)
- Letter, G02-86-677, G.C.
Sorensen (SS) to E.G.
Adensam (NRC),
same subject, dated 7/22/86 The reference letters requested exemptions and Technical Specification changes related to Appendix J, Type BSC leak rate testing and provided information as to the criteria used to identify testing schedules.
In subsequent telephone conversations with the Staff supplementary infor-mation on the proposed WNP-2 Type C testing program was requested.
The attachment to this letter provides the requested information.
It should be noted that the attached program description expands upon and com-pletely replaces the information provided in Reference 2.
'he requested exemptions and Technical Specification change are desired prior to commencing the next refueling outage, nominally scheduled for April 1987.
As discussed in Reference 1 strict compliance with the present schedules misdirects resources, has the potential for imposing plant shutdown during a period of high energy demand combined with low hydroelectric capacity, and is not in keeping with as low as reasonably achieveable (ALARA) exposure programs.
t E.
G.
Aden Page Two January 9,
1987 REQUEST FOR EXEMPTION/TECHNICAL SPECIFICATION CHANGE APPENDIX J AND SECTION 4.6.1.2.d The potentially large expenditure of manpower, resources, and exposure represented by complete Type B and C-testing requires a considerable amount of planning, scheduiling and resource allocation.
Any expedited processing of this request will be beneficial to the resource alloca-tion and scheduling presently underway in sunport of the April refueling outage.
Should you requi re any further assistance to aid in evaluating this request,
'please contact Mr. P.L. Powell,
- Manager, WNP-2 Licensing Yery truly yours, G.
C.
- orensen, Manager Regulatory Programs PLP/bk Attachment cc:
JO Bradfute -
NRC C Eschels -
NRC RV E
Revell - BPA NS Reynolds - BLCP8R NRC Site Inspector
WNP-2 APPENDIX J - TYPE C TESTING PROGRAM DESCRIPTION The scope of WNP-2's Appendix J Type C testing presently encompasses 357 valves acting as containment isolation boundaries contained in 77 pene-trations.
Depending on piping configurations, valves in a given penetra-tionn are tested individually, in-series with other isolation valves, or in parallel.
From a group of tests on a given penetration, single failure criteria is applied for all possible leak paths, with the configuration yielding the largest leakage rate being used to arrive at a total leakage rate for that containment penetration.
Appendix J and Plant Technical Specifications limit the sum total of all Type C and Type B (electrical penetrations, airlock, hatches) penetration leakages to 0.60 La which equates to 67,920 sccm.
As a function of valve size and valve type, the acceptable leakage rate for valves will vary.
Using the values established by ASME (IWY-3426) defining permissable leakage limits for safety related valves, excessive leakage limits have been established for each Type C test performed.
This limit is directly proportional to the valve size.
A specific test configuration may concurrently test several isolation valves.
In such instances, the excessive leakage limit assigned to the group of valves is equal to that which is permissable per IWY-3426 for one valve of a diameter equal to the largest valve in that group.
As substantiated by leak testing data from three previous outages, 70Ã of the isolation valves leak at rates far below the excessive leakage limit established per IllY-3426.
These low leakage values have maintained over 504 of the containment penetrations in, a low leakage category.
Plant Technical Specifications require that containment isolation valves be leak tested at intervals not to exceed 24 months.
Based on the typical 12 month refueling cycl'e at WNP-2, roughly half of the containment isola-tion valves can be tested during each outage with no valve seeing more than two years of service without being tested.
This approach reduces the man-rem exposure received from testing all valves during each outage.
Based on data obtained from previous testing in 1985 and 1986, several valves have leaked at a rate in excess of the limit set forth in IWY-3426.
These valves have been repaired when possible (considering function,
- schedule, spare parts availability, ALARA) or have been left as-found when a substantial margin existed between the total leakage computed to date and the Appendix J/Technical Specification limit of 0.6La.
The degree of confidence in low leakage rates exhibited by over 70% of the isolation valves is not maintained by these valves which have exceeded their permissable leakage rates.
Therefore, testing more frequently than at 24 month intervals for these valves is warranted until repeated acceptable leakage rates are obtained from consecutive tests.
The critical attributes of the WNP-2 program are as follows:
o All Type C containment isolation valves will be tested at a minimum of every 24 months.
o Valves not meeting acceptance criteria (excessive leakage limits) will be tested during the subsequent outage (typically within 12 months) until acceptable as-found leakage rates are obtained.
o A 'Total Leakage Rate to Oate'abulation will be maintained re-flecting the following:
I)
Results of Type C tests performed to date during an outage, plus 2)
As-left leakage rates of all valves not requiring testing in a given outage due to acceptable leakage rates from previous outages, pl Us 3)
Results of Type B tests performed to date during an outage, plus 4)
As-left Type B leakage rates from previous outages for those not being tested during a given outage, plus 5)
As-left leakage rates from previous tests on containment purge supply and exhaust valves, plus 6)
As-left leakage rate from previous tests on the containment personnel airlock.
The suranation of all six categories above shall not exceed the limit set forth in Appendix J and Technical Specifications of 0.6La.
o The following valves/penetrations are on our augmented testing schedule as required by Technical Specifications and are not subject to considera-tion for a change in testing frequency:
I)
Hain Steam Isolation Valves - minimum of once per 18 months.
(For WNP-2, this testing presently occurs annually).
2)
Containment Purge Supply and Exhaust Valves - minimum of once per 6 months.
3)
Personnel Airlock - minimum once per 6 months.
o Reactor Feedwater check valves performing a containment isolation function at WNP-2 utilize a dual seat arrangement (resiliant seat and normal stelli te seating surface on valve disc).
Although the dual seat has improved the ability to obtain low leakage
- rates, the resiliant seats are subject to deterioration due to various, system characteristics.
Industry experience is mixed as are the
leak testing results at WNP-2 during the previous outages.
The leak testing performed during the 1985 outage'ielded high leakage rates and resulted in replacement of the soft seats.
During the 1986 outage, all four check valves exhibited low leakage, with three of the four less than 10 sccm each.
WNP-2 will continue to test these valves every refueling outage until a clear trend of low leakage rates is recognized.
At that time, these valves will be evaluated as to their testing frequency, within the bounds of the Type C testing program established herein.
Based on the above positions and past testing results, the following test-ing program has been developed (independant of augmented testing require-ments for HSIV's, Purge Valves, Feedwater Check Valves and Personnel Airlock):
1987 Outage -
Test approximately 50% of Type C containment pene-trations to include all penetrations containing valves which failed to meet the excessive leakage criteria in the as-found condition during 1986 outage testing.
1988 Outage -
Test all remaining penetrations not tested during previous outage ylus all penetrations containing valves which fail~e to meet the excessive leakage limit in the as-found condition during the 1987 outage.
1989 Outage -
Test all 'penetrations not tested during previous outage plus all penetrations containing valves which fbied to meet the excessive leakage limit in the as-found condition during the 1988 outage.
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