ML20136G506
| ML20136G506 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 03/11/1997 |
| From: | Ross M GENERAL PUBLIC UTILITIES CORP. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| 6710-97-2060, NUDOCS 9703180062 | |
| Download: ML20136G506 (3) | |
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GPU Nuclear, Inc.
A Route 441 South NUCLEAR Post Office Box 480 Middletown, PA 17057-0480 Tel 717-944 7621 March 11,1997 6710-97-2060 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555
Dear Sir:
Subject:
Three Mile Island Nuclear Station, Unit 1 (TMI-1)
Operating License No. DPR-50 Docket No. 50-289 Technical Specification Change Request (TSCR) No. 259, Supplement No.1, Implementation of 10 CFR 50 Appendix J, Option B This letter supplements GPU Nuclear letter 6710-96-2221, dated June 28,1996 which transmitted Technical Specification Change Request No. 259," Implementation of 10 CFR 50, Appendix J, Option B." Included was a change to adopt the performance based testing program for the Containment Purge Valves (AH-VI A/B/C/D) consistent with 10 CFR 50, Appendix J, Option B testing requirements. In support of this change GPU Nuclear stated that this change was based on test results these valves have demonstrated over the years since the NRC imposed a quarterly test frequency for TMI-l valves. GPU Nuclear attributed these favorable test results to improved purge valve maintenance and testing procedures and stated that these procedures would be preserved as appropriate by the performance based Reactor Leakage Rate Testing Program. In a conference call on February 7,1997 the NRC requested that GPU Nuclear submit test data to support this change. Attached is the requested information.
The attached table of test data gives the purge valve test results since April 1986. TMI-l purge valves are normally tested by pressurizing the interspace between the two valves in series and measuring the pressure decay rate. A soap test has oRen been used to determine if an individual valve is leaking, and consequently, which vdve should be adjusted prior to retest. Where two test values are shown for a particular test date, these represent the "as found" and "as left" test results.
Often we have performed an "as found" test near the beginning of a refueling outage and the "as fDY0)/
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6710-97-2060 Page 2 of 2 leR" test at the end after cleaning, inspecting, lubricating, and cycling the valves. Where no adjustments were made between the "as found" and "as left" tests and the results were different, we believe that the leak rate measurement was affected by routine maintenance and cycling. In
- the few cases where a valve was found to be leaking excessively,' the test result for the other j
valve in series was good.
Vey little purge valve corrective maintenance has been necessary since all purge valve seats were last replaced in 1985, although periodic seating readjustments were needed until the seats were 2
fully stable around 1990. In conjunction with our efforts to determine the appropriate guidance for replacement of purge valve seats, we instituted a preventive maintenan:e (PM) program m
)
which the valve seats are inspected, cleaned, hardness tested, and re-lubricated periodically (currently at 24-month intervals) for protection from aging. If evidence of significant seat deterioration is noted, the seats would be replaced. The TMI-l purge valve test histoy supports the adequacy as well as the need to continue this PM program.
Based on the current test history, our evaluation in accordance with the performance based requirements permitted by Appendix J, Option B concludes that purge valve testing on an annual basis isjustified. Although recent test results have been good, adjustments are planned for the next refueling outage to improve the performance of the AH-VIC/D valve pair. With continued good performance in the future, we believe that a longer test frequency may be justified. But we also believe that it is unlikely that the maximum Option B test interval could be justified. Because
- of the special nature of these valves, their size and past performance history in conjunction with the importance of these valves toward maintaining containment integrity, we believe that additional attention will always need to be given to the purge valves to assure that containment integrity will not be compromised.'
This supplement has no effect on the safety evaluation justifying the proposed amendment or on the corresponding significant hazards consideration conclusions included with our June 28,1996 submittal.
Sincerely, i
M. J. Ross Director, TMI(Acting)
MRK Attachment cc: Administrator, NRC Region I TMI Senior NRC Resident Inspector TMI Senior NRC Project Manager
' The administrative limit on rate of pressure drop is equivalent to a leakage rate of approximately 8700 SCCM. This is based on more than 20 years of maintenance and testing of TMI l valves and represents a reasonable expectation of valve prformance.
TMI-l does not perform pre-scheduled seat replacements as we found that this could be unnecessary or even undesirable.
~_
'6710-97 2060 Attachtnent TMI-1 Containment Purge Valve Test Results.(From April 1986)
AH V1 A/B AH-V1 C/D Test Date Leakaoe (SCCM)'
Remarks Test Date Leakaae (SCCM)'
Remarks 04/15/86 897/2028 04/18/86 2026/3995 06/14/86 18433/234 See Note #
06/14/86 1560 09/25/86 780 09/17/86 1229 11/04/86 No test See Note
- 11/04/86 1989 See Note
- 4 03/16/87 546 03/16/87 2750 06/25/87 410 06/24/87 1580 09/14/87 429 09/13/87 1404 12/15/87 68020/234 See note
- 12/14/87 7098/2124 03/15/88 371 03/14/88 2691 4
06/11/88 429 06/12/88 1404 l
08/04/88 468 08/06/88 6474 12/14/88 1794 10/30/88 6767 03/26/89 1209 03/24/89 2496/7566 06/26/89 1229 06/24/89 3783 09/26/89 897 09/24/89 9946/10665 I
12/27/89 995 12/25/89 13924 See Note *
[
03/29/90 1794/5885 03/27/90 1209/1599 j
06/29/90 351 06/27/90 1053 09/29/90-624 09/27/90 2397 12/29/90 468 12/28/90 1560 7
04/01/91 24844/2184 See Note 03/30/91 2379 07/02/91 1365 06/30/91 819 09/22/91 683 09/21/91 410 11/12/91 546 See Note '
11/12/91 1599 See Note
- 01/02/92 527 03/25/92 1989 06/30/92 819 06/28/92 4017 09/28/92 1521 09/26/92 1443 12/27/92 975 12/25/92 3939 03/26/93 254 03/25/93 2379 06/02/93 1638 06/23/93 624 09/14/93 1248 09/13/93 1794 12/01/93 741 11/04/93 1229 03/01/94 1404 03/20/94 3588 05/29/94 1014 06/18/94 1989 09/23/94 1014 09/16/94 1794 11/26/94 858 12/15/94 4914 02/24/95 546 03/15/95 1833 05/25/95 624 06/13/95 1014 08/30/95 819/761 See Note '
08/30/95 6162 11/21/95 663 12/10/95 1794 02/19/96 1580 03/09/96 4290 05/19/96 663 06/09/96 2964 08/17/96 624 09/05/96 3159 12/10/96 1014 12/04/96 3451
' Where two values are shown, the first number is the "as found" and the second is the "as left." "As found" are not usually recorded.
2 AlI-VIB required seat adjastment.
3 All-VIB had no leakage when tested using a oap solution. De plant was in a 5-month refueling outage.
- All-VIC appeared to have less than the total 1989 SCCM leakage, based on a soup solution test.
5 An intermediate test yielded 5675 SCCM, and AII-VI A appeared to have less that this total, based on a soap solution test.
- Al1-VIC gaskets were replaced and the operatmg mechanism was repaired on 1/8/90.
' All-V1B required seat adjustment.
- AII-VIA and All-VIB both required seat adjustnents.
' All-VIC required seat adjastment.
Re second test was conducted due to instrument problems on the initial ted