ML20087A363
| ML20087A363 | |
| Person / Time | |
|---|---|
| Site: | Salem  |
| Issue date: | 08/01/1995 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20087A360 | List: |
| References | |
| NUDOCS 9508040288 | |
| Download: ML20087A363 (3) | |
Text
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t UNITED STATES e
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g, NUCLEAR REGULATORY COMMISSION 2
WASHINGTON, D.C. 2006M001
'+9.....,d SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NOS.172 AND 153 TO FACILITY OPERATING LICENSE NOS. DPR-70 AND DPR-75 j
PUBLIC SERVICE ELECTRIC & GAS COMPANY PHILADELPHIA ELECTRIC COMPANY 1
DELMARVA POWER AND LIGHT COMPANY ATLANTIC CITY ELECTRIC COMPANY l
SALEM NUCLEAR GENERATING STATION. UNIT N05. 1 AND 2 DOCKET NOS. 50-272 AND 50-311
1.0 INTRODUCTION
By letter dated April 18, 1995, the Public Service Electric & Gas Company (the licensee) submitted a request for changes to the Salem Nuclear Generating Station, Unit Nos. I and 2, Technical Specifications (TSs). The requested changes would delete the quarterly ' leak rate test for the containment pressure-vacuum relief valves that is currently required because of the valves' resilient seat material. The changes are being requested to accommodate the replacement of the resilient valve seat material with a hard seat (metal-to-metal) design.
2.0 EVALUATION l
Leakage tests of large butterfly valves installed in containment vent and purge systems have shown that resilient valve seat materials in these valves have a history of relatively rapid and severe failures (reference I&E Circular 77-11, dated September 6, 1977). Because of this, the TSs include augmented testing requirements to ensure that seal degradation is detected and repaired in a timely manner. The requested change deletes this augmented testing requirement, which is quarterly in the Salem TSs.
Instead, the new metal-to-metal seated valves would be tested in accordance with the 24-month test interval specified in 10 CFR Part 50, Appendix J.
Because the new valve design does not rely on resilient seating seals, inclusion of the valves in the Type C testing interval of 24 months specified in Appendix J is acceptable.
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3.0 STATE CONSULTATION
In accordance with the Commission's regulations, the New Jersey State ' official was notified of the proposed issuance of the amendments.
By letter dated July 20, 1995, the State of New Jersey,. Department of Environmental Protection (NJOEP), provided the following comments:
NJOEP Comment:' No operating experience information is provided or referanced' in support of the licensee's statement that augmented quarterly testing is no
-longer needed based on the improved design and operating experience of the.
replacement valves.
Staff Reply: As discussed in Section 2.0 of this safety evaluation, augmented testing of valves with resilient seals was required because these valves have a history of relatively rapid and severe failures. This is due to
' installation and adjustment problems and deterioration from high temperatures and thermal cycling. Operating experience has shown that valves with metal-to-metal seats are not subject to the same maladjustment problems, heat deterioration and temperature cycling deterioration of valves with resilient seals.
NJOEP Comment: Valves with metal-to-metal seats are subject tc sticking shut due to corrosion.
Staff Comment:
In addition to leak testing, isolation valves are subject to
" operability" testing. This encompasses quarterly " cycling" (full open and full closed) of such valves. This ensures that the valves are free to move.
NJDEP Comment:
If replacement of resiliently sealed valves with metal-seated.
valves is the solution, why was it not done earlier?
Staff Comunent: Use of valves with metal-to-metal seats is the best solution if the they can achieve'the necessary leak-tightness. However, valves ~with resilient seals, when properly adjusted, generally provide a greater degree of leak tightness than valves with metal-to-metal seats.
If overall (total containment leakage) limits can be met with valves with metal-to-metal seats, i
utilities may elect to use them. Utilities will also use them in order to eliminate the maintenance requirement to frequently replace resilient seals.
The valve vendor typically recommends replacing resilient seals every 5 years.
Therefore, the decision to replace valves with resilient seals to valves with metal-to-metal seats involves many factors,' including economic factors. The NRC staff's concern is limited to valve operability and leak tightness.
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4.0 ENVIRONMENTAL CONSIDERATION
3 The amendments change a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20. The NRC staff has determined that the amendments involve no significant increase in the amounts, and no significant change in the types, of any effluents that may be released offsite, and that there is no
f,.
. significant increase in individual or cumulative occupational radiation exposure. The Commission has previously issued a proposed finding that the amendments involve no significant hazards consideration, and there has been no public comment on such finding (60 FR 27342). Accordingly, the amendments meet the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).
Pursuant to 10 CFR 51.22(b) no environmental impact statement or i
environmental assessment need be prepared in connection with the issuance of the amendments.
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5.0 CONCLUSION
i The Commission has concluded, based on the considerations discussed above, that:
(1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendments will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor:
L. Olshan Date: August 1, 1995 i
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