ML20029C950
| ML20029C950 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 04/22/1994 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20029C948 | List: |
| References | |
| NUDOCS 9405030072 | |
| Download: ML20029C950 (3) | |
Text
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E UNITED STATES 3 #
NUCLEAR REGULATORY COMMISSION
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WASHINGioN, D.C. 20MH001 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO.173 JfLFACILITY OPERATING LICENSE NO. DPR-65 NORTHEAST NUCLEAR ENERGY COMPANY THE CONNECTICUT LIGHT AND POWER COMPANY IlfE_ WESTERN MASSACHUSETTS ELECTRIC COMPANY MILLSTONE NUCLEAR POWER STATION. UNIT NO. 2 DOCKET NO. 50-336 1.0 INTRODUCTLQB By letter dated March 14, 1994, the Northeast Nuclear Energy Company (the licensee) submitted a request for changes to the Millstone Nuclear Power Station, Unit No. 2 Technical Specifications (TS).
The requested changes would provide a one-time extension of the surveillance frequency from the required 18-month to the next refueling outage but no later than September 30, 1994, of the power-operated valves in the service water system (TS 4.7.4.1.b) and in the boron injection flowpaths (TS 4.1.2.2.c).
This would extend the surveillance for these valves approximately 5 months.
Technical Specification 4.1.2.2.c requires that each power-operated valve in each boron injection flowpath be exercised through at least one complete cycle at least once per 18-months, during shutdown. This TS requirement is particularly applicable to valve 2-CH-508 since this valve is the only one in the system that has not satisfied the requirement. Technical Specification 4.7.4.1.b requires each power-operated valve in each of the service water system loops be exercised through one full cycle at least once per 18-months.
3 This TS requirement is particularly applicable to valves 2-SW-3.lA and 2-SW-3.1B since these valves are the only valves in the system that cannot be cycled during operation and have not been cycled since the last refueling outage.
Currently, TS 4.1.2.2.c is required to be performed no later than April 23, 1994, for valve 2-CH-508 and TS 4.7.4.1.b is required to be performed no later than May 5, 1994, for valves 2-SW-3.lA and 2-SW-3.18 (these due dates include the 25 percent allowance per Millstone Unit No. 2 TS 4.02).
As a result of an extended Millstone Unit No. 2 Steam Generator Replacement Outage, the start of the 1994 refueling outage was rescheduled from March 1994 to July 1994. As a result, the 18-month surveillance for the power-operated valves in the baron injection flowpath and the power-operated valves of the service water system has been impacted. The proposed change would preclude the necessity of a plant shutdown specifically to perform the surveillance and allow the surveillance to be completed during the next shutdown or no later than September 30, 1994.
9405030072 940422 PDR ADOCK 05000336-P PDR
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4 5 2.0 EVALVATION The licensee has indicated that valve 2-CH-508 in the boron injection flowpath was exercised through a complete cycle on March 7,1994, during a weekly surveillance procedure SP 2601A, " Borated Water Source and Flow Path Verification" while the plant was operating.
This surveillance verified the.
valve's operability; however, the performance of this surveillance did not satisfy the literal compliance with TS 4.1.2.2.c, because it was not performed while the unit was shut down.
For all practical purposes, the valve has been verified to be operable and it is acceptable to extend the formal 18-month surveillance to the next refueling or not later than September 30, 1994.
Power-operated valves 2-SW-3.l A and 2-SW-3.lB located on the ' A' and 'B' service water headers, immediately upstream of the service water supply piping to the reactor building closed cooling water heat exchangers, provide isolation of the upstream piping in the event of a significant leak in the piping. The valves are normally open, and are designed to fail in the "as is" condition.
The valves do not perform any safety function, nor do they provide isolation between the two service water headers.
Their primary function is to isolate the downstream portion of the header for maintenance activities.
Past operational history of the service water system valves did not identify any previous problems with the ability of the valves to open or close or to meet any other design requirements.
In addition, the licensee has reviewed the proposed one-time extensions for these valves utilizing probabilistic risk assessment techniques and have determined that the one-time increase to the surveillance frequencies would have negligible impact on the overall public risk. The intent of the Technical Specification requirement to cycle the power-operated valves in the service water system is to ensure that the valves actuate on the appropriate safety signal; however, these valves receive no safety signal and would not be subject to the surveillance except that the requirement specifies "all" power-operated valves.
The licensee notes that a short duration shutdown to replace a 'D' reactor coolant pump seal may occur.
In discussions with the licensee on March 17, 1994, the staff asked if the two service water valves could be stroked during power operations.
Stroking these valves would create a temperature transient on the component cooling water system which cools the reactor coolant pump seals. Any temperature fluctuation could result in seal failure on the
'D' reactor coolant pump seal. Additionally, stroking the valves, even one at a time, removes a service water header from service.
It is not the policy to operate the plant at full power conditions with one service water header out of service, even for the short period of time that would be required to stroke the valves.
The risk significance of stroking the valves appears to be greater than extending the surveillance.
Based on the above, we determine it acceptable to extend the surveillance frequency of these valves to the next refueling outage or not later than September 30, 1994.
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3.0 STATE CONSULTATION
In accordance with the Commission's regulations, the Connecticut State official was notified of the proposed issuance of the amendment. The State official had no comments.
4.0 ENVIRONMENTAL CONSIDERATION
The amendment changes surveillance requirements.
The NRC staff has determined that the amendment involves 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 significant increase in individual or cumulative occupational radiation exposure.
The Commission has previously issued a proposed finding that the amendment involves no significant hazards consideration, and there has been no public comment on such finding (59 FR 13751). Accordingly, the amendment meets 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 environmental assessment need be prepared in connection with the issuance of the amerdment.
5.0 CONCLUSION
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 amendment will not be inimical to the common defense and security or to the health and safety of the public.
principal Contributors:
G. Vissing P. Campbell Date: April 22, 1994 W
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