ML17056A062
| ML17056A062 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 06/16/1989 |
| From: | NRC |
| To: | |
| Shared Package | |
| ML17056A061 | List: |
| References | |
| GL-83-28, NUDOCS 8906220168 | |
| Download: ML17056A062 (4) | |
Text
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"o UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 SAFETY EYALUATION NINE MILE POINT NUCLEAR STATION UNIT NO. I GENERIC LETTER 83-28 ITEM 4.5.2 REACTOR TRIP SYSTEM-RELIABILITY-ON-LINE TESTING INTRODUCTION Generic Letter 83-28 was issued by NRC on July 8, 1983, indicating actions to be taken by applicants and licensees based on the generic implications of the Salem ATMS events.
Item 4.5 states a staff position that requires, for all plants, on-line functional testing of the reactor trip system, including independent testing of the diverse trip features of the reactor trip system, including independent testing of the diverse trip features of the reactor trip breakers.
Item 4.5.2 requires applicants and licensees having plants not currently designed to permit this periodic on-line testing to justify not making modifications to permit such testing.
By letters dated November 8,
'983, July 31, 1984, December 31, 1984 and April 13, 1989, the licensee, Niagara Mohawk Power Corporation (NMPCI, responded to the staff position regarding Item 4.5.2 of Generic Letter 83-28 as it applies to Nine Mile Point IJnit 1 (NMP-1).
Our evaluation of these responses is given below.
EVALUATION In its first submittal, dated November 8, 1983, the licensee stated that the reactor trip system was designed to permit on-line testing and that periodic on-line testing was performed.
However, on-line testing of the backup scram valves would not be performed because it would cause a plant scram.
In its July 31, 1984 submittal, the licensee committed to evaluate the feasibility of testing the backup scram valves during refueling outages.
In the December 31, 1984 response, the licensee stated that it had decided to implement functional testing of these valves at refueling outages and that the testing would begin with the next refueling outage.
In a letter dated ApriI 13, 1989, NMPC confirmed that the backup scram valves are tested during each refueling outage.
CONCLUSION The NMP-1 reactor trip system is periodically tested on-line during reactor operation, except the backup scram valves which are tested during refueling outages.
The backup scram valves are not relied upon to produce reactor
- scram, no credit for them is taken in safety analyses, and they are not required to be designed as safety-related equipment.
The staff believes it is not desirable to scram the reactor at power just to test the scram backup valves; they can be tested adequately during refueling outages.
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Based upon -the above, the staff concludes that the licensee has provided acceptable commitments to meet the functional testing requirements of Item 4.5.2 of Generic Letter 83-28.
PRINCIPAL CONTRIBUTOR:
D. Lasher
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