ML20237L657
| ML20237L657 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 08/24/1987 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20237L648 | List: |
| References | |
| NUDOCS 8708280199 | |
| Download: ML20237L657 (3) | |
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NUCLEAR REGULATORY COMMISSION WASHINGTON D. C. 20555 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATIOs RELATED TO AMENOMENT NO. 1n TO FACILITY OPERATING LICENSE NO. NPF-49 NORTriEAST NUCLEAR ENERGY COMPANY, ET AL.
MILL 5 TONE NUCLEAR POWER STATION, UNIT NO. 3
1.0 INTRODUCTION
DOCKET NO. 50-423 The existing Technical Specification 4.8.1.1.2 requires the diesel generator to attain voltage and frequency within 10 seconds and the loss of voltage recovery time in Table 3.3-5 to be less than or equal to 12 seconds. By letter dated May 5, 1987, Northeast Utilities requested a revision to the Millstone 3 Tech-nical Specifications for the diesel generator start time from 10 to 11 seconds and loss of voltage recovery tjme from 12 to 13 seconds.
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2.0 EVALUATION Northeast Utilities has proposed a change to the Millstone 3 Technical Specifica-tions surveillance requirement 4.8.1.1.2.
The licensee states that the emergency
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diesel generators are currently starting in approximately 9.5 seconds, leaving a very small margin for meeting the Technical Specification limit of 10 seconds.
This has resulted in declared diesel generator failures (10.1 second starting time)ontwooccasions. The licensee has requested that the diesel generator start up time should be increased from 10 seconds to 11 seconds. The licensee plans to maintain the current ESF response time requirements in Table 3.3-5 except Item 11.a for a loss of voltage event without a safety injection signal.
In this case, the 12 second requirement will be increased to 13 seconds. The licensee has performed the analyses to show that the proposed changes do not re-present an unreviewed safety question.
In the previous analysis, the licensee had assumed 2 seconds for the signal generator to the start circuitry of the diesel generator and additional 10 seconds for the diesel generator to come up to the rated voltage and speed. The licensee has found that a margin of I second existed in the response time of signal generator due to the fast acting relays.
The response time of the signal generator can be reduced from 2 seconds to 1 second which would compensate for the increase in start up i.ime of the diesel generator. The relaxation of the diesel generator start-up time does not create the possibility of an accident or malfunction or a different type than any evalu-ated previously in the safety analysis report. We find *.his to be acceptable.
8708280199 B70824 PDR ADOCK 05000423 P
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The staff has reviewed the proposed Technical Specification changes which reflect the increase in the diesel generator start-up time of Ib seconds to 11 seconds and loss of voltage recovery time from 12 seconds to 13 seconds 1
and has concluded that they do not represent an unreviewed safety question and i
the changes are, therefore, acceptable.
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3.0 ENVIRONMENTAL CONSIDERATION
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This amendment changes a requirement'with respect to instal 1ation or use l
of a facility component locatbd within the restricted area as cefined in l
10 CFR Part 20 and changes surveillance requirements. The~ staff has determined that the amendment involves ng 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 Connission has previously pubitsbed a proposed finding that the amendment involves no'significant hazards consideration and there has been no public comment on such finding. Accordingly, the amend-l ment meets the eligibility criteria for categorical exc1psion set forth in10CFR551.22(c)(9).
Pursuant to 10 CFrl 951.22(b), no environmental impact statement or environmental assessment need be prepared in connection I
with the issuance of the amendment.
4.0 CONCLUSION
l We have concluded, h sed on the considerations discussed above, that (1) there is reasonable assurance that the haith and safety of the public will not be l
endangered by operation in the proposed manney, and (2) such activities will
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be conducted in compliance'with the Conrnission's regulations, dnd the issuance l
of the amencycrt wil'1 not be ibimical to the common defense and security or to the he61th and safety of the public.
Dated: August 24, 1987 Principal Contributors:
R. Ferguson N. Trehan, 4
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