ML20198S656

Safety Evaluation Supporting Amend 94 to License DPR-3

ML20198S656
Person / Time
Site:	Yankee Rowe
Issue date:	05/28/1986
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML20198S627	List: ML20198S621 ML20198S637 ML20198S656
References
NUDOCS 8606100507
Download: ML20198S656 (3)

Text

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. */  %'g UNITED STATES e4  % NUCLEAR REGULATORY COMMISSION E j

• WASHINGTON. D. C. 20555 e

SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 94 TO FACILITY OPERATING LICENSE N0. DPR-3 YANKEE ATOMIC ELECTRIC COMPANY YANKEE NUCLEAR POWER STATION DOCKET NO.50-029

1.0 INTRODUCTION

o By letter dated September 30, 1985, the Yankee Atomic Electric Company (YAEC) submitted a request for changes to the Yankee Nuclear Power Station Technical Specifications (TS).

The amendment modifies the TS to increase the required setpoint for the low main steam line pressure isolation trip.

2.0 EVALUATION The current Yankee TS require that the setpoint for the low main steam line pressure trip be greater than, or equal to, 200 psig. This minimum setpoint is based on reducing the severity of the cooldown that is caused by a main steam line break.

The licensee proposes to increase the minimum allowable setpoint for the low main steam line pressure trip to a value of 262.5 psig (250 psig plus instrumenterror). This higher valve will provide an earlier steam line isolation and reactor trip during a main steam line break than the current value of 200 psig, which conserves more secondary system inventory in the steam generators. This increase in inventory is required specifically for a seismically-induced main steam line break during which it is postulated that the plant operators would have to use the dedicated Safe Shutdown System (SSS) to achieve cold shutdown. The increased steam generator inventory provides the necessary time for the operators to initiate secondary coolant flow from the SSS.

8606100507 860528 PDR ADOCK 05000029 P PDR

The proposed change is within the range for the low main steam isolation trip that is cllowed by the current TS. The increased minimum setpoint provides additional margin for an isolable main steam line break, since the resultant cooldown is reduced. The conservation of inventory provides additional time during events for which the SSS is necessary, providing the operators the time to initiate flow to the steam generators from the SSS. On these bases, the staff finds the proposed change acceptable.

3.0 ENVIRONMENTAL CONSIDERATION

This amendment involves a change to a requirement with respect to the installation or use of facility components located within the restricted -

area as defined in 10 CFR Part 20. The 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 this amendment involves no significant hazards consideration and there has been no public comment on such finding. Accordingly, this 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 this amendment.

4.0 CONCLUSION

The staff 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; and (2) such activities will be conducted in compliance with the Comission's regulations and the issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public.

5.0 ACKNOWLEDGEMENT Principal Contributor: J. W. Clifford Dated: May 28, 1986

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Docket: Files NRC PDR Local PDR J. Clifford G. Lear P. Shuttleworth OELD L. Harmon E. Jordan B. Grimes J. Partlow T. Barnhart (4)

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