ML20069B876

Responds to NRC Re Proposed Design for Alternate Safe Shutdown.Suppression Pool Temp & Level Indication Will Be Provided as Part of App R Mod Effort Currently Scheduled for Completion by June 1987

ML20069B876
Person / Time
Site:	Pilgrim
Issue date:	03/11/1983
From:	Harrington W BOSTON EDISON CO.
To:	Vassallo D Office of Nuclear Reactor Regulation
References
83-70, NUDOCS 8303170316
Download: ML20069B876 (2)

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BOSTON EDISON COMPANY 800 BovLsTON STREET BOSTON MASSACHUSETTS 02199 WILLIAM D. HARRINGTON

...... ... ........, March 11,1983 BECo Letter No. 83-70 i

Mr. Domenic B. Yassallo, Chief Operating Reactors Branch #2 Division of Licensing Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, D.C. 20555 License No. DPR-35 Docket No. 50-293 Information on 10CFR50 Appendix R Items III.G and III.L

Reference:

NRC letter dated January 17, 1983

Dear Sir:

The referenced letter concluded that our proposed design for alternate safe shutdown at Pilgrim Station was acceptable except for three areas. Boston Edison Company (BECo) was requested to reconsider its proposed actions in these areas and implement suggested changes accordingly.

. Also, BECo was requested to provide written confirmation that all of the post-fire alternative shutdown circuits that share a ccmon bus have coordinated protection.

Our responses are provided as follows:

1) NRC Conclusion Suppression pool temperature and level indications, independent of the control room, is not provided.

BECo Response Suppression pool temperature and level indication, independent of a Control Room fire, will be provided at Pilgrim Station as part of the Appendix "R" modification effort, currently scheduled for completion by June 1987.

2) NRC Conclusion A positive means of isolating the RHR isolation valves to prevent spurious operation of these valves at high pressure during a fire is not provided.

BECo Response The control circuits for motor operated valve M0-1001-47 will be modified so that the control circuits will not be affected by the same fire condition as its redundant counterpart valve, H0-1001-50.

8303170316 830311 M PDR ADOCK 05000293 F PDR

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, .1, EDITON EDCON COMPANY Mr. Domenic B. Vassallo, Chief March 11, 1983 Page 2 Spurious operation of valve M0-1001-60 or M0-1001-63 will be prevented by de-energizing the power to one of these valves, at the motor co . trol center,  !

during normal operation. '

3) NRC Conclusion Switches or similar devices are not provided to obviate the need for pulling fuses to achieve isolation in order to prevent spurious signals during hot shutdown conditions.

BECo Response We disagree with the need for additional modifications for compliance with Appendix P. in this area. The prevention of spurious operation of breakers is procedurally controlled at Dj] grim station such that power is assured to components required for safe shutdown. The procedures for shutdown from outside the Control Room require the operator to verify breaker status on the safety related 480V. load centers B1 and B2 and then to remove the fuses in the "close' and " trip" breaker circuits to prevent the breakers from changing position due to a fire affecting the control circuit of the breakers.

The operators are trained in the use of the procedures and the hazard expo-sure during this operation is minimal; additionally the clear identification of the control fuses reduces the possibility of removing the wrong fuse.

Making a modification in this case would only serve to degrade the overall System through the introduction of a potential failure mode.

Protection - Coordination We have reviewed the fuse to breaker coordination at PNPS and determined that a fuse will not always blow before a breaker trips. As a result we will r.ake modifications as necessary for compliance in accordance with our schedule for final closeout of Appendix R modifications.

Very truly yours,

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