ML20052B717

Application for Amend to License NPF-5.Amend Changes Safety Relief Valve Tailpipe Pressure Switch Setpoint Tech Specs

ML20052B717
Person / Time
Site:	Hatch
Issue date:	04/23/1982
From:	Beckham J GEORGIA POWER CO.
To:	Office of Nuclear Reactor Regulation
Shared Package
ML20052B718	List: ML20052B717 ML20052B725
References
TAC-48338, TAC-48339, NUDOCS 8205030495
Download: ML20052B717 (2)

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NRC DOCKET 50-366 4 W

8 OPERATING LICENSE tFF-5 EDWIN I. HATCH NlELEAR PLANT UNIT 2 PROPOSED CHANGE TO SAFETY RELIEF VALVE TAIL-PIPE PRESSURE SWITCH SETPOINT TECHNICAL SPECIFICATIONS Centlemen:

In accordance with the provisions of 10 CFR 50.90 as required by 10 CFR 50.59(c)(1), Georgia Power Compary (GPC) hereby proposes an amendment to the Edwin I. Hatch Unit 2 Technical Specifications (Appendix A to the Operating License). The proposed change would raise the setpoint of each main steam safety-relief valve (SRV) tail-pipe pressure switch from 20 psig .to 85 psig.

It has been determined that the present setpoint on the SRV tail-pipe pressure switches of 20 psig may not be high enough to ensure that the reactor operator would receive the correct information regarding the open/ closed condition of these valves, during and following a LOCA. An accident involving an increase in drywell pressure above 20 psig could cause a false indication in the control room that the safety relief valves have opened. This is possible since a vacuum breaker on the SRV tail-pipe would open on a high drywell pressure transient, raising the tail-pipe pressure to that of the drywell.

Assuming a primary containment LOCA design pressure of 65 psig, when combined with a static -head pressure in the tail-pipe of 10 psig caused ty possible flooding of the pipe, yields a potential condition of 75 psig at a pressure switch whose respective SRV may be closed. Therefore, a setpoint higher than 75 psig is desirable to provide assurance against a spurious SRV open indication from these pressure switches resulting from high drywell pressure. By using an additional 10 psig to account for instrument inaccuracles and to provide margin, the new pressure switch setpoint should be 85 psig. Furthermore, this new setpoint is still low enough to provide rapid annunication in the event an SRV opens. -

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GeorgiaPower A Director of Nuclear Reactor Regulation U. S. Nuclear Regulatory Comission Washington, D. C. 20555 April 23, 1982 Page Two Application of this proposed Technical Specification change would in no way constitute an unreviewed safety question as determined by the Plant Review Board and the Safety Review Board. The probability of occurrence or the consequences of an accident or malfunction of safety-related equipment are not increased above those analyzed in the FSAR due to this change, because the pressure switches provide a monitoring function for operator information only. The possibility of an accident or malfunction of a type different than that analyzed in the FSAR does not result from this change because the new setpoint will still allow the pressure switch to perform its intended monitoring function reliably, while decreasing the probability of a false actuation due to a drywell pressure transient. The margin of safety as defined in Technical Specifications is not reduced due to this change, because the pressure switches do not perform a safety funct',on.

Instructions for incorporation of these changes along with copies of the affected Technical Specification page are enclosed.

Included with this proposal is a determination of amendment class. We have determined this to be one Class III amendment, and have enclosed the

. appropriate payment.

'J. T. Beckham, Jr. states that he 's Vice President of Georgia Power Company and is authorized to execute this oath on behalf of Georgia Power Company, and that to the best of his knowledge and belief the facts set forth in this letter are true.

GEORGIA POWER COMPANY By : O . b h.

yJ.T.Beckham,Jf.

Sworn to and subscribed before me this 23rd day of April,1982 b)Wn IbG Notary Public CBS/mb notary Public, cecreia. state at tarn 3 My Commission Dpires Sept. 20,1983 Enclosure xc: H. C. Nix R. F. Rogers, III J. P. O'Reilly (NRC-Region II)  ;

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