ML20028C327

Application to Amend License DPR-57 Revising Tech Spec to Raise Setpoint of Each Main Steam Safety Relief Valve tail-pipe Pressure Switch from 30+5 Psig to 85,+15,-5 Psig

ML20028C327
Person / Time
Site:	Hatch
Issue date:	01/03/1983
From:	Beckham J GEORGIA POWER CO.
To:	Office of Nuclear Reactor Regulation
Shared Package
ML20028C328	List: ML20028C327 ML20028C329
References
TAC-49318, NUDOCS 8301070340
Download: ML20028C327 (2)

Text

. Georg.a Pw.o CO:*pany 333 P:edmor! Avenue

. Atlanta Geerma 30308

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Tewphcre 404 526JO20 Maing Address Post Coce Eu 4545 Acama omm m January 3, 1983 Georgia Power J. T. Beckham, Jr.

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%ce Pres cc9 rd Gewa' Varam i Nuclear Gerw I m Director of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Washington, D. C. 20555 NRC DOCKET 50-321 OPERATING LICENSE DPR-57 EIMIN I. HA'ICH NUCLEAR PIANP UNIT 1 PROPOSED CHANGE 'IO SAFETY RELIEF VALVE TAIL PIPE PRESSURE SWI'ICH SEI'POINP TECHNICAL SPECIFICATIONS Gentlemen:

In accordance with the provisions of 10 CFR 50.59(c) (1), Georgia Power Company hereby proposes an amendment to the alwin I. Hatch Unit 1 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 30+5 psig to 85,+15,-5 psig.

It has been determined that the present setpoint of the SRV tail-pipe pressure switches of 30 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 30 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.

l A primary containment LOCA design pressure of 65 psig, when combined with a static head pressure in the tail-pipe of 10 psig caused by possible elevated water level in the torus, yields a potential condition of 75 psig at the subject pressure switches. Therefore, a setpoint higher than 75 psig is desirable to provide assurance against a spurious SRV open indication from these pressure switches as a result of high drywell pressure. By using an additional 10 psig to account for inaccuracies and to provide margin, the l new pressure switch setpoint becomes 85 psig. Furthermore, this new setpoint is still low enough to provide rapid annunication in the event an SRV opens. The allowable values of 100 psig and 80 psig, which result from operation at 85+15 psig and 85-5 psig, are derived from test data which indicate the above values should adequately allow for setpoint drift during operation. Operation at those values is above expected post-IOCA drywell conditions, but is still low enough to provide positive indication of SRV actuation.

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Georgia Power d Director of Nuclear Reactor Regulation U. S. Nuclear Regulatory Conmission Washington, D. C. 20555 January 3, 1983 Page Two Application of this proposed Technical Specification change does not 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 ESAR due to this change, because the pressure switches provide a monitoring function for operator information only, and not a control function. 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 'Ibchnical Specifications is not reduced due to this change, because the pressure switches do not perform a safety function.

Included along with the proposed changes are instructions for incorporation and a determination of amendment class.

J. T. Beckham, Jr. states that he is Vice President of Georgia Power Company and is authorized to execute this oath on behalf of Georgia Power Conpany, and that to the best of his knowledge and belief the facts set forth in this letter are true.

GEOFGIA POWER COMPANY By -

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J. T. Beckham, Jr{

Sworn to and subscribed before me this 3rd day of January,1983

&f w-w Notary Public Notary Public, G8orgia. State at Large My Commission Egires Aug26,1986 REB /mb Enclosures xc: H. C. Nix, Jr.

Senior Resident Inspector J. P. O'Reilly (NBC-Region II) 700775

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