ML17244A583

Forwards Revised Safety Assessment of SEP Topic IV-A: Operation W/Less than All Loops in Svc

ML17244A583
Person / Time
Site:	Ginna
Issue date:	05/29/1979
From:	Ziemann D Office of Nuclear Reactor Regulation
To:	White L ROCHESTER GAS & ELECTRIC CORP.
References
TASK-04-01.A, TASK-RR NUDOCS 7907060233
Download: ML17244A583 (9)

Text

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." Docket

'l MAY 29 1979 No. 50-244 Hr. Leon 0. White, Jr.

Vice President Electric

& SteamI Production Rochester Gas

& Electric Corporation 89 East Avenue Rochester, New York 14649 Gear Hr. White:

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TOPIC IV-1-A - R. E.

GINNA NUCLEAR POWER PLANT r

Enclosed is a copy of our revised safety assessment of Topic IV-l.A, Operation With Less Than All Loops In Service.

This revision includes consideration of the comments received on the assessment issued by our letter dated February 6, 1979.

Your letter dated February 21, 1979, provided comments on the assessment.

This revfsion completes our assessment of Topic IV-1.A which will be used as input to the integrated review of the Ginna Plant.

If there are any errors in the facts of this revised assessment, please supply cor rected information within 30 days of the date you receive this letter. If no response is received within that time, we will assume that you have no further comments or corrections.

Sincerely,

, Origi'nal Signed by:.

Dennis T.. Ziemann Dennis L. Ziemann, Chief Operating Reactors Branch 82 Division of Operating Reactors

Enclosure:

Revised Assessment for Topic IV-l.A cc w/enclosure:

See next page

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Mr. Leon D. Mhite, Jr.

May-29, 1979 CC Lex K. Larson, Esqui re

LeBoeuf, Lamb, Leiby & MacRae 1/57 N Street, N.

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Washington, D. C.

20036 Mr. Michael Slade 1250 Crown Point Drive

Mebster, New York 14580 Rochester Committee for Scientific Information Robert E. Lee, Ph.D.

P. 0.

Box 5236 River Campus Station Rochester, New York *14627 Jeffrey Cohen New York State Energy Office Swan Street Building Core 1, Second Floor Empire State Plaza

Albany, New York 12223 Director, Technical Development Programs State of New York Energy Office Agency Building 2 Empire State Plaza

Albany, New York 12223 Rochester Public Library 115 South Avenue Rochester, New York 14604

. SYSTEMATIC EVALUATION PROGRAN TOPIC IV-I-A: Operation with less than all loops in service PLANT:

R.

E, Ginna Nuclear Power Plant Discussion The majority of the presently operating BWR's and PWR's are designed to permit operation with less than full reactor coolant flow, That

$s, if a PWR reactor coolant pump-or a

BWR recirculation pump becomes inoperative, the flow provided by the remaining loop or loops is sufficient for steady state operation at some definable power level, usually less than full power.

Plants authorized for long term operation with one reactor coolant pump out of'ervice have submitted, and the staff has approved, the necessary ECCS, steady state, and transient analysis, The remaining PWR and BWR licensees have Technical Specifications which require reactor shutdown within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> if one of the operating loops become inoperable and cannot be returned to operation within the lime period, Evaluation The docketed material for the Ginna Nuclear Power Plant has been reviewed with respect to operation with less than all loops in service, The Ginna Technical Specifications [3,l,l,l.c,(i) and 3,1,1,1,c,{ii)j permit operation with less than all loops in service up to 8,5 per cent (130%t) of full power provided that a predetermined shutdown margin ts maintainable.

The supporti.ng analysis was provided by lettel dated September 22,

1975, and inc)uded specific shutdown margin requirements 4epending upon whether one or both primary coolant loops were operable,

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5n a safety evaluation supporting Amendment No.

10 to the Provisional Operating License, ate arc d t d H rch 30 1976 the staff approved the shutdown margin analyses an iss 1

nd issued the proposed Technical Specifications.

Current staff criteria require that, unless an ECCS analysis is per-formed and approved, a reactor must be shut down within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> if one of the operative loops becomes inoperable and cannot be returned to operation within that time period, The Ginna Technical Specifi-cations state that if the appropriate shutdown margin cannot be maintained the reactor will be brought to a hot shutdown condition until the proper shutdown margin can be established, There is no time limit on how long the plant can remain at 8,5 per.cent power )n the n-1 loop configuration,

However, based on the low power level, it is our judgment that the amount of stored energy in the fuel and the decay heat generated after shut down following a postulated loss of coolant accident (LOCA) will be sufficiently reduced to assure that peak clad temperatures are less than those calculated in the ECCS performance analyses.

This is based on the fact that peak clad temper-atures are strongly affected by the stored energy of the fuel and the decay heat.

If the power level is reduced to less than 10 per cent of full power, the stored energy in the fuel is proportionally reduced resulting in peak clad temperatures significantly below those calculated for the accidents at full power.

Fuel burnup and the clad gap affect the relationship between power level and stored energy in the fuel but these are secondary e

ec s

ff t so that reducing power level by a factor of 10 reduces the stored energy by approximately 10 with a substantial decrease in calculated peak clad temperature during the

LOCA, He find that although the restrictions at Ginna are different than those in our critet )a, e

i th d fference is of no significant consequence.

Therefore, we conclude that continut;d operation in this mode is

acceptable.

Topic IV-l.A, "Operation With Less Than All Loops In Service", is acceptably resolved and complete for the Ginna Plant.

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