ML20209E347

Forwards Auxiliary Sys Branch Sser Re Tech Spec Requirements for Auxiliary Feedwater Sys,Per NUREG-0737 Item II.E.1.1. Review of Tech Spec Restrictions on Cranes Will Be Evaluated by Structural & Geotechnical Engineering Branch

ML20209E347
Person / Time
Site:	05000000, Diablo Canyon
Issue date:	04/22/1985
From:	Rubenstein L Office of Nuclear Reactor Regulation
To:	Novak T Office of Nuclear Reactor Regulation
Shared Package
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References
FOIA-86-197, REF-GTECI-A-01, REF-GTECI-PI, RTR-NUREG-0737, RTR-NUREG-737, TASK-2.E.1.1, TASK-A-01, TASK-A-1, TASK-OR, TASK-TM NUDOCS 8504300426
Download: ML20209E347 (2)

Text

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APR 2 21985

-MEMORANDUM FOR: Thomas M. Novak, Assistant Director for Licensing, Division of Licensing FROM:

L. S. Rubenstein, Assistant Director for Core and Plant Systems, Division of Systems Integration

SUBJECT:

SUPPLEMENTAL SAFETY EVALUATION REPORT INPUT - DIABLO CANYON UNITS 1 AND 2 - AUXILIARY SYSTEMS BRANCH Enclosed is the Auxiliary Systems Branch's (ASB's) supplemental safety _evalua-tion report (SSER) input for Diablo Canyon Nuclear Power Station, Units 1 and 2.

This input was requested by DL in order to resolve apparent inconsis-tencies in previous SSERs regarding technical specification requirements.

Based on subsequent staff efforts, ASB has determined that there is no longer a need for technical specificatons concerning steam generator water level recovery rate as a means of limiting potential feedwater hammer (SSER No. 4, Section 10.4). We have provided SSER input to this effect. We were also asked to review the need for technical specifications concerning restrictions on cranes (SSER No. 7 Section 3.8.5.4.8).

Because this concern involves the need to restrict crane movement based on plant response during the Hosgic seismic event, the Structural and Geotechnical Engineering Branch will evaluate the need for technical specifications in this regard. We have' discussed this con-cern with SGEB (P. T. Kuo) and they have agreed to provide SSER input as necessary.

The preparation of this SSER involved no interaction with the licensee, and therefore, no SALP input is provided.

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L. S. RGb stein, Assistant Director for Core and Plant Systems Division of Systems Integration

Enclosure:

As Stated cc w/ enclosure:

R. Bernero H. Thompson J. P. Knight 1

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G. Lear P. T. Kuo J. Wermiel H. Schierlina g

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SUPPLEMENTfL SAFETY EVALUATION REPORT INPUT DIABLO CANYON NUCLEAR STATION, UNITS 1 AND 2 AUXILIARY SYSTEMS BRANCH 10.4 Auxiliary Feedwater System In SSER No. 4, the staff identified the need for technical specifications to limit the steam generator refill rate via-the auxiliary feedwater system in order to further limit the potential for adverse (damaging) feedwater hamer.

Since issuance of SSER No. 4 (May 1976), the staff has completed generic studies of waterhamer concerns including resolution of USI A-1 and has com-pleted study of auxiliary feedwater system reliability in connection with Item II.E.1.1 of the TMI-2 Task Action Plan, NUREG-0737. Based on the-results of this work, we now conclude that throttling auxiliary feedwater flowrate to limit steam generator level recovery as a means of reducing waterhamer poten-tial is no longer necessary or desirable. Preoperational testing at Diablo Canyon Unit 1 as well as operating experience at other Westinghouse reactors has shown that modifications to the feedring and revised plant operating pro-cedures have effectively limited waterhamer concerns. Further, the practice of throttling to avoid waterhamer was rereviewed with an intent to eliminating it in order not to adversely _ affect auxiliary feedwater system rel.iability as indicated in the implementation of Item II.E.1.1 of NUREG-0737 (Recomendation l

l GS-3). Diablo Canyon was previously reviewed against this recomendation and l

found acceptable.

Based on the above, we conclude that technical specifications to limit steam generator refill rate are not necessary for Diablo Canyon Units 1 and 2, as suitable measures for limiting feedwater hammer via the auxiliary feedwater system are provided.

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