ML17258A999

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Safety Evaluation Re Primary Coolant Sys Pressure Isolation Valves (WASH-1400,Event V)
ML17258A999
Person / Time
Site: Ginna Constellation icon.png
Issue date: 04/20/1981
From:
Office of Nuclear Reactor Regulation
To:
Shared Package
ML17258A998 List:
References
NUDOCS 8105040097
Download: ML17258A999 (1)


Text

Pe UNITED STATES NUCLEAR REGULATORY COMIVIISSION WASHINGTON, D. C. 20555 Attachment I

SAFETY EVALUATION REPORT R. E.

GINNA NUCLEAR POWER PLANT PRIMARY COOLANT SYSTEM PRESSURE ISOLATION VALVES (WASH-1400i EVENT V),

1.0 Introduction The Reactor Safety Study (RSS),

WASH-1400, identified in a PWR an intersystem loss of coolant accident (LOCA) which is a significant contributor to risk of core melt accidents (Event V).

The design examined i n the RSS contai ned in-series check valves isolating the high pressure Primary Coolant System (PCS) from the Low Pressure Injection System (LPIS) piping.

The'scenario which leads to the Event V accident is initiated by the failure of these check valves to.function as a pressure isolation barrier..

This causes an overpressurization and rupture of the LPIS low pressure piping which results in a LOCA that bypasses containment.

In order to better define the Event V concern, all light water licensees were requested by 10 CFR 50.54(f) letter,",.dated February 23, 1980, to identify va 1 ve conf i gurat i ons of concern and p'ri or va 1 ve test resul ts, if any.

By letter dated March 14, 1980, the licensee responded to our'equest and this

.information was subsequently transmitted to our contractor, the Franklin Research Center for verification that the licensee had correctly identified the subject valve configurations.

2.0 Evaluation In order to prepare the attached Technical Evaluation Report (TER) it was necessary that the contractor verify and evaluate, the licensee's response to our February 1980 letter.

The NRC acceptance criteria used by Franklin were based on WASH-1400 findings, probabilistic analyses and appropriate Standard Review Plan requirements.,

With respect to the verification of the licensee's response to our information request, the Franklin evaluation was based on FSAR information, ISI/IST site visit data, and other previously docketed information.

The attached Franklin TER correctly identifies the subject valve configurations..

3.0 Concl us i on Based on our review of the Franklin TER we find that the valve configurations of concern have been correctly identified.

Since periodic testing of these PCS pressure isolation-valves will reduce the probability of an intersystem LOCA we, therefore, conclude that the requirement to test these valves should be incor-porated into the plarit's Technical Specifications.

Dated:

April 20, 1981 II C 0504 0~~: I