ML20052A068

Technical Evaluation of Response to Position 5 of Item II.E.4.2 of NUREG-0737,Containment Isolation Setpoint.

ML20052A068
Person / Time
Site:	Davis Besse
Issue date:	05/31/1981
From:	Broderick N, Ruvalcapa W, Wade W EG&G, INC.
To:	NRC
Shared Package
ML20052A065	List: ML20052A068
References
RTR-NUREG-0737, RTR-NUREG-737, TASK-2.E.4.2, TASK-TM SRO-246, TAC-44841, NUDOCS 8204270020
Download: ML20052A068 (2)

Text

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1 i TECHNICAL EVALUATION OF THE RESPONSE TO POSITION NO.5 ,

OF ITEM H. E. 4.2 OF NUREG-0737 l t

CONTAINMENT ISOLATION SETPOINT t

FOR THE DAVIS BESSE -  !

NUCLEAR POWER PLANT (DOCKET NO 50-346) by W. O. Wade Approved for Puolication  ;

Wl l W. R. Ruvalcaca Department Manager l I

This document is UNCLASSIFIED l

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Nicnoias E drocericx,

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i Department Manager I

Work P erformed for Lawrence Livermore National Laboratory under U.S. Department of Energy Contract No. DE-ACOS-76 NVO 1183.

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INTRODUCTICN AND BACKGROUND As a consequence of the incident at TMI-2, implementation of a number of new requirements nas been reconnended for operating reactors.

Tnese new requirements are described in NOREG-0660, "NRC Action Plan Devel-oped as a Result of the TMI-2 Accident," May 1980, and NUREG-0737, "Clari-fication of TMI Action Plan Requirements,' November 1980. The NRC staff has also. requested licensees to suDmit information sufficient to permit an independent evaluation of their response to these new requirements. Tnis report provides an evaluation of tne response to Action Plan Item II.E.4.2, position 5, by the designated licensee.

DESIGP BASIS OR REVIEW CRITERIA Position 5 requires tnat the containment pressure setpoint tnat initiates containment isolation for non-essential system containment vessel penetrations be at, or reduced to, "...tne minimum compatiale witn normal operating conditions."

TECHNICAL EVALUATION Response evaluation is based upon tne values provided for tne following parameters:

(1) The maximum observed or expected containment pressure during normal operation.

(2) The loop error and observed drift in tne pressure sensing instrumentation providing the isolation signal (see note).

(3) The containment isolation pressure setpoint.

NOTE: The clarification document (NUREG-0737) provided only the expected margin for instrument error and did not speci fy acceptable values for instrument drift or atmospheric loop error.

cnanges contributing to tne total sensing Additional staff guidance estab11sned a limit of 3.0 psi for an isolation setpoint margin over .

the normal containment pressure to account for total loop error. In addition, for subatmospneric contain-ments, a 3.0 psi setpoint margin over atmospneric pressure is also considered acceptable.

In consideration of tnese values, the isolation pressure setpoint is to be as low as practical witnout increasing tne probability of inadver-tent activation of the isolation signal.

CONCLUSIONS The letter of January 30, 1981, submitted my Toledo Edison, pro-vided sufficient information to conclude that the containment isolation pressure setpoint for Davis Besse Nuclear Power Plant meets tne NUREG-0660/0737 requirements and is witnin tne additional limiting guidelines provided by tne NRC staff. -

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