ML20209C477

Forwards SER Re Util 811207 Response to NRC Questions on Generic Ltr 81-21 Concerning Reactor Vessel Upper Head Steam Formation During Natural Circulation Cooldown.Licensee Submittal,Referring to Westinghouse Study,Acceptable

ML20209C477
Person / Time
Site:	Diablo Canyon
Issue date:	09/29/1983
From:	Houston R Office of Nuclear Reactor Regulation
To:	Lainas G Office of Nuclear Reactor Regulation
Shared Package
ML16340C148	List: ML16340C147 ML20209B134 ML20209B144 ML20209B172 ML20209B176 ML20209B206 ML20209B218 ML20209B249 ML20209B270 ML20209B277 ML20209B283 ML20209B298 ML20209B443 ML20209B450 ML20209B492 ML20209B597 ML20209B601 ML20209B605 ML20209B682 ML20209B777 ML20209C156 ML20209C239 ML20209C268 ML20209C274 ML20209C285 ML20209C293 ML20209C318 ML20209C326 ML20209C333 ML20209C442 ML20209C446 ML20209C477 ML20209C533 ML20209C551 ML20209C621 ML20210A699 ML20210A793 ML20210A831 ML20210A898 ML20210A977 ML20210B079 ML20210B125 ML20210B142 ML20210B176 ML20210B198 ML20210B218 ML20210B230 ML20210B246 ML20210B256 ML20210B260 ... further results
References
FOIA-86-151 GL-81-21, TAC-51638, TAC-51994, NUDOCS 8310070127
Download: ML20209C477 (2)

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UNITED STATES A

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WASHINGTON, D. C. 20856 A

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SEP 2 9 583 A<

g MEMORANDUM FOR:

Gus Lainas Assistant Director for Operating Reactors Division of Licensing FROM:

R. Waync Houston, Assistant Director for Reactor Safety Division of Systems Integration

SUBJECT:

DIABLO CANYON UNITS 1 & 2 NATURAL CIRCULATION C00LDOWN, B-66

Reference:

(1)

Generi_c Letter 81-21, " Natural Circulation Cooldown,"

May 5, 1981 (2)

P. A. Crane, Jr., Pacific Gas & Electric Co., to F. J.

Miraglia, Jr., NRC, dated December 7,1981 Plant Name:

Diablo Canyon Docket Number:

50-275/323 Project Manager:

H. Schierling Review Branch:

Reactor Systems Branch Review Status:

Complete Enclosed.is our Safety Evaluation Report of the Pacific Gas & Electric Company's response, (Ref. 2) to NRC questions (Ref.1) regarding reactor vessel upper head steam formation during natural circulation cooldown.

The licensee's submittal refers to a Westinghouse study that evaluates

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the potential for steam formation in Westinghouse NSSS's and recommends modifications to the operating guidelines.

The licensee has revised it's' natural circulation cooldown procedures in accordance with the Westinghouse recomendations to prevent reactor vessel voiding.

The licensee has verified that it has sufficient condensate grade water consistent with the procedures.

CONTACT:

S. Diab, RSB X29440 f

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1. p1>7 4. d i

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Gus Lainas,

The staff concludes that the licensee's response is acceptable. Upper head voiding is not a safety. concern provided the operator has adequate 1

l training and procedures.

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R. Wayne Houston, Assistant Director for Reactor Safety, DSI

Enclosure:

As stated cc:

R. Mattson R. Capra J. Rosenthal W. Hodges N. Lauben K. Heitner l

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