NSD-NRC-97-5196, Forwards WCAP-14800, AP600 PRA Thermal/Hydraulic Uncertainty Evaluation for Passive Sys Reliability. Rept Contains Both short-term Cooling & long-term Recirculation Cooling PRA T/H Uncertainty Evaluation

Forwards WCAP-14800, AP600 PRA Thermal/Hydraulic Uncertainty Evaluation for Passive Sys Reliability. Rept Contains Both short-term Cooling & long-term Recirculation Cooling PRA T/H Uncertainty Evaluation

ML20141C930
Person / Time
Site:	05200003
Issue date:	06/19/1997
From:	Mcintyre B WESTINGHOUSE ELECTRIC COMPANY, DIV OF CBS CORP.
To:	Quay T NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20141C931	List: ML20141C934 NSD-NRC-97-5196, Forwards WCAP-14800, AP600 PRA Thermal/Hydraulic Uncertainty Evaluation for Passive Sys Reliability. Rept Contains Both short-term Cooling & long-term Recirculation Cooling PRA T/H Uncertainty Evaluation
References
NSD-NRC-97-5196, NUDOCS 9706260095
Download: ML20141C930 (3)

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A...oghouse Energy Systems Ba 355 Electric Corporation Pittsburgh PennsyIvania 15230-0355 NSD-NRC-97-5196 DCP/NRC0924 Docket No.: STN-52-003 June 19,1997 Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555 ATTENTION: T.R. QUAY

SUBJECT:

WCAP-14800, AP600 PRA TilERMAL/IlYDRAULIC UNCERTAINTY EVALUATION FOR PASSIVE SYSTEM BELIABILITY, KEY ISSUE 21

Dear Mr. Quay:

J Enclosed please find the Westinghouse topical report WCAP-14800, "AP600 PRA Thermal /llydraulic Uncertainty Evaluation for Passive System Reliability." This report contains both the short-term cooling and long-term recirculation cooling PRA T/fl uncertainty evaluation.

A draft of the PRA expanded event trees used for the T/11 uncertainty evaluation and the short-term cooling success path categorization was sent to the NRC on January 2,1997 (Westinghouse letter DCP/NRC0695). The structure of Sections 1 through 5 remains the same as the draft report.

Ilowever, the integration of the long-term cooling work scope into this report required the re-structuring of subsequent sections. The information contained in Sections 6,7, and 8 of the draft report is re-structured within Section 6 of WCAP-14800. Enhancements have been made to Sections 1 I

through 6 of this report to address RAls and provide additional clarification of the categorization of f

j the success paths. Sections 7 through 12 of this report contain new material, including: categorization p

of success paths to define cases for long-term cooling, comparison of short-term cooling and long-term

+()4 1 cooling case definitions, results of conservative T/II a talyses for short-term and Cong-term cooling, and a discussion of the PRA effect due to the T/fl analysis results.

Submittal of this topical report addresses Key issue 21. The NRC technical staff should review the enclosed material.

Submittal of WCAP-14800 closes, from the Westinghouse perspective, DSER open item 19.1.3.1-3 (OITS #1400), and the Westinghouse status column in the OITS will be changed to " Action N." Tne NRC should inform Westinghouse of the status to be designated in the "NRC Status" column of the OITS.

9706260090 970619

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DCP/NRC0924 June 19,1997 Please contact Cynthia L. Haag on (412) 374-4277 if you have any questions concerning this transmittal.

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Brian.A. McIntyre, Manager Advanced Plant Safety and Licensing jml Enclosures cc:

W. Iluffman, NRC (2 copies Enclosure)

A. Levin, NRC (Enclosure)

J. Flack, NRC (Enclosure)

G. Holahan, NRC (w/o Enclosure)

N. J. Liparulo, Westinghouse (w/o Enclosure) l 3263A wpf r

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Enclosure to Westinghouse Letter DCP/NRC0924 June 19,1997 1

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