ML20155F609

Advises That NRC Will Perform Audit of PRA During 881101-02. Objective & Scope of Audit Discussed in Encl

ML20155F609
Person / Time
Site:	Browns Ferry
Issue date:	10/07/1988
From:	Black S NRC OFFICE OF SPECIAL PROJECTS
To:	White S TENNESSEE VALLEY AUTHORITY
References
TAC-63178, NUDOCS 8810130324
Download: ML20155F609 (3)

Text

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. . October 7, 1983 Docket Nos. 50 259/260/296 i

Mr. S. A. White l Senior Vice President Nuclear Power Tennessee Valley Authority 6N 38A Lookout Place )

1101 Market Street Chattanooga, Tennessee 37402-2801

SUBJECT:

NRC PROBABILISTIC RISK ASSESSMENT AUDIT FOR BROWNS FERRY (TAC 63178)

The NRC will perform an audit of the Browns Ferry Probabilistic Risk Assessment (PRA) during the period of November 1 and 2, 1988 at Knoxville.

The objective and scope of this audit are identified in the enclosure. An exit meeting with you or members of your staff will be conducted on November 2, 1988 at 3:00 p.m. (Building W10 B86).

If you have any questions regarding this activity, please contact the NRC Project Manager, G. Gears at (301) 492-0767.

Sincerely.

Original Signed by Sezanne Black, Assistant Director for Projects TVA Projects Division Office of Special Projects

Enclosure:

PRA Audit Scope cc w/ enclosure:

g See next page sm8 881 OfSTRIBUTION

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M. Sims E. Chelliah

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OFFICIAL RECORD COPY

.o ENCLOSURE PRA AUDIT BROWNS FERRY Audit Topic: Browns Ferry Probabilistic Risk Assessment Date: November 1 and 2, 1988 NRC Audit Erulappa Chelliah Members: Gerald E. Gears (Project Manager)

Objective: To obtain additional, detailed information to assist NRC in writing its Safety Evaluation.

Audit Scope: 1. Review of the bases for the dominant sequences identified in Reference 1 Table 6-1. Why is Dominant Sequence State 3 now important?

2. Review and examination of the chances to the fault tree model for each of the major top events. (A sampling of approximately three systens will be covered).

3. For the fault tree tredels identified in item 2, examination of how impacts due to changes in the plant configuration (hardware and procedural) were evaluated.

(Refer to Reference 1, Section 3.1 4 Detennination on how containnient venting has been considered in Dominant Sequences 2, 4, 5, and 10 in Peference 1, Table 6-2, Determination of whether the venting approach from the BWR Owners Group had been incorporated into Browns Ferry Emergency Operating Precedures or into the PRA.

5. Review and exanination of the Anticipated Transient Without Scram (ATWS) hardware and procedural changes. (Refer to Reference 2, Table 3. Items 1 and 2, and Reference 1, Table 4-1.)

Peferences: 1. Letter dated August 25, 1988 from TVA to NRC, transmitting the Browns Ferry PRA Sumary Report.

2. Letter dated October 1, 1987 from NRC to TVA, transmitting NRC staff coments on the January 1986 version of the Browns Ferry PRA.

Mr. S', A. White Browns Ferry Nuclear Plant CC' General Cour.sel Regional Administrator, Regior, II Tennessee Valley Authority U.S. Nuclear Regulatory Comrir,sion 400 West Summit Hill Drive 101 Marietta Street, N.W.

E11 833 Atlanta, Georgia 30323 Knoxville, Tennessee 37902 Resident Inspector /Rrowns Ferry NP Hr. R. L. Gridley U.S. Nuclear Regulatory Cernission Tennessee Valley Authority Route 12 Box 637 SN 157R Lookout Place Athens, Alabama 35611 Chattanooga, Tennessee 37402-?801 Mr. C. Mason Dr. Henry Myers, Science Advisor Tennessee Valley Authority -

Committee on Interior Browns Ferry Nuclear Plant and Insular Affairs P.O. Box 2000 U. f. House of Representatives Decatur, Alabama 35602 Washington, D.C. 20515 Tennessee Valley Authority Mr. F. Carter Rockville Office Tennu3see Valley Authority 119?1 Pockville Pike Browns Ferry Nuclear Plant Suite 402 P.O. Box 2000 Rockville, Maryland 20852 Decatur, Alabama 35600 Pr. D. L. Williams Tennessee Valley Authority 400 West Summit Hill Drive W10 B85 Knoxville, Tennessee 37902 Chairman, Limestone County Commission P.O. Box 188 Athels, Alabai. 35611 Clauve Earl Fox, M.D.

State Health Officer State Departrent of Public Health State Office Building P.ontgomery, Alabama 36130

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