ML18033A525

Forwards Safety Evaluation Re Util Compliance w/10CFR50.62 Concerning Alternate Rod Injection & Reactor Pump Trip Sys. One Area of Plant ATWS Design Not in Full Conformance W/Atws Rule.Response Requested within 30 Days of Ltr Receipt

ML18033A525
Person / Time
Site:	Browns Ferry
Issue date:	01/22/1989
From:	Black S Office of Nuclear Reactor Regulation
To:	Kingsley O Tennessee Valley Authority
Shared Package
ML18033A526	List: ML18033A525 ML18033A527
References
TAC-59072, TAC-59073, TAC-59074 NUDOCS 8902010006
Download: ML18033A525 (3)

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UNlTED STATES UCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 January 22, 1989 Docket kos.

50-259 50-260 and 50-296 DUE TO REPRODUCTION

ERROR, THIS LETTER IS BEING REDISTRIBUTED.

Mr. OIiver D. Kfngsley, Jr.

Senior Vice president,'Nuciear power Tennessee Valley Authority 6N 38A Lookout Place 1101 Market Street Chattanooga, Tennessee 37402-2801

SUBJECT:

COMPLIANCE WITH RULE 10 CFR 50.62 RELATING TO A TERNATE ROD INJECTION AND REACTOR PUMP TRIP SYSTEMS (TAC 59072, 59073 AND 59074)

The ATWS Rule (10 CFR 50.62, "Requirements for Reduction of Risk from Anticipated Transients Without Scram (ATWS) Events for Light-Water-Cooled Nuclear Power Plant" ) requires improvements in the design and operation of corrIIercia1 nuclear power facilities to reduce the likelihood of failure to shutdown the reactor following anticipated transients, and to mitigate the consequences of an ATWS event.

The requirements for a boiling water reactor are to install an alternate rod injection (ARI) system, a standby lfquid control system (SLCS) and to trip the reactor coolant recirculation pumps (RPT) automatfcally under conditions indicative of an ATWS.

Tennessee Valley Authority provided information by letters dated March 1, July 15 and August 4, 1988 concerning their implementation of the ATWS Rule.

The Instiumentatfon and Control Systems Branch has reviewed this information.

The staff finds that one area of the Browns Ferry ATWS design is not in full conformance with the ATWS Rule.

The Browns Ferry's ARI and RPT designs utilize the same analog trip units (ATU) for both the ATWS system and the reactor trip system (RTS).

Although diversity of application is provided by setting two internal switches so that the ARI and RPT are energized to trip while the RTS is de-energized to trip, we conclude that the application of different energizatfon states is not sufficient to minimize the potential for common cause failures in the ARI/RPT systems and RTP ATUs. If alternate boards by a different manufacturer were used in these

systems, sufficient diversity would exist between the ATWS mitigation system and the RTS.

We believe that it is prudent for the licensee to consider installation of the diverse ATU circuit boards pr ior to the restart of the plant.

The licensee is also required :o document the preoperational test to verify the ARI function time.

This documentation will be verified during the staff inspection of the Aih'S couipment implementa+'.or..

We request your resporrse to the above positions withir. 3C days of the I-eceipt of rhis letter.

0P) i 89020i0006 S5'Qi22 PDR ADOCK 05000259 P

PDC

Mr. Oliver D. Kingsley, Jr.

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By letter dated August 4, 1988, the licensee requested an amendment to licenses DPR<<33, DPR-S2 and DPR<<68 to change the technical specifications with respect to ATMS/RPT.

The staff is currently reviewing the proposed changes.

Our safety evaluation, which provides the review details of the ARI and RPT

systems, is enclosed.

If you have any questions concerning the above, please contact the Browns Ferry Project Manager, Gerald E. Gears. at 301-492-0767.

The reporting and/or recordkeeping requirements contained in this letter affect fewer than ten respondents; therefore, OMB clearance is not required.

Sincerely,

'riginal signed by R. Auluck for Distribution NRC PDR Local PDR Proiects Reading OSP Reading

.J. Partlow B.

D. Liaw S. Black R. Pierson F.

McCoy M. S. Little M. Simms D. Moran G. Gears J. Rutberg D. Crutchfield B. Grimes E. Jordan A. Thadani H. Li ACRS (10)

GPA/CA GPA/PA BFN Rdg. File cc:

Plant Service list Suzanne C. Black, Assistant Director for Projects TVA Projects Division Office of Nuclear Reactor Regulation

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Mr. Oliver D. Kingsley, Jr. Browns Ferry Nuclear Plant CC:

General Counsel Tennessee Valley Authority 400 West Summit Hill Drive Ell B33 Knoxville, Tennessee 37902 Mr. R. L. Gridley Tennessee Valley Authority 5N 157B Lookout Place Chattanooga, Tennessee 37407-2801 Mr. C.

Mason Tennessee Valley Authority Browns Ferry Nuclear Plant P.O.

Box 2000

Decatur, Alabama 35602 Mr. P. Carier Tennessee Valley Authority Browns Ferry Nuclear Plant P.O.

Box 2000

Decatur, Alabama 35602 Mr. D. L. Williams Tennessee Valley Authority 400 West Summit Hill Drive W10 B85 Knoxville, Tennessee 37902 Chairman, L.imestone County Commission P.O.

Box 188

Athens, Alabama 35611 Claude Earl Fox, M;D.

State Health Officer State Department of Public Health State Office Building Montgomery, Alabama 36130 Regional Administrator, Region II U.S. Nuclear Regulatory Commission 101 Marietta Street, N.W.

Atlanta, Georgia 30323 Resident Inspector/Browns Ferry NP U.S. Nuclear Regulatory Commission Route 12, Box 637

Athens, Alabama 35611 Dr. Henry Myers, Science Advisor Committee on Interior and Insular Affairs U. S.

House of Representatives Washington, D.C.

20515 Tennessee Valley Authority Rockville Office 11921 Rockville Pike Suite 402 Rockvil le, Maryland 20852