ML20085G085

AO BFAO-50-26/753W:on 750119,relief Valve PCV-1-4 Operated Spuriously Several Times.Caused by second-stage & pilot- Stage Leakage Due to Indentation in Seat & Disc.Relief Valve Replaced

ML20085G085
Person / Time
Site:	Browns Ferry
Issue date:	01/29/1975
From:	Eric Thomas TENNESSEE VALLEY AUTHORITY
To:	Case E Office of Nuclear Reactor Regulation
Shared Package
ML20085G086	List: ML20085G085 ML20085G090
References
NUDOCS 8308240247
Download: ML20085G085 (2)

Text

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' HOR!nL CCCTBRENCE REFDRT I

Report No.: BFAO-50-260/753W Report Date: January 29, 1975 Occurrence Date: January 19, 1975 Facility: Browns Ferry nuclear Plant unit 2 Identification of Occurrence On January 19, 1975, beginning at approximately 0100 hours0.00116 days <br />0.0278 hours <br />1.653439e-4 weeks <br />3.805e-5 months <br />, relief valve PCV-1-4 operated spuriously ceveral ti=es.

t Conditions Prior to Occurrence The reactor was operating at approximately 340 Mle.

Deceription of Occurrence During powcr ascension, the main steam relief valve PCV-1-4 operated several times while reactor preocure was nor=al.

Designatica of Annarent Cause of Occurrence Disassemb37 and in pection of the relief valve revealed both second-stage and

> pilot-stage leakage. The pilot-ctage leakage resulted from an indentaticn in both the cent and disc. It appears that clocure of the pilot on a foreign object caused the indentation. No foreign material was found in the valve.

It ic concluded that pilot leakage cauced the cpurious talve actuation.

Analysis of Occurrence There were no adverse effects to the public health and safety or damage to cyctems, components, or structures as a result of this occurrence. An orderly

. unit chutdown was conducted. No extended blowdown occurred.

Corrective Action The relief valve va: replaced. Post-maintenance functional tests at approximately 250 poi and at rated pressure were satisfactori3tf performed. Repairs were made to the valve that was removed, and steam setpoint tests will be conducted. A torus inspection conducted cubsequent to this event confirmed normal conditions.

s Failure Data Previous failures are reported on Abnormal Occurrence Reports BFAO-50-260/7430W; BFAO-50-260/7429W;LFAO-7426W, unit 1;BFAO-749W, unit 1;BFAO-7349W, unit 1;and

-BFAO-7314W, unit 1.

Valve Data Mtnufacturer - Target Rock Corporation Model - 67F Design Pressure - 1,200 psi Setpoint - 1,080 pcig Capacity - 800,000 lb/hrsaturatedstcas Serial No. - 57 8308240247 750129 PDR ADOCK 05000260 '

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$ . . TENNESSEE V/sLLEY AU~iHORITY 0

CH ATTANCOGA, TENNE 55CE 374o1

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's January 29, 1975

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Mr. Edcon G. Case i'  !- 14

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Acting Director of Licencing -

U.S. Muclear Regulatory Corniscion JN' Washington, DC 2051+5 's.

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Dear Mr. Case:

n '.'" I &' -~Y'u TEIII!ESSEE VALLEY AUTHORITY - BRO'..'!S FERRY ITUCLFAR PLtdiT UIIIT 2 -

DOCl3T I:0, 50-260 - FACILITI OPERATII!G LICI2iSE DPR ABliORMAL OCCURRIUCI: REIORT BFAO-50-260/753'T The enclosed report ic to provide details concerning relief valve PCV-1 14 which operated cpuriously several times and is submitted in accordance with Appendin A to Iiegulator Guide 1.16, Revicion 1, October 1973. Tnic event occurred on Browns Ferry liuclear Plant unit 2 on January 19, 1975 Very truly yours, TE!IITESSEE VALLEY AUTHORITY d

. . dji.-m E. F. Thomas Director of Fower Production Enclosure CC (Enclosure):

1'.r. I!ornen C. Moseley, Director U.S. I!ucleer Rer;ulatory Cocaission Regione.1 01'fice 230 Peachtree Street, I!U. , Guite 818 Atlanta, Georgia 30303 l

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