ML18024A521
| ML18024A521 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 11/08/1978 |
| From: | Fox H TENNESSEE VALLEY AUTHORITY |
| To: | NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| NUDOCS 7811140165 | |
| Download: ML18024A521 (4) | |
Text
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REGULATORY FORMATION DISTRIBUTXON TEM DOCKET NBR: 50-296 BROWNS FERRY 3
DOC DATE:
78 1108 RECXPIENT-O'REXLLY J.P.
ORXGXNATOR: FOX H-S-ACCESSION NBR:
7811140165 COPIES RECEIVED:
COMPANY NAME:
TN VALLEY AUTH LTR 1
ENCL 1
SUBJECT:
SIZE:
3 Forwards suppl Reportable Occurrence
'Rept 'BFRO-'0-296/7822 on 780822.
During startup at 3 percent thermal pwr, MSRV 1-4 opened S did not completely close resulting in excessive cooldown rate.
~ Caused by excessive pilot leakage.
DISTRIBUTION'QDEf
$ 002 DISTRIBUTION'ITLE !.
INCIDENT REPORTS NOTARIZED ENCL2 W/4 ENCL
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November S,
1978 KK"~.'."':.'"
"....'": IIPIt TENNESSEE VALLEYAUTHORlTY CHATTANOOGA. TENNESSEE 37401 Mr. James P. O'Reilly, Director U.S. Huclear Regulatory Cornnission Office of Inspection and Enforcement Region II 101 Marietta Street, Suite 3100 Atlanta, Georgia 30303
Dear Hr. O'Reilly:
TENNESSEE VALLEY AUTHORITY BROWNS FERRY NUCLEAR PLANT UNIT 3 DOCKET NO. 50-296 FACILITY OPERATING LICENSE DPR REPORTABLE OCCURRENCE REPORT BFRO-50-296/7822 This refers to my letter dated September 1, 1978.
Enclosed is supplemental reportable occurrence report BFRO-50-296/7822 which provides details concerning main steam relief valve 1-4 which opened during startup at 3-percent thermal power.
This report is submitted in accordance with Browns Ferry unit 3 technical specification 6.7,2,A,(2) ~
Very truly yours, TENNESSEE VALLEY AUTHORITY H. S. Fox Director of Power Production Enclosure (3) cc (Enclosure):
Director (3)
Office of Management Information and Program Control U.S, Nuclear Regulatory Com ission Washington, D.C.
20555 Director (40)
Office of Inspection and Fnforcement U.S. Nuclear Regulatory Commission Washington, D.C, 20555 7ZhY~P~<<
An Equal Opportunity Employer
LER SUPPLEMENTAL INFORMATION BFRO-50-296/7822 Technical Specification Involved:
3.6.A.l Reported under Technical Specification:
6.7.2.a.(2)
Date of Occurrence:
August 22, 1978 Time of Occurrence:
9:23 a.m.
Unit:
3 Identification and Descri tion of Occurrence During startup at 3-percent thermal power, MSRV 1-4 opened and did not completely reclose resulting in excessive cooldown rate of the vessel.
The torus temperature 0
reached approximately 128 F.
Conditions Prior to Occurrence Reactor at approximately 3-percent MWt.
A arent Cause of Occurrence Excessive pilot and second-stage leakage.
MSRU 1-4 exhibited steam cuts on the pilot and second-stage seats and discs'his condition was similar to conditions found on valves that have experienced the same type of failure.
Anal sis of Occurrence It was determined that the transient was less severe than the design blowdown transient.
The fatigue usage factors are as folio-.<s:
Feedwater nozzles Rx vessel at waterline Closure studs 0.00091 0.000033 0.000667 Corrective Action The topworks were replaced on this valve.
The blowdown was analyzed in accordance with standard heatup/cooldown analysis techniques and fatigue usage factors assigned.