ML18283B400

LER 1978-010-00 for Browns Ferry Nuclear Plant, Unit 3, Both RBM Channels Which Became Continuously Bypassed During Power Ascension

ML18283B400
Person / Time
Site:	Browns Ferry
Issue date:	05/01/1978
From:	Fox H Tennessee Valley Authority
To:	O'Reilly J NRC/IE, NRC/RGN-II
References
LER 1978-010-00
Download: ML18283B400 (8)

Text

REGULATORY INFORMATION DISTRIBUTION SYSTEM <RIDS)

DISTRIBUTION FOR INCOMING MATERIAL 50-296 REC: OREILLY J P ORG: FOX H S DOCDATE: 05/04/78 NRC TN VALLEY AUTH DATE RCVD: 05/ii/78 DOCTYPE: LETTER NOTARIZED: NO COPIES RECEIVED

SUBJECT:

LTR i ENCL i FORWARDING LlCENSEE EVENT REPT (RO 50-296/78-0i0) ON 04/09/78 CONCERNING RBM CHANNELS BECAME CONTINUOUSLY BYPASSED... ALL ROD MOVEMENT WAS TERMINATED.... W/ATT.

PLANT NAME:BROWNS FERRY UNIT 3 REVIEWER INITIAL: X JM DlSTRIBUTOR INITIAL:Q~

DISTRIBUTION OF THIS MATERIAL IS AS FOLLOWS INCIDENT REPORTS (DISTRIBUTION CODE A002>

FOR ACTION: BR CHIEF LEA .

0/4 ENCL INTERNAL: REG FILE++W/ENCL NRC PDR++W/ENCL E~4W/2 ENCL MIPC<4W/3 ENCL S ITO>+W/ENCL HOUSTON++W/ENCL NOVAK/CHECK4~W/ENCL EEB~+W/ENCL KNIGHTS +W/ENCL BUTLER~~~W/ENCL HANAUER~~~W/ENCL TEDESCO+4W/ENCL EISENHUT++W/ENCL BAER~~W/ENCL SHAO<+W/ENCL VOLLMER/BUNCHw+W/ENCL KREGER/J. COLLINS>~W/ENCL ROSA~~W/ENCL K SEYFRIT/IE+~~W/ENCL EXTERNAL: LPDR S ATHENS'L++W/ENCL TIC4+W/ENCL NSIC++W/ENCL ACRS CAT B++W/16 ENCL COPIES NOT SUBNITTED GUIDE 10 ' PEP.,'EGULATORY DISTRIBUTION: LTR 45 ENCL 45 CONTROL NBR: 78i320020 8 I ZE: iP+ iP+ iP

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TENNESSEE VALLEY AUTHORITY CHATTANOOGA, TENNESSEE 37401 MN c '197S Itll,II@II(Ogrffl g~[ tropIr" Mr. James P. O'Reilly, Dirac r U.S. Nuclear Regulato Comnission Cp Office of Inspection and Enforcement C~

r Region II r 230 Peach ree Street, m., Suite 1217 roc, .,

CT Atlanta, Georgia 30303 >-c~~

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Dear Mr. O'Reilly:

TENNESSEE VALLEY AUTHORITY DOCKET NO. 50-,296 -

- BROGANS PERRY NUCLEAR FACILITY OPERATING LXCENSE OCCURRENCE REPORT BPRO-50-296/7810

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Crs The enclosed report provides details concerning both RBM channels which became continttously bypassed during power ascension. This report is submitted in accordance with Browns Perry unit 3 Technical Specification 6.7.2.a.(2).

Very truly yours, TENNESSEE VALLEY AUTHORXTY H. S. Pox Director of. Power Production Enclosure (3) cc {Enclosure):

Director (3)

Office of Management Information and Program Control U.S. Nuclear Regulatory Co ssion Washington, DC ,20555 Director (40)

Office of Xnspection and Enforcement U.S. Nuclear Regulatory Commission Hashington, DC 20555 gng A'

An Equal Opportunity Employer

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~o 1 Durin ower ascension both RBM channels became'continuously bypassed.

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REPORTABLE OCCURRENCE REPORT Report Number  : BFRO<<'50-296/7810 Report Date  : May 2, 1978 Occurrence Date: April 9, 1978 Facility Browns Ferry Nuclear Plant Unit 3 Identification of Occurrence Operator observation of RBM recorders downscale and RBM bypass lights on.

Conditions Prior to Occurrence Normal operation at 77-percent power, during ascension to full load.

Descri tion of Occurrence Both RBM channels became continuously bypassed. Review of potential reportable occurrence report revealed report should have been a prompt report as required by Technical Specification 6.7.2.a.(2).

, Desi nation of A arent Cause of Occurrence Maintained voltage on edge rod selected bus. Misinterpretation of the technical specifications.

Anal sis of Occurrence Contact 5-6 of rod select relay KXB for CRD 38-03 stuck closed.

Corrective Action Replacement of defective relay. Discussed meaning of technical specification with plant staff.

Failure Data No previous failures.

JGD: SGS 5/A/78

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