05000318/LER-1981-005, Forwards LER 81-005/01T-0

Forwards LER 81-005/01T-0

ML20003A287
Person / Time
Site:	Calvert Cliffs
Issue date:	01/29/1981
From:	Russell L BALTIMORE GAS & ELECTRIC CO.
To:	Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML20003A288	List: 05000318/LER-1981-005, Forwards LER 81-005/01T-0 05000318/LER-1981-005-01, /01T-0:on 810118,w/reactor Coolant Sys at 220 F & 230 Psia,Presssure Transmitter Failed High,Causing Power Relief Valve RC-404-ERV to Open.Caused by Loose Oscillator/ Amplifier Assembly within Transmitter 2-PT-103-1
References
NUDOCS 8102030422
Download: ML20003A287 (2)

LER-1981-005, Forwards LER 81-005/01T-0

Event date:
Report date:
3181981005R00 - NRC Website

text

4 B ALTIMORE G AS AND ELECTRIC COMPANY P.O. B O X 14 7 5 B A LTI M O R E. M A R Y L A N D 21203 NUCLEAR power DEPARTMENT CALVERT CLIFFS NUCLEAR POWER PLANT LUS8Y. M ARYLAND 20657 January 29,1981 Mr. Boyce H. Grier, Di: sctor Docket No. 50-313 Office of Inspection & Enforcement License No. DPR-69 U.S. Nuclear Regulatory Commission Region 1 631 Park Avenue King of Prussia, PA 19406

Dear Mr. Grier:

Per Technical Specification 6.9.1.3.b, please find attached the fourteen day follow-up report for LER 31-05/IT.

Should you have any questions regarding this report, we would be pleased to discuss them with you.

Very truly yours, M

L.B. Russell Plant Superintendent LBR:PGR:mmr cc:

Director, Office of Management Information and Program Control i

Messrs:

A.E. Lundvall, Jr.

3.A. Tiernan i

ADO t-m i

S

//

810 S O.: 0 YN F

a LER NO.

81-05/1T DOCKET NO.

50-318 LICENSE NO.

DPR-69 EVENT DATE 01-18-81 l

REPORT DATE 01-29-81 ATTACHMENT EVENT DESCRIPTION AND PROBABLE CONSEQUENCES (CONTD) 0 At 0847 on 1-18-81 with the Reactor Coolant System (RCS) at 220 F and 230 psia during a cooldown for a scheduled refueling outage, pressure indicator controller PIC-103-1 failed high causing RC-404-ERV to open.

PIC-103-1 monitors pressurizer pressure and proviges a signal to open RC-404-ERV at 430;6 psia when the PCS is below 275 F. When the valve opened the operator received "PORV/ Safety Valve Acoustic Monitor" and "PORV Energized" alarms. After acknowledging the alarms, the operator noted that RC-404-ERV was open and shut power relief isolation RC-405-MOV terminating the discharge. RC-404-ERY was open less than one minute and RCS pressure decreased approximately six ps!. The redundant over pressure protection system remained operable during the event.

CAUSE DESCRIPTION AND CORRECTIVE ACTIONS (CONT'D)

Several attempts were made to find the cause of transmitter failure.

During first attempts the transmitter output was normal and proper call-bration was attained. Af ter placing the transmitter on line, however, signal current would again increase.

On January 22,1981, a technician found that the oscillator / amplifier was loose and he could change the signal current by moving the assembly.

Af ter tightening the assembly mounting screws, there has been no i

recurrences of faulty indication.

Transmitters employing this mounting method are in general use in the plant. This has not been a recurring problem. It is, therefore, surmised that the screws were not adequately tightened during surveillance testing approximately one year earlier, and had loosened during that time.

Technicians have been tratructed to ensure mounting and adjustment screws are properly tightened af ter maintenance.

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