05000272/LER-1978-072, Forwards LER 78-072/01X-1.Detailed Event Analysis Encl

Forwards LER 78-072/01X-1.Detailed Event Analysis Encl

ML18085B131
Person / Time
Site:	Salem
Issue date:	03/25/1981
From:	Uderitz R Public Service Enterprise Group
To:	Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML18085B132	List: 05000272/LER-1978-072, Forwards LER 78-072/01X-1.Detailed Event Analysis Encl 05000272/LER-1978-072-01, /01X-1:on 781107,svc Water Isolation Valves to All Five Containment Fan Coil Units Found Tripped Closed.Caused by Design Deficiency in Installation of RMS Detectors for Containment Fan Coil Unit Svc Water.Detectors Shielded
References
NUDOCS 8104020604
Download: ML18085B131 (3)

LER-1978-072, Forwards LER 78-072/01X-1.Detailed Event Analysis Encl

Event date:
Report date:
2721978072R00 - NRC Website

text

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f PS~G Public Service Electric and Gas Company 80 Park Plaza Newark, N.J. 07101 Phone 201/430-7000 March 25, 1981 Mr. Boyce H. Grier Director of USNRC Off ice of Inspection and Enforcement Region 1 631 Park Avenue King of Prussia, Pennsylvania 19406

Dear Mr. Grier:

LICENSE NO. DPR-70 DOCKET NO. 50-272 REPORTABLE OCCURRENCE 78-72/0lX-l SUPPLEMENTAL REPORT Pursuant to the requirements of Salem Generating Station Unit No. 1 Technical Specifications, Section 6.9.1, we are submitting supple-mental Licensee Event Report for Reportable Occurrence 78-72/0lX-l.

Sincerely yours,

,-7.. *?'

/_ <

{/': l -~"'

R. A. Uderit'z General Manager -

Nuclear Production CC:

Director, Off ice of Inspection and Enforcement (30 copies)

Director, Office of Management Information and Program Control

( 3 copies) 8104020604

L Report Number:

Report Date:

Occurrence Date:

Facility:

78~2/0lX-l March 25, 1981 11/7/78 Salem Generating Station - Unit 1 Public Service Electric & Gas Company Hancocks Bridge, New Jersey 08038 IDENTIFICATION OF OCCURRENCE:

Inoperable Fan Coil Units CONDITIONS PRIOR TO OCCURRENCE:

Operational Mode 5 DESCRIPTION OF OCCURRENCE:

During the week of October 19, 1978, while the plant was shutdown for a maintenance outage, all five Containment Fan Coil Unit's service water isolation valves were found to be tripped closed.

The problem was traced to the CFCU service water radiation monitors alarming due to radiation emitting from the residual heat removal piping passing through* the area where the detectors are located.

PSE&G Engineering Department was notified of this occurrence on October 19, 1978, and a resolution was requested.

On November 6, 1978, the Engineering Department notified the station that this was a potential unreviewed safety question and the Resident NRC Inspector was immediately notified.

DESIGNATION OF APPARENT CAUSE OF OCCURRENCE:

The cause of this occurrence is an apparent design deficiency for the RMS detector installation.

The purpose of these detectors is to monitor radioactivity in the service water discharge from the Fan Coil Units during normal operation.

Since the detectors are sensitive to changes in background radiation levels, they will cause service water isolation to the Fan Coil Units when the radiation levels are sufficient to cause the RMS detectors to initiate an alarm condition.

ANALYSIS OF OCCURRENCE:

The five Fan Coil Units use service water for cooling with a por-tion of the outlet flow diverted to a radiation monitor designed to initiate automatic isolation of the service water flow if there is radioactivity in the water, thus preventing radioactive water from being discharged to the river.

This possibility existed; if the service water system failed during a LOCA with the containment at peak pressure, since the peak pressure was thought to be greater than service water pressure.

However, as documented in the Mechanical Division Safety Evaluation SE-004, the service water pressure in the containment would be greater than the peak containment pressure.during a LOCA.

LER 78-72/0lX-l 2 -

March 25, 1981 The radiation levels in the area of the monitors will be extremely high during a LOCA due to the* activity present in the RHR lines or from streaming through the containment penetrations.

These radiation levels would trip the monitors, thus isolating service water flow, resulting in inoperative Fan Coil Units.

The isolation function is not applicable or necessary for the LOCA condition since no leakage of activity into the service water lines will occur.

Shielding necessary to effectively alternate radiation levels during a LOCA would be in the range of tons per unit (approximately 12 to 16 inches of lead) and would require structural steel supports.

The immediate solution is to remove the isolation function circuitry and leave remote manually operated isolation valves in these service water lines.

By maintaining only the alarm function, administrative action could be taken to manually isolate service water flow to these components, if an alarm is received and determined to be valid.

This also eliminates the possibility of no service water flow to the Fan Coil Units during a LOCA due to high background radiation from the RHR lines or other sources.

CORRECTIVE ACTION

Design Change lEC-0448 was completed on January 11, 1979 which removed the control function of the Fan Coil Units radiation monitors.

The detectors have been shielded with lead blankets to reduce their sensitivity to general area radiation.

No further corrective action is planned.

FAILURE DATA:

Not Applicable Prepared By W. J. Steele

• erating Station SORC Meeting No.

81-19