05000272/LER-1981-028, Forwards LER 81-028/03X-1.Detailed Event Analysis Encl

Forwards LER 81-028/03X-1.Detailed Event Analysis Encl

ML19350E776
Person / Time
Site:	Salem
Issue date:	06/12/1981
From:	Uderitz R Public Service Enterprise Group
To:	Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML19350E777	List: 05000272/LER-1981-028, Forwards LER 81-028/03X-1.Detailed Event Analysis Encl 05000272/LER-1981-028-03, /03X-1:on 810311,discovered Detector C Would Not Enter Normal Thimble Path & Leak Alarm Annunciated.Reactor Coolant Overflowed & Thimble Tube H11 Found Leaking.Cause Undetermined.Thimble Tube Capped on Top Side
References
NUDOCS 8106230512
Download: ML19350E776 (3)

LER-1981-028, Forwards LER 81-028/03X-1.Detailed Event Analysis Encl

Event date:
Report date:
2721981028R00 - NRC Website

text

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O PSIEG Publ.c Service Electric ar.d Gas Company 80 Park Plaza NewarF, N.J. 07101 Phone 201/430-7000 June 12, 1981 Mr. Boyce H. Grier g

Director of USNRC d

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, (' ]\\rIIT Office of Inspection and Enforcement Region 1

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.d 631 Park Avanue

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[ j gtl 2 3 19 M " g King of Prussia, Pennsylvania 19406 9.5.$isN

Dear Mr. Grier:

N LICENSE MO. DPR-70 i

DOCKET NO. 50-272 REPORTABLE OCCURRENCE 81-28/03X-1 SUPPLLMENTAL REPORT Pursuant to the requirements of Salem Generating Station Unit No. 1 Technical Specifications, Section 6.9.1, we are submitting supple-mental Licensec Event Report for Reportable Occurrence 81-28/03X-1.

Sincerely yours,

[

f R. A.

Uderita '

General Manager -

Nuclear Prodtction CC:

Director, Office of Inspection and Enforcement (30 copies)

Director, Office of Management Information ar.d Program Control (3 copies)

IBIOG2",0SM S

The Energy People

o

. Report Number:

81-28/03X-1 Report Date:.

June 12, 1981

- Occurrence Date:. 3/11/81 Facility:

Salem Generating' Station, Unit 1 l

Public Service Electric & Gas Company Hancocks Bridge, New Jersey 08038 IDENTIFICATION OF OCCURRENCE:

Thimble Leak in the Incore Flux Mapping System CONDITIONS PRIOR TO OCCURRENCE; Mode 1 - Rx Power 100% - Unit Load 1130 MW DESCRIPTION OF OCCURRENCE:

During normal operation, while performing a Run Normal Full Core Flux Map IAW Part 13 of the Reactor Engineering Manual, it was discovered that the C Detector would not enter its normal chimble paths.

Coincident with this discovery at 1330 hours0.0154 days <br />0.369 hours <br />0.0022 weeks <br />5.06065e-4 months <br />, a Leak Alarm was annunciated on the Incore Detector Operating Console in the Control Room.

Investigation revealed that Reactor Coolant was overflowing from the C Box of the 10 Path Rotary Transfer Device.

Core Position Hll Thimble Isolation Valve was closed isolating the leak and stopping the overflow.

Further investigation revealed that the water backed up through the drain lines into all six 10-Path Transfer Devices partially or completely filling all the thimble tubes in the reactor.

On March 15, 1981, a flux map of the core was completed that included all the thimble tubes in the C Box except for Hll which was and remains isolated.

This occurrence constituted abnormal degradation of a system designed to contain radioactive material resulting from the fission process IAW Technical Specification 6.9.1.9.d.

DESIGNATION OF APPARENT CAUSE OF OCCURRENCE:

The exact source of the leak cannot be determined at this time.

However, phone conversations with the vendor (Teleflex) concur I

with our assumption that the Thimble Tube End Cap on tube Hll is leaking.

s t -

LER 81-28/03X-1 6/12/81 ANALYSIS OF OCCURRENCE:

Technical Specification.3.3.3.2 requires that the movable incore detection system shall be operable with at least 75% of the detector thimbles operable or the system cannot be used for the

'recalibration if the excore neutron flux detection system, mgnitoring the quadrant power tilt ratio, or the measurement of F AH and FQ(Z).

With tuDe Hll isolated, only one of the 58 thimbles in the system is inoperable.

' CORRECTIVE ACTION:

During the perio3 of March 28, 1981, through April 17, 1981, all of the thimble tLLos were cleaned, flushed and dried.

The leaking thimble tube (Hil) was capped on the top side of the Core Position Hll Thimble Isolation Valve und the valve tagged out.

On April 22, 1981, all remaining thimble paths were tested and found to be free and clear of any water or foreign matter.

During the next refueling outage when thimble Hll can be extracted out of the core, the exc.ct source of the leak will be identified.

A supplementary report will be submitted at that time.

FAILURE DATA:

Teleflex Flux Mapping System PN re.'ed By W.

J. Steele

/

tet h SORC Meeting No.

81-36