ML20086A237

Special Rept:On 911026,auxiliary Bldg Vent Stack wide-range Noble Gas Monitor Declared Inoperable & Removed from Svc for More than 7 Days.Caused by Need to Perform 18-month Channel Calibr.Channel Returned to Operable Status on 911107

ML20086A237
Person / Time
Site:	Braidwood
Issue date:	11/12/1991
From:	Simpkin T COMMONWEALTH EDISON CO.
To:	Davis A NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
NUDOCS 9111180317
Download: ML20086A237 (2)

Text

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' O' Down rs Grova,Illinoi: 60515 November 12, 1991 Mr. A. Bert Davis Regional Administratar U.S. Nuclear Regulatory Commission Region III 799 Roosevelt Road Glen Ellyn, IL 60137

Subject:

Braidwood Station Unit 1 Accident Monitoring Instrumentation Special Report NRC Docket No. 50-456

Reference:

(a) NUREG-1276, Technical Specification

(

Dear Mr. Davis:

L Section 3.3.3.6 of reference (a) requires that a Special Report be f submitted to the NRC pursuant to Specification 6.9.2 in the event that an inoperable channel is not restored within the required time-frame. The enclosure provides a report detailing the failure of the Un?t 2 Hide Range Noble Gas Monitor.

l Please direct any questions concerning this submittal to this office.

t Very Truly yours, i

'( 4uel g d l- T.H. Simpkin i Nuclear Licensing Administrator l

cc: R. Pulsifer-NRR H. Shafer-RIII ResidentInspector-Braidwood[

NRC Document Control Desk t/

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PDR ADOCK A3000456 s PDR

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Title:

Auxiliary Building Vent Stack Hide Range Noble Gas Monitor Inoperable

- d% for Greater than Seven Days Des:ription:

At 0842 on October 26, 1991, Process Radiation Monitor 2PR03J, Unit 2 Auxiliary Building Vent Stack Hide Range Noble Gas Monitor was declared inoperable and removed from operation for the performance of Braidwood Instrument Surveillance Bwls 3.3.6-211, the 18-month channel calibration of the 2PR03J. The appropriate Technical Specification Action Statements were entered and complied with. At 0354 on November 7, 1991, the calibration procedure was satisfactorily completed and the monitor was returned to operable status. This report is being submitted in accordance with Action C of Technical Specification 3.3.3.6 - with the number of operable channels for the Auxiliary Building Vent Stack Hide Range Noble Gas Monitor less than the minimum channel operable requirement restore the Inoperable channel to operable status within 7 days or prepare and submit a special report to the Commission pursuant to Specification 6.9.2 within 14 days that provides actions taken, cause of the inoperability and plans and schedule for restoring channel to operable status.

Cause of the Inoperability:

The cause of the inoperability was removing the monitor from operation to perform a required, regularly scheduled 18-month channel calibration. The cause for the completion of the calibration exceeding seven days was ode to the following:

1. During the performance of BwlS 3.3.6-211, a discrepancy was identified between testing methodology and actual plant conditions. This discrepancy necessitated halting the calibration and performing a temporary procedure change which required detailed review and approval prior to continuing the calibration.

2. The Low Channel Sample Pump failed late in the calibration sequence requiring replacement of the pump and subsequent re-performance of several conditions of BwIS 3.3.6-211.

Actions Taken:

The scheduled calibration was satisfactorily completed and the monitor was returned to operable status.

Plans and Schedule for Restoring the Channel to Operable Status:

The channel was returned to operable status at 0354 on November 7, 1991. The channel has performed satisfactorily since being returned to service.

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