ML20151J895

Special Rept:On 970628,Unit 2 WR Noble Gas Monitor Was Inoperable for Period in Excess of Seven Days.Caused by Failure of Low Range Channel High Voltage Power Supply. Replacement Power Supply Was Installed

ML20151J895
Person / Time
Site:	Calvert Cliffs
Issue date:	07/24/1997
From:	Katz P BALTIMORE GAS & ELECTRIC CO.
To:	Miller H NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
NUDOCS 9708050276
Download: ML20151J895 (2)

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PE1r.a E. KArz Baltimore Gas and Electric Company Plant General Manager Calvert Cliffs Nuclear Power Plant Calven Cliffs Nuclear Power Plant 1650 Calven Cliffs Parkway Lusby. Maryland 20657 410 495-4101 July 24,1997 U. S. Nuclear Regulatory Commission Region I 475 Allendale Road King of Prussia, PA 19406 ATTENTION:

Mr. II. J. Miller, Regional Administrator SUlllECT:

Calvert Cliffs Nuclear Power Plant Unit No. 2; Docket No. 50-318 Wide Range Noble Gas Monitor -- Special Report The attached special report is submitted in accordance with Calvert Cliffs Unit 2 Tec;tnical Specification 3.3.3.1.

The report concerns the inoperability of the Unit 2 Wide Range Noble Gas Monitor for a period in excess of seven days.

Should you have questions regarding this matter, we will be pleased to discuss them with you.

Very truly yours, f

. ?.AL f PEK/RCG/bjd Attachment cc:

-Document Control Desk, NRC Director, Project Directorate I-1, NRC R. S. Fleishman, Esquire Resident Inspector, NRC l

J. E. Silberg, Esquire R. I. McLean, DNR A. W. Dromerick, NRC J. H. Walter, PSC f

9708050276 970724 DR ADOCK 0500 8

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N ATTACIIMENT (1)

UNIT 2 WIDE RANGE NOBLE GAS MONITOR - SPECIAL REPORT Bahimore Gas and Electric Company (BGE) submits this Special Report concerning the inoperable Unit 2 Wide Range Noble Gas Monitor (WRNGM) as required by Technical Specification 3.3.3.1, j

Table 3.3-6, item 2.b.i.

j ACTION TAKEN j

He Unit 2 WRNGM was removed from OPERABLE status on June 28,1997 at approximately 1440 following the failure of the low range channel automatic checksource test. A manual checksource test was performed, which also failed. Troubleshooting performed on June 30,1997 determined that the low range channel high voltage power supply, which supplies operating voltage to the detector, had failed. A replacement power supply was not readily available.

In March 1997, BGE contacted the vendor to obtain replacement low range channel high voltage power supplies. At that time, the vendor indicated that the power supply was obsolete and proposed a replacement power supply.

Baltimore Gas and Electric Company was reviewing the vendor documentation for the proposed power supply when the failure of the Unit 2 WRNGM low range channel high voltage power supply occurred on June 28,1997. In response to the failure, BGE expedited the shipment of a replacement power supply at-risk and expedited the required engineering to accept the use of the replacement power supply. The required engineering to accept the replacement power supply was completed on July 8,1997 at which time the replacement power supply was released for use.

The replacement power supply was installed on July 10,1997 and the Unit 2 WRNGM was returned to OPERABLE status on July 11,1997 at approximately 2225.

1 EFFECT ON OPERATION Unit 2 Technical Specification 3.3.3.1 Action Statement (30) was entered when the Unit 2 WRNGM was removed from service. In accordance with this Action Statement and our Accidental Radioactivity Release Monitoring and Sampling Methods procedure (Emergency Response Plan Implementation Procedure-821), the preplanned alternate monitoring method was implemented. During the period that the Unit 2 WRNGM was not OPERABLE, the Unit 2 Main Vent Radiation Monitor remained OPERABLE. The inoperability of the WRNGM did not affect Unit 2 operation.

CAUSES OF INOPERABILITY The cause of the inoperability was the failure of the low range channel high voltage power supply.

PLANS AND SCIIEDULES FOR RESTORING TIIE SYSTEM TO OPERABLE STATUS The Unit 2 Wide Range Noble Gas Monitor was removed from OPERABLE status on June 28,1997 at approximately 1440 and retprned to OPERABLE status on July 11,1997 at approximately 2225. No fmther actions are required.

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