ML20206Q322
| ML20206Q322 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 01/11/1999 |
| From: | Katz P BALTIMORE GAS & ELECTRIC CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9901140143 | |
| Download: ML20206Q322 (2) | |
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.x PETEu E. K4rz Baltimore Gas and Electric Company Plant General Manager Calvert Cliffs Nuclear Power Plant Calvert Cliffs Nuclear Power Plant 1650 Calvert Cliffs Parkway Lusby Maryland 20657 410 495-4101 January 11,1999 U. S. Nuclear Regulatory Commission Wash'ington, DC 20555 r
ATTENTION:
Document Control Desk
SUBJECT:
Calvert Cliffs Nuclear Power Plant Unit No. 2; Docket No. 50-318 Snecial Renort - Wide Range Noble Gas Effluent Radiation Monitor The attached special report is submitted in accordance with Calvert Cliffs Updated Final Safety Analysis Report Section 15.3.1, Contingency Measure B.2.2. The report is required due to the inoperability of the Unit 2 Wide Range Noble Gas Effluent Radiation 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 trulv yours, PEK/RCG/bjd Attachment cc:
R. S. Fleishman, Esquire
- 11. J. Miller, NRC f
g J. E. Silberg, Esquire Resident inspector, NRC S. S. Bajwa, NRC R.1. McLean, DNR j
A. W. Dromerick, NRC J. II. Walter, PSC o
V L.-
/b 9901140143 990111 t
PDR ADOCK 05000318 y
S PDR l
ATTACHMENT (1)
UNIT 2 WIDE RANGE NOBLE GAS EFFLUENT RADIATION MONITOR SPECIAL REPORT Baltimore Gas and Electric Company (BGE) submits this Special Report concerning the inoperable Unit 2 Wide Range Noble Gas Effluent Radiation Moni'or Channel as required by Calvert Cliffs Updated Final Safety Analysis Report Section 15.3.1, Contingency Measure B.2.2.
ACTION TAKEN The Unit 2 Wide Range Noble Gas Emuent Radiation Monitor was removed from OPERABLE status on December 26, 1998 at approximately 0845 due to spiking on each of the three channels which subsequently resulted in the Wide Range Noble Gas Emuent Radiation Monitor locking up. It was found that the mid-range channel checksource had become stuck. This sticking resulted in high counts on the mid-range channel thus initiating a mid-range pump start signal. This attempted stan of the mid-range pump with the low range pump in operation resulted in the Wide Range Noble Gas Emuent Radiation Monitor locking up.
Initial troubleshooting freed the stuck checksource. Once freed the checksource would work for several attempts before stiching again. Further troubleshooting found that a washer which secures a spring was sticking in a groove worn in the checksource guide tube. Upon further examination it was discovered that a roll pin which secures the washer and the spring in the mid-range checksource assembly guide tube had worn. This allowed the washer to become cocked in the guide tube and to wear a groove in the guide tube. It was in this groove that the checksource would, on occasion, stick. The checksource assembly was replaced and all required post-maintenance testing was completed on January 4,1999.
Thus, the restoration time of seven days, as specified in Calvert Cliffs Updated Final Safety Analysis
.hprt hetion 15.3.1, for returning the Wide Range Noble Gas Emuent Radiation Monitor to OFUMLE status was not met.
EFFECT ON OPERATION In accordance with the Contingency Measure B.! of Calvert Cliffs Updated Final Safety Analysis Report Section 15.3.1 and our Accidental Radioactivity Release Monitoring and Sampling Methods procedure (ERPIP-821), the preplanned alternate monitoring method was implemented. During the period that the Unit 2 Wide Range Noble Gas Emuent Radiation Monitor was not OPERABLE, the Unit 2 Main Vent Radiation Monitor remained OPERABLE. The inoperability of the Wide Range Noble Gas Emuent Radiation Monitor did not affect Unit 2 operation.
CAUSES OF INOPERABILITY The initial cause of the inoperability was the failure of the mid-range checksource to properly rescat resulting in high counts on the mid-range channel and subsequently Wide Range Noble Gas Emuent Radiation Monitor lock-up. The inoperability period was extended beyond the seven day restoration time requirement due to the need to accurately identify the root cause of the failure, to complete maintenance, and to complete required post-maintenance testing.
PLANS AND SCHEDULES FOR RESTORING TIIE SYSTEM TO OPERAHLE STATUS The Unit 2 Wide Range Noble Gas Emuent Radiation Monitor was returned to OPERABLE status on January 4,1999 following the completion of maintenance and post-maintenance testing. The Wide Range Noble Gas Effluent Radiation Monitor was inoperable for approximately ten days.
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