ML20115J005
| ML20115J005 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 10/22/1992 |
| From: | Cruse C BALTIMORE GAS & ELECTRIC CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9210280004 | |
| Download: ML20115J005 (2) | |
Text
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e B ALTIMORE GAS AND ELECTRIC CALVERT CLIFFS NUCLEAR POWER PLANT 1650 CALVERT CLIFFS PARKWAY
- LUSBY, MARYLAND 20657-4702 CHARLES H CRUSE PLANT OCNERAL MANAGER CALVERT Clif f S October 22,1992 U. S. Nuclear Regulatory Commission Washington,DC 20555 ATTENTION:
Document Control Desk
SUBJECT:
Calvert Cliffi. Nuclear Power Plant Unit No.1; Docket No. 50-317 Egaetor Vessel Level Monitorine System (RVLMS)
Gentlemen:
Per the requirements of Technical Specification 3.L.J. Table 3.3-10, Item Number 14, we hereby submit the following Special Report concerning Renctor /cssel Level Monitoring System Channel A-out of service for more than seven days.
- Should you have any further questions regarding this matter, we will be pleased to discuss them with you.
Very truly yours, l
8//
NY CHC/DWM/bjd
,e Attachment cc.
D. A. Brune, Esquire J. E. Silberg, Esquire R. A. Capra, NRC D. G. Mcdonald, Jr., NRC T. T. Martin, NRC P. R. Wilson, NRC R. I. McLean, DNR J. rt Walter, PSC iT003J 4(
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REACTOR VESSEL LEVEL MONITORING SYSTEM '
SPECIAL REPOliT ACTION TAKlW:
- On September 21,1992, the Unit 1 Channel A Reactor Vessel Level Monitoring System (RVLMS) was removed from service at approximately 0840_ to perform a Surveillance Test Procedure (STP);
s During performance of the STP, Channel A failed the open thermocouple test.: On September 24, 1992, the STP was stopped and corrective maintenance began. Ou October 1,1992, an improper ground isolation was discovered _ allowing incorrect voltages to exist on a circuit board. During troubleshooting, it was verified that the_RVLMS, in its as-found condition, responded correctly to an.
open thermocouple. The ground fault affected testing only. - With channel A out of senice, there -
was no adve.ac affect on the operation of Unit 1 since Channel B remained in service the whoic time.
'Ihe isolation was restored and on October 2,1992, Channel A successfully passed its STP and wu returned to senice.
CAUSE OF INOPERAltliflY:
'lhe cause of the testing problem was found to be improper installation of ground isolation to which
- the affected circuit board was attached.
PI ANS ANI) SCilEI)ULE FOR RESTORING Tile SYSTEM TO OPERAllLE:
Channel A was returned to service on October 2,1992.
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