On July 21, 2003 the
limit switch lead for Motor Operated Valve (
MOV) 2CV8111, (i.e., Chemical and Volume Control System charging pump mini-flow isolation valve) was discovered lifted and taped. The
lead had not been relanded following
MOV diagnostic testing at the completion of the test on July 9, 2003. Also, the post maintenance testing (
PMT) for this work did not detect the problem before the valve was returned to service. This resulted in the 2A train Centrifugal Charging pump (cv) being declared
inoperable for 12 days since the mini-flow isolation valve was incapable of auto closure, however, valve 2CV8111 was still available for manual repositioning.
The Root Cause for the event was the failure of Maintenance management to adequately enforce the required Maintenance Fundamentals (i.e., basic expected good work practices). They did not ensure that the personnel involved followed the standards, policies and administrative controls required to successfully perform the required work on the 2CV8111 valve. The corrective action is that Maintenance management will ensure that each worker knows the expectations for each job prior to starting the work, including performance of a pre-job brief, reviewing applicable operating experience (OPEN), reviewing critical steps and potential configuration control issues.
This event is being reported pursuant to 10CFR50.73(a)(2)(1)(8).
FACILITY NAME (I) � DOCKET (2) � STN 05000457 LEA NUMBER 6) NRCFORM366A � us. NUCLEAR REGULATORY COMMISSION (1-2001) A. � Plant Operating Conditions Before The Event:
Unit: 2 � Event Date: July 21, 2003 � Event Time: 1300 MODE: 1 � Reactor Power: 100 percent Reactor Coolant System (RCS)[AB1 Temperature: 580 degrees F, Pressure: 2235 psig S. � Description of Event:
There were no additional systems or components inoperable at the beginning of this event that contributed to the severity of the event.
On July 8, 2003, electricians set up Motor Operated Valve (MOV) 2CV8111 (i.e., Chemical and Volume Control System (CV)IBM charging pump mini-flow isolation valve) to perform routine diagnostic testing on the valve.
To facilitate the diagnostic testing, a local dual control pushbutton switch was installed at the valve to allow the electricians performing the work to locally operate the valve. This is standard practice at Braidwood Station when performing MOV diagnostic testing. Installation of the local dual control pushbutton involves alteration of the MOV control circuit by installing the pushbutton in aeries with the open and close circuit wiring and the placement of jumpers in the motor control center (MCC). Additionally, for this MOV, a lead in a parallel closure circuit for auto-closure of the valve was lifted to prevent auto-closure while the valve was being tested. Configuration control of the 'valve -control - circuit. wiring was to be maintained by.using.concurrent verification practices documented in the testing procedure. The setup work was completed on the afternoon shift.
The required control circuit changes to support the testing were supplied by the MOV Engineer as directed by plant procedures. Another engineer independently verified the accuracy of the control circuit changes. Four leads in the control circuit were lifted including a black-white wire in the auto-close control circuit. This lead was lifted to prevent auto closure of the valve during testing. The instructions provided to the electricians by the MOV Engineer specifically stated that lifting the black-white wire would disable the auto close function. The end of the wire was taped with black electrical tape. All lifted leads were concurrently verified as required by the testing procedure.
On the following shift (i.e., midnight shift) on July 9, 2003, two different electricians were assigned to support the diagnostic testing. Prior to starting the testing, the MOV Engineer gave a briefing of the work to be performed to the electricians. The engineer's briefing concentrated on the technical aspects of the work. The FLS was confident that the workers understood the work to be performed and he knew that they were experienced at this type of work. Thus, a formal pre-job brief wee not considered necessary by the FLS.
The diagnostic testing was completed during the midnight shift. After removal of the test equipment, Electrician #1 performed the steps to re-land the
leads from memory. After landing the
leads, he told Electrician *2 that they had been landed. The electricians did not verify the specific
leads landed using three-