05000352/LER-2003-002

LER-2003-002,

Docket Number
Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications
3522003002R00 - NRC Website

Unit Conditions Prior to the Event Unit 1 was in Operational Condition (OPCON) 1 at 100% power and Unit 2 was in Operational Condition (OPCON) 5 (Refueling) for 2R07 at approximately 488 inches in the cavity. There were no structures, systems or components out of service that contributed to this event.

Description of the Event

On March 16, 2003 the activity to exercise control rods for 2R07 was in progress. Control rod exercising was suspended during the day shift due to problems encountered with control rod 02-31. The problem was initially believed to be associated with the control rod drive system (EDS:AA). At 22:00 hours a briefing was conducted in which the loss of secondary containment was discussed, however, the requirement to suspend core alterations was not properly addressed. A contributing factor was less than adequate and incorrect precautions in the operating procedure.

Troubleshooting activities isolated the control rod movement problems to control rod 02-31 only. At 22:35 hours exercising rods began in the C and D quadrants.

On March 17, 2003 at 1:06 hours secondary containment was breached in preparation for the cavity drain down. Between 01:17 hours and 02:17 hours 24 rods in Quadrant C were exercised.

Drain down began at 2:37 hours and was secured at 4:08 hours. At 04:30 hours control rods in the D quadrant of the core were exercised. The activity was completed by the end of the night shift (06:30 hours) when all control rods had been exercised. At 10:00 hours the relieving shift manager recognized that control rod exercising had occurred while refuel enclosure secondary containment was inoperable.

I his event involved.an operation or

• condition

• that-was prohibited by the Unit 1 and Unit 2 TS 3.6.5.1.2 which prohibits core alterations without refuel enclosure secondary containment.

Therefore, this LER is being submitted pursuant to the requirements of 10CFR50.73(a)(2)(i)(B)

Analysis of the Event

There were no actual safety consequences associated with this event. During the time period of March 17, 2003 at 1:06 hours to 11:14 hours while refuel enclosure secondary containment was secured there were no radiological events which would have resulted in a ground level release of radioactivity. During the event, the required decay heat removal systems, inventory control systems, electrical power sources and supporting instrumentation remained operable.

The potential safety consequences of this event were also minimal. No fuel handling was in progress and the control rods were being exercised under constraints of the one-rod-out interlock.

Cause of the Event

Two root causes were identified for the event. The primary cause of the event was less than adequate procedural guidance to verify refuel enclosure secondary containment is established prior to control rod withdrawal. The second root cause was the failure of shift management to verify Technical Specification compliance upon breach of refuel enclosure secondary ---containmentintegrity:This action would have properly suspended core alterations:

Corrective Action Completed The corrective actions performed included revisions to the "Pre Control Rod Withdrawal Check" procedure (ST-6-047-30-1 & 2) .The revision verifies refuel enclosure secondary containment integrity prior to the withdrawal of each control rod when containment is required. Procedure S53.4.A "Draining Reactor Well and Dryer/Separator Storage Pool" was also revised to ensure no core alterations are performed while refuel enclosure secondary containment is breached.

Corrective Actions Planned Plans are in place to address management oversight issues and reinforce management expectations on Technical Specification compliance.

Previous Similar Occurrences There were no previous occurrences of loss of refuel enclosure secondary containment during core alterations.