05000305/LER-2005-007

LER-2005-007,

Docket Number
Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(v)(A), Loss of Safety Function - Shutdown the Reactor 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition
Initial Reporting
ENS 41539	10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition
3052005007R00 - NRC Website

FACILITY NAME (1) DOCKET NUMBER (2) LER NUMBER (6 PAGE (3) Kewaunee Nuclear Power Plant 05000305

DESCRIPTION

On March 28, 2005 with the plant in Refueling Shutdown Mode, a past operability concern was identified with the plant's Component Cooling Water (CCW) [CC] System. Specifically, on January 23, 2002, plant personnel identified a potential "run out" concern with the CCW pumps [P]. The condition assumed CCW being aligned to both Residual Heat Removal (RHR) heat exchangers [HX] and both CCW pumps running. If a loss of power caused the loss of one CCW train and the associated train's isolation valve to the RHR heat exchanger could not be closed, there would be a potential concern with pump "run out" and pump damage for the CCW pump that continued to run.

The pump "run-out" concern was determined to be an original plant design issue and was initially resolved by isolating the non-safeguards loads on the CCW system and installing a valve position limiter on a non-critical CCW system flow control valve. Isolation of the non-safeguards loads on the CCW system and the installation of the valve position limiter on a non-critical CCW system flow control valve were completed approximately 49.75 hours8.680556e-4 days <br />0.0208 hours <br />1.240079e-4 weeks <br />2.85375e-5 months <br /> from the time the potential concern was identified. The valve position limiter that was installed was proven effective upon the completion of special operating procedures which verified by testing that a single CCW pump would not experience "run-out" flow conditions when all CCW safeguards loads, including both trains of RHR heat exchangers were supplied by a single CCW pump.

CAUSE OF THE EVENT

The plant's original design did not preclude the CCW pump "run out" condition.

EVENT ANALYSIS AND SAFETY SIGNIFICANCE

This event is being reported under 10CFR50.73(a)(2)(ii)(B), any event or condition that resulted in the plant being in an unanalyzed condition that significantly degraded plant safety, and 10CFR50.73(a)(2)(v)(A), any event or condition that could have prevented the fulfillment of the safety function of structures or system that are needed to shut down the reactor and maintain it in a safe shutdown condition.

This event was initially reported on March 28, 2005 as a 10CFR50.72 non-emergency event under criterion (b)(3)(ii)(B), any event or condition that resulted in the plant being in an unanalyzed condition that significantly degraded plant safety (reference Event Notification EN# 41539).

This report involves a safety system functional failure.

CORRECTIVE ACTIONS

Plant design changes have been implemented to alleviate the CCW pump "run out" concern. These design changes installed valve travel limiting devices on non-safeguards CCW system flow control air operated valves. These modifications limit total CCW flow to prevent CCW pump "run out" under the specified conditions described in this Licensee Event Report.

PREVIOUS SIMILAR EVENTS

None.