Event Notification Report for December 02, 1999

TRIP ROLLER - HK CIRCUIT BREAKER, ABB PART # 180097A00

During the 4kV ABB Type HK breaker refurbishment at the DC Cook Plant on October 21, 1999, newly installed trip rollers, ABB Part Number 180097A00, were determined to be below the minimum hardness specification, Rockwell C 50-55. One roller was observed to be "scoring" after 200 cycles. This roller was one of 130 rollers sent to DC Cook through a purchase order from ABB Service Company in Cleveland, Ohio. A sample of rollers indicated that all were below the hardness specification. After communicating this to ABB Service and the ABB Florence facility, the roller with the lowest measured hardness, Rockwell C13, was returned for evaluation at the ABB-Florence factory.

ABB Power T&D Company received notification from ABB Service Company, The Woodlands, TX, of a trip roller, 180097A00, problem occurring in November 11, 1998, purchased under ABB Service Company Purchase Order Number 27-04459-P4031, ABB Power T&D Company Order Number CCN0449. The initial investigation points to a roller that has not been heat-treated to its hardness specification as well. This information will serve to address the trip roller issue here as well.

An HK Circuit Breaker that contains trip rollers that are not properly hardened may fail to trip at some point during the life of the breaker. ABB Power T&D Company testing indicates that a very soft trip roller measuring Rockwell C13 was able to operate 4000 operations before minimum trip voltage failed to operate the circuit breaker.

The information of the defect of the trip roller was obtained on October 21, 1999

This information affects trip rollers that were shipped as Component Orders or as part of Complete Circuit Breakers from October 30, 1995 through June 1999.

The hardness critical characteristic was added to the QC Record Card in June 1999 for the trip roller, 180097A00.

ABB will notify all customers who purchased this product.

Replacement trip rollers may be obtained from ABB Power T&D Company, Sanford, FL, by contacting the Components Group.

CONTAINMENT SUMP LEVEL DETECTION DOES NOT MEET REQUIREMENT FOR RCS LEAK DETECTION

"While investigating concerns with the containment instrument tunnel sump leak detection capabilities and satisfying the requirements for RCS leak detection in the Improved Tech Specs (TS 3.4.15) an issue was identified with the Normal Containment Sump Level Monitoring capability. From review and investigation of this issue, it was identified that the current calculation for the instrument tunnel sump leak rate would not always be able to detect a 1 gpm leak in one hour to satisfy the Reg Guide 1.45 basis for this Tech Spec. After even further review, it has been concluded that the current calculation for the containment normal sumps is performed in a similar manner. Thus, the containment normal sumps will not always provide adequate leak detection to ensure that a 1 gpm RCS leak is detected in one hour.

"The Wolf Creek Updated FSAR states that one of the design bases of the reactor coolant system leakage detection systems is to be capable of detecting a 1 gallon per minute leak consistent with Regulatory Guide 1.45 and 10 CFR 50, Appendix A, General Design Criteria 30. Regulatory Guide 1.45 states that the systems must be capable of detecting a 1 gpm leak within 1 hour. Since the Wolf Creek Containment Normal sump does not meet this design basis, it is believed that the plant may be outside its design basis, in accordance with the reporting criteria of 10 CFR 50.72(b)(1)(ii)."

The fix is a software change to the Plant Computer and the licensee has it and intends to have it in operation well within the 30 day shutdown requirement of Tech Specs.

The licensee has notified the NRC Resident Inspector.

MANUAL REACTOR TRIP AFTER MAIN FEEDWATER PUMP TRIP ON LOW SUCTION PRESSURE

The reactor was manually tripped (all rods fully inserted) after two of three main feedwater pumps tripped due to low suction pressure. The low suction pressure was due to a secondary system transient which caused the loss of one of the high pressure heater drain pumps. The transient was from feedwater heater level system. The exact cause is under investigation.

All auxiliary feedwater pumps started, as designed, on low steam generator level and the steam dumps opened to the condenser to remove excess heat. The unit is stabilized in Mode 3.

The licensee intends to notify the NRC Resident Inspector.

PERFORMANCE OF RHR LOGIC FUNCTIONAL TEST DEFEATS THE AUTOMATIC START OF ALL FOUR RHR PUMPS.

A review of the Residual Heat Removal (RHR) logic system functional test identified that during part of the performance of the test, the automatic start of all four RHR pumps was defeated. Manual initiation remained available. This test was last performed on both Unit 2 and Unit 3 in 1997. This report is being made due to the loss of the automatic initiation of the Low Pressure Coolant Injection (LPCI) mode of RHR. This alone could have prevented the fulfillment of a safety function.

The NRC resident inspector will be notified of this event by the licensee.