Headquarters Daily report APRIL 18, 1994 *************************************************************************** REPORT NEGATIVE NO INPUT ATTACHED INPUT RECEIVED RECEIVED HEADQUARTERS X REGION I X REGION II X REGION III X REGION IV X *************************************************************************** PRIORITY ATTENTION REQUIRED MORNING REPORT - REGION III APRIL 18, 1994 Licensee/Facility: Notification: Illinois Power Co. MR Number: 3-94-0081 Clinton 1 Date: 04/15/94 Clinton,Illinois TELEPHONE Dockets: 50-461 BWR/GE-6 Subject: POWER EXCURSION DUE TO EQUIPMENT MALFUNCTION Reportable Event Number: 27104 Discussion: At 1115 CDT on 4/15/94 the "A" reactor recirculation flow control valve (FCV) failed fully open during a maintenance activity. The accompanying recirculation flow increase resulted in reactor power increasing from 100 percent to a maximum of 109.8 percent. I&C technicians were performing post-maintenance testing on a temperature control loop for the cooling water supply to the FCV's hydraulic pressure unit (HPU). The written guidance used by the technician led to the HPU tripping on warm oil temperature at 11:00 am. At this time, as expected, the FCV did not change position. After verifying that no personnel hazards existed, and after the temperature alarm cleared, a reactor operator restarted the A2 subloop at 11:13 a.m. and placed it in standby. Another reactor operator was reviewing the procedure for clearing the motion inhibit interlock, and did not notice the FCV ramping open by itself over a 30 second period. When alarms came in that operator observed that the FCV was 93 percent open (the full open stop position) and that power was above 106 percent. He then attempted to close the FCV; however, the other operator had tripped the HPU upon hearing the alarms. The operators then started the A1 subloop and the FCV rapidly closed automatically to 47 percent because the FCV controller had been integrating a closing signal while the operator attempted to close it with the HPU tripped. The operators stabilized the plant and returned the FCV to its original position of 57 percent open. The entire transient lasted 75 seconds. While the FCV was at its full open stop, power stabilized at a mean value of approximately 107.5 to 108 percent for about 34 seconds with the highest peak at 109.76 percent power. Process radiation monitors and reactor coolant samples indicated no increased radiation levels or fuel leakage. The licensee commenced a previously planned 8 day outage at 8:00 p.m. on 4/15/94 to replace the A reactor recirculation pump seal. There were several occasions during the previous cycle when an FCV drifted slowly open when an HPU tripped. The licensee replaced the FCV actuators and other components during last fall's refueling outage. Licensee troubleshooting activities are still in progress. Regional Action: The resident inspectors responded to this event and are following the licensee's investigation. Regional specialist inspectors are also assisting. Contact: B. CLAYTON (708)829-9602 PRIORITY ATTENTION REQUIRED MORNING REPORT - REGION IV APRIL 18, 1994 Licensee/Facility: Notification: Gulf States Utilities Co. MR Number: 4-94-0031 River Bend 1 Date: 04/18/94 St Francisville,Louisiana Senior Resident Inspector Dockets: 50-458 BWR/GE-6 Subject: PLANT SHUTDOWN FOR REFUELING Reportable Event Number: N/A Discussion: On April 16, 1994, at 12:15 a.m., the reactor was shut down to commence Refueling Outage 5. The outage has been scheduled for a duration of 53 days. The refueling will include in-core fuel assembly sipping of all fuel that will remain in the core to identify any leaking assemblies. This will be the first application of in-core sipping in the United States. Other major plant activities planned include: (1) mechanical stress improvement on the reactor vessel nozzles, (2) reactor jet pump beam replacement, (3) turbine low pressure rotor replacement, (4) modification of all eight main steam isolation valves with antirotation internals, (5) installation of a reactor vessel water level instrument reference leg constant fill system, and (6) a large number of modifications and repairs to correct long-standing degraded equipment conditions. The outage is scheduled to complete on June 8, 1994. Regional Action: Routine followup by the resident inspectors. Contact: J. E. Gagliardo (817)860-8270