Headquarters Daily report FEBRUARY 15, 1995 *************************************************************************** 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 II FEBRUARY 15, 1995 Licensee/Facility: Notification: Duke Power Co. MR Number: 2-95-0017 Catawba 1 Date: 02/15/95 York,South Carolina Dockets: 50-413 PWR/W-4-LP Subject: UNIT 1 LOSS OF RESIDUAL HEAT REMOVAL (RHR) Reportable Event Number: 28381 Discussion: This is an update to the February 13, 1995 loss of RHR event at Catawba Unit 1. Specifically, at 4:33 p.m., with the Unit in Mode 5 (Cold Shutdown) and RHR train A tagged out, the outboard RHR train B suction isolation valve (1ND37A) closed, causing an interruption of RHR. Reactor coolant system temperature went from 115 degrees F to approximately 135 degrees F during the resultant 23 minute loss of RHR cooling. Throughout the event, the reactor coolant system loops were filled with all four steam generators available. Additionally, it is estimated that RHR train A could have been returned to service within 15 - 20 minutes. Both RHR trains have separate suction lines from the reactor coolant system, each with two isolation valves in series. The outboard (inboard) valve for each loop is actuated by the A (B) train autoclosure interlock and powered from A (B) train. The cause of the inadvertent closure of the RHR train B outboard isolation valve was due to a modification which was in progress to remove the A train autoclosure interlock. A similar modification had been performed on Unit 2 during its last refueling outage with the RHR loop isolation valves de-energized in the open position during No Mode (Defueled). It appears that during the development of the implementation package for the Unit 1 modification, a change was incorporated which indicated that the modification could be performed in Modes 5, 6 (Refueling), or No Mode, without adequate attention to the status of the RHR loop isolation valves. As cavitation was evident prior to securing the B RHR pump, an assessment of B train RHR components was performed by the licensee. No degradation was identified. Further work on the modification was suspended and both RHR trains' loop isolation valves were opened and de-energized. The licensee's root cause evaluation of the related work control issue and determination of appropriate corrective actions is in progress. In addition, a Significant Event Investigation Team, led by Duke Power's Nuclear Assessment and Issues Manager, has begun an investigation of this event. Regional Action: The resident inspectors responded to the control room at the time of the event and will continue to followup. Contact: R. CARROLL (404)331-5543 PRIORITY ATTENTION REQUIRED MORNING REPORT - REGION II FEBRUARY 15, 1995 Licensee/Facility: Notification: Georgia Power Co. MR Number: 2-95-0018 Vogtle 1 Date: 02/15/95 Waynesboro,Georgia Dockets: 50-424 PWR/W-4-LP Subject: VOGTLE UNIT 1 MAIN GENERATOR HYDROGEN COOLER DAMAGE Reportable Event Number: N/A Discussion: Vogtle Unit 1 has reduced power to repair a main generator hydrogen leak of 4,000 standard cubic feet per day. The licensee initiated a decrease in load at 4:00 p.m., Monday, February 13, to remove the main generator from service to repair the leak. Reactor power was established at 30% on Tuesday, February 14, with the generator off-line. On February 14, the licensee discovered damage to the sealing rings and flange surface for the leaking hydrogen cooler. The cooler flange sealing mechanism consists of two metal rings which sandwich a rubber gasket. Damage found on regions of the metal surface of the rings and flange was attributed to electrical arcing. The rubber gasket had lost its pliability in the damaged areas and could not seal effectively when the flange was tightened. The cause of the arcing damage is not yet known. Generator vendor representatives are on-site to assist in determining the cause of the arcing. Repairs to the pits in the cooler flange from the arcing damage are being initiated and new rings and a new gasket are planned to be installed to restore the generator to service. The licensee lowered reactor power to 12% to conserve fuel while repairs are being made. Regional Action: Resident Inspectors are monitoring repairs. Contact: S. CAHILL (404)331-4198 PRIORITY ATTENTION REQUIRED MORNING REPORT - REGION IV FEBRUARY 15, 1995 Licensee/Facility: Notification: Nebraska Public Power District MR Number: 4-95-0018 Cooper 1 Date: 02/15/95 Brownville,Nebraska Senior Resident Inspector Dockets: 50-298 BWR/GE-4 Subject: UPDATE OF 2/14 MORNING REPORT ON MOV FAILURE Reportable Event Number: 28366 Discussion: This information updates the information provided in a morning report, issued on February 14, 1995, relative to the failed motor-operated valve (MOV) at the Cooper Nuclear Station. Based on reviews performed by NRC inspectors, it has been established that the replacement stem caps installed on the MOVs were fabricated in accordance with a maintenance work request (MWR). The MWR stated that a cap should be fabricated and installed on the MOV. No instructions or drawing was provided with the MWR to provide guidance in how to fabricate the cap and neither engineering nor QA was involved in the effort. The craftsman used a piece of threaded conduit to replace the threaded pipe stem cap. The conduit threads and the pipe threads are of different tolerances, thus, the fit of the conduit was relatively loose when compared to the fit of the original stem cap. This loose fit accounted for the self-threading of the conduit into the MOV casing, which resulted in the binding of the stem. Regional Action: Additional reviews of this event are continuing. Contact: P. H. Harrell (817)860-8250