Headquarters Daily Report OCTOBER 27, 1995 *************************************************************************** REPORT NEGATIVE NO INPUT ATTACHED INPUT RECEIVED RECEIVED HEADQUARTERS û REGION I û REGION II û REGION III û REGION IV û PRIORITY ATTENTION REQUIRED MORNING REPORT - REGION I OCTOBER 27, 1995 Licensee/Facility: Notification: New York Power Authority MR Number: 1-95-0136 Indian Point 3 Date: 10/23/95 Buchanan,New York SRI PC Dockets: 50-286 PWR/W-4-LP Subject: SERVICE WATER CONTAINMENT ISOLATION VALVE WALL THINNING Reportable Event Number: 29490 Discussion: On October 21, 1995, at 12:41 pm, NYPA commenced a technical specification required cooldown to cold shutdown due to a loss of containment integrity. Valve 43-5, service water supply side drain to 35 fan cooler unit, was noted as leaking from the valve body by a plant maintenance worker. Subsequent ultrasonic testing identified possible valve body wall thinning which resulted in NYPA declaring the valve inoperable. Leakage through the valve body affects containment because the valve is located in part of the service water system that penetrates the containment boundary. The plant was in hot shutdown preparing to return to power operation when the issue was identified. NYPA has aggressively pursued an evaluation of similar valves to determine the extent of the problem. Engineering evaluated 241 valves by either visual or ultrasonic methods. To date, 10 valves required replacement. The valves requiring replacement were one inch carbon steel drain valves and two inch stainless steel fan cooler unit motor cooler isolation valves. NYPA is still evaluating the corrosion mechanism. NYPA is scheduling replacement of all deficient valves prior to exceeding cold shutdown. Regional Action: Routine followup by the resident inspectors. Contact: Curtis Cowgill (610)337-5233 _ REGION III MORNING REPORT PAGE 2 OCTOBER 27, 1995 Licensee/Facility: Notification: Commonwealth Edison Co. MR Number: 3-95-0161 Byron 1 Date: 10/27/95 Byron,Illinois SRI/TELEPHONE Dockets: 50-454 PWR/W-4-LP Subject: UNIT 1 RCS LOOP DRAIN Discussion: On October 26 with Unit 1 in a mid-cycle outage in Mode 5 (cold shutdown) at approximately 7:45 p.m. (CST), the licensee commenced Unit 1 RCS loop drain operation on loop A, as part of the routine evolution for SG tube inspection preparation. Loop A was the second loop to be drained, draining of loop C had been completed earlier at 7:00 p.m.. RCS loop draining requires that the loop stop isolation valves (LSIV), hot and cold leg, to be closed. Once the LSIVs are closed the loop is then initially lined up to allow gravity drain from two loop drain lines to the reactor coolant drain tank (RCDT). After gravity draining of the loop and no apparent indication of flow through the drain lines, nitrogen pressurization is then lined up to blow out any residual water through the isolated portion of the loop. At 10:37 p.m., during the portion of the nitrogen pressurization of the loops, the nuclear station operator (NSO) observed that the pressurizer level was increasing and received the reactor vessel level indication system (RVLIS) alarm. The NSO order the nitrogen pressurization to be secured, concluding that something was wrong due to an unexpected pressurizer level increase and RVLIS alarm. Within approximately 6 minutes from the time the problem was recognized and nitrogen secured, pressurizer level increased from approximately 30 percent to 42 percent. The RVLIS indication noted head region of 31 percent. (RVLIS indication is divided into two sections, head and plenum regions. RVLIS levels are ranged and set points are indicated from 100 percent, 31 percent in the head region and 100 percent, 81 percent, 55 percent, 37 percent, 27 percent, and 15 percent in the plenum region.) The licensee estimated that about 1400 gallons was displaced between the vessel head and pressurizer. The licensee took action to vent the reactor vessel head. At approximately 11:38 p.m., RVLIS indication returned to 100 percent head region and the pressurizer level had returned to approximately the original indication, 30 percent. By 1:11 a.m., the licensee secured head venting and the vessel head was refilled solid. The licensee theorized that one of the LSIVs did not adequately hold and allowed nitrogen to vent through the loop to the vessel head. The licensee suspects that the cold leg LSIV is not seated or holding properly. This was found after the event when the licensee placed LSIV disc pressurization on each valve one at a time and noticed that the SI accumulator level (system used for disc pressurization) was decreasing when applied to the cold leg LSIV. All RCS work activities are presently on hold, until investigation is completed. During this event, reactor vessel level did not decrease below the vessel REGION III MORNING REPORT PAGE 3 OCTOBER 27, 1995 MR Number: 3-95-0161 (cont.) flange and the loop suctions remained covered, as indicated by the RVLIS instrumentation. RCS temperature remained the same. No temperature increase or boron dilution had occurred. No indication of nitrogen binding of the RH pump. Shutdown cooling was not lost or interrupted. Regional Action: The resident inspector responded to the event. Plant parameters were verified and it was determined that shutdown cooling was not interrupted or lost. The inspector will continue to monitor licensee's corrective actions and investigation. Contact: M. FARBER (708)829-9605 _ REGION IV MORNING REPORT PAGE 3 OCTOBER 27, 1995 Licensee/Facility: Notification: Nebraska Public Power District MR Number: 4-95-0133 Cooper 1 Date: 10/27/95 Brownville,Nebraska SRI Dockets: 50-298 BWR/GE-4 Subject: UPDATES TO EVENT NOTIFICATIONS - INADVERTENT ESF ACTUATION AND TECHNICAL SPECIFICATION VIOLATION Discussion: This report is provided to augment Event Notifications 29512 and 29514. On October 26, 1995, during routine outage work on nonsafety-related 4160 VAC Bus A, the incorrect installation of an electrical jumper resulted in the tripping of a feeder breaker and subsequent loss of power to safety-related 4160 VAC Bus F. As designed, a fast transfer of power to the station emergency transformer occurred and the loss of power to Bus F was momentary. However, the momentary deenergization did result in actuation of Group 6 (Primary Containment Ventilation System isolation, Standby Gas Treatment System actuation, and Secondary Containment Isolation) of the Primary Containment Isolation System. Emergency Diesel Generator A did not receive a start signal since power was restored to Bus F prior to the designed time delay expiring. The plant outage safety systems, including shutdown cooling, were powered by protected Division II, fed from 4160 VAC Bus G, and were not adversely affected. The affected safety systems were reset without incident. The licensee preliminarily attributes the cause of the event to inadequate work instructions. In an unrelated event on October 27, 1995, operations received a work request that involved isolation of the nonessential control building HVAC system. Although the clearance order specified the proper tagout, the main control room supply fans were inadvertently secured. Refueling operations were in progress at the time and Technical Specifications require that the control room ventilation system be operable during these evolutions. The error was promptly identified by the licensee and the control room supply fan was restored to operation within 9 minutes. Regional Action: The resident inspectors will perform routine followup of these events and will continue to monitor outage work. Contact: T. Reis (817)860-8185 _