Headquarters Daily Report JUNE 27, 1996 *************************************************************************** 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 - HEADQUARTERS JUNE 27, 1996 MR Number: H-96-0050 NRR DAILY REPORT ITEM GENERIC COMMUNICATIONS NRC Generic Letter 96-04, "Boraflex Degradation in Spent Fuel Pool Storage Racks," dated June 26, 1996. The NRC issued this generic letter to inform all addressees of issues concerning the use of Boraflex in spent fuel storage racks. Technical contacts: Larry Kopp, NRR (301) 415-2879 Krzysztof Parczewski, NRR (301) 415-2705 _ REGION III MORNING REPORT PAGE 2 JUNE 27, 1996 Licensee/Facility: Notification: Commonwealth Edison Co. MR Number: 3-96-0069 La Salle 1 Date: 06/26/96 Marseilles,Illinois SRI VIA TELCON Dockets: 50-373 BWR/GE-5 Subject: MSIV ISOLATION AND REACTOR SCRAM Discussion: At 2056 on June 26, 1996, with Unit 1 at 100 percent power, a reactor scram occurred when the MSIVs closed. Instrument technicians were performing a surveillance on a main steam line high flow channel "A2" when channel "B2" tripped. This met the coincident logic for a MSIV isolation and subsequent reactor scram. All equipment responded as expected after the scram. The unit is presently in Mode 3 (Hot Shutdown) maintaining 800 - 900 psig. Four SRVs opened and reactor level dropped to - 35 inches during the transient. Operators manually started RCIC in the steam pressure control mode at 2107. The Group 1 isolation signal was reset at 0008 on June 27 and pressure control was shifted to the main condenser via the main steam line drains. RCIC was shut down by 0130 and MSIVs were reopened by 0715. The licensee had revised the emergency operating procedures to expand the reactor level control band after the last MSIV isolation and operators noted that the plant was now easier to control. In December 1994, a similar event occurred (LER 373/94015) involving a main steam line flow transmitter spuriously tripping and causing a MSIV isolation. The flow transmitters were made by SOR (Static O-Ring Corporation) and have a long history of problems at LaSalle and in the industry. The licensee has entered its forced outage plan and currently expects to restart at 2300 on June 27, 1996. Regional Action: Resident and regional inspectors are onsite and following the licensee root cause and forced outage activities. Contact: B. CLAYTON (708)829-9602 M. MCCORMICK-BARGER (708)829-9619 _ REGION IV MORNING REPORT PAGE 3 JUNE 27, 1996 Licensee/Facility: Notification: Texas Utilities Electric Co. MR Number: 4-96-0069 Comanche Peak 2 Date: 06/27/96 Glen Rose,Texas Resident Inspector Dockets: 50-446 PWR/W-4-LP Subject: SAFETY INJECTION THERMAL RELIEF VALVES MALFUNCTIONING Discussion: On June 24, 1996, licensee personnel identified that both trains of the Unit 2 safety injection system were pressurized to 1920 pounds per square inch gauge (psig). This was in excess of the system design pressure, 1750 psig. The licensee determined that the reactor coolant system was the source of the increased pressure. The reactor coolant system was leaking into the safety injection system via pressure isolation check valves at approximately 0.11 gallons per minute. The licensee initially concluded that the three thermal relief valves, which were installed in the system to relieve pressure increases in sections of piping which may be heated after they are isolated, were not operating properly to restore system pressure to the design pressure. The licensee determined that compliance with existing procedures would ensure that the systems would not be aligned in a configuration which would require thermal reliefs. While the licensee did not initially consider that these reliefs also functioned to relieve reactor coolant system pressure from back leakage into the system, they stated that their piping analysis demonstrated that the installed safety injection piping system was actually capable of withstanding full reactor coolant system pressure. The licensee considers the system to be operable. As of June 27, 1996, the licensee is continuing to investigate the cause of the safety inspection system presentation and relief valve anomaly and are currently speculating that the relief valves are operating properly in response to very small check valve leakage. The licensee is working with the valve vendor to develop test methodology to confirm their theory. In parallel, they are continuing to investigate the possibility of some blockage in the relief valve discharge path. Regional Action: The region is continuing to evaluate the licensee's operability determination and monitor the licnesee's root cause investigation. Contact: L. J. Smith (817)860-8183 _