Headquarters Daily Report MARCH 13, 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 - REGION I MARCH 12, 1996 Licensee/Facility: Notification: Northeast Utilities MR Number: 1-96-0021 Millstone 1 Date: 03/12/96 Waterford,Connecticut 3/11/96 RI PC Dockets: 50-245 BWR/GE-3 Subject: EROSION INDUCED BORAFLEX DEGRADATION Discussion: Boraflex material is used at Millstone 1 as a reactivity holddown device (neutron absorbing material) to ensure that the spent fuel remains subcritical under all postulated conditions. Boraflex normally experiences gamma induced degradation in the form of shrinkage, cracks, and gaps. It is postulated that the gaps observed recently at Millstone Unit 1 were the result of gamma damage and fuel pool flow current attack. In September 1995, blackness (neutron absorption) testing of the Unit 1 spent fuel racks was performed to determine if cracks had developed in the boraflex material. The testing, performed by HOLTEC International, revealed a total of 7 gaps ranging between 0.3 and 0.9 inches. The majority of the gaps were situated in a localized area (rack D2) indicating a failure mechansim different than that normally experienced at other utilities. Only new fuel or aged fuel has been placed in rack D2 since the licensee installed the boraflex material. This was the first blackness testing performed at Millstone Unit 1. Racks containing boraflex were first introduced into the Unit 1 spent fuel pool during the 1988 rerack. This new degradation mechanism has not been accounted for in the modeling and criticality analysis for the unit. An operability determination was performed by the licensee which concluded that rack D2 was still operable and that the criticality analysis remained valid. Regional Action: The resident inspectors are following licensee response to this event. Contact: Art Burritt (860)447-3170 _ HEADQUARTERS MORNING REPORT PAGE 2 MARCH 13, 1996 MR Number: H-96-0020 NRR DAILY REPORT ITEM GENERIC COMMUNICATIONS NRC Information Notice 96-16, "BWR Operation With Indicated Flow Less Than Natural Circulation," dated March 14, 1996. The NRC is issuing this information notice to alert addressees to two instances of power operation in which the core flow appeared to be less than that normally attributed to operation on or near the natural circulation line. Technical contacts: Howard J. Richings, NRR (301) 415-2888 T. Jerrell Carter, NRR (301) 415-1153 _ REGION IV MORNING REPORT PAGE 3 MARCH 13, 1996 Licensee/Facility: Notification: Entergy Operations, Inc. MR Number: 4-96-0025 Arkansas Nuclear 2 Date: 03/13/96 Russelville,Arkansas Resident Inspector Dockets: 50-368 PWR/CE Subject: REACTOR COOLANT SYSTEM (RCS) LEAK IN THE AUXILIARY BUILDING Discussion: At approximately 10:40 a.m., Unit 2 operators began routine sampling of the RCS system. At approximately, 10:49 a.m., the RCS sample was secured when the operators noted a slight decrease in pressurizer level and when fire alarms actuated on the lower level (317 foot elevation) of the auxiliary building. An operator was dispatched to that elevation to investigate the cause of the fire alarms and found steam and water present. Health Physics surveyed the general area and found gross contamination levels of 200,000 to 500,000 cpm. The highest derived air concentration (DAC) in the auxiliary building was determined to be 1.6 percent of 1 DAC. Calculated site boundary doses were 6.9 E-5 mr/hr total effective dose equivalent and 9.3 E-8 mr/hr child thyroid. The licensee had determined the source of the water was from two drain valves (2PS-1028A and -1028B) which were previously opened to drain the postaccident sampling system (PASS) to perform maintenance on PASS Valve 2CV-5963. The PASS, which is connected to the RCS sampling system, was assumed fully isolated from the RCS sampling system by closing a single 1/2-inch gate valve, Valve 2PS-162. The isolation valve was independently verified shut and danger tagged earlier. Following the event, an operator was dispatched to verify the position of Valve 2PS-162 and found that he was able to close the valve with three additional turns. The licensee speculated that corrosion products inside the gate valve had prevented the operators from fully closing the isolation valve during the tag-out. The licensee assumed that Valve PS-162 had leaked when the corrosion products were flushed from the valve as the operators aligned the system for RCS sampling. The water leaked past the isolation valve and flowed through open drain Valves 2PS-1028A and -1028B to the auxiliary building. The licensee estimated that 55 to 60 gallons of RCS water over a 6-minute period leaked to the 317 foot elevation of the Unit 2 auxiliary building. Decontamination efforts of the elevation have been completed. However, the area where the drain valves are located is posted as a contaminated area. Three personnel contaminations occurred as a result of this event. The licensee is evaluating the use of double valve protection in the tag-out prior to proceeding with maintenance on the PASS. Regional Action: The resident inspectors will follow up on this issue. Contact: K. M. Kennedy (501)968-3290 S. J. Campbell (501)968-3290 T. Reis (817)860-8185 _