Headquarters Daily Report SEPTEMBER 10, 1998 *************************************************************************** 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 SEP. 10, 1998 MR Number: H-98-0139 NRR DAILY REPORT ITEM GENERIC COMMUNICATIONS Subject: INFORMATION NOTICE 98-35 ISSUED NRC INFORMATION NOTICE 98-35: THREAT ASSESSMENTS AND CONSIDERATION OF HEIGHTENED PHYSICAL PROTECTION MEASURES Dated September 4, 1998 The IN described additional physical protection measures that the NRC suggests be considered for threat conditions detailed in the IN. The IN is marked "Safeguards Information" and must be accorded the protection required under 10 CFR 73.21. Technical contacts: Eugene McPeek, NRR 301-415-3210 E-mail: ewm2@nrc.gov John Davidson, NMSS 301-415-8130 E-mail: jjd@nrc.gov _ REGION III MORNING REPORT PAGE 2 SEPTEMBER 10, 1998 Licensee/Facility: Notification: Northern States Power Co. MR Number: 3-98-0063 Monticello 1 Date: 09/10/98 Monticello,Minnesota E-Mail Dockets: 50-263 BWR/GE-3 Subject: MANUAL REACTOR SCRAM DUE TO STEAM JET AIR EJECTOR ISOLATION Reportable Event Number: 34754 Discussion: On September 9, 1998, at about 5:06 a.m. with the reactor operating at full power, both trains of the off-gas recombiner systems tripped and the suction valves to the steam jet air ejectors isolated. Control room operators immediately entered their rapid power reduction procedure. With the steam jet air ejectors isolated, the operators were concerned about maintaining condenser vacuum. At 5:30 a.m., the operators inserted a manual reactor scram from about 30 percent of full power when it became apparent that condenser vacuum would not be restored immediately. Reactor vessel water level decreased to about 9 inches (which is a typical response to a scram) and resulted in a Containment Isolation Group II and Group III isolation. Water level returned to normal levels using the feedwater and condensate systems. Operators reset the reactor scram at about 5:42 a.m. All control rods fully inserted, no safety relief valves lifted during the event, all equipment reacted as expected. The operators were able to maintain enough condenser vacuum to cool down the reactor using the bypass valves. The reactor is currently in cold shutdown. The licensee is investigating the cause of this event. Among the possibilities identified to date is a burn in the off-gas system. Currently, startup has not been scheduled. Regional Action: The residents reported to the control room shortly after this event and will monitor the licensee's root cause investigation and corrective actions. Contact: K. WALTON (630)829-9872 _