Headquarters Daily Report APRIL 29, 1997 *************************************************************************** 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 APRIL 29, 1997 Licensee/Facility: Notification: Gpu Nuclear Corp. MR Number: 1-97-0031 Oyster Creek 1 Date: 04/29/97 Forked River,New Jersey RI PC Dockets: 50-219 BWR/GE-2 Subject: POTENTIAL GENERIC MATERIAL DEFICIENCY FOR SCRAM SOLENOID PILOT VALVE SEATS (PNO-I-97-024) Reportable Event Number: 32196 Discussion: On April 22, 1997, Oyster Creek Nuclear Generating Station completed a controlled unit shutdown after a representative sample of control rods revealed "slow" insertion times for the first 5 percent of the control rods' total travel. The cause of the slow 5 percent insertion times was attributed to degradation of the Viton (elastomer) diaphragm material in the scram solenoid pilot valve assemblies that had previously (9/94) replaced Buna-N diaphragms as an equipment upgrade. The reference sample (7 of 137 total control rods) periodic testing was being performed due to a known, industry-wide problem with the Viton diaphragms, currently under review. The licensee completed replacing the diaphragms for all 137 scram solenoid pilot valve assemblies (each assembly has four diaphragms) on 4/26/97 with an upgraded Viton elastomer. Gross air leakage tests, as a part of the post-maintenance testing, identified air leakage from the pilot valve seat on several of the scram solenoid pilot valve head assemblies. Subsequent laboratory testing and chemical analysis identified that the pilot valve seats chemically resembled the Buna-N material vice the specified Viton material. The testing identified the hard and relatively brittle pilot valve seats could shatter upon failure, calling into question the safety function of the scram solenoid pilot valves. All 137 scram solenoid pilot valve assemblies were replaced during the 15R refueling outage in 9/94. They all contained the Viton diaphragm material and the pilot valve seats were supposed to similarly be made from Viton. The licensee has elected to replace the pilot valve head assemblies associated with all 137 scram solenoid pilot valves. The ASCO valve assemblies were purchased from ASCO through General Electric. Those companies have been notified of the deficiency and are currently considering 10 CFR Part 21 reporting. Regional Action: Resident inspector followup. Contact: Pete Eselgroth (610)337-5234 _