Headquarters Daily Report SEPTEMBER 19, 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 - HEADQUARTERS SEP. 19, 1995 MR Number: H-95-0123 NRR DAILY REPORT ITEM GENERIC COMMUNICATIONS NRC Information Notice 95-40, "Supplemental Information to Generic Letter 95-03, `Circumferential Cracking of Steam Generator Tubes,'" dated September 20, 1995. The NRC is issuing this information notice to provide additional information on steam generator tube examination results from Maine Yankee Atomic Power Station as previously discussed in Generic Letter 95-03, "Circumferential Cracking of Steam Generator Tubes." Technical contacts: Kenneth J. Karwoski, NRR (301) 415-2754 Eric J. Benner, NRR (301) 415-1171 _ REGION IV MORNING REPORT PAGE 2 SEPTEMBER 19, 1995 Licensee/Facility: Notification: Pacific Gas & Electric Co. MR Number: 4-95-0113 Diablo Canyon 1 Date: 09/18/95 Avila Beach,California Call from licensee Dockets: 50-275 PWR/W-4-LP Subject: MAIN STEAM SAFETY VALVE LIFT PRESSURES OUTSIDE LIMITS Reportable Event Number: 29332 Discussion: In preparation for a scheduled refueling outage for Unit 1, the licensee performed routine testing on all 20 of the unit's main steam safety valves (MSSVs) on September 12 and 13, 1995. As a result of the testing, the licensee determined that the initial lift pressures (as-found) on 18 of the 20 MSSVs exceeded the Technical Specification (TS) setpoint tolerance of +/-1 percent. Five of the MSSVs were found to be between 1 and 5 percent above their TS lift setpoint, and 13 MSSVs exceeded their setpoint by greater than 5 percent. Preliminary analysis of the initial lift results by the licensee indicates that the unit was outside its design basis for a loss of load/turbine trip scenario because steam generator pressure could exceed 110 percent of design pressure. The licensee notified the NRC on September 14, 1995, in accordance with 10 CFR 50.72. In accordance with the licensee's testing procedure, MSSV setpoints are validated by achieving two consecutive lifts within the TS tolerance of +/-1 percent. Of the 18 valves that exceeded the TS tolerance on their first lift, 8 required adjustment while the remaining 10 valves needed no adjustment to achieve two consecutive lifts within tolerance. Each valve was tested, adjusted if necessary, and its setpoint verified to be within TS tolerances prior to testing the next valve. As a result, no more than one valve was considered inoperable at any time during the testing. The unusual characteristics of these results are that all MSSVs were found above the setpoint and the number of MSSVs (13) that were greater than 5 percent above the setpoint. During the last Unit 1 outage in March 1994, all 20 valves were removed for refurbishment and reset using live steam prior to reinstallation. The testing conducted on September 12 and 13, 1995, was the first testing performed on these valves since their reinstallation. It is also noted that the licensee implemented a new testing methodology for the first time in performing the MSSV tests. The licensee utilized AVK Industries' UltraStar relief valve test equipment in lieu of Fermanite's Trevitest equipment, which had been used on the Unit 1 MSSVs for the last six refueling outages. The UltraStar test equipment was qualified in August 1994 using spare relief valves from Diablo Canyon with live steam at a test facility. The licensee is evaluating the differences in the two test methodologies to determine possible impact on the test results. The licensee is also evaluating other possible causes of the test results, including verifying test equipment calibration and disc-to-seat adhesion phenomena. The licensee is considering the need to verify the Unit 2 MSSV setpoints and plans to send three Unit 1 MSSVs to the Westinghouse test facility to be REGION IV MORNING REPORT PAGE 3 SEPTEMBER 19, 1995 MR Number: 4-95-0113 (cont.) internally inspected during the upcoming outage. Regional Action: A conference call was held with the licensee, Region IV, and NRR personnel to discuss the licensee's evaluation and planned investigation. The resident inspectors continue to monitor the licensee evaluation and corrective actions. Contact: H. Wong (510)975-0296 M. Tschiltz (805)595-2354 _