Headquarters Daily Report JUNE 17, 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 JUNE 17, 1997 Licensee/Facility: Notification: New York Power Authority MR Number: 1-97-0037 Indian Point 3 Date: 06/17/97 Buchanan,New York SRI PC Dockets: 50-286 PWR/W-4-LP Subject: NOUE DECLARED DUE TO LOSS OF 138 KV OFFSITE POWER Discussion: On June 16, 1997, at 10:20 a.m., while in the refueling condition, the 138 kilovolt (kv) off-site power supply to the plant was lost due to an improper grounding activity in the Buchanan switchyard controlled by Con Edison. At the time of the event, plant power was being supplied by the 138 kv system. A second offsite power supply (13.8 kv) and the Appendix R diesel generator were available, and the 32 and 33 emergency diesel generators were operable. The 31 emergency diesel generator was out of service for preventive maintenance. During the previous day, NYPA had stopped fuel offloading due to an unrelated equipment problem. One hundred and nineteen (119) fuel bundles had been offloaded into the spent fuel pool and 74 fuel bundles remained in the reactor vessel. The 32 and 33 emergency diesel generators started and energized their respective safety buses. However, equipment could not be loaded onto the 32 diesel generator safety bus because the fuse supplying one phase of the undervoltage relay primary transformer blew during the event. Due to this condition, the 32 residual heat removal pump was not started immediately and the restoration of shutdown cooling to the fuel in the reactor vessel was delayed. NYPA subsequently restored offsite power from the alternate 13.8 kv system, and energized the buses fed by the 31 EDG. The 31 residual heat removal pump was started and shutdown cooling was restored about 44 minutes later. The fuse on the undervoltage relay power supply was replaced one hour later, thus returning power to the 32 RHR pump as well. The residual heat exchanger inlet temperature rose about 5-7 degrees Fahrenheit during the event, although the bulk temperature increase of the refueling cavity was <2 degrees Fahrenheit. No other significant equipment problems were encountered during the event. The 32 spent fuel cooling pump was restarted from the 33 diesel generator bus 37 minutes after the loss of offsite power. The spent fuel pool heat up was about 1 degrees Fahrenheit. Contingency measures were implemented to restore containment integrity after RHR cooling was lost. No personnel injuries occurred. NYPA declared an Unusual Event at 10:45 a.m. due to a loss of offsite power for this duration. The Unusual Event was terminated at 12:11 p.m. when the 138 kv off-site supply was restored to the station. Both NYPA and Con Edison are conducting internal reviews of this event. NYPA issued a press release. The State of New York was informed of the event. REGION I MORNING REPORT PAGE 2 JUNE 17, 1997 MR Number: 1-97-0037 (cont.) Regional Action: Routine resident followup of the licensees' event reviews. Contact: Richard Barkley (610)337-5065 _ REGION II MORNING REPORT PAGE 2 JUNE 17, 1997 Licensee/Facility: Notification: Tennessee Valley Authority MR Number: 2-97-0047 Watts Bar 1 Date: 06/17/97 Spring City,Tennessee Dockets: 50-390 PWR/W-4-LP Subject: AUTOMATIC TURBINE RUNBACK - LOSS OF 1B MAIN FEEDWATER PUMP (MFP) Discussion: On June 17, 1997 at approximately 6:35 a. m., EST while operating at 100% power level the 1B MFP pump shaft sheared near the inboard pump bearing. The loss of the 1B MFP resulted in an automatic turbine runback and reactor power stabilized at approximately 78 % power. All systems responded to the automatic turbine runback as designed. The licensee had been monitoring the 1B MFP shaft vibration for the last several days as levels had increased, but remained below the vibration alarm setpoint and required action level. A similar sheared shaft event occurred on the 1B MFP on March 6, 1997 and the root cause was attributed to high cycle metal fatigue. The licensee and pump vendor are comparing and evaluating data for both pump shaft failures to determine the root cause. The assessment of pump damage and repairs or replacement is estimated to take five days. The reactor plant will remain at the current power level with steam generator water levels being maintained with the 1A MFP and the Standby MFP. Regional Action: Resident inspectors are continuing to follow licensee event analysis and corrective actions. Contact: MARK LESSER (404)562-4560 _