Event Notification Report for November 17, 2000

UNIT 2 ENTERED TS 3.0.3 AFTER DECLARING BOTH LOOPS ECCS INOPERABLE

"Tech Spec 3.5.2 requires two independent Emergency Core Cooling System (ECCS) loops, each capable of taking suction from the Refueling Water Storage Tank (RWST) and being transferred to the containment recirculation sump. This spec applies in modes 1 - 3. Following evaluation of recent modifications to the containment recirc sump ECCS suction isolation valves, it has been determined that neither of the two isolation valves (2-ICM-305 and 2-ICM-306) could be relied upon to open when transfer of ECCS suction is required. This is attributed to a lack of assurance that between seat relief valves on 2-ICM-305 and 2-ICM-306 would lift and preclude thermal hydraulic locking of the valves in the closed position. Since neither ECCS loop recirc sump suction is operable, the action statement of TS 3.5.2 is not valid. This led to the Shift Manager declaring entry into TS 3.0.3 with a requirement to place the unit in a mode for which TS 3.5.2 does not apply. A unit shutdown at 2% per hour has been initiated. Plans are to implement compensatory actions or have the unit in hot standby within 6 hours."

The licensee anticipates exiting TS 3.0.3 after bleeding the fluid trapped between the double disk valves in approximately two hours. The licensee informed the NRC resident inspector.

* * * UPDATE 0310 11/18/2000 FROM RICHARDSON TAKEN BY STRANSKY * * *

The united exited the shutdown LCO at 2315. Reactor power had been reduced from 100% to 90%. The licensee removed approximately 4.5 gallons of water from the body of each valve in order to prevent thermal locking. The NRC resident inspector will be informed. Notified R3DO (Jorgensen).

***** UPDATE AT 1834 ON 12/18/00 FROM BRENDA L'ROURKE TO LEIGH TROCINE *****

The licensee is retracting this event notification. The following text is a portion of a facsimile received from the licensee:

"The Donald C. Cook Nuclear Plant is withdrawing [its] 1-hour Non-Emergency notification made to the NRC at 2041 hours on [11/17/00] (Event # 37532). At that time, it was reported that Unit 2 entered TS 3.0.3 after declaring both ECCS loops inoperable. Both loops were declared inoperable because neither of the two containment recirculation sump ECCS suction isolation valves (2-ICM-305 and 2-ICM-306), could be relied upon to open when transfer of ECCS suction is required. This was attributed to a lack of assurance that the thermal relief valves (2-SV-344 East and West) installed between the seats of 2-ICM-305 and 2-ICM-306, would lift at the required 20 psid design pressure to preclude thermal hydraulic locking of the normally closed ECCS suction valves. These relief valves were installed prior to Unit 2 entering Mode 4. On [11/18/00] at 2315 hours, Unit 2 exited the TS-required shutdown after 2-ICM-305 and 2-ICM-306 were declared operable after approximately 4.5 gallons of water was drained from each valve."

"Further Engineering evaluation concluded that both ECCS loops are and have been operable because 2-ICM-305 and 2-ICM-306 were determined not to be in a 'water solid' condition and, therefore, not susceptible to thermal hydraulic locking. This conclusion was confirmed by draining the volume of fluid present between the ECCS suction valve seats and comparing the total amount of fluid drained to the free space available inside each valve. It was determined, by calculation, that of the 30 gallons of free space available inside each valve, only 2 gallons of free space are needed to ensure the valves will open when transfer of ECCS suction is required. Both valves were drained on three separate occasions between 11/17/00 and 11/22/00. A total of 6.74 gallons was drained from 2-ICM-305, and a total of 8.25 gallons was drained from 2-ICM-306. Based on the total amount of fluid drained from each valve, both 2-ICM-305 and 2-ICM-306 have been operable during all periods when the ECCS is required to be operable."

The licensee notified the NRC resident inspector. The NRC operations officer notified the R3DO (Kozak).

PLANT HAD A REACTOR TRIP FROM 53% POWER DUE TO A TURBINE TRIP

A "Turbine Trip/Reactor Trip" occurred at 53% reactor power due to a sudden pressure relay actuation on C phase Main Bank transformer which sent signal to the generator resulting in the turbine trip. Motor Driven Auxiliary Feedwater pumps started as required when level decreased to less than 10% in one Steam Generator and the Turbine Driven Auxiliary Feedwater pump started as required on less than 10% in two steam generators. Preliminary walkdown of the transformer showed no visible exterior damage or degradation. Investigation is in progress to determine the cause of this event. The Unit is stable and operating in accordance with Plant General Operating procedures. All rods fully inserted, there were no ECCS actuations and no safety relief valves lifted.

The NRC Resident Inspector was notified.