Event Notification Report for June 30, 2002
U.S. Nuclear Regulatory Commission
Operations Center
EVENT REPORTS FOR
06/29/2002 - 06/30/2002
EVENT NUMBERS
39032
Power Reactor
Event Number: 39032
Facility: SAN ONOFRE
Region: 4 State: CA
Unit: [] [2] []
RX Type: [1] W-3-LP,[2] CE,[3] CE
NRC Notified By: CONOSCENTI
HQ OPS Officer: JOHN MacKINNON
Region: 4 State: CA
Unit: [] [2] []
RX Type: [1] W-3-LP,[2] CE,[3] CE
NRC Notified By: CONOSCENTI
HQ OPS Officer: JOHN MacKINNON
Notification Date: 07/01/2002
Notification Time: 00:33 [ET]
Event Date: 06/30/2002
Event Time: 18:58 [PDT]
Last Update Date: 07/01/2002
Notification Time: 00:33 [ET]
Event Date: 06/30/2002
Event Time: 18:58 [PDT]
Last Update Date: 07/01/2002
Emergency Class: NON EMERGENCY
10 CFR Section:
50.72(b)(2)(iv)(B) - RPS ACTUATION - CRITICAL
10 CFR Section:
50.72(b)(2)(iv)(B) - RPS ACTUATION - CRITICAL
Person (Organization):
WILLIAM JOHNSON (R4)
WILLIAM JOHNSON (R4)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 2 | A/R | Y | 18 | Power Operation | 0 | Hot Standby |
AUTOMATIC REACTOR TRIP ON LOW STEAM GENERATOR PRESSURE DUE TO TWO ADDITIONAL STEAM DUMP VALVES FULLY OPENING DURING STARTUP.
System Affected
"Primary: Rx Trip, CEA, RCP's stayed on, PLCS"
"Secondary: SBCS Open, MSIV's, ADV, MFW, AFW"
Actuations and Their Initiating Signals
"MSIS A & B @ 741 PSIA. Lowest Seen = MSIS setpoint"
Causes
"Prelim: 4 SBCS All Fast Open . . . "
Effect Of Event Plant
"Low S/G Pressure Rx Trip, Turbine Trip, MSIS isolated secondary. CVCS remained in service. MSIS verified and rest, then AFW initiated. (Did not want cooldown from steam-driven AFW Pp. Adequate S/G water level maintained throughout. Approx. 50% NR)."
Actions Taken or Planned
"EOI's: S023-12-1 (SPTA's), S023-12-2 (RTR), OI: S023-S-1.3.1 S0123-0-14 4 Hour"
"E-PLAN Review P S/G" [decreased])
The licensee was going to bring the main turbine on line which was rolling at 1800 rpm. Two steam dump bypass valves were open dumping steam to the main condenser to help maintain reactor power at 18%. Unexpectedly two additional steam dump bypass valves opened. When these two additional steam dump bypass valves opened the first two open valves initial started to close then they went full open. Steam generator pressure decreased to the low steam generator pressure setpoint of 741 psia at which point an automatic reactor trip plus a main steam isolation signal (MSIS) was generated, main steam isolation valves (MSIV's) closed. All rods fully inserted into the core. Atmospheric steam dump valves were used to maintained proper reactor coolant system temperature. The licensee said that they did not have any leaking steam generator tubes. Proper steam generator water inventory was verified at which time the MSIS signal was reset, then one Motor Driven Auxiliary Feedwater Pump was manually initiated to maintain proper steam generator water level. Main feedwater system isolated due to the MSIS signal and the reactor trip. All emergency core cooling systems, emergency diesel generators are fully operable if needed. The electrical grid is stable. The licensee is investigating why the two additional steam dump bypass valves opened.
The NRC Resident Inspector was notified of this event by the licensee.
System Affected
"Primary: Rx Trip, CEA, RCP's stayed on, PLCS"
"Secondary: SBCS Open, MSIV's, ADV, MFW, AFW"
Actuations and Their Initiating Signals
"MSIS A & B @ 741 PSIA. Lowest Seen = MSIS setpoint"
Causes
"Prelim: 4 SBCS All Fast Open . . . "
Effect Of Event Plant
"Low S/G Pressure Rx Trip, Turbine Trip, MSIS isolated secondary. CVCS remained in service. MSIS verified and rest, then AFW initiated. (Did not want cooldown from steam-driven AFW Pp. Adequate S/G water level maintained throughout. Approx. 50% NR)."
Actions Taken or Planned
"EOI's: S023-12-1 (SPTA's), S023-12-2 (RTR), OI: S023-S-1.3.1 S0123-0-14 4 Hour"
"E-PLAN Review P S/G" [decreased])
The licensee was going to bring the main turbine on line which was rolling at 1800 rpm. Two steam dump bypass valves were open dumping steam to the main condenser to help maintain reactor power at 18%. Unexpectedly two additional steam dump bypass valves opened. When these two additional steam dump bypass valves opened the first two open valves initial started to close then they went full open. Steam generator pressure decreased to the low steam generator pressure setpoint of 741 psia at which point an automatic reactor trip plus a main steam isolation signal (MSIS) was generated, main steam isolation valves (MSIV's) closed. All rods fully inserted into the core. Atmospheric steam dump valves were used to maintained proper reactor coolant system temperature. The licensee said that they did not have any leaking steam generator tubes. Proper steam generator water inventory was verified at which time the MSIS signal was reset, then one Motor Driven Auxiliary Feedwater Pump was manually initiated to maintain proper steam generator water level. Main feedwater system isolated due to the MSIS signal and the reactor trip. All emergency core cooling systems, emergency diesel generators are fully operable if needed. The electrical grid is stable. The licensee is investigating why the two additional steam dump bypass valves opened.
The NRC Resident Inspector was notified of this event by the licensee.