Event Notification Report for August 12, 2001
U.S. Nuclear Regulatory Commission
Operations Center
EVENT REPORTS FOR
08/11/2001 - 08/12/2001
EVENT NUMBERS
38202
Power Reactor
Event Number: 38202
Facility: DUANE ARNOLD
Region: 3 State: IA
Unit: [1] [] []
RX Type: [1] GE-4
NRC Notified By: DEAN CURTLAND
HQ OPS Officer: LEIGH TROCINE
Region: 3 State: IA
Unit: [1] [] []
RX Type: [1] GE-4
NRC Notified By: DEAN CURTLAND
HQ OPS Officer: LEIGH TROCINE
Notification Date: 08/12/2001
Notification Time: 12:16 [ET]
Event Date: 08/12/2001
Event Time: 07:46 [CDT]
Last Update Date: 08/12/2001
Notification Time: 12:16 [ET]
Event Date: 08/12/2001
Event Time: 07:46 [CDT]
Last Update Date: 08/12/2001
Emergency Class: NON EMERGENCY
10 CFR Section:
50.72(b)(2)(iv)(B) - RPS ACTUATION - CRITICAL 50.72(b)(3)(iv)(A) - VALID SPECIF SYS ACTUATION
10 CFR Section:
50.72(b)(2)(iv)(B) - RPS ACTUATION - CRITICAL 50.72(b)(3)(iv)(A) - VALID SPECIF SYS ACTUATION
Person (Organization):
ANNE MARIE STONE (R3)
ANNE MARIE STONE (R3)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 1 | M/R | Y | 100 | Power Operation | 0 | Hot Shutdown |
MANUAL REACTOR SCRAM DUE TO DECREASING REACTOR WATER LEVEL AND GROUP 1 ISOLATION DUE TO LOW REACTOR PRESSURE WHILE IN RUN
The following text is a portion of a facsimile received from the licensee:
"At 07:46:00 [CDT], a reactor water low-level alarm was received. The reactor operator verified the low-level condition and took manual control of feedwater level control. The operator matched feedwater and steam flow. At 07:46:28 [CDT], the 'B' feedwater pump tripped on low suction pressure. A manual scram was inserted at 07:46:42 [CDT] due to lowering reactor water level. Level dropped below 170 [inches] on the reactor scram [as expected], and [Group 2, 3, and 4 isolations] were received. All isolations went to completion. At 07:47:48 [CDT], a Group 1 isolation was received on the 850 psig low reactor pressure in Run isolation signal. The operator was in the process of [taking] the mode switch [out of] Run, but the isolation occurred before this action could be completed. All [main steam isolation valves] closed on the Group 1 isolation signal. Reactor level increased to the high level trip following the reactor scram, as expected, and the 'A' feedwater pump tripped. Due to the Group 1 isolation, the operating crew elected to manually initiate Low Low Set pressure control using the safety relief valves. A relief valve was opened, arming Low Low Set, and the two valves lowered reactor pressure to 900 psig. The Group 1 was reset, and main steam line drains to the condenser are being used to control pressure. The 'A' feedwater pump high level trip has been reset and is maintaining level."
"All systems responded as expected. The plant is currently in Hot Shutdown at 800 psig. Plans are being reviewed to determine the length of the forced outage. Preliminary investigations indicate that the 'B' feedwater pump minimum flow valve may have failed open to initiate the event."
The licensee stated that there were no maintenance or surveillance activities ongoing at the time of the event. All control rods fully inserted following the manual reactor scram. All containment parameters are currently normal, and offsite power is available.
The licensee notified the NRC resident inspector.
The following text is a portion of a facsimile received from the licensee:
"At 07:46:00 [CDT], a reactor water low-level alarm was received. The reactor operator verified the low-level condition and took manual control of feedwater level control. The operator matched feedwater and steam flow. At 07:46:28 [CDT], the 'B' feedwater pump tripped on low suction pressure. A manual scram was inserted at 07:46:42 [CDT] due to lowering reactor water level. Level dropped below 170 [inches] on the reactor scram [as expected], and [Group 2, 3, and 4 isolations] were received. All isolations went to completion. At 07:47:48 [CDT], a Group 1 isolation was received on the 850 psig low reactor pressure in Run isolation signal. The operator was in the process of [taking] the mode switch [out of] Run, but the isolation occurred before this action could be completed. All [main steam isolation valves] closed on the Group 1 isolation signal. Reactor level increased to the high level trip following the reactor scram, as expected, and the 'A' feedwater pump tripped. Due to the Group 1 isolation, the operating crew elected to manually initiate Low Low Set pressure control using the safety relief valves. A relief valve was opened, arming Low Low Set, and the two valves lowered reactor pressure to 900 psig. The Group 1 was reset, and main steam line drains to the condenser are being used to control pressure. The 'A' feedwater pump high level trip has been reset and is maintaining level."
"All systems responded as expected. The plant is currently in Hot Shutdown at 800 psig. Plans are being reviewed to determine the length of the forced outage. Preliminary investigations indicate that the 'B' feedwater pump minimum flow valve may have failed open to initiate the event."
The licensee stated that there were no maintenance or surveillance activities ongoing at the time of the event. All control rods fully inserted following the manual reactor scram. All containment parameters are currently normal, and offsite power is available.
The licensee notified the NRC resident inspector.