Event Notification Report for January 10, 2016
U.S. Nuclear Regulatory Commission
Operations Center
EVENT REPORTS FOR
01/09/2016 - 01/10/2016
EVENT NUMBERS
51784
51784
Power Reactor
Event Number: 51784
Facility: RIVER BEND
Region: 4 State: LA
Unit: [1] [] []
RX Type: [1] GE-6
NRC Notified By: DAN PIPKIN
HQ OPS Officer: JOHN SHOEMAKER
Region: 4 State: LA
Unit: [1] [] []
RX Type: [1] GE-6
NRC Notified By: DAN PIPKIN
HQ OPS Officer: JOHN SHOEMAKER
Notification Date: 03/09/2016
Notification Time: 16:53 [ET]
Event Date: 01/10/2016
Event Time: 02:43 [CST]
Last Update Date: 03/09/2016
Notification Time: 16:53 [ET]
Event Date: 01/10/2016
Event Time: 02:43 [CST]
Last Update Date: 03/09/2016
Emergency Class: NON EMERGENCY
10 CFR Section:
50.73(a)(1) - INVALID SPECIF SYSTEM ACTUATION
10 CFR Section:
50.73(a)(1) - INVALID SPECIF SYSTEM ACTUATION
Person (Organization):
DAVID PROULX (R4DO)
DAVID PROULX (R4DO)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 1 | N | N | 0 | Cold Shutdown | 0 | Cold Shutdown |
INVALID ACTUATION OF THE PRIMARY CONTAINMENT ISOLATION LOGIC
"On January 10, 2016, at 0243 CST, with the plant in cold shutdown, the primary containment isolation logic was actuated as the result of an invalid signal. This condition occurred while operators were installing electrical jumpers designed to bypass certain isolation signals for the suction valves in the residual heat removal (RHR) system that comprise the shutdown cooling flow path. These jumpers are installed under procedural guidance for the purposes of increasing the reliability of the shutdown cooling loop by disabling isolation signals that are not required to be operable in certain plant operating modes. Although it could not be proven, it appears that inadvertent contact with an energized circuit occurred during the jumper installation, causing a fuse to blow, de-energizing part of the primary isolation logic. This caused the automatic closure of Division 1 suction and return valves in the shutdown cooling loop, as well as valves connecting the reactor plant sampling systems to the RHR system. The main control room crew implemented recovery procedures to restore shutdown cooling to service at 0401 CST, prior to exceeding any temperature limits.
"This event resulted from the failure to maintain corrective actions in place that were develop after a similar event in 1994. Additionally, the operators were not using the type of jumpers required by the procedure, which likely contributed to the blown fuse.
"The RHR system operating procedure has been revised to require that the potentially affected valves in the shutdown cooling loop will be de-energized during jumper installation to eliminate the possibility of inadvertent isolation.
"This is being reported in accordance with 10 CFR 50.73(a)(1) as an invalid actuation of the primary containment isolation logic."
During this event, the RCS temperature increased from approximately 130 to 190 degree F.
The licensee will notify the NRC Resident Inspector.
"On January 10, 2016, at 0243 CST, with the plant in cold shutdown, the primary containment isolation logic was actuated as the result of an invalid signal. This condition occurred while operators were installing electrical jumpers designed to bypass certain isolation signals for the suction valves in the residual heat removal (RHR) system that comprise the shutdown cooling flow path. These jumpers are installed under procedural guidance for the purposes of increasing the reliability of the shutdown cooling loop by disabling isolation signals that are not required to be operable in certain plant operating modes. Although it could not be proven, it appears that inadvertent contact with an energized circuit occurred during the jumper installation, causing a fuse to blow, de-energizing part of the primary isolation logic. This caused the automatic closure of Division 1 suction and return valves in the shutdown cooling loop, as well as valves connecting the reactor plant sampling systems to the RHR system. The main control room crew implemented recovery procedures to restore shutdown cooling to service at 0401 CST, prior to exceeding any temperature limits.
"This event resulted from the failure to maintain corrective actions in place that were develop after a similar event in 1994. Additionally, the operators were not using the type of jumpers required by the procedure, which likely contributed to the blown fuse.
"The RHR system operating procedure has been revised to require that the potentially affected valves in the shutdown cooling loop will be de-energized during jumper installation to eliminate the possibility of inadvertent isolation.
"This is being reported in accordance with 10 CFR 50.73(a)(1) as an invalid actuation of the primary containment isolation logic."
During this event, the RCS temperature increased from approximately 130 to 190 degree F.
The licensee will notify the NRC Resident Inspector.