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| Entered date | Event description | |
|---|---|---|
| ENS 50533 | 14 October 2014 07:37:00 | This notification is being made as required by 10 CFR 50.72(b)(2)(iv)(B) due to a Farley Nuclear Plant Unit 2 manual reactor trip. The trip was initiated when the in service train of CCW cooling to the Reactor Coolant Pumps was lost due to a loss of the 2B Start Up Transformer (SUT). The control room team manually tripped the reactor then tripped all three reactor coolant pumps as required by station procedure. There was a line of severe thunderstorms with lightning passing through the plant site at the time of loss of the 2B Start Up Transformer. The 2B emergency diesel generator was out of service for maintenance therefore there was a loss of the 'B' train emergency power 4160V electrical bus ('B' train LOSP (Loss of Offsite Power)). 'A' train emergency power remained energized from offsite sources. The plant is stable at normal operating pressure and temperature. At 0433 (CDT), 2B Reactor Coolant Pump was re-started when support conditions were re-established. Heat sink is adequate using the 2A Motor Driven Auxiliary Feedwater Pump. Unit 2 'B' train power was restored by starting the 2C emergency diesel generator at 0523 (CDT). This restored power to the Digital Rod Position Indication system, and control rod K-8 in control bank 'C' indicated full out, and all other control rods fully inserted. An emergency boration is in progress to compensate for the stuck rod. Additionally, the reactor trip resulted in a valid actuation of the Aux Feedwater system which is an eight hour non-emergency report per 10 CFR 50.72(b)(3)(iv)(A). During the transient, one primary PORV momentarily opened, then reseated. Decay heat is being directed to the atmospheric relief valves with no indicated primary to secondary leakage. There was no impact on Unit 1. The licensee notified the NRC Resident Inspector.
Digital rod position indication troubleshooting was conducted on 10/14/2014 and confirmed all control rods, including control rod K-8, fully inserted following the reactor trip. The licensee notified the NRC Resident Inspector. Notified the R2DO (Ayres), NRR EO (Davis) and IRD (Gott). |
| ENS 49744 | 18 January 2014 14:48:00 | At 10:20 (CST) on January 18, 2014, the Unit 2 Pyro Panel (fire/smoke detection panel) was declared non-functional due to an unknown equipment problem. Compensatory measures (e.g. continuous roving fire watches) have been established for all affected areas with the exception of the Unit 2 Containment Building. Containment fire watches have been established per the FSAR, which includes monitoring various temperatures, pressures, and other parameters for Containment, and systems associated with containment. However, this is not considered a satisfactory compensatory measure for maintaining effective assessment capability. Since a fire in Containment is an entry condition for the site's Emergency Plan, this is considered a loss of emergency assessment capability, and is being reported per 10CFR50.72(b)(3)(xiii). The NRC Senior Resident Inspector has been informed.
At 0404 CST on 1/20/14 the Unit 2 Pyro panel was declared functional following the replacement of the fire indicating unit (FIU) and the power supply, and successful post maintenance testing. The emergency assessment capability for the site's Emergency Plan has been fully restored concerning a Containment fire. The licensee notified the NRC Resident Inspector. Notified R2DO (King). |
| ENS 45946 | 22 May 2010 19:10:00 | Unit 2 was operating at 100% power in the normal operating procedure, FNP-2-UOP-3.1, Power Operation, when multiple alarms were received associated with 2C Steam Generator (S/G) level, and a process cabinet failure. The control room team noticed there was no power or control capability on the 2C S/G Feedwater Regulating Control Valve (FRV), and 2C S/G level was decreasing. The control room team attempted to take manual control of the 2C FRV, which did not respond. The reactor was manually tripped when 2C S/G narrow range level reached 40%. The automatic trip set point for S/G level is 28%. All systems responded properly for the reactor trip and there were no complications. The investigation indicates there was an Nuclear Controller Driver (NCD) card failure in Process Control Cabinet 8. The controller card controls the 2C S/G FRV controller, which prevented any automatic, or manual control of the 2C S/G FRV, or 2C S/G level. There were no safety or relief valves that lifted and decay heat is being removed via steam dump control valves. Auxiliary feedwater pumps are maintaining level in the steam generators. Electrical lineup is normal. The licensee has notified the NRC Resident Inspector. |
| ENS 45889 | 1 May 2010 02:01:00 | Unit 2 was performing a planned refueling outage surveillance test, FNP-2-STP-40.0, Safety Injection with Loss of Off-Site Power. The system was being returned to normal following the actuation portion of the test. When the B2F Sequencer was reset, a loss of off-site power (LOSP) occurred, which caused a loss of the 'A' Train 4kV busses, and an LOSP signal was generated. The 1-2A Diesel Generator was already running at normal speed, and voltage. Therefore, the diesel generator output breaker opened, and then reclosed which then allowed the LOSP loads to automatically start. This included the 2A Motor Driven Auxiliary Feedwater Pump, and the 2A High Head Safety Injection Pump. Therefore, during the test, the system actuated in a way that was not part of the planned evolution. The investigation indicated that a recent design change on the diesel generator output breaker circuitry had not been fully incorporated into the test procedure. The test procedure currently in progress was revised to provide guidance for operating the B2G Sequencer Test Trip Override switch. The restoration section for the 'B' Train was completed with no further complications when the B2G Sequencer Test Trip Override switch was operated before resetting the B2G Sequencer. The licensee has notified the NRC Resident Inspector. |
| ENS 40666 | 11 April 2004 12:47:00 | At 1247 EDT on 04/11/04, the licensee reported that at 1105 CDT on 04/11/04, control room operators were performing low power physics testing in accordance with FNP-2-STP-101 during startup of Unit 2 following a refueling outage. With reactor power at 10E-8 amps in the intermediate range in Mode 2, the 'B' reactor trip breaker opened for unknown reasons. All control rods inserted completely. The licensee is investigating the cause. The licensee notified the NRC Resident Inspector. |