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| Entered date | Event description | |
|---|---|---|
| ENS 45071 | 15 May 2009 10:13:00 | At 0519 on 5/15/09, a Group 1 isolation signal was received which resulted in all eight Main Steam Isolation Valves closing. The signal was received based upon a valid main condenser low vacuum signal coincident with reactor mode switch placed in RUN position. The isolation was an unanticipated result of a special purpose procedure which was being performed as a functional test for maintenance work that had been performed on intermediate range nuclear instrumentation. The procedure had installed jumpers to bypass the Group 1 isolation for Mode Switch in Run, but did not account for low condenser vacuum isolation. The low condenser vacuum switches were in the bypass position, but this logic does not prevent Group 1 isolation in the Run mode. The Group 1 isolation was completed successfully with all MSIVs and small bore valves closing as designed. MSIV closure with Mode Switch in Run position also caused a RPS actuation / full scram. The reactor was subcritical and all control rods were already fully inserted as the reactor was being maintained in Cold Shutdown. The licensee has notified the NRC Resident Inspector. |
| ENS 45055 | 11 May 2009 17:11:00 | (The licensee was) Notified by chemistry, that while performing (the procedure for monitoring) the annual releases via unplanned routes for gamma sampling for groundwater well P17B, which is located near the southeast corner of the Diesel Generator (DG) building, a strong diesel / fuel oil odor in the groundwater being collected was detected by the sampling technician. In addition to the strong petroleum odor, the groundwater from the well had a reddish tint. This color is indicative of the red dye used to identify off-road diesel. The P17B is normally sampled annually for tritium and gamma. The last sample from this well was taken in January 2009 for the tritium sample surveillance. Southern Nuclear Company (SNC) Corporate Environmental Affairs was contacted to make the appropriate communications. Environmental Affairs has contacted the National Response Center. (The licensee's) Plans are to excavate in the area of well P17B to determine potential source of fuel oil to (the) ground water well. The licensee has notified the NRC Resident Inspector. |
| ENS 45052 | 10 May 2009 12:52:00 | During Startup of HNP-1, after reaching greater than or equal to 7% RTP (rated thermal power), the crew placed the Reactor MODE switch to 'RUN,' in accordance with the Startup Procedure 34GO-OPS-001-1. Upon placing the MODE switch to 'RUN,' a full RPS actuation occurred due to upscale trip signals on the Intermediate Range Nuclear Instrumentation (IRM) 1C51K601A, 1C51K601D and 1C51K601H. Placing the Reactor MODE switch to 'RUN' bypasses the IRM inputs to the RPS system, so actuation of the RPS from the IRMS was not expected. All withdrawn control rods inserted properly upon receipt of the full SCRAM signal. All equipment functioned as expected, with the exception of the unexpected upscale trips of IRMs 1C51K601A, 1C51K601D and 1C51K601H and the subsequent RPS actuation from the IRMs. No reactivity changes were in progress at the time to cause the upscale trip signals. At this time, investigation is in progress, but the investigation and corrective action have not yet been completed. The shift crew is progressing to Cold Shutdown, MODE 4 at this time. The decay heat is being removed by main turbine sealing steam with makeup provided via the control rod drive system. Offsite power is provided by the normal shutdown electrical lineup. The licensee notified the NRC Resident Inspector. |
| ENS 45049 | 8 May 2009 17:29:00 | At 1515 on 5/8/09, a Group 1 isolation signal was received which resulted in all eight Main Steam Isolation Valves closing. The signal was received based upon a valid main condenser low vacuum signal coincident with a main turbine reset signal which opened the turbine stop valves. The reset of the turbine was an unanticipated result of ongoing Mark VI turbine control system processor repair work. The reactor was maintaining hot shutdown while conducting nuclear instrumentation repair. The Group 1 isolation was completed successfully with all MSlVs and small bore valves closing as designed. The condition causing the turbine reset has been cleared and the turbine tripped with all valves closed. The Group 1 isolation signal has been reset and the MSIVs have been re-opened. The cause of the turbine reset signal is being investigated by Station Engineering and the on-site GE representative. The reactor is being taken to cold shutdown for intermediate range nuclear instrument maintenance. The licensee notified the NRC Resident Inspector. |
| ENS 44038 | 6 March 2008 05:45:00 | With Unit 1 in Mode 4 for a planned refueling outage, a pin hole leak was discovered on a 1 inch line between the 'A' Main Steam Line (MSL) and MSL flow instrument condensing chamber (1B21-D006B) in a weld at a 45 degree elbow. Leakage was identified as approximately 2 gallons per hour (GPH). This leakage was identified during RPV pressure test while test pressure was 1050 psig. This elbow is near the 1B21-D006B condensing chamber and is located in the Unit 1 drywell (primary containment). This item constitutes a primary coolant boundary leak discovered while shutdown. The licensee notified the NRC Resident Inspector. |
| ENS 43968 | 7 February 2008 05:16:00 | In preparation for scheduled Motor Control Center (MCC) cleaning activities, the Health Physics normal HVAC system had to be shutdown and the Health Physics emergency HVAC was to be started while the MCC that supplies power to the normal HVAC would be out of service. When the emergency HVAC system was started per the system operating procedure (34S0-Z41-006-0), the air handling unit (1Z41-B100) started, but neither compressor units (1Z41-B101) started. Maintenance has been notified and is currently working to restore the system to operable status. This event is reportable per 10CFR50,72 (b)(3)(xiii) as described in NUREG-1022, rev. 2 as an emergency facility (Plant Hatch Operational Support Center) is affected with the Health Physics emergency HVAC out of service. Update: maintenance cleaned electrical contactors and have both compressors running at 0436 hours. The licensee notified the NRC Resident Inspector. |
| ENS 43658 | 22 September 2007 03:52:00 | Jacksonville National Weather service has notified Plant Hatch that the capability to broadcast prompt notification messages is NOT available at this time. Plant Hatch security notified the Operations Shift Manager at 0315 hours to notify the NRC. Also, site Emergency Preparedness on call person has been contacted and he in conjunction with security has notified the state and local agencies. Information Technology (IT) has been notified of problem with 'land lines.' Compensatory measures are in effect. There is no estimate at this time for restoration of the Jacksonville "land lines. The licensee will inform the NRC Resident Inspector.
The licensee received notification from the Jacksonville National Weather service that the 'land lines' have been restored. Plant Hatch has regained the capability to broadcast prompt notification messages. The licensee will inform the NRC Resident Inspector. Notified R2DO (Bonser). |
| ENS 39712 | 29 March 2003 04:44:00 | HPCI TURBINE FAILS TO COME TO SPEED DURING SURVEILLANCE TES
"While starting up Unit Two reactor from a planned refueling/maintenance outage, the HPCI system would not pass the required tech spec surveillance when tested at 160 psig reactor pressure. The HPCI turbine failed to come up to speed due to its turbine steam control valve did not open after the turbine stop valve was opened per system operability surveillance. The system engineer and maintenance are investigating the speed control circuit at this time. The licensee has notified the NRC Resident Inspector. |