Semantic search
| Entered date | Event description | |
|---|---|---|
| ENS 47850 | 19 April 2012 11:10:00 | Limerick Unit 1 was manually scrammed from 100% power at 0753 hours on 4/19/12 in accordance with plant procedure OT-112 'Recirculation Pump Trip' when both 1A and 1B Recirculation Pump Adjustable Speed Drives (ASDs) tripped due to an electrical fault affecting the 144D and 114A non-safety related 480V Load Centers. The shutdown was normal and the plant is stable in Hot Shutdown with normal pressure control via the Main Steam Bypass valves to the main condenser and normal level control using feedwater. The manual RPS actuation is reportable under 10 CFR 50.72(b)(2). The Technical Support Center (TSC) Normal Air conditioning systems shut down due to loss of power from the 144D Load Center. The loss of power also affects the flow indication for the Emergency Ventilation system. This is considered a Loss of Emergency Assessment Capability, and reportable under 10 CFR 50.72(b)(3)(xiii). The Emergency TSC Ventilation system is available but flow cannot be verified. During a required activation the TSC, responders would report to the TSC. If conditions required use of the Emergency Ventilation system, the Station Emergency Director would assess habitability in accordance with Station procedures. TSC relocation of personnel would be directed as required until such time that the TSC ventilation system is returned to service The licensee notified the NRC Resident Inspector.
The Technical Support Center (TSC) 144D load center has been re-energized, restoring the emergency ventilation flow indication and emergency assessment capability to its normal stand-by condition." The switchgear was inspected for any potential grounds and then reenergized at approximately 0800 EDT on 4/20/2023. The licensee notified the NRC Resident Inspector. Notified the R1DO (Joustra). |
| ENS 46973 | 20 June 2011 16:59:00 | During 24 month Technical Support Center (TSC) Ventilation System Charcoal Analysis testing, the charcoal failed due to Methyl Iodine penetration of 3.1%, which is above the procedural limit of 1%. The TSC non-emergency ventilation system remains functional. Charcoal replacement is planned. If an emergency is declared requiring TSC activation during this period, the TSC will be staffed and activated using existing Emergency Planning procedures and checklists. If radiological conditions require TSC facility evacuation prior to completion of charcoal replacement; the Station Emergency Director will evacuate and relocate the TSC staff in accordance with applicable site procedures. The licensee informed the NRC Resident Inspector. |
| ENS 46919 | 3 June 2011 12:06:00 | Limerick Unit 1 automatically scrammed from 100% power at 1021 EDT hrs on 6/3/11. The RPS actuation occurred as designed upon an automatic trip of the Main Turbine. The cause of the Main Turbine trip is under investigation. Plant response to the Main Turbine trip was per design without complications. All control rods fully inserted. No ECCS or RCIC initiations occurred. No Primary or Secondary Containment isolations occurred. The plant is currently in Hot Shutdown with the normal Feedwater system maintaining reactor water level, and the Main Turbine Bypass valves maintaining reactor pressure. Limerick Unit 2 was unaffected. The post-scram electrical alignment is normal. The licensee has notified the NRC Resident Inspector and plans to notify appropriate state and local authorities. The licensee is also planning a press release. |
| ENS 46474 | 12 December 2010 16:44:00 | During quarterly operability verification of the HPCI Turbine Overspeed Trip Assembly, the Trip/Reset knob was manually lifted and released to time the automatic reset function. Upon release of the knob, the Trip Assembly failed to automatically reset (the HPCI Turbine Stop and Control Valves remained closed). Adjustment of the Trip/Reset needle valve was unsuccessful. The HPCI Turbine Stop and Control Valves remain in the tripped condition, rendering HPCI unavailable. Engineering and Maintenance have been dispatched to troubleshoot and repair the Overspeed Trip Assembly and restore HPCI to operable status. All other required systems are available, operable, and protected. The licensee is in the 14 day LCO 3.5.1. The licensee has notified the NRC Resident Inspector. |
| ENS 46330 | 13 October 2010 09:50:00 | This ENS is being issued in advance of a planned activity. On 10/14/10 at 0100 hours Limerick Generating Station will apply a clearance to inspect and repair fire suppression equipment associated with the onsite Technical Support Center (TSC) Emergency Ventilation System and perform corrective maintenance associated with the MD-1 (outside air) damper. While the clearance is applied, the TSC Emergency Ventilation system will not be available to be restored within the time period required to staff and activate the TSC Emergency Response Organization (ERO). This work is expected to be completed 10/14/10. If an emergency is declared requiring TSC ERO activation, the TSC will be staffed and activated using emergency planning procedures unless the TSC becomes uninhabitable due to ambient temperature, radiological, or other conditions. If relocation of TSC staff becomes necessary, the Station Emergency Director will relocate the staff to an alternate TSC location in accordance with applicable procedures. This notification is being made in accordance with 10CFR50.72(b)(3)(xiii) due to the loss of an Emergency Response Facility because of the planned unavailability of the TSC Emergency Ventilation system. The NRC Resident Inspector has been informed.
The Technical Support Center Emergency Ventilation System maintenance is complete and the system has been returned to service. The licensee has notified the NRC Resident Inspector. Notified R1DO (Jackson). |
| ENS 45693 | 11 February 2010 08:00:00 | On Thursday, February 11, 2010, the Limerick Technical Support Center (TSC) emergency ventilation system will be removed from service for planned preventative maintenance activities on the damper flow controller and air filtration charcoal system. During the maintenance, the non-emergency ventilation system will be functional. The TSC air filtration fan and dampers will be non-functional, rendering the TSC HVAC accident mode non-functional. This maintenance is scheduled to minimize out of service time. The planned TSC ventilation outage is scheduled to be completed within 12 hours. If an emergency is declared requiring TSC activation during this period, the TSC will be staffed and activated using existing EP (Emergency Planning) procedures and checklists. If radiological conditions require TSC facility evacuation during ventilation system restoration, the Station Emergency Director will evacuate and relocate the TSC staff in accordance with applicable site procedures. The licensee has notified the NRC Resident Inspector.
The maintenance on the Limerick Technical Support Center (TSC) emergency ventilation system has been completed and the TSC is available. The licensee has notified the NRC Resident Inspector. Notified R1DO (Powell) |
| ENS 45153 | 23 June 2009 22:40:00 | A partial loss of the ability to send ERDS data to the NRC for greater than 60 minutes occurred. The loss affects transmission of Standby Liquid Control Tank levels, Main Condenser Vacuum levels, and data for North and South Ventilation Stacks and Drywall Post LOCA radiation monitors. The (Safety Parameter Display System) SPDS, (Health Physics Network) HPN and (Emergency Notification System) ENS systems are not affected. Troubleshooting to identify and correct the data loss to ERDS is in progress. The licensee notified the NRC Resident Inspector.
Data for North and South Ventilation Stacks and Drywell Post LOCA radiation monitors was restored to ERDS at 2345 hours on 6/23/09" The licensee will notify the NRC Resident Inspector.
Data gathered from Standby Liquid Control and Main Condenser Vacuum is not plant data that is transmitted to ERDS. ERDS was fully restored with the required input data at 2345 hours on 6/23/2009. The licensee informed the NRC Resident Inspector. Notified R1DO (Henderson). |
| ENS 43898 | 12 January 2008 19:09:00 | An overvoltage condition occurred on the D23 Safeguards 4kv bus during planned system outage window EDG governor testing. The EDG output breaker was immediately opened and the engine secured per test direction. Due to the output breaker being opened, the D23 bus then experienced an undervoltage condition. Bus voltage monitoring instrumentation automatically initiated automatic closure of the 201-D23 Bus Offsite Supply Feed Breaker after a 1 second time delay and re-energized the D23 Safeguards Bus per design. The remaining three 4kv buses and Emergency Diesel Generators were unaffected and remain operable. The voltage regulation circuit is being investigated at this time to assist in determining the cause of the overvoltage condition. The EDG was out of service and inoperable during the testing. The EDG governor was replaced during the outage window and was being fine tuned when the event occurred. The licensee is currently in day 6 of a 30 day LCO (3.8.1.1). The licensee notified the NRC Resident Inspector. |