Semantic search
| Entered date | Event description | |
|---|---|---|
| ENS 54054 | 9 May 2019 07:01:00 | On May 9, 2019 at 0348 CDT, an automatic scram was received on Unit 2 following a turbine trip. All rods inserted to their full-in positions. All Group 2 and Group 3 automatic isolations actuated as expected. Systems operated as expected. Reactor vessel inventory and pressure are being maintained in normal control bands. This event is being reported pursuant to 10 CFR 50.72(b)(2)(iv)(B), any event or condition that results in actuation of the reactor protection system (RPS) when the reactor is critical. The NRC Resident Inspector has been notified. Decay heat is being removed using the steam bypass valves to the condenser and the safety relief valves did not lift as a result of the trip. |
| ENS 52370 | 16 November 2016 18:22:00 | At 1105 CST on Wednesday, November 16th, 2016, the Dresden Nuclear Power Station (DNPS) Technical Support Center (TSC) Emergency Ventilation System was emergently declared inoperable due to an unplanned loss of the pneumatic air supply compressor. The loss of the air compressor resulted in the emergency air filtration unit flow control damper failing to the full open position. In this condition, the emergency air filtration unit could exceed the max flow rate of 1100 SCFM and the max differential pressure of 6 inches H2O at rated flow rate resulting in degraded performance. This results in a potential loss of protective action function provided by the emergency ventilation filtration system and could impede the ability to perform Emergency Assessments should a radiological emergency event occur requiring the system to be in service. Actions are being taken to repair the pneumatic air system to restore functionality of the TSC ventilation system. In the interim, contingency actions are being developed to manually control the emergency air filtration unit flow control damper in a degraded condition. In the event that ventilation cannot be restored, Station Procedures provide guidance to relocate the TSC to an alternate facility. This event is being reported under 10 CFR 50.72(b)(3)(xiii), 'Any event that results in a major loss of emergency assessment capability, offsite response capability, or offsite communications capability (e.g., significant portion of control room indication, Emergency Notification System, or offsite notification system).' The licensee has notified the NRC Resident Inspector.
The pneumatic air supply compressor has been repaired and tested satisfactorily. The Technical Support Center is now considered operable. The licensee will be notifying the NRC Resident Inspector. Notified R3DO (Peterson). |