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| Entered date | Event description | |
|---|---|---|
| ENS 51440 | 2 October 2015 14:50:00 | On October 2nd, at approximately 0825 EDT, maintenance technicians were performing as-found torque checks on the discharge flange of the 'B' Safety Relief Valve (SRV). 12 of the 16 bolts were not adequately torqued. The 'B' Safety Relief Valve is credited for Remote Shutdown. The as-found condition of inadequate torque potentially impacts the seismic qualification of the 'B' SRV. An investigation and extent of condition review is ongoing. The NRC Resident Inspector has been notified. Before the outage, there were no abnormal indications of leakage as indicated by a rise in drywell temperature or pressure. The SRVs had been cycled under pressure with no abnormal indications. The four bolts that were tight were in a diagonal pattern. The looses bolts were described as "finger tight." The licensee is determining the actions to take regarding the remaining 14 SRVs.
As part of the event investigation and extent of condition review, the as-found torque values of the inlet and outlet Safety Relief Valve (SRV) flange connections were measured and an engineering evaluation of the as-found condition was performed. The evaluation confirmed that all 15 SRVs would have remained operable during a design basis earthquake. Any potential discharge flange connection leakage during SRV operation would be bounded by the design basis Loss of Coolant Accident analysis described in the UFSAR. Subsequent investigation activities of the as-found condition of SRV 'B' determined that the four tight bolts were not oriented in a diagonal pattern across the discharge flange as originally reported. This information is provided only to clarify previously reported information and does not affect the original basis for reporting or the current basis for retraction. The licensee notified the NRC Resident Inspector. Notified R3DO (McCraw). |
| ENS 51391 | 14 September 2015 02:46:00 | At 2305 EDT on September 13, 2015, a manual scram was initiated in response to a loss of all Turbine Building Closed Cooling Water (TBCCW). All control rods fully inserted. The lowest Reactor Water Level (RWL) reached was 137 inches. All isolations and actuations for RWL 3 occurred as expected. Decay heat was initially being removed through the Main Turbine Bypass System to the Main Condenser, however, as a result of the loss of TBCCW, the Main Feed Pumps lost cooling and had to be secured. At 2310, Standby Feedwater was initiated and Main Feedwater was secured. The loss of TBCCW also caused all Station Air Compressors (SACs) to trip on loss of cooling. The loss of SACs caused the Instrument Air header pressure to degrade to the point at which the Secondary Containment isolation dampers drifted closed. This resulted in the Reactor Building vacuum exceeding the Technical Specification limit. At 2325, operators started the Standby Gas Treatment system and manually initiated a Secondary Containment isolation signal. Secondary Containment vacuum was promptly restored to within Technical Specification limits. Additionally, Operators were monitoring for expected MSIV drift due to the degraded Instrument Air header pressure. When outboard MSIVs were observed to be drifting, Operators closed the outboard and inboard MSIVs at 2345. At 2352, Safety Relief Valves (SRVs) reached the Low-Low Setpoint and began cycling to control reactor pressure. RWL is currently being maintained in the normal level band with the Standby Feedwater and Control Rod Drive systems. Reactor Pressure is being controlled with Safety Relief Valves. Operators are currently in the Emergency Operating Procedure for Reactor Pressure Vessel control. Investigation into the loss of TBCCW continues. No safety-related equipment was out of service at the time of the event. All offsite power sources were adequate and available throughout the duration of the event. The NRC resident inspector has been notified.
At 0409 EDT the Reactor Core Isolation Cooling (RCIC) system was placed in service due to identification of an unisolable leak in the Standby Feedwater System. Reactor water level and pressure is now being controlled though the RCIC system and Safety Relief Valves. This event update is reportable as a valid manual initiation of a specified safety system under 10CFR50.72(b)(3)(iv)(A). The NRC resident inspector has been notified. The leak rate was reported as approximately 5-10 gallons per minute from a weld on the standby feedwater pump header drain valve F326. The licensee reported the leak stopped once RCIC was placed into service. The licensee is still investigating the issue. Notified the R3DO (Pelke), IRD Manager (Grant), NRR EO (Morris).
At 1847 EDT on September 14, 2015, a valid automatic Reactor Protection System (RPS) actuation occurred due to Reactor Water Level 3 while shutdown in MODE 3. Operators were manually controlling Reactor Pressure Vessel (RPV) level and pressure with Reactor Core Isolation Cooling (RCIC) and Safety Relief Valves (SRV). While operators were cycling SRVs, the RPV level went below the Level 3 setpoint. Operators promptly restored RPV level by manual operation of RCIC. The Level 3 actuation and associated isolations were verified to operate properly. The scram signal has been reset. Fermi 2 remains in MODE 3 controlling RPV Level and Pressure through manual operation of RCIC and SRVs. This is the second occurrence of a valid specified safety system actuation reportable under 10CFR50.72(b)(3)(iv)(A) for this ongoing event. The NRC Resident Inspector has been notified. Notified R3DO (Riemer), IRD Manager (Grant), and NRR EO (Morris)
This update provides clarification of the applicable reporting criteria for this Event associated with primary containment isolation actuations. Upon the manual reactor scram at 2305 EDT on September 13, 2015, Reactor Protection System (RPS) Level 3 actuated and Primary Containment Isolation System (PCIS) Groups 4, 13 and 15 actuated as expected. The applicable reporting criterion for these actuations is 10 CFR 50.72(b)(3)(iv)(A). The applicable reporting criterion for the manual closure of the inboard and outboard main steam isolation valves at 2345 EDT on September 13, 2015, is also 10 CFR 50.72(b)(3)(iv)(A). In addition, the manual closures of all MSIV lead to a loss of condenser vacuum which resulted in the actuation of PCIS Group 1 at 0001 EDT on September 14, 2015, as expected. The applicable reporting criterion for this actuation is also 10 CFR 50.72(b)(3)(iv)(A). Upon reaching Level 3 at 1847 EDT on September 14, 2015, PCIS Groups 4, 13 and 15 actuated as expected. The applicable reporting criterion for this actuation is 10 CFR 50.72(b)(3)(iv)(A). The licensee informed the NRC Resident Inspector. Notified the R3DO (Stone). |
| ENS 51202 | 7 July 2015 16:07:00 | On 7/7/2015 at approximately 1435 EDT, the Technical Specification for Secondary Containment Pressure Boundary was not met when vacuum could not be maintained greater than or equal to -0.125 inches of water gauge for approximately 41 seconds. As part of post-maintenance testing for the non-safety related Reactor Building HVAC Center Exhaust Fan, the fan was started while the safety-related Standby Gas Treatment system was also in operation. Shortly after the fan was started, operators observed degrading vacuum in secondary containment and subsequently secured the center exhaust and supply fans. Vacuum continued to degrade momentarily after the fans were secured, and then returned to a Technical Specification allowable value. Subsequent inspections discovered that the affected fan was operating in the reverse direction. This is believed to have caused Secondary Containment pressure to increase. Since vacuum could not be maintained with the safety-related Standby Gas Treatment system operating, the plant operated in an unanalyzed condition. The cause of the reverse rotation is under investigation. There were no radiological releases associated with this event. The NRC Senior Resident Inspector has been notified.
Based on plant configuration at the time of the event and further review of the Fermi 2 UFSAR, the plant did not operate in an unanalyzed condition. The Reactor Building HVAC fans would have tripped, as designed, upon receipt of a safety-related Standby Gas Treatment actuation signal during the time of the event. Therefore, the fans' pressurizing effect on secondary containment would have ceased within the time limits assumed in the existing accident analysis. The reporting criteria of 10CFR50.72(b)(3)(v)(C) remains valid. The licensee notified the NRC Resident Inspector. Notified the R3DO (Stone). |
| ENS 51186 | 27 June 2015 13:19:00 | On 6/27/2015 at 1100 EDT, a spill to the environment was determined to be reportable to the state environmental and local health agencies. A press release is planned. The spill occurred when a portable chemical toilet tipped over and was identified at approximately 0925 EDT. The contents and exact quantity of the spill are unknown, but the toilet has a capacity of 60 gallons. The spill flowed to nearby gravel and two storm drains; one of which discharges to navigable state waters. Rainfall was present when the spill was identified. Cleanup efforts are in progress. The NRC Senior Resident Inspector has been notified. |
| ENS 49030 | 14 May 2013 18:22:00 | A licensed operator had a confirmed positive for alcohol during a for cause fitness-for-duty test. The employee's access to the plant has been terminated. The licensee notified the NRC Resident Inspector. |
| ENS 48973 | 26 April 2013 12:25:00 | A licensed operator had a confirmed positive test for illegal drugs during a random fitness-for-duty test. The licensed operator's plant access has been terminated. The licensee notified the NRC Resident Inspector |