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| Start date | Reporting criterion | Title | Event description | System | LER | |
|---|---|---|---|---|---|---|
| ENS 51253 | 23 July 2015 06:15:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown | Initiation of Plant Shutdown Due to Rcs Leakage | On July 23, 2015 at 0115 (CDT), Callaway Plant initiated a shutdown required by Technical Specifications (TS). At 2139 (CDT) on July 22, 2015, TS 3.4.13 Condition A was entered due to unidentified RCS leakage being in excess of the 1 gpm TS limit. The leak was indicated by an increase in containment radiation readings, increasing sump levels, and decreasing levels in the Volume Control tank (VCT). A containment entry identified a steam plume; due to personnel safety the exact location of the leak inside the containment building could not be determined. At this time radiation levels inside (the) containment are stable and slightly above normal. There have been no releases from the plant above normal levels. The (NRC) Senior Resident Inspector was notified.
Callaway entered TS 3.4.13 Condition B at 0053 (CDT on July 23, 2015) for the subject leakage since reactor coolant pressure boundary leakage could not be ruled out by visual inspection. The estimated leak rate when the decision was made to shut down the plant was approximately 1.8 gpm. The plant entered Mode 3 at 0600 CDT. Additionally, at approximately 1315, it was determined that the duration of the required outage would be greater than three days, thus requiring notification to the Missouri Public Service Commission. This offsite notification is reportable to the NRC (per 10CFR50.72(b)(2)(xi)), and the above table has been updated to reflect this reporting requirement. The licensee notified the NRC Resident Inspector. Notified R4DO (Gepford).
Clarification to the initial event notification: the term 'RCS' used above means 'Reactor Coolant System.' Therefore the second sentence from the initial notification is clarified to read, 'At 2139 (CDT) on July 22, 2015, TS 3.4.13 Condition A was entered due to unidentified Reactor Coolant System (RCS) leakage being in excess of the 1 gallon per minute (gpm) TS limit.' The licensee notified the NRC Resident Inspector. Notified the R4DO (Gepford). | Reactor Coolant System | 05000483/LER-2015-004 05000483/LER-2015-001 05000483/LER-2015-002 Completion of a Shutdown Required by the Technical Specifications - TS 3.4.13 Manual Auxiliary Feedwater System Actuation Auxiliary Feedwater Control Valve Inoperable Due To Faulty Electronic Positioner Card |
| ENS 44863 | 19 February 2009 11:30:00 | 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown | Power Supply Failure Resulting in a Tech Spec Required Shutdown | The plant was operating in MODE 1 at 100% power. At 0228 on 2/19/09, a power supply to cabinet SA036D, Channel 1 of the Engineered Safety Features Actuation System (ESFAS) failed. As a result of the failure, both trains of control room ventilation isolation signal (CRVIS), containment purge isolation signal (CPIS), and fuel building isolation signal (FBIS) inadvertently actuated. The cause of the failure of SA036D is under investigation. Technical Specification (TS) Action 3.3.2.Q was entered which requires the plant to be in MODE 3 in 6 hours and MODE 4 in 12 hours. Load reduction began at 0530. MODE 2 was entered at 0750. MODE 3 was entered at 0817. All systems functioned properly. The NRC Resident Inspector has been notified. The licensee is replacing the entire power supply and will investigate the cause. | ||
| ENS 41781 | 17 June 2005 00:02:00 | 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown | Unit Commenced a Tech Spec Required Shutdown Due to an Electrical Problem Affecting a Safety Related Battery | At 1302 (CDT), 6/16/05, during investigation of an electrical ground affecting safety related battery NK04, a channel failure alarm actuated for SA075B, Main Steam and Feedwater Isolation Actuation control panel. Work at KJ122, 'B' Emergency Diesel Generator (EDG) local control panel, was suspended and troubleshooting efforts commenced to determine the cause of the SA075B alarm. Concurrently, SA075B was declared Inoperable at 1302 (CDT) and Engineered Safety Feature Actuation System Technical Specification Action statement 3.3.2.S was entered which allowed 6 hours to restore the train to Operable status, or be in Mode 3 within the following 6 hours. As of 1902 (CDT), all repairs and retests had not been completed. A reactor shutdown was commenced at 1902 (CDT) in accordance with Technical Specification 3.3.2.S, which is reportable per 10CFR50.72(b)(2)(i). The licensee is continuing their investigation to identify cause of the electrical ground but does not anticipate exiting the LCO Action Statement before completing the Unit shutdown. Safety related battery NK04 is currently operable with the faulted loads isolated. The "B" EDG remains Inoperable at this time for troubleshooting. The licensee informed the NRC Resident Inspector. | Feedwater Emergency Diesel Generator Main Steam | |
| ENS 41527 | 26 March 2005 09:00:00 | 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown | Technical Specification Required Shutdown Due to Inoperable Esw Train. | The following information was faxed by the licensee: At 0300, 3/23/05, 72-hour Technical Specification Action 3.7.8.A was entered when a pinhole leak was discovered in 'B' Essential Service Water (ESW). Subsequent ultrasonic testing (UT) determined that approximately seven linear feet of piping in the 'B' ESW train was affected and required replacement. UT testing was satisfactorily performed on the 'A' ESW train to ensure a similar problem did not exist. 'B' ESW train piping replacement was performed in accordance with planned work documents, however at 2100, 3/25/05 all necessary repairs and retests had not been completed. Although only 66 hours had expired since entering 72-hour Technical Specification Action 3.7.8.A, Callaway Plant proactively decided to commence a reactor plant shutdown in accordance with Technical Specification Action 3.7.8.B for an inoperable 'B' Essential Service Water train. Once entered, Technical Specification Action 3.7.8.B requires the reactor plant to be in Mode 3 within 6 hours and Mode 5 within 36 hours. The Licensee notified the NRC resident inspector." The licensee will perform other maintenance activities during this outage. All systems functioned as required.
The licensee completed repairs on the B ESW system and exited the LCO at 0249 on 03/27/05. Notified R4DO (Pick). | Service water | 05000483/LER-2005-002 |
| ENS 40263 | 21 October 2003 06:00:00 | 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown | Plant Shutdown Required by Technical Specifications | Due to failure of an instrument power inverter (NN11) which supplies vital 120Vac bus NN01, Callaway Plant entered L.C.O. 3.8.7, Electrical Power Systems, Inverters - Operating, Condition A at 0721 on October 20, 2003. The inverter supplying the bus is required to meet the LCO. Since the initiation of the inverter failure, the vital instrument bus has been energized from alternate power supply transformers in accordance with plant design and procedures. It is not an acceptable alternative to meet the LCO OPERABILITY requirement. Details of the impact on the plant due to this failure are detailed in Corrective Actions Program Report (C.A.R.) 200307636. In summary, the bus voltage was lost momentarily, then restored by operation of the inverter static transfer switch. The failure and subsequent restoration of power to AC Vital Bus caused some control systems responses that were corrected by the control room staff. After the event was stabilized, power remained at 100%. The LCO Action is to restore the inverter to OPERABLE status within twenty four (24) hours, otherwise be in MODE 3 in 6 hours AND be in Mode 5 in thirty six (36) hours. The twenty four hour period ends at 0721 October 21, 2003. In advance of the action time, a controlled plant shutdown to Mode Three (3) was commenced at 0100 on October 21, 2003 at a rate of ten (10) percent per hour. At the time of this report, maintenance efforts have determined that the problem is internal to the inverter Static Transfer Switch, therefore the reduction of power will continue. No safety system actuations resulted from the control power transfer. The licensee has notified the NRC Resident Inspector. | 05000483/LER-2003-009 |