Semantic search
| Entered date | Event description | |
|---|---|---|
| ENS 51308 | 11 August 2015 05:19:00 | Reactor trip caused by turbine trip. Turbine tripped immediately following the trip of one of four 345KV offsite lines. The reason for protective relaying not preventing the grid disturbance from tripping the turbine generator is not known at this time. All normal offsite and onsite power sources are available. Auxiliary Feedwater actuated as expected on low steam generator level following the trip from 100% power. All systems functioned as expected in response to the trip. The NRC Senior Resident Inspector has been notified. An electrical fault on a 345 kV line 2 miles from the site caused the bus to strip and reclose, which cleared the fault. All control rods fully inserted and the plant is in its normal shutdown electrical lineup. |
| ENS 45989 | 8 June 2010 19:57:00 | At approximately 0430 CDT on June 8, 2010, during restoration following an addition of 10 gallons of hydrazine and a flush of 2 gallons of demineralized water to the Condensate Storage Tank (CST), a water-hydrazine mixture began to leak from check valve KHV0179. KHV0179 is a nitrogen supply check valve that can also be used for hydrazine addition. Chemistry technicians estimated that a water-hydrazine mixture on the order of 2 gallons leaked through KHV0179 before the line could be isolated. Samples taken from the atmosphere above the spill contained 0.25 ppm hydrazine. The fluid on the ground was measured to contain 15% hydrazine. The Department of Natural Resources (DNR) was notified of this event at approximately 1000 CDT on June 8, 2010. The Nuclear Regulatory Commission (NRC) Resident Inspectors will be notified. |
| ENS 43240 | 14 March 2007 22:22:00 | A pinhole leak was discovered on B train Essential Service Water (ESW) system piping while preparing the pipe surface for non-destructive examination. Control room personnel were notified of the leak at 1435. B ESW was immediately declared inoperable. At the time of control room notification, surveillance testing on the Turbine Driven Auxiliary Feedwater Pump (TDAFP) was in progress. This surveillance testing made the TDAFP inoperable and non-functional. The surveillance activities were terminated and the TDAFP was returned to operable status at 1438. B ESW is the safety related water source for B train of auxiliary feedwater (AFW). For the three minute period between notification of the pinhole leak until the TDAFP was restored to operable status, there were two auxiliary feed pumps inoperable. This met the conditions for entry into T/S LCO Action 3.7.5.D which requires a plant shut down to Hot Standby within 6 hours. This action was exited when the TDAFP surveillance testing was terminated. Additionally, with 2 of 3 auxiliary feedwater pumps non-functional for 3 minutes, there was a condition which could have prevented fulfillment of a safety function for those 3 minutes. The licensee notified the NRC Resident Inspector.
The licensee provided the following information as the basis for retracting this report: On March 14, 2007, (Event Number 43240) Callaway Plant reported a condition that, at the time, was believed to be a condition which could have prevented fulfillment of a safety function. At that time the 'A' motor driven auxiliary feedwater pump (MDAPP) was operable, the turbine driven auxiliary feedwater pump was not functional because of a surveillance test in progress. The 'B' MDAFP was presumed to be non-functional because of a pinhole leak in the 'B' train essential service water (ESW) system piping. 'B' ESW is the safety related water source for the 'B' MDAFP. Subsequent inspection, non-destructive examination, analysis and evaluation of the 'B' train ESW piping determined that the structural integrity of the pipe was retained. 'B' ESW pump was able to provide the required flow to the train. 'B' train ESW was functional with the pinhole leak. With the 'B' ESW train functional, the 'B' train of auxiliary feedwater had its emergency water source. The auxiliary feedwater system would have been able to fulfill its safety function. This event is not reportable per 10CFR50.72(b)(3)(v). The licensee will inform the NRC Resident Inspector. Notified R4DO (O'Keefe). |
| ENS 42852 | 21 September 2006 12:20:00 | On 9/08/2006 at 1015 during painting activities in a safety-related area the Methanol Short Term Exposure Limit was exceeded. In accordance with Callaway Plant procedures the location was determined to contain a Hazardous ATMOSPHERE. Subsequently, Callaway Plant Emergency Action Levels (EAL) were reviewed and it was determined that the event did not meet the EAL criteria for Callaway Plant EAL 3J related to release of flammable or toxic gases in a safety - related area. On 9/21/2006 following a debrief that was conducted by Region IV NRC personnel, it was determined at 1025 that an inappropriate change to the intent of EAL 3J was made in 1997. As a result of this discussion, it was determined that an Alert should have been declared in accordance with plant EAL 3J. Per guidance given in NUREG 1022, Revision 2, Section 3.1.1. "Immediate Notifications", an ENS notification is being made within one hour of discovery of the event. No actual declaration of the emergency class will be made since the event has been concluded and the basis for the emergency no longer exists. The NRC Resident Inspector has been notified." Licensee also notified State, Local Officials and other government agencies. |