Semantic search
| Entered date | Event description | |
|---|---|---|
| ENS 51429 | 28 September 2015 21:54:00 | At approximately 1327 CDT on September 28, 2015, both D1 and D2 Diesel Generators (EDG) were inoperable simultaneously until corrected at 1345 CDT. The D2 Diesel Generator had been declared inoperable for the planned performance of SP1307, D2 Diesel Generator 6 Month Fast Start Test. Tech Spec LCO 3.8.1 Condition B had been entered for D2 Diesel Generator. Subsequently, D1 Diesel Generator was determined to be inoperable but available due to Train A Cooling Water Header being inoperable during post maintenance testing of SV-33133, Backwash Water Supply to the 121 Safeguards Traveling Screen. Tech Spec LCO 3.7.8 Condition B was entered for the Cooling Water Header inoperability, which forced a cascade to Tech Spec 3.8.1 Condition B for D1 Diesel Generator. With both Emergency Diesel Generators inoperable, Tech Spec 3.8.1 Condition E was entered, which required the restoration of one Emergency Diesel Generator to operable status within 2 hours. D2 was returned to operable status through completion of SP 1307, and Tech Spec 3.8.1 Condition E was exited at 1345 CDT. With both Emergency Diesel Generators inoperable, this condition is reportable under 10 CFR 50.72 (b)(3)(v)(D), Event or Condition that Could Have Prevented Fulfillment of a Safety Function. The plant remains safe, and this condition does not pose any additional risk to the public. Additionally, our defense in depth strategies are relied upon to take actions to protect the health and safety of the public. D2 Diesel Generator remained available with full cooling water flow during this time. The safety significance of this event is low, as engineering hydraulic analysis has demonstrated that with the safeguards traveling screen backwash water supply valve fully opened, the Cooling Water System would have continued to provide full cooling flow to the D1 Diesel Generator. The licensee has notified the NRC Resident Inspector.
An evaluation has been performed and it has been determined that SV-33133 and SV-33134 do not have an active close safety function. The Cooling Water System analysis of record, calculation ENG-ME-820, Rev 0B shows that the Cooling Water System continues to have flow margin with screen wash control valves SV-33133 and SV-33134 open. Therefore, there is no need for the valves to close to ensure the Cooling Water System's safety function. Because the valves do not have a safety function to close, this event was not an event or condition which could have prevented the fulfillment of a safety function of an SSC (structures, systems and components) required to mitigate the consequences of an accident and, therefore, did not require an 8 hour notification in accordance with 10 CFR 50.72(b)(3)(v)(D) for an event or condition that could have prevented fulfillment of a safety function (i.e., accident mitigation) under 10 CFR 50.72(b)(3)(v)(D). The notification is hereby retracted. The licensee has notified the NRC Resident Inspector." Notified R3DO (Orlikowski). |
| ENS 50672 | 12 December 2014 11:34:00 | At 0248 CST on December 12, 2014, 2R-30, Auxiliary Building Normal Vent Radiation Monitor, failed. This monitor was the redundant monitor for 2R-37, Auxiliary Building Normal Vent Radiation Monitor, which was previously taken out of service for planned maintenance. With 2R-30 and 2R-37 out of service, there are no monitors that will allow for timely classification of two Emergency Action Levels (EALS) - NUE (Notification of Unusual Event) and Alert Classifications. This results in a loss of emergency assessment capability while 2R-30 and 2R-37 are out of service. This is a reportable condition in accordance with 10CFR50.72(b)(3)(xiii). The Auxiliary Building ventilation effluent monitor readings were normal and there were no elevated readings in Auxiliary Building area monitors prior to the unavailability of these monitors. The health and safety of the public was not affected by this issue. The activity to repair and return one of the monitors to service is continuous until restored. The licensee has notified the NRC Resident Inspector. |
| ENS 50702 | 23 December 2014 13:00:00 | This 60-day telephone notification is being made under reporting requirements specified by 10 CFR 50.73(a)(2)(iv)(A) and 10 CFR 50.73(a)(1) to describe an invalid actuation of the Unit 1 11 RHR Pump while Unit 1 was at NO MODE. It was a complete actuation. This was not the result of a preplanned sequence during testing and the system was not removed from service. At 0340 CDT on October 26, 2014, the Unit 1 11 RHR Pump was noted to have started while investigating an NSSS (nuclear steam supply system) annunciator system ground. The operator verified that the pump had adequate suction path via the RCS Cold Leg and stable pump discharge pressure. The 11 RHR Pump was stopped per the plant's abnormal operating procedure. Evaluation of this event has shown that the auto-start of 11 RHR pump was due to a human performance error while performing relay replacements. Following troubleshooting of the auto-start and completion of the relay maintenance, the 11 RHR pump was run; the pump and system operated properly. The health and safety of the public was not affected by this issue. The licensee has notified the NRC Resident Inspector. |
| ENS 50446 | 11 September 2014 11:32:00 | At 1009 CDT on September 11, 2014, 1R-22 Shield Building Vent Gas Radiation Monitor was removed from service for planned maintenance. This monitor has no compensatory measure that will allow timely classification of two Emergency Action Levels (EALs) - NUE (Notification of Unusual Event) and Alert classifications when out of service. It is also used for offsite dose projection calculations. This results in a Loss of Emergency Assessment Capability while 1R-22 is out of service. This is a reportable condition in accordance with 10 CFR 50.72(b)(3)(xiii). Unit 1 Shield Building Ventilation Stack is also monitored by high range monitor, 1R-50, which is used for the same purpose in Site Area or General Emergency classifications. 1R-50 is being monitored and is indicating normal values. There are no radioactive leaks that will impact the Shield Building as evidenced by normal readings on 1R-22 prior to its removal from service. The duration of this maintenance is scheduled for 8 hours and will continue until the monitor is returned to service. Maintenance will not result in the unplanned release of radioactivity to the environment and will not affect the safe operation of the plant or health and safety of the public. The licensee has notified the NRC Resident Inspector. |
| ENS 49259 | 9 August 2013 17:01:00 | During the performance of SP (Surveillance Procedure) 1027.2A, NMC Radiation Monitor Train A Calibration, Radiation Monitor R-21, Circulating Water Discharge Radiation Detector failed the source test point three times and was removed from service. R-21 has an emergency response function to provide indication of gaseous or liquid effluent release to the environment. This monitor has no compensatory measure that will allow timely classification of two NUE (Notification of Unusual Event) and Alert classifications when out of service. This is a priority 1 activity to repair the monitor. The repair activity is continuous and is in progress. There are not radioactive leaks that impact the Circulating Water System. The NRC Resident Inspector was notified. |
| ENS 48464 | 31 October 2012 15:41:00 | The licensee declared an Unusual Event based upon a security condition at the site. Compensatory measures are being put in place. Contact the Headquarters Operations Officer for additional details. The NRC Resident Inspector has been notified. Notified DHS SWO, FEMA, DHS NICC and NuclearSSA via email.
The licensee terminated the NOUE at 1754 CDT. Notified NRR EO (Nieh), IRD (Morris), and R3DO (Kozak), DHS SWO, FEMA, DHS NICC and NuclearSSA via email. |
| ENS 47569 | 5 January 2012 05:18:00 | A section of piping between sodium hypochlorite tanks(tanks 121 and 122) broke and resulted in a unisolable leak in one of the tanks. The spill was contained within the berm of the chlorine house. The spill resulted in airborne concentrations exceeding Immediately Dangerous to Life and Health (IDLH) conditions in the chlorine house, which is contiguous to the plant screen house. Alert declared based upon HA3.1 - Report or detection of toxic gases within or contiguous to Table H-1 areas in concentrations that may result in an atmosphere Immediately Dangerous to Life and Health (IDLH). The licensee will remain in the Alert until IDLH conditions have been terminated. An offsite HAZMAT team has been notified and is expected to be on-site today at 0630 CST to clean up the spill. The licensee will notify the Resident Inspectors.
The licensee reports that the HAZMAT contractor has arrived on-site. Licensee personnel are preparing a clearance for the sodium hypochlorite system in order to support HAZMAT contractor work. The licensee will notify the NRC Resident Inspector. Notified the R3DO (Valos)
The Alert declaration due to HA3.1, Report or detection of toxic gases within or contiguous to Table H-1 areas in concentrations that may result in an atmosphere Immediately Dangerous to Life and Health (IDHL): Prairie Island terminated from the Alert declaration at 1408 CST on Jan 5, 2012. The following additional conditions were established prior to termination: 1. The permanent berm containing the sodium hypochlorite released by 121 Sodium Hypochlorite Tank piping break was pumped down. 2. Clean-up and remediation of the affected area is in progress. 3. Inspection of the unaffected sodium hypochlorite tank piping has been conducted to ensure satisfactory integrity. NRC Resident has been informed. Notified NRR EO (Ruland), R3DO (Valos), IRD (Morris), DHS (Beach), FEMA (Blankenship), DOE (Jackson), USDA (Timmons), and HHS (Fajardo). |
| ENS 47122 | 3 August 2011 16:58:00 | A non-licensed supervisor tested positive for alcohol during a random fitness-for-duty test. The employee's access to the facility has been suspended. Contact the Headquarters Operations Officer for further details. NRC Resident has been informed. |
| ENS 47010 | 1 July 2011 15:06:00 | At 1344 CDT on June 27, 2011, off-site A.C. power sources to Unit 2 were declared inoperable as a result of Transformer 2RY lockout and less than the required minimum voltage on the transmission system. At 1310 CDT on June 27, 2011, Transformer 2RY was locked out. The Transformer 2RY lockout resulted in entering Technical Specification 3.8.1, Condition A and a single path to the transmission system. At 1344 CDT, the site was notified by transmission systems operations that the 345 KV grid voltage could not be maintained at the minimum voltage required per procedure C20.3. The path to the transmission system was declared inoperable and Unit 2 entered Technical Specification 3.8.1, Condition C. Although inoperable, transmission system sources remained connected to Unit 2; emergency diesel generators were available but not required to run. By securing a cooling tower pump and fans, the required minimum transmission system voltage was met and determined to be sustainable. Technical Specification 3.8.1, Condition C, was exited on June 28, 2011 at 0038 CDT. After additional analysis, it was determined that this condition was a safety system function failure for Unit 2 and reportable under 10 CFR 50.72(b)(3(v)(D). This condition should have been reported on June 27, 2011 under the eight-hour reporting criteria. The NRC Resident Inspector has been informed. |
| ENS 43859 | 21 December 2007 07:14:00 | This notification is being made to report a Technical Specification required shutdown due to Prairie Island Nuclear Generating Plant (PINGP) Train B Unit 1 emergency diesel generator (D2) being out of service for maintenance and Prairie Island Nuclear Generating Plant (PINGP) Train A Unit 1 emergency diesel generator (D1) being declared inoperable as a result of the Bus 15 load sequencer failure. On 12/20/07, at approximately 2355 hours (CST), with PINGP Unit 1 in MODE 1, D2 out of service for maintenance activities, SP 1306, D2 Diesel Generator Relay Functional Test, was being performed. This surveillance test requires the performance of SP 1094; Bus 15 Load Sequencer Test which failed during the test. This resulted in the Bus 15 Load Sequencer being declared inoperable per T.S. 3.3.4 and D1 Diesel Generator being declared inoperable. With D2 and D1 EDG's inoperable entered TS 3.8.1.F which requires Unit 1 to be in Mode 3 within 6 hours. Unit 1 shutdown commenced at 0413. Corrective actions for this event are in progress and are being tracked via the corrective action program. The NRC Resident Inspector was notified of this event by the licensee. |