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| Start date | Reporting criterion | Title | Event description | System | LER | |
|---|---|---|---|---|---|---|
| ENS 49759 | 22 January 2014 18:15:00 | 10 CFR 70.50(b)(2) | Inoperable Criticality Warning System Local Alarm in Wilmington Field Services Center Building Number 1 | On 1/22/14 at 1:15 PM (EST), it was discovered during routine testing on an outdoor Criticality Warning System (CWS) Data Acquisition Module (DAM #21), that the module had inadequate voltage to properly sound a portion of the local alarm horns in the Wilmington Field Services Center (WFSC) building #1. While another module provides overlapping detector coverage, it does not provide overlapping horn audibility in the affected areas. The cause of the event is believed to be related to a battery component failure. Personnel were immediately removed from the affected areas and repairs initiated to restore normal operation of the system. The module was repaired and the system returned to normal on 1/22/14 at approximately 3:00 PM. The affected outdoor CWS horns were retested to ensure proper system operability. There are no active fissile material operations at the WFSC, thus no unsafe condition existed. Longer term preventive actions are being evaluated. This event is being reported pursuant to the requirements of 10CFR70.50 (b)(2). The licensee will be notifying NRC NMSS Licensing Project Manager, NRC Region II Inspection Coordinator, State of North Carolina Radiation Protection Branch, and the New Hanover Emergency Response Branch. | ||
| ENS 48100 | 11 July 2012 21:40:00 | 10 CFR 70.50(b)(2) | Criticality Horns Rendered Inoperable Due to Lightning Strike | At approximately 1740 EDT on 7/11/12, lightning strikes near the Wilmington Field Service Center (WFSC) rendered several alarm annunciators (horns) of the Criticality Accident Alarm System (CAAS) inoperable. There are no active fissile material operations in WFSC, thus no unsafe condition existed. Until the system is repaired, personnel have either been removed from the affected area or other compensatory measures have been established. Longer term preventative actions are being evaluated. This event is being reported pursuant to the requirements of 10CFR70.50(b)(2). The licensee will notify NRC R2 (Thomas), and the State and Hanover County Emergency Management Agencies. | ||
| ENS 47851 | 18 April 2012 17:45:00 | 10 CFR 70.50(b)(2) | Local Alarm Horn Was Found to Be Inaudible During Routine Testing | At approximately 1345 EDT on 4/18/12, during routine testing on an outdoor Criticality Accident Alarm System (CAAS) Data Acquisition Module (DAM #22), the local alarm horn in the Wilmington Field Services Center (WFSC) building #3 inspection records area was found to be inaudible. The cause and extent of the condition is under investigation. Personnel were removed from the inspection records area until compensatory measures were established. There are no active fissile material operations impacted by this discovery, thus no unsafe condition existed. This event is being reported pursuant to the requirements of 10CFR70.50 (b)(2). The licensee notified the NC Division of Radiation Protection and the New Hanover County Emergency Response Center.
Upon further review, GNF-A has determined that the reported condition (EN 47851) was not required to be reported by the plain letter of the regulation (10 CFR 70.50(b)(2)) and the filing of the report was inconsistent with industry practice. As such, this report is being retracted. GNF-A has entered the condition identified in the course of the monthly tests (i.e., areas where audibility of the CAAS should be enhanced) into its corrective action program and is addressing them accordingly. The licensee will notify NRC Region II (Thomas). Notified R2DO (Shaeffer) and NMSS (Stablein). | ||
| ENS 47724 | 7 March 2012 18:15:00 | 10 CFR 70.50(b)(2) | Local Alarm Horn Was Found to Be Inaudible During Routine Testing | At approximately 1315 EST on 3/7/12, it was discovered during routine testing on an outdoor Criticality Accident Alarm System (CAAS) Data Acquisition Module (DAM #21), that the local alarm horn in the Wilmington Field Services Center (WFSC) building #1 in-vessel tooling refurbishment area was inaudible. The cause of the condition is under investigation. Personnel were removed from the in-vessel tooling refurbishment area until compensatory measures were established. There are not active fissile material operations impacted by this discovery, thus no unsafe condition existed. The licensee notified the NC Division of Radiation Protection and New Hanover County. | ||
| ENS 47220 | 29 August 2011 17:00:00 | 10 CFR 70.50(b)(2) | Criticality Accident Alarm System Horn Discovered Inoperable | On 8/29/11, it was discovered during troubleshooting on an outdoor Criticality Accident Alarm System (CAAS) Data Acquisition Module (DAM #21), that the module had inadequate voltage to properly sound its local alarm horn. The module has been repaired and the system was returned to normal on 8/29/2011. An investigation into the cause of the failure has been initiated. There are indications that the apparent cause of the failure is an AC to DC converter that had a component short circuit. There were no active fissile material operations impacted by this failure. Consequently, no unsafe condition existed. This event is being reported pursuant to the requirements of 10CFR70.50 (b)(2). The licensee stated that the system had been tested satisfactorily within the last month. The licensee will notify state and local authorities. The licensee also plans to notify NRC Region 2 (Sykes). | ||
| ENS 47061 | 14 July 2011 20:55:00 | 10 CFR 70.50(b)(2) | Inoperable Criticality Accident Alarm System Warning Horns | As part of the corrective actions for the event reported on 7/13/11 (EN #47047), GNF-A performed a Criticality Accident Alarm System (CAAS) audibility test covering the Controlled Access Area (CAA) at approximately 1655 on 7/14/11. The subsequent test revealed that the installed CAAS system failed to immediately activate the horn signal generators as expected. Activation of the associated warning horns was delayed approximately 3 minutes. This response time to activate horns did not meet the design requirement. Additionally, a review determined an approximately 3 minute horn signal delay was noted in a previous test on 7/12/11. An investigation into these matters is ongoing. The FMO (Fuel Manufacturing Operations) complex fissile material process operations were suspended on 7/14/11 and personnel evacuated. The emergency organization was activated and efforts to troubleshoot the root cause in the horn signal activation circuit delay initiated. All production activities involving Special Nuclear Material are shut down. The installed CAAS is a safety-significant system and is maintained through routine response checks and scheduled functional tests conducted in accordance with internal procedures. These events are being reported pursuant to the requirements of 10CFR70.50(b)(2). The licensee notified NRC Region 2 personnel (Sykes), State of North Carolina Radiation Protection, and New Hanover County EMA.
The cause of the inoperable Criticality Accident Alarm System (CAAS) has been identified as a hardware failure - specifically a capacitor on a circuit board. The CAAS has been repaired and a comprehensive testing plan is under development. The licensee continues to withhold personnel from the Controlled Access Area and all production activities remain shut down. A root cause analysis and recovery plan are underway. The licensee has contacted R2 (Sykes) and will be notifying state and local authorities. R2DO (Freeman notified). See related Events #47047 and #47066. | ||
| ENS 47047 | 12 July 2011 21:30:00 | 10 CFR 70.50(b)(2) | Inaudible Criticality Warning Siren | At approximately 1730 on 7/12/2011, a regularly scheduled test of the inside Criticality Warning System (CWS) covering the Fuel Manufacturing Operation (FMO) was conducted. It was discovered that a CWS warning horn in the ChemMet lab was determined to be inaudible. Compensatory measures were immediately implemented. All other horns of the inside CWS in all other areas were functional and clearly audible. The affected area will remain shut down pending an investigation and implementation of additional corrective actions. The event is being reported within 24�hours pursuant to 10CFR70.50(b)(2) as a safety equipment failure. A CWS warning horn in the ChemMet lab was determined to be inaudible. All other CWS warning horns operating correctly. Investigation results pending. Affected area access was restricted. The faulty CWS horn has been replaced and tested. The licensee notified Region 2(Coovert) and will notify the state radiation protection agency and New Hanover Emergency Management. | ||
| ENS 47066 | 1 May 2011 16:00:00 | 10 CFR 70.50(b)(2) | Previous Inoperability of Criticality Accident Alarm System Warning Circuit Not Identified | As part of the corrective actions for the Criticality Accident Alarm System (CAAS) events reported on 7/13/11 (EN #47047) and 7/15/11 (EN #47061), GNF-A is performing an investigation into the cause of the delayed audible alarm actuation. The investigation has determined that this delay existed at the time of the May and June 2011 functional tests and was not adequately identified and thus not reported. The response time to activate the horns did not meet the design requirement for CAAS. These events are being reported pursuant to the requirements of 10CFR70.50 (b)(2). The licensee states that the delay in the alarm actuation existed during surveillance testing in May and June of 2011 but the delay was not recognized at the time. This condition rendered the system inoperable since May 2011. The licensee has notified R2 (Sykes) and will notify state and local authorities. R2DO (Freeman) notified. | ||
| ENS 44724 | 16 December 2008 11:00:00 | 10 CFR 70.50(b)(2) | Criticality Warning System Disabled | At approximately 0600 on 12/16/2008, the horns of the inside Criticality Warning System (CWS) covering the Fuel Manufacturing Operation (FMO) were discovered to be in manual mode. On 12/12/08 at approximately 0700, the horns had been taken out of automatic mode and placed in manual mode as part of system maintenance activities at 0700 and inadvertently remained in this condition until this morning at 0600. According to a preliminary investigation, it appears that following maintenance on 12/12/08, incomplete system restoration left the automatic horn function disabled but the detection system remained operational. Once identified, the system was immediately restored to the automatic mode and the inside FMO CWS system was returned to normal operation. Follow-up tests have confirmed that the warning system horns are fully operational. The event is being reported within 24-hours pursuant to 10CFR70.50(b)(2) as an event in which safety equipment was disabled. During the time that the warning system was disabled, there were no conditions that would have resulted in warning system activation. Corrective actions have been taken to prevent re-occurrence. The licensee will be notifying NRC Region 2 as well as State and local governments. | ||
| ENS 43267 | 30 March 2007 11:40:00 | 10 CFR 70.50(b)(2) | Criticality Warning System Alarm Actuation Due to Power Fluctuation | At approximately 0740 on 3/30/2007, a segment of the inside Criticality Warning System (CWS) covering the Fuel Manufacturing Operation (FMO) failed due to an apparent voltage fluctuation in the power supply to the system. The fluctuation resulted in activation of the CWS evacuation alarm. All personnel promptly evacuated the facility and the emergency organization assembled in accordance with normal procedures. A total of 5 out of 6 FMO CWS Data Acquisition Modules (DAMS) were affected by apparent power supply fluctuation. Two additional DAMS, which are independent, continued to provide coverage of the Dry Conversion Process (DCP) process areas. The Emergency Director determined that the processes should stay shut down and all personnel not engaged in troubleshooting or recovery actions remain out of the area while investigations and additional testing was conducted. Follow-up tests replaced select hardware, and installed additional power supply monitoring equipment to aid diagnostics. All DAMS have been successfully reset and the inside FMO CWS system returned to normal operation. Current plans are to resume normal operations beginning with the 1500 (evening) shift. The event is being reported within 24-hours pursuant to 10CFR70.50(b)(2) as a safety equipment failure. The licensee will also be providing a courtesy notification to the North Carolina Department of Radiological Protection and the New Hanover County Emergency Management organization. | ||
| ENS 42979 | 9 November 2006 10:00:00 | 10 CFR 70.50(b)(2) | Failure of Warning Horns | At 0500 on 11/09/06, during a routine monthly test of the Criticality Warning System (CWS), a segment of the system covering the Dry Conversion Process (DCP) was found to have no functioning evacuation horns. Appropriate personnel were notified, the DCP processes were shut down, DCP personnel evacuated, and the area cordoned off. The activation of the evacuation horns in the balance of the plant were fully functional. A follow-up test was immediately scheduled for 0900. The building was evacuated and the emergency organization assembled in accordance with normal procedures. During this test, the DCP horns again failed to function. The Emergency Director determined that the processes stay shut down and all personnel remain out of the area while investigations and testing were conducted. The problem was located in the interface between the Data Acquisition Modules (DAM's) and the Auto-Call system that initiates the alarm signals. After a repair was completed, a re-test was completed which confirmed functionality of the DCP process area horns. Current plans are to resume normal operations beginning with the 1500 (evening) shift. This event is being reported within 24-hours pursuant to 10CFR70.50(b)(2) as a safety equipment failure. The licensee will notify NRC Region II. | ||
| ENS 42747 | 1 August 2006 09:00:00 | 10 CFR 70.50(b)(2) | Audible Horn System Malfunction | During a routine monthly test of the Criticality Warning System (CWS), a segment of that system (DCP & DOP Warehouse) was found to have no audible horns functioning. Processes were shutdown, the personnel evacuated and the emergency organization assembled. The preliminary investigation found that an Uninterruptible Power Supply (UPS) that supplies power to the CWS horn amplifiers was not functioning. After a retest verified that the horns in the balance of the plant were functioning, those areas were allowed to resume operations. At the same time, the UPS for the DCP/DOP Warehouse segment of the system was replaced with a new unit and allowed to charge. Once charged, the system was tested and verified to have audible horn coverage. Operations were then allowed to restart in these areas. As of approximately 1210 PM the CWS horns were fully operational and the facility was returned to normal operational status. Investigation of the incident is continuing including an attempt to determine the root cause of the UPS malfunction. The licensee notified Region II (J. Pelchat) and will notify State and local organizations. | ||
| ENS 40633 | 1 April 2004 18:00:00 | 10 CFR 70.50(b)(2) | Outdoor Area Criticality Warning System Horn Inoperative | At approximately 1:00 p.m. on April 1, 2004 it was discovered a Criticality Warning System (CWS) horn had been rendered inoperative in an unoccupied remote outdoor area due to maintenance conducted on the system on March 31, 2004. Maintenance was conducted on the system to remove a tree that had fallen across the communication line to Data Acquisition Module (DAM) #25 which provides coverage for the outdoor process lagoon area. During maintenance activities to remove the tree, a temporary system was installed and the permanently installed system horn was disconnected. Following completion of the maintenance, the restoration effort failed to reinstall a local horn relay. Throughout the maintenance, the DAM remained operable and indications of normal conditions were available. With the exception of the local horn at the remote outdoor area, all other system functions remained operable. Upon discovery of the local horn being disabled, the horn relay was promptly restored and tested, confirming restoration of full system operability. This condition is reported pursuant to 10CFR70.50(B)(2) as an event in which equipment designed to mitigate the effects of an incident are disabled or fails to function as designed. Incident investigation and evaluation of additional corrective actions are continuing. SAFETY SIGNIFICANCE OF EVENTS: Low safety significance - The potential for a criticality event in this area is highly unlikely because of the very low uranium concentration, low material density, and high levels of non-uranium materials. This is consistent with the Integrated Safety Analysis (ISA) for the area. POTENTIAL CRITICALITY PATHWAYS INVOLVED: There is no known process upset that would change the highly unlikely potential for a criticality in this area. CONTROLLED PARAMETERS (MASS, MODERATION, GEOMETRY, CONCENTRATION ETC.): Density and Mass (concentration) ESTIMATED AMOUNT, ENRICHMENT, FORM OF LICENSED MATERIAL (INCLUDE PROCESS LIMIT AND % WORST BASE CRITICAL MASS): N/A. Affected area is final wastewater process lagoon. Uranium concentration in the affected area is approximately (deleted) parts per million (PPM) NUCLEAR CRITICALITY SAFETY CONTROL(S) OR CONTROL SYSTEMS AND DESCRIPTION OF THE FAILURES OR DEFICIENCIES: N/A CORRECTIVE ACTIONS TO RESTORE SAFETY SYSTEMS AND WHEN EACH WAS IMPLEMENTED: System was restored to normal operation at 1300 on 4/1/04 and subsequently tested. Investigation of event and evaluation of additional corrective actions pending. The licensee will notified the local County, the State of North Carolina, and NRC Region II. |