Semantic search
| Start date | Reporting criterion | Title | Event description | System | LER | |
|---|---|---|---|---|---|---|
| ENS 56256 | 2 December 2022 20:30:00 | Part 70 App A (B)(2) | Fuel Cycle Facility - Loss or Degradation of Safety Items | The following information was provided by the licensee via email: It was discovered on 12/2/2022, that an Item Relied on For Safety (IROFS) had failed because it was determined to not be available and reliable in the sinter test grinder (STG) dust collection system. On 11/29/2022, a mass of dry uranium oxide powder greater than expected was identified in the grinder swarf collection can, prompting a shutdown of the STG and further investigation. Subsequent equipment cleanout identified approximately 28.4 kilograms of dry uranium oxide compared to the system safety limit of 43.39 kg. The investigation determined that the safety limit could have been challenged. The failed IROFS resulted in a failure to meet performance requirements. The STG operation remains shut down. Additional controls on moderation remained intact, and at no time was an unsafe condition present. Additional corrective actions, extent of condition, and extent of cause are being investigated. This event is being communicated to meet the reporting requirements of 10CFR70, Appendix A (b)(2). | ||
| ENS 53331 | 12 April 2018 23:00:00 | Part 70 App A (B)(2) | Potentially Degraded Items Relied on for Safety | GNF-A's (Global Nuclear Fuels - Americas) Fuel Manufacturing Operation maintains a safe geometry Radwaste accumulation tank to receive certain liquid discharges from operations. During the annual shutdown work activities and routine inspections, an accumulation of material was identified in a safe geometry Radwaste accumulation tank. The accumulation appears to have occurred due to reduced recirculation flow, an engineered feature that mixes the contents of the tank as part of a density control. The accumulation of material is an indication that the tank density control had degraded. Plant operations attempted to remove and quantify the material per normal requirements. On 4/12/18 at approximately 1900 (EDT), GNF-A determined that the material could not be quantified in a timely manner. In the absence of quantification, GNF-A has conservatively determined that this condition is a failure to meet performance requirements and is therefore reporting it within 24 hours of discovery pursuant to Part 70 Appendix A (b)(2). Additional controls on the tank geometry remained intact and at no time was an unsafe condition present. In addition, there are no sources that could result in a rapid addition of uranium to the system. Additional corrective actions, extent of condition, and extent of cause are being investigated. The licensee will be notifying their NRC Program Manager (Vukovinsky), the Radiation Protection Section at North Carolina Department of Health and Human Services, and Hanover County Emergency Management Agency. | ||
| ENS 52251 | 19 September 2016 10:00:00 | Part 70 App A (B)(2) | Uf6 Scrubber Exhaust System Not Operating as Required | EVENT DESCRIPTION: It was determined at approximately 6 AM today (Eastern) that an Item Relied on for Safety (IROFS) associated with a Fuel Manufacturing Operation (FMO) exhaust system was not operating as required. An FMO scrubber exhaust system blower was determined to be not operating and resulted in a failure to meet performance requirements. The safety function of the scrubber exhaust system is to limit the release of uranium hexafluoride (UF6) and its byproducts to the environment in the unlikely event of an accidental airborne release in a process area. Other upstream controls remained available and reliable and prevented significant quantities of UF6 and its byproducts from being released into the scrubber exhaust system. There was no release of material and at no time was an unsafe condition present. The Dry Conversion Process has been shutdown. An investigation is continuing which will provide additional corrective actions and extent of condition. While this did not result in an unsafe condition, the event is being reported pursuant with the reporting requirements of 10CFR70 Appendix A (b)(2) within 24 hours of discovery. SAFETY SIGNIFICANCE OF EVENT: At no time was an unsafe condition present SAFETY EQUIPMENT STATUS: The Dry Conversion Process (DCP) was shutdown. STATUS OF CORRECTIVE ACTIONS: Additional corrective actions, extent of condition, and extent of cause are being investigated. There was no offsite release of UF6 as a result of the IROF failure. The licensee will inform the State of North Carolina, New Hanover County and the NRC Resident Inspector. | ||
| ENS 51662 | 19 January 2016 02:00:00 | Part 70 App A (B)(2) | Accumulation of Uranium Oxide Powder in the Dry Scrap Recycle Furnace Off-Gas System | It was discovered on 1/18/16, that an accumulation of uranium oxide existed that indicated a degradation of an IROFS (Item Relied On For Safety) in the dry scrap recycle furnace off-gas system. Approximately 42 kg of uranium oxide powder was removed from the favorable geometry off-gas dropout. The degraded IROFS resulted in a failure to meet performance requirements in the event of a fire. The dry scrap recycle operation had been shut down on 1/14/16 and was not in operation at the time. Additional controls on combustibles, geometry and moderation remained intact and at no time was an unsafe condition present. Additional corrective actions, extent of condition, and extent of cause are being investigated. This event is being communicated to meet the reporting requirements of 10CFR70, Appendix A(b)(2). The licensee will inform State and local agencies and NRC Region II. | ||
| ENS 49969 | 28 March 2014 17:30:00 | Part 70 App A (B)(2) Part 70 App A (A)(4) | Items Relied on for Safety Not Operable | It was determined at 1:30PM today (3/28/14) that one of the Items Relied on for Safety (IROFS) associated with the Dry Conversion Process recycle operation was inoperable. Although the second IROFS preventing moderation intrusion to the recycle container continued to operate within its allowable parameters, it alone was not sufficient to meet performance requirements. The affected equipment has been shut down and at no time was an unsafe condition present. While this did not result in an unsafe condition, the event is being reported pursuant with the reporting requirements of 10CFR70 Appendix A (b)(2) within 24 hours of discovery. Additional corrective actions, extent of condition, and the cause of the failure are being determined. The licensee will notify NRC Region 2, State of North Carolina Radiation Protection, and New Hanover County Emergency Management.
After further review, it was determined, at approximately 1125 EDT on 3/31/2014, that the second IROFS (mentioned in the initial report) was not reliable to meet performance requirements. As a result, the report is amended as follows: The second IROFS preventing significant moderator intrusion to the recycle container was available, but its reliability could not be confirmed. The control continued to limit significant moderator intrusion and an unsafe condition did not exist. The remaining IROFS was not sufficient to meet performance requirements. As a result, the event report is being conservatively amended pursuant with the reporting requirements of 10CFR70 Appendix A (a)(4) within 1 hour of discovery. The IROFS that was inoperable in the initial report was a process flow moisture probe. The second IROFS that was believed to be available in the initial report but later determined to not be reliable was a set of process control valves used to prevent moderation intrusion to the recycle container. The licensee will notify NRC Region 2, State of North Carolina Radiation Protection, and New Hanover County Emergency Management. Notified R2DO (Sykes) and NMSS EO (Rahimi) | ||
| ENS 49341 | 13 September 2013 14:45:00 | Part 70 App A (A)(4) | Item Relied on for Safety May Not Be Reliable | At about 1045 EDT on 9/13/13, it was discovered that the feed tube level sensor on a press operation is not fail safe upon loss of signal. The sensor is a sole IROFS (Item Relied On For Safety) for a particular sequence. Criticality controls remained in place. Affected equipment has been shut down. No unsafe condition exists. Feed tube level sensor is in place for the sequence to limit mass. At no time was the mass limit exceeded. We are reporting under Part 70, Appendix A, (a)(4) which states that credited IROFS must remain available and reliable. We cannot evaluate reliability in the time required for a 1 hour report. In addition, the affected equipment has been secured. An investigation is underway to determine corrective actions and extent of condition. The license will notify NRC Region 2.
On 9/13/13, GNF-A conservatively made a 1 hour event notification (EN 49341) due to a discovery that a feed tube level sensor is not fail safe upon loss of signal. After further review, it has been determined that the control remained available, reliable and continued to meet performance requirements. As a result, the event notification is retracted. The licensee has notified NRC Region 2. Notified R2DO (Sykes), NMSS EO (Rubenstone), and IRD (Grant). | ||
| ENS 48807 | 5 March 2013 13:45:00 | Part 70 App A (A)(4) | Sole Irofs Pressure Mat Did Not Function as Designed | During a post maintenance test of a sole IROFS (Item Relied On For Safety) in the scrap press area, it was discovered that a sole IROFS of a pressure mat did not function as designed. The pressure mat is designed to ensure operator presence. The clutch that would be disengaged when the pressure switch is not active failed to do so. The press was immediately shut down. Similar presses have also been shut down. Double contingency was maintained (Moderation and Mass). The sole IROFS is designed for prevention of a fire scenario. At no time was an unsafe condition present. There were no radiological or chemical hazards resulting from this event. The licensee is conducting an investigation to determine the cause of the failure. The licensee has notified NRC R2 Inspectors and State and Local Agencies. | ||
| ENS 48038 | 19 June 2012 21:00:00 | Part 70 App A (B)(2) | Degradation of Safety Equipment | It was discovered at approximately 1700 EDT on 6/19/2012 that the moderation control in the gadolinia pellet press operation had been degraded. An operator error allowed a can containing approximately 14 kg of uranium powder to be processed without the required material move transaction, a process control that ensures the container and material type are allowed at the designated location. This resulted in a temporary degraded item relied on for safety (IROFS) condition involving a criticality control. The press moderation control is one of four IROFS to prevent a criticality accident. The gadolinia press station material control system functioned as designed and prompted the operator of an error. The other criticality controls on geometry were maintained at all times. At no time was an unsafe condition present. The gadolinia pellet press operation has been shut down and additional corrective actions, extent of condition, and extent of cause are being evaluated. This event is being conservatively reported pursuant to 10 CFR 70, Appendix A (b) (2).
On 6/20/12, GNF-A conservatively made a 24 hour event notification (EN 48038) due to a single missed Fuel Business System (FBS) transaction on 6/19/12 at the gadolinia press operation. After further review of the identified condition, it has been determined to be not reportable to NRC and the event notification can be retracted. Notified R2DO (Blamey) and NMSS EO (Silva). | ||
| ENS 48057 | 13 February 2012 13:20:00 | Part 70 App A (B)(2) | Mass Control Limit Exceeded | It was discovered on 2/13/12 that the mass control limit in the gadolinia pellet press operation was exceeded. An improperly installed valve allowed a total of 43 kg of uranium powder into the favorable geometry press feed tube, exceeding the 36 kg limit. This resulted in a failed item relied on for safety (IROFS) < 1 hour condition where a criticality control was not maintained. The press feed mass control is a sole IROFS for a fire accident sequence. Control indications functioned as designed and provided notification of the malfunction to the operator and the operation was secured. The other controls on geometry and moderation were maintained at all times. At no time was an unsafe condition present. The gadolinia pellet press operation was shut down and the powder was removed by 1000 on 2/13/2012. Additional corrective actions, extent of condition, and extent of cause have been documented. SAFETY SIGNIFICANCE OF EVENTS: At no time was an unsafe condition present SAFETY EQUIPMENT STATUS: Equipment was shut down and powder removed STATUS OF CORRECTIVE ACTIONS: Additional corrective actions, extent of condition, and extent of cause have been documented. This event is being communicated in order to administratively meet the reporting requirements of 10CFR70, Appendix A. The licensee has spoken with Region 2 (Thomas) regarding this issue, and discussed the issue in a Reply to Notice of Violation dated 6/29/2012 letter book number SPM12-030. | ||
| ENS 46669 | 10 March 2011 14:15:00 | Part 70 App A (B)(2) | Malfunctioning Valve Leads to a Loss of Defense in Depth | During a performance of temporary operating procedure on a laser optical device, it was identified that one of two valves used to isolate the device failed to operate. The valves are operated as a pair and the valves are redundant to provide defense in depth. One valve shut as expected. The second valve did not shut. The valves are identified as an Item Relied on For Safety (IROFS). The system was not operating and one of the valves operated as designed. No unsafe condition existed. Operability of both valves is required to meet the performance requirements of 10CFR70.61. This event is being reported pursuant to the requirements of 10CFR70 Appendix A(b)(2) within 24 hours. The affected device will remain shutdown pending further investigation and implementation of associated corrective actions. (This event is of) low safety significance - the discovery did not result in an unsafe condition. | ||
| ENS 46486 | 16 December 2010 15:44:00 | Part 70 App A (B)(2) | Both Hf Detectors in Ghs Test Loop Failed to Be Available and Operable | During a performance of internal procedure to verify functionality of installed HF detectors in the Test Loop (TL) Gas Handling System (GHS) room, it was discovered at about 1044 (EST on) 12/16/10, that both IROFS TL-HF-01 and IROFS TL-HF-02 failed to pass internal test requirements. At least one of these HF detector IROFS is required to be available and operable to meet 10 CFR 70.61 performance requirements. The installed HF detector electrochemical sensors performance appears to have been degraded as a result of low room 'relative humidity' as a result of unusually cold outdoor conditions. The independent IROFS TL-HF-04 (an administrative control) remained intact, thus no unsafe condition existed. While one documented IROFS remained functional (TL-HF-04) to assure the consequence of chemical and radiological exposure is maintained low, TL-HF-04 could not alone meet 10 CFR 70.61 performance requirements. No loss of UF6 containment occurred in affected process equipment. The degradation of TL-HF-01 and TL-HF-02 was observed as part of the IROFS' periodic surveillance. This event is therefore being reported pursuant to the requirements of 10 CFR 70 Appendix A(b)(2) within 24 hours. The affected TL bench scale experiment equipment will remain shutdown pending further investigation and implementation of associated corrective actions. SAFETY SIGNIFICANCE OF EVENTS - Low safety significance - the discovery did not result in an unsafe condition. SAFETY EQUIPMENT STATUS - Required IROFS TL-HF-01 and TL-HF-02 functionality being re-established. STATUS OF CORRECTIVE ACTIONS - The affected TL process operation remains shutdown pending investigation and implementation of corrective actions. The licensee will be contacting NRC Region 2, state and local government agencies. | ||
| ENS 46244 | 10 September 2010 14:00:00 | Part 70 App A (B)(2) | Degradation of Safety Equipment | At approximately 1000 (EDT) on September 10, 2010 during normal operation of a Gad slugger feed hood in the Fuel Manufacturing Building, a connection between the powder hopper and the vibrating feeder was observed as being not properly secured. After starting the vibrating feeder a small amount of powder leaked from the vibrating feeder into the hood. The base of the hood is equipped with a photo-sensor that detected the powder accumulation and automatically shut down the vibrating feeder to stop the leak. A total of 2.2 kg of powder was removed from the hood. An investigation determined that a clamp on the feed tube had not been properly reinstalled following an equipment cleanout. The two controlled parameters for criticality safety of this equipment are moderation and geometry and Items Relied on for Safety (IROFS) are established for both. With the clamp improperly installed, the geometry-related IROFS was in a degraded state. Additional IROFS on moderation remained available to perform their intended safety functions and were not challenged. Geometry control was maintained by the photo-sensor interlock; however this IROFS is not credited for this accident sequence in the ISA. Although, this event did not result in an unsafe condition and double contingency was maintained, the performance requirements could not be met when taking no credit for the degraded IROFS. As a result, this report is conservatively being made per 10CFR70 Appendix A (b)(2). The Gad slugger and similar equipment have been shutdown pending implementation of additional corrective actions. The licensee will notify the NRC Region 2 Office, the North Carolina Radiation Protection Section and the New Hanover County Emergency Preparedness Organization. | ||
| ENS 46168 | 25 January 2010 13:50:00 | Part 70 App A (B)(2) | Degradation of an Item Relied on for Safety | On January 25, 2010 during normal operation of a slugger press in the Fuel Manufacturing Building, a tube connecting the feed hood to the press became disconnected. After starting the vibrating feeder, an operator discovered the feed tube was slightly misaligned and some (uranium) powder had spilled into the hood. The operator immediately used the emergency stop button and the equipment was shutdown. A total of 6.9 kg was removed from the hood. An investigation determined that a clamp on the feed tube came loose, allowing the tube to separate from the fit up device. The two controlled parameters for criticality safety for this equipment are moderation and geometry and Items Relied on for Safety (IROFS) are established for both. When the tube became misaligned, one geometry related IROFS became unavailable to perform its intended safety function. Additional lROFS on geometry and moderation remained available to perform their intended safety functions and were not challenged. Therefore, this did not result in an unsafe condition. GNF-A's (Global Nuclear Fuel-Americas) initial review determined this event was not reportable. However, during an inspection February 22 to 26, 2010, NRC evaluated the event and determined that during the period when the tube was misaligned, one IROFS was not available to perform its intended safety function. Therefore, facility performance requirements were not met and a report to the NRC was required. The NRC issued a notice of violation to GNF-A on March 26, 2010 (70-1113/2010-002-01) for failure to report the event pursuant to 10CFR70 Appendix A(b)(2). The event is now being reported retroactively to satisfy this reporting requirement. The licensee notified the NRC Region 2 Office, the North Carolina Radiation Protection Section and the New Hanover County Emergency Response Organization. | ||
| ENS 43637 | 12 September 2007 15:30:00 | Part 70 App A (B)(2) | Moderation Control Item Relied on for Safety Degradation | During an investigation of an unusual sinter test measurement result, it was determined that one of the Items Relied On For Safety (IROFS), as documented in the (Integrated Safety Analysis) (ISA) summary, had degraded. This report is submitted for administrative reporting pursuant to 10 CFR 70.50 Appendix A (b)(2). The IROFS described for the moderation control of the powder additive at the Dry Conversion Process (DCP) blender operation did not function as required because of an error that occurred at the Dry Scrap Recycle (DSR) container transfer station. At no time did an Unsafe condition exist. The existing criticality safety analysis of the operation bounded the situation, was effective and was not challenged. The container transfer station operation is shut down pending completion of an investigation and implementation of corrective actions. |