ENS 48091
ENS Event | |
|---|---|
16:30 Jul 10, 2012 | |
| Title | Metallurgical Sample Pans Exceeded Volume Limit |
| Event Description | The following is a redacted summary of the event report provided by the licensee:
EVENT DESCRIPTION: Metallurgical samples at B&Ws NOG-L facility are contained in 'bread pans'. The bread pans are used to transport and store samples. Each bread pan has U235 quantity limits as well as spacing and volume limits for maintaining criticality controls. The volume of the bread pan is an Item Relied on For Safety (IROFS). On July 10, 2012, at approximately 1230 EDT, a Nuclear Criticality Safety (NCS) engineer identified during a routine quarterly audit that the bread pans in use exceeded the volume liter limit. At the time of discovery, the mass controls for the bread pans were not exceeded. Neither was there excess moderation between storage locations. EVALUATION OF THE EVENT: Although an IROFS was lost (the bread pan volume), other IROFS (operator control of mass, operator control of interspersed moderation) were available at the time of discovery of this condition to ensure the risk of a criticality remained highly unlikely. However, 10 CFR 70.61 (d) states in part: '...the risk of nuclear criticality accidents must be limited by assuring that under normal and credible abnormal conditions, all nuclear processes are subcritical, including use of an approved margin of subcriticality for safety.' Further evaluation of the as-found condition of the bread pans indicated the licensed keff limit may have been exceeded. Therefore, the performance requirements of 10 CFR 70.61 were not maintained. There was no immediate risk of a criticality or threat to the safety of workers or the public as a result of this event. However, the bread pan storage area is being shutdown. NOTIFICATION REQUIREMENTS: B&W is making this 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> report in accordance with 10 CFR 70, Appendix A, (b)(1) Any event or condition that results in the facility being in a state that was not analyzed, was improperly analyzed, or is different from that analyzed in the Integrated Safety Analysis, and which results in failure to meet the performance requirements of 70.61. STATUS OF CORRECTIVE ACTIONS: An investigation of the root causes of this event is ongoing. Corrective actions will be determined as a result of the investigation. The licensee has notified the NRC Resident Inspector.
The following is a redacted summary of the event report provided by the licensee: The event was reported in 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> in accordance with 10 CFR 70. Appendix A. (b)(1): 'any event or condition that results in the facility being in a state that was not analyzed, was improperly analyzed, or is different from that analyzed in the Integrated Safety Analysis, and which results in failure to meet the performance requirements of 70.61'. Upon further evaluation it was determined that keff limit in the NRC License was not exceeded. Therefore, the performance requirements of 10 CFR 70.61 were maintained. This is the basis for correcting Event Notification#48091 and withdrawing the report. A conservative approach was initially taken in evaluating the event in order to ensure compliance with the specified time periods established in the regulations. A reanalysis calculated keff less than the keff safety limit in NRC License SNM-42. Although the facility was in a state that was not analyzed, was improperly analyzed, or is different from that analyzed in the Integrated Safety Analysis, the performance requirements of 10 CFR 70.61 were maintained. In accordance with 10 CFR 70.61 (b) and FCSS Interim Staff Guidance-12, although an IROFS was lost, the situation did not pose a safety concern that is significant enough to report to NRC. Other IROFS were available at the time of discovery of the condition to ensure the risk of a criticality remained highly unlikely. In addition, the calculated keff using an approved approach described in Section 5.2.2 of NRC License SNM-42 demonstrates compliance with 10 CFR 70.61 (d). The system remained subcritical, including use of an approved margin of subcriticality for safety, during a credible abnormal condition. Therefore, in accordance with the guidance of FCSS ISG-12, Rev 0, '10 CFR Part 70, Appendix A - Reportable Safety Events,' B&W is correcting Event Notification#48091 in accordance with 10 CFR 70.74(a)(4) and withdrawing the 10 CFR 70, Appendix A, (b )(1) notification. The licensee notified the NRC Resident Inspector. Notified the R2DO (Ernstes), NMSS (Stablein), and the Fuels Group OUO (via e-mail). Contact the Headquarters Operations Officer for additional details on this event. |
| Where | |
|---|---|
| B&W Nuclear Operating Group, Inc. Lynchburg, Virginia (NRC Region 2) | |
| License number: | SNM-42 |
| Reporting | |
| Part 70 App A (B)(1) | |
| Time - Person (Reporting Time:+19.82 h0.826 days <br />0.118 weeks <br />0.0271 months <br />) | |
| Opened: | Tony England 12:19 Jul 11, 2012 |
| NRC Officer: | John Knoke |
| Last Updated: | Aug 10, 2012 |
| 48091 - NRC Website | |
B&W Nuclear Operating Group, Inc. with Part 70 App A (B)(1) | |
WEEKMONTHYEARENS 519982016-06-09T17:30:0009 June 2016 17:30:00
[Table view]Part 70 App A (B)(1) Unanalyzed Condition Due to a Chemical Processing Malfunction ENS 507762015-01-09T21:00:0009 January 2015 21:00:00 Part 70 App A (B)(1) Unanalyzed Condition While Cleaning the Catch Tray ENS 504252014-09-04T15:00:0004 September 2014 15:00:00 Part 70 App A (B)(1) Unanalyzed Condition Related to Potential Material Transfer Cart Tipping ENS 492582013-08-09T17:00:0009 August 2013 17:00:00 Part 70 App A (B)(1) Storage Racks Determined to Be in an Unanalyzed Condition ENS 480912012-07-10T16:30:00010 July 2012 16:30:00 Part 70 App A (B)(1) Metallurgical Sample Pans Exceeded Volume Limit ENS 460012010-06-11T13:45:00011 June 2010 13:45:00 Part 70 App A (B)(1) Unanalyzed Accumulation of Material in the Uranium Recovery Area 2016-06-09T17:30:00 | |