ENS 47360
ENS Event | |
|---|---|
16:10 Oct 20, 2011 | |
| Title | One Hour Report Due to a Failed Item Relied on for Safety |
| Event Description | At approximately 0910 [PST] on 10/20/2011, during discussions with an NRC inspector, the AREVA Richland NCS Manager concluded that a previous determination made on Friday, 7/22/2011 that an IROFS (a criticality drain on a HEPA filter housing) declared to be in a degraded state was, in fact, failed in that a pre-filter in the HEPA housing was sitting on the drain and could have prevented it from performing the required safety function. This original discovery was made during a routine PM of the system (a management measure prescribed to this IROFS). On 7/22/2011 (the initial day of discovery) the criticality drain was modified so that it would remain unobstructed and free flowing.
At 1303 EDT, AREVA's EHS&L Manager notified the NRC Operations Center of this condition per the requirements of 10CFR70 Appendix A criterion (a)(5) (1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> report) which requires reporting if '... only one IROFS remains available and reliable to prevent a nuclear criticality and has been in that state for greater than 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />,' and indicated that potentially criterion (b)(1) (24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> report) was also met. This 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> criterion requires reporting '... the facility being improperly analyzed, or different than analyzed in the Integrated Safety Analysis, and which results in failure to meet the performance requirements of 10CFR 70.61.' Subsequent to the initial report, AREVA has concluded that the performance requirements of 10CFR 70.61 were met and the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> reporting criteria (b)(1) do not apply. Safety Significance of Event: The safety significance of this event is low. This process is used to recover incinerator ash and the ISA team was unable to identify any mechanism whereby a critical concentration of approximately 285 g U/liter of solution could be created in the process connected to the duct work. Potential Nuclear Criticality Pathways Involved: The only potential pathway is for uranium bearing liquids that exceed 285 g U/liter to gradual build up in the HEPA filter housing. Controlled Parameters (Mass, Moderation, Geometry, Concentration, Etc.): Uranium mass/concentration is controlled. Nuclear Criticality Safety Control(s) or Control System(s) and description of the failures or deficiencies: No control system failures occurred. Corrective Actions to Restore Safety Systems and When Each Was Implemented: A grate was installed over the criticality drain inlet on July 22, 2011 and has been present since that time.
After careful consideration of the guidance contained in FCSS ISG-12 and NUREG 1520, Rev. 1, AREVA has concluded that this condition did not meet the reporting requirements set forth in 10CFR70 Appendix A and formally retracts the previously made report. Notified R2DO (Freeman) and NMSS EO (Hiltz). |
| Where | |
|---|---|
| Areva Np Inc Richland Richland, Washington (NRC Region 2) | |
| License number: | Snm-1227 |
| Reporting | |
| Part 70 App A (A)(5) | |
| Time - Person (Reporting Time:+-3.12 h-0.13 days <br />-0.0186 weeks <br />-0.00427 months <br />) | |
| Opened: | Robert Link 13:03 Oct 20, 2011 |
| NRC Officer: | Vince Klco |
| Last Updated: | Nov 23, 2011 |
| 47360 - NRC Website | |
Areva Np Inc Richland with Part 70 App A (A)(5) | |
WEEKMONTHYEARENS 494752013-10-27T17:55:00027 October 2013 17:55:00
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