ENS 47908
ENS Event | |
|---|---|
14:30 May 8, 2012 | |
| Title | Improperly Analyzed Condition |
| Event Description | This plant condition is being reported under 10CFR70, Appendix A criterion (b)(1), 'Any event or condition that results in the facility being in a state that ... was improperly analyzed ... and which results in a failure to meet the performance requirements of 10CFR70.61.'
AREVA's conclusion that such a condition exists at the AREVA Richland facility is based on an NRC issued letter dated May 7, 2012 from John D. Kinneman to Janet R. Schlueter which among other things states: 'It is not acceptable, however, to conclude that a process does not need IROFS because an event is 'not credible' due to the characteristic provided by some other controls or features of the plant that are not IROFS.' Based on this NRC position, AREVA did not adequately analyze the facility (in accordance with the May 7th position) because unacceptable consequences resulting from some process upsets were determined to be 'not credible' based on plant conditions or features that were not declared as IROFS. For example, an accidental criticality accident resulting from a solution leak onto the floor was declared not credible because gravity would cause the leak to spread out on the floor into a safe geometry. However, the floor was not declared an IROFS. Another example is that accidental criticality in a 1-inch diameter pipe was declared 'not credible' due to the geometry of the pipe and no credible mechanism being identified that could cause the pipe to balloon into an unfavorable geometry, yet the pipe diameter was not declared an IROFS. Other similar conditions exist at the Richland facility. Therefore, AREVA Richland has concluded that the NRC approved ISA does not meet the performance requirements of 10CFR70.61(e). However, the safety significance of this technical non-compliance is considered to be low because all proposed changes to the facility are evaluated for potential impact to the facility ISA before they are made. These changes are reviewed and approved by a diverse group of people including staff who is familiar with the safety basis for each process system and the 10CFR70.72 change control requirements and will not authorize changes that could invalidate the safety basis. Additionally, although these items are not individually identified as IROFS, the ISA summary on pg. 7-9 states: '... the following general criticality safety program elements are considered IROFS, albeit that they differ from other listed IROFS in that although they are key to safety, they are not always individually identified and used in specific accident sequences: -- equipment dimensions and materials forming the basis for a nuclear criticality safety analysis (NCSA); and -- bounding assumptions used in an NCSA'. |
| Where | |
|---|---|
| Areva Np Inc Richland Richland, Washington (NRC Region 2) | |
| License number: | SNM-1227 |
| Reporting | |
| Part 70 App A (B)(1) | |
| Time - Person (Reporting Time:+1.42 h0.0592 days <br />0.00845 weeks <br />0.00195 months <br />) | |
| Opened: | Robert E Link 15:55 May 8, 2012 |
| NRC Officer: | Donald Norwood |
| Last Updated: | May 8, 2012 |
| 47908 - NRC Website | |
Areva Np Inc Richland with Part 70 App A (B)(1) | |
WEEKMONTHYEARENS 517572016-02-25T19:45:00025 February 2016 19:45:00
[Table view]Part 70 App A (B)(1) Potential Common Mode Failure of Item Relied on for Safety ENS 483662012-10-02T14:30:0002 October 2012 14:30:00 Part 70 App A (B)(1) Unanalyzed Conditions May Lead to Intermediate Consequence Events ENS 479082012-05-08T14:30:0008 May 2012 14:30:00 Part 70 App A (B)(1) Improperly Analyzed Condition ENS 449972009-04-16T23:00:00016 April 2009 23:00:00 Part 70 App A (B)(1) Unanalyzed Condition Due to Possible Unfavorable Geometry ENS 432342007-03-13T21:30:00013 March 2007 21:30:00 Part 70 App A (B)(1) Potential Hazard Affecting Criticality Controls Discovered ENS 429812006-11-09T23:30:0009 November 2006 23:30:00 Part 70 App A (B)(1) Hydrogen Accumulation Due to Loss of Water Seal ENS 429362006-10-23T17:50:00023 October 2006 17:50:00 Part 70 App A (B)(1), Part 70 App A (B)(3) Workers Exposed to Hydrogen Floride Release 2016-02-25T19:45:00 | |