ENS 46138
ENS Event | |
|---|---|
18:00 Jul 28, 2010 | |
| Title | Incorporation of 'Incredible' Criticality Sequences Into Integrated Safety Analysis |
| Event Description | This notification is being made based on 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 10 CFR 70.61.'
Westinghouse Environmental Health and Safety (EH&S) staff evaluated the compliance posture concerning the extent of condition for an open Notice of Violation (NOV) 70-1151/2009-201-01, and evaluation of the information provided in the 'Summary of the June 28, 2010, Public meeting to discuss the use of Design Features to meet the performance requirements of Title 10 of the Code of Federal Regulations part 70, Subpart H,' (ML101950377). This evaluation identified a contradiction between the guidance and [the] approved SNM-1107 License and procedures. Therefore, criticality events evaluated as incredible in accordance with procedure NCS-010 'Categorizing Potential Criticality Scenarios and Criticality Safety Significant Controls' are no longer deemed in compliance with 10 CFR Part 70. Following the NCS-010 methodology allowed for an incredibility conclusion 'based on crediting passive engineered controls or passive design features.' When the logic demonstrated that the passive control or design feature absolutely prevented the scenario from leading to a criticality, the scenario was categorized as incredible; the control was designated as a Safety Significant Control (SSC) in the Integrated Safety Analysis (ISA). SSCs are subject to Management Measures required by the SNM-1107 License to ensure they are available and reliable to perform their intended function. However, failure to identify these accident sequences as credible led to these sequences not being included in the ISA Summary, and therefore Items Relied on For Safety (IROFS) were not designated for these sequences. Immediate Corrective Actions: A governing policy was issued as an interim compensatory measure to identify all current Nuclear Criticality Safety (NCS) engineered SSCs as IROFS. A currently in place NCS Facility Walk-through Assessment process, procedure RA-316, is also designated as an Administrative IROFS as a verification activity of the engineered controls. Interim controls are being established on modifications pertaining to Criticality Safety Related SSCs to ensure no situation occurs where a modification may require NRC pre-approval. This event has been entered into the Facility Corrective Action Process CAPS #10-210-C002. |
| Where | |
|---|---|
| Westinghouse Electric Corporation Columbia, South Carolina (NRC Region 2) | |
| License number: | SNM-1107 |
| Reporting | |
| Part 70 App A (B)(1) | |
| Time - Person (Reporting Time:+19.67 h0.82 days <br />0.117 weeks <br />0.0269 months <br />) | |
| Opened: | Gerard Couture 13:40 Jul 29, 2010 |
| NRC Officer: | Eric Simpson |
| Last Updated: | Jul 29, 2010 |
| 46138 - NRC Website | |
Westinghouse Electric Corporation with Part 70 App A (B)(1) | |
WEEKMONTHYEARENS 561992022-11-01T15:29:0001 November 2022 15:29:00
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