ENS 41933
ENS Event | |
|---|---|
19:30 Aug 19, 2005 | |
| Title | Nrc Bulletin 91-01 Violation of Criticality Spacing Requirements |
| Event Description | Criticality spacing configuration requirements for Integrated Fuel Burnable Absorber (IFBA) rod caskets were violated in the IFBA loading dock (Dock 9). IFBA rod caskets are used for transport of IFBA rods from the IFBA loading dock to the Quality Control (QC) Inspection Area. Criticality spacing requirements for the caskets are posted on the lid of each container. The requirements state that loaded caskets are required to remain in the same horizontal array with 12-inch spacing between all other containers not in the same array. As such, stacking of loaded caskets is prohibited. Contrary to this requirement, Westinghouse operations personnel identified several caskets loaded with IFBA rods that were stacked in the IFBA loading dock (Dock 9). It is believed that this spacing condition was present for less than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, although this has not yet been confirmed.
Notification is being made based on the loss of spacing of the caskets in conjunction with the failure to limit the potential pathway for moderator introduction into the caskets (see discussion below for more detail). Double Contingency Protection The criticality safety analysis considers criticality not credible for normal and credible process upset conditions. However, the criticality safety analysis (ISA-12) also establishes that criticality is possible if large quantities of rods were stacked and interstitial moderation was provided and retained among the stacked fuel rods. Introduction of interstitial moderation is limited by the casket covers and through limitation of available sources. While no liquid moderator was present in any of the caskets, the potential pathway for moderator introduction was not addressed by either the criticality safety posting (deficiency in the criticality safety analysis) or operating procedures. In addition (as discussed under the Reason for Notification), the caskets were improperly spaced in a stacked configuration. It was determined that the criticality safety analysis is deficient and that less than two unlikely, independent, and concurrent changes in process conditions would be required before a criticality accident would be possible. A criticality is judged to be credible through the introduction of moderation and the incorrect configuration of the caskets. In accordance with Westinghouse Operating License (SNM-1107), paragraph 3.7.3 (b.3), this event satisfies the criteria for a 4-hour notification. Summary of Activity: IFBA casket loading operations were discontinued. Operations Management reviewed the procedural requirements prohibiting stacking of caskets with all of the operations personnel. The program to train and re-certify all Operations personnel is continuing, per schedule. The program to assess and reconstitute the plant's criticality safety basis is continuing, per schedule. "Conclusions: Problem was self identified by Westinghouse Operations personnel. As stated previously it is believed that the improper spacing configuration was present for less than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. Less than double contingency protection remained. No liquid moderator was present in any of the caskets. At no time was the health or safety to any employee or member of the public in jeopardy. No exposure to hazardous material was involved. The Incident Review Committee (IRC) determined that this is a safety significant incident in accordance with governing procedures. A causal analysis will be performed. The plant programs for training and recertification of operations personnel and for assessment and reconstitution of the plant's criticality safety basis are appropriate corrective actions for this type of event and are continuing according to plan. There is no NRC Resident Inspector at the site. The loading operations are estimated to be discontinued for 3 to 7 days. |
| Where | |
|---|---|
| Westinghouse Electric Corporation Columbia, South Carolina (NRC Region 2) | |
| License number: | SNM-1107 |
| Reporting | |
| Response | |
| Time - Person (Reporting Time:+-0.7 h-0.0292 days <br />-0.00417 weeks <br />-9.5886e-4 months <br />) | |
| Opened: | Ralph Winiarski 18:48 Aug 19, 2005 |
| NRC Officer: | John Knoke |
| Last Updated: | Aug 19, 2005 |
| 41933 - NRC Website | |
Westinghouse Electric Corporation with Response | |
WEEKMONTHYEARENS 419332005-08-19T19:30:00019 August 2005 19:30:00
[Table view]Response Nrc Bulletin 91-01 Violation of Criticality Spacing Requirements ENS 417232005-05-20T22:40:00020 May 2005 22:40:00 Response, Part 70 App A (B)(5) Deviation from Integrated Safety Analysis, and a 24 Hour Notification - Bulletin 91-01 Criticality Control ENS 414182005-02-17T17:00:00017 February 2005 17:00:00 Response, Part 70 App A (B)(1) 24 Hour 91-01 Response Bulletin and Part 70 App a Unanalyzed Condition ENS 413722005-02-04T14:00:0004 February 2005 14:00:00 Response 24-Hour Notification-Bulletin 91-01 Criticality Control ENS 409852004-08-24T14:05:00024 August 2004 14:05:00 Response 24 Hour 91-01 Response Bulletin ENS 408882004-07-21T13:00:00021 July 2004 13:00:00 Response 4-Hour 91-01 Nrc Bulletin Notification Due to Adu in Non-Favorable Geometry Nitrogen Accumulator Tank ENS 408552004-07-07T21:00:0007 July 2004 21:00:00 Response Nrc Bulletin 91-01 - 4 Hour Report ENS 407932004-06-04T22:00:0004 June 2004 22:00:00 Response Licensee Reported a 4 Hour 91-01 Response Bulletin ENS 405672004-03-04T20:00:0004 March 2004 20:00:00 Response 24-Hour Notification - Bulletin 91-01 Criticality Control ENS 404402004-01-12T20:45:00012 January 2004 20:45:00 Response 24 Hour Notification Bulletin 91-01 Criticality Control ENS 402552003-10-16T19:30:00016 October 2003 19:30:00 Response 24 Hour Bulletin 91-01 Notification from Westinghouse Columbia Fuel Facility ENS 402462003-10-14T11:30:00014 October 2003 11:30:00 Response 24-Hour Nrc 91-01 Bulletin Report Involving Improper Mass Control ENS 401522003-09-12T14:32:00012 September 2003 14:32:00 Response Improper Scanning of Lead Rods for the Product Engineering Laboratory 2005-08-19T19:30:00 | |