ENS 40873
ENS Event | |
|---|---|
18:00 Jul 14, 2004 | |
| Title | Criticality Control 24-Hour (Bulletin 91-01) Report |
| Event Description | At 1300 [CDT] on 7/14/04, the Plant Shift Superintendent (PSS) was notified that a cylinder, which was to be washed, was determined to contain heel material. The cylinder had been filled a single time with natural material at Honeywell (2/2001) since its last wash in 8/1999. An examination of the associated Nuclear Material Control and Accountability (NCM&A) data and cylinder card indicated that the only other filling was in 9/1982 with depleted material at C-315. The cylinder was fed to the cascade in 9/2003 at C-337-A.
A total of 4 gas over solid samples were taken of the cylinder and all indicated that the cylinder contains material. Nuclear Criticality Safety Evaluation 085 and Nuclear Criticality Safety Analysis 400-012 establish double contingency to ensure that a fissile cylinder is not washed in the non-fissile cylinder wash facility. The NRC Resident Inspector has been notified of this event. PGDP Assessment and Tracking Report No. ATR 04-2756; PGDP Event Report No. PAD 2004-019; Responsible Division: Operations. SAFETY SIGNIFICANCE OF EVENTS: NMC&A showed this cylinder contained a heel of around 8 lbs. Gas over solid sampling determined this non-fissile cylinder contained fissile material and could not be washed. Although the cylinder was not washed, an unlikely failure occurred that allowed fissile material to enter a cylinder controlled as non-fissile. CONTROLLED PARAMETERS: The process condition relied upon for double contingency for this scenario is enrichment. NUCLEAR CRITICALITY SAFETY CONTROL OR CONTROL SYSTEMS AND DESCRIPTION OF THE FAILURES OR DEFICIENCIES: The first leg of double contingency relies on a gas over solid sample of the cylinder to demonstrate that the cylinder contains non-fissile material prior to washing. The second leg of double contingency relies on an argument that back- or cross-feeding at C-337A is unlikely to result in a significant amount of fissile material to be transferred to the cylinder. Since fissile material was found in the cylinder after it was fed at C-337A, this unlikely argument appears to have failed. However, the cylinder was not washed, maintaining this parameter. Although the parameter was maintained, double contingency is based on two controls on one parameter and one of the controls (unlikely argument) failed. Therefore double contingency was not maintained. CORRECTIVE ACTIONS TO RESTORE SAFETY SYSTEMS AND WHEN EACH WAS IMPLEMENTED: 1. Correct NMC&A database for this cylinder to show the correct assay in the cylinder and that the cylinder is fissile. |
| Where | |
|---|---|
| Paducah Gaseous Diffusion Plant Paducah, Kentucky (NRC Region 2) | |
| License number: | GDP-1 |
| Reporting | |
| Response | |
| Time - Person (Reporting Time:+5.75 h0.24 days <br />0.0342 weeks <br />0.00788 months <br />) | |
| Opened: | Tom White 23:45 Jul 14, 2004 |
| NRC Officer: | Bill Gott |
| Last Updated: | Jul 15, 2004 |
| 40873 - NRC Website | |
Paducah Gaseous Diffusion Plant with Response | |
WEEKMONTHYEARENS 483982012-10-10T18:05:00010 October 2012 18:05:00
[Table view]Response Double Contingency Control for Empty Cylinders Not Maintained ENS 479112012-05-08T21:16:0008 May 2012 21:16:00 10 CFR 76.120(c)(2), Response Autoclave High Pressure Isolation System Failure ENS 474832011-11-28T15:30:00028 November 2011 15:30:00 Response 24-Hour Report Concerning a Localized Loss of a Geometry Criticality Control Contingency ENS 473102011-09-30T13:54:00030 September 2011 13:54:00 Response 24-Hour Nrc Bulletin 91-01 Report Involving a Loss of One Leg of Double Contingency ENS 471762011-08-19T13:15:00019 August 2011 13:15:00 Response 24-Hr Loss of Criticality Control Report Required Under Bulletin 91-01, Supplement 1 ENS 465922011-02-03T15:30:0003 February 2011 15:30:00 Response 24 Hour Notification Under Bulletin 91-01 Concerning Leakage of Moderating Liquid ENS 463122010-10-06T16:06:0006 October 2010 16:06:00 Response 24 Hour Notification Under Bulletin 91-01 Concerning Cooldown Verification of Uf6 Cylinders ENS 461052010-07-17T19:07:00017 July 2010 19:07:00 Response 24 Hour 91-01 Bulletin Report on Loss of One of Two Criticality Control Contingencies ENS 454922009-11-12T17:15:00012 November 2009 17:15:00 Response Violation of a Nuclear Criticality Safety Control ENS 450422009-05-04T10:07:0004 May 2009 10:07:00 Response 24 Hour 91-01 Bulletin Report on Loss of One of Two Criticality Control Contingencies ENS 445582008-10-09T20:37:0009 October 2008 20:37:00 Response 24-Hours Bulletin 91-01 Report Involving Failure to Visually Inspect Storage Cylinders ENS 442232008-05-18T22:21:00018 May 2008 22:21:00 Response Violation of a Nuclear Criticality Safety Approval - 24-Hour Report ENS 441512008-04-17T21:44:00017 April 2008 21:44:00 Response 24-Hour Nrc Bulletin 91-01 Report Involving an Excessively Large Container Found in a Fissile Control Area ENS 441002008-03-26T19:57:00026 March 2008 19:57:00 Response 24 Hour Report of Degraded Criticality Control ENS 440562008-03-11T19:57:00011 March 2008 19:57:00 Response Two Cylinders Identified with Weight Change Prior to Wash ENS 432322006-09-23T03:00:00023 September 2006 03:00:00 Response Reported Under Nrc Bulletin 91-01 24 Hour Notification ENS 421652005-11-22T18:05:00022 November 2005 18:05:00 Response Improper Criticality Spacing for Waste Drum ENS 411582004-10-29T14:45:00029 October 2004 14:45:00 Response Criticality Control Report ENS 410202004-09-04T18:45:0004 September 2004 18:45:00 Response Violation of Nuclear Criticality Safety Control in the Process Building ENS 408732004-07-14T18:00:00014 July 2004 18:00:00 Response Criticality Control 24-Hour (Bulletin 91-01) Report ENS 408602004-07-08T20:50:0008 July 2004 20:50:00 Response 24 Hour Nrc Bulletin 91-01 Loss of Criticality Control ENS 407232004-05-03T21:00:0003 May 2004 21:00:00 Response Criticality Control 24-Hour (Bulletin 91-01) Report ENS 407002004-04-23T13:45:00023 April 2004 13:45:00 Response Criticality Control 24-Hour (Bulletin 91-01) Report ENS 408052004-04-23T10:53:00023 April 2004 10:53:00 Response Paducah Gaseous Diffussion Plant - Response Bulletin 91-01 24 - Hour Report ENS 406412004-04-04T19:30:0004 April 2004 19:30:00 Response 24-Hour Nrc Bulletin 91-01 Loss of Criticality Control Notification ENS 404552004-01-16T21:27:00016 January 2004 21:27:00 Response 24 Hour Notification for Bulletin 91-01 Loss of Criticality Safety Controls Involving Waste Drum ENS 404472004-01-13T19:00:00013 January 2004 19:00:00 Response 24 Hour Notification for Bulletin 91-01 Loss of Criticality Safety Controls Involving Waste Drum ENS 403562003-11-25T09:45:00025 November 2003 09:45:00 Response 24 Hour Nrc Bulletin 91-01 Notification Regarding Loss of Double Contingency Protection ENS 401512003-09-11T13:45:00011 September 2003 13:45:00 Response Double Contingency Was Not Maintained for Non-Fissile Nams. ENS 401392003-09-07T12:50:0007 September 2003 12:50:00 Response Criticality Controls Degradation at Paducah ENS 401092003-08-27T14:00:00027 August 2003 14:00:00 Response Procedural Deficiency Omission 2012-05-08T21:16:00 | |