ENS 40860
ENS Event | |
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20:50 Jul 8, 2004 | |
Title | 24 Hour Nrc Bulletin 91-01 Loss of Criticality Control |
Event Description | At 1550, on 07-08-04 the Plant Shift Superintendent was notified that three centrifugal compressor impellers were received as part of a shipment from Portsmouth GDP. The existence of the impellers was not recognized as being part of this shipment and, as a result, applicable NCS [Nuclear Criticality Safety] controls were not implemented. NCSA GEN-20 requires receipt of documented NDA [Non Destructive Analysis] inspections of equipment prior to receipt (unloading) in the shipping/receiving area and completion of a second NDA prior to removing the equipment from the shipping/receiving area to a location within the plant. The purpose of this control is to ensure that equipment containing greater than a safe mass will not be received from offsite.
The three centrifugal compressor impellers have subsequently been characterized as a group, by NDA, to be less than the safe mass assuming 100 wt.% 235U. SAFETY SIGNIFICANCE OF EVENTS: NDA measurements have been completed and the results indicate less than a safe mass of uranium. POTENTIAL CRITICALITY PATHWAYS INVOLVED (BRIEF SCENARIO(S) OF HOW CRITICALITY COULD OCCUR): In order for a criticality to be possible, greater than a critical mass of uranium would have to be present in the equipment in a configuration favorable for a criticality. CONTROLLED PARAMETERS (MASS, MODERATION, GEOMETRY, CONCENTRATION, ETC): Double contingency is maintained by implementing two controls on mass. ESTIMATED AMOUNT ENRICHMENT, FORM OF LICENSED MATERIAL (INCLUDE PROCESS LIMIT AND % WORST CASE CRITICAL MASS): The group of equipment contains less than the safe mass assuming 100 wt.% 235U. NUCLEAR CRITICALITY SAFETY CONTROL(S) OR CONTROL SYSTEMS) AND DESCRIPTION OF THE FAILURES OR DEFICIENCIES: The first leg of double contingency relies on the review of characterization results prior to receipt (unloading) at PGDP. Characterization results were not reviewed prior to receipt. The three centrifugal compressor impellers have subsequently been characterized as a group, by NDA, to be less than the safe mass assuming 100 wt.% 235U. Although, the NCS controls were violated, the parameter was maintained. The second leg of double contingency relies on an independent NDA measurement prior to release from the shipping/receiving area. NDA characterization did not occur prior to release from the shipping/receiving area. The three centrifugal compressor impellers have subsequently been characterized as a group, by NDA, to be less than the safe mass assuming 100 wt% 235U. Although, the NCS controls were violated, the parameter was maintained. Although the parameter was maintained, double contingency is based on two controls on one parameter. Therefore, double contingency was not maintained. CORRECTIVE ACTIONS TO RESTORE SAFETY SYSTEMS AND WHEN EACH WAS IMPLEMENTED : 1. Post equipment according to CP2-MA-MT1034. Completed 07/09/04 The NRC Resident lnspector has been notified of this event. PGDP Problem Report No. ATRC-04-2682, PGDP Event Report No. PAD-2004-18; Event Worksheet #40860 Responsible Division: Maintenance |
Where | |
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Paducah Gaseous Diffusion Plant Paducah, Kentucky (NRC Region 2) | |
License number: | GDP-1 |
Reporting | |
Response | |
Time - Person (Reporting Time:+20.92 h0.872 days <br />0.125 weeks <br />0.0287 months <br />) | |
Opened: | Tom White 17:45 Jul 9, 2004 |
NRC Officer: | Jeff Rotton |
Last Updated: | Jul 9, 2004 |
40860 - NRC Website
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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 | |