ENS 40151
ENS Event | |
|---|---|
13:45 Sep 11, 2003 | |
| Title | Double Contingency Was Not Maintained for Non-Fissile Nams. |
| Event Description | NRC BULLETIN 91-01 24 HOUR NOTIFICATION
At 0845 on 9/11/03, it was discovered that non-fissile negative air machines (NAMs) were not verified by two individuals to contain approved and properly installed filters, as specified in NCSA GEN-09, "Operation and Maintenance of Negative Air Machines". Procedure CP4-GP-BG2108, "Negative Air Machine and in-place HEPA System Internal Inspection and Filter Replacement", did not adequately flowdown requirements specified in NCSA GEN-09 was revised to make non-fissile portable negative air machines (NAMs) readily available for fissile use in emergency situations. Contrary to requirements specific in NCSA GEN-09, procedure CP4-GP-BG2108 did not include requirements for two individuals to perform independent verification that approved filters are selected and properly installed. This control prevents mass loadings of fissile material that are outside the scope of that analyzed in NCSE KY/S-249. SAFETY SIGNIFICANCE OF EVENTS: Double contingency was not maintained for non-fissile NAMs because the second verification was not performed. However, the non-fissile NAMs were not used for fissile material releases. The non-fissile NAMs have been subsequently verified to contain approved and properly installed filters. POTENTIAL CRITICALITY PATHWAYS INVOLVED (BRIEF SCENARIO(S) OF HOW CRITICALITY COULD OCCUR: In order for a criticality to be possible, a non-fissile NAM would have to be used in a fissile material release and greater than a safe mass of uranium would have to accumulate within the NAM in a configuration favorable for criticality. CONTROLLED PARAMETERS (MASS, MODERATION, GEOMETRY, CONCENTRATION, ETC.): Double contingency for the accumulation of an unsafe fissile mass is maintained by implementing two controls on mass. ESTIMATED AMOUNT, ENRICHMENT, FORM OF LICENSED MATERIAL (INCLUDE PROCESS LIMIT AND % WORST CASE CRITICAL MASS): This system has a process limit of (xx) wt% U235. NUCLEAR CRITICLITY SAFETY CONTROL(S) OR CONTROL SYSTEM(S) AND DESCRIPTION OF THE FAILURES OR DEFICIENCIES: The first leg of double contingency is based on one individual verifying and documenting that approved filters are selected and properly installed. This control prevents loadings of fissile material that are outside the scope of that analyzed in NCSE KY/S-249. This verification was performed, therefore, this control was maintained. The second leg of double contingency is based on a different individual verifying and documenting that approved filters are selected and properly installed. This control prevents loadings of fissile material that are outside the scope of the analyzed in NCSE KY/S-249. Because this verification was not performed, this control was lost. No events have occurred to introduce fissile material into any non-fissile NAMs. Therefore, though the control was violated, the parameter was maintained. Since double contingency is based on two controls on one parameter, and one control was violated, double contingency was not maintained. CORRECTIVE ACTIONS TO RESTORE SAFETY SYSTEMS AND WHEN EACH WAS IMPLEMENTED: 1. Non-fissile Nams verified to contain the correct filters and installed in the correct orientation. Completed 9/11/2003. 2. Procedure CP4-GP-BG2108 placed on hold pending revision to include independent verification requirements specific in NCSA GEN-09. Completed 9/11/2003. The NRC Senior Resident Inspector has been notified of this event. |
| Where | |
|---|---|
| Paducah Gaseous Diffusion Plant Paducah, Kentucky (NRC Region 3) | |
| License number: | Gdp-1 |
| Reporting | |
| Response | |
| Time - Person (Reporting Time:+17.85 h0.744 days <br />0.106 weeks <br />0.0245 months <br />) | |
| Opened: | S. Skaggs 07:36 Sep 12, 2003 |
| NRC Officer: | John Mackinnon |
| Last Updated: | Sep 12, 2003 |
| 40151 - 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 | |