ENS 48398
ENS Event | |
|---|---|
18:05 Oct 10, 2012 | |
| Title | Double Contingency Control for Empty Cylinders Not Maintained |
| Event Description | At 1305 CDT, on 10-10-12 the Plant Shift Superintendent (PSS) was notified that during reviews of paperwork for a customer, it was discovered that four clean, empty cylinders used for transfer did not have a hydrocarbon test performed prior to filling, in violation of NCSA 360-005. NCSA 360-005 requires a test for never used non-USEC owned cylinders prior to filling to detect the presence of hydrocarbons. The presence of moderator in the cylinders could lead to either an 'explosion' that ruptures the cylinder and releases UF6 or criticality from moderation of greater than a safe mass of uranium. The controls ensure that double contingency exits to prevent filling a cylinder containing enough moderator to support criticality.
Cylinders affected are GE0195, GE0191, JM0226, and GE0407 and were filled on 9/16/12 and 9/22/12. Since one leg of double contingency was lost, this is being reported to the NRC as a 24-hour Event Report in accordance with NRC BL 91-01 Supplement 1. The NRC Resident Inspector has been notified of this event. PGDP Problem Report No. ATRC-12-2554; PGDP Event Report No. PAD-2012-06. Responsible Division: Production Support & Product Scheduling SAFETY SIGNIFICANCE OF EVENTS: A control relied upon for double contingency was violated. A cold pressure check and cylinder weight check performed prior to initial transfer of UF6 did not indicate the presence of moderator, and customer compliance with ANSI N14.1 also ensures that cylinders received at PGDP would not contain moderator. There was no indication of an adverse reaction noted during the filling of the cylinders. A cold pressure check performed after filling and cooldown did not indicate that an adverse reaction associated with UF6 and moderator had occurred. The introduction of UF6 eliminates the possibility of any residual moderator remaining in the cylinder; therefore, the cylinders are now in compliance with double contingency. POTENTIAL CRITICALITY PATHWAYS INVOLVED: In order for criticality to be possible, sufficient undetected moderator would have to be present in the cylinder prior to the initial transfer of UF6. Although a control was violated, the cold pressure check ensured the moderation parameter was not exceeded. CONTROLLED PARAMETERS: Double contingency for this scenario is provided by two controls on moderation. ESTIMATED AMOUNT, ENRICHMENT, FORM OF LICENSED MATERIAL: 20,000 lbs. of UF6 at approximately 4.0% U235 enrichment. Plant limit is 5.5 wt.% U235 enrichment NUCLEAR CRITICALITY SAFETY CONTROL(S) OR CONTROL SYSTEM(S) AND DESCRIPTION OF THE FAILURES OR DEFICIENCIES: The first leg of double contingency is based on cylinder compliance with ANSI N14.1 and the performance of a cold pressure check prior to initial transfer of UF6. ANSI N14.1 compliance ensures that the cylinders are clean and free of moderator. The cold pressure check provides a positive indication that no moderator is present inside the cylinder. The cold pressure check was adequately performed prior to initial UF6; therefore, this control was not violated. The second leg of double contingency is based on performing a hydrocarbon test on the internal valve opening of the UF6 cylinder prior to initial transfer of UF6. The presence of hydrocarbon material in a UF6 cylinder could result in a cylinder rupture or criticality prior to initial transfer of UF6. The hydrocarbon test will give telltale signs that the inside of the cylinder may contain oil or other potential moderators. The hydrocarbon test was not performed; therefore, this control was violated. This leg of double contingency is considered to have been lost. Since double contingency for this scenario is based on two controls on one parameter and a control was violated, double contingency was not maintained. CORRECTIVE ACTIONS: None are needed. |
| Where | |
|---|---|
| Paducah Gaseous Diffusion Plant Paducah, Kentucky (NRC Region 2) | |
| License number: | GDP-1 |
| Reporting | |
| Response | |
| Time - Person (Reporting Time:+4.63 h0.193 days <br />0.0276 weeks <br />0.00634 months <br />) | |
| Opened: | Derek Warford 22:43 Oct 10, 2012 |
| NRC Officer: | Charles Teal |
| Last Updated: | Oct 10, 2012 |
| 48398 - 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 | |