ENS 40805
ENS Event | |
|---|---|
10:53 Apr 23, 2004 | |
| Title | Paducah Gaseous Diffussion Plant - Response Bulletin 91-01 24 - Hour Report |
| Event Description | At 1550 on 6-09-04, the Plant Shift Superintendent was notified of a failure of a Safety Related Item (SRI) relied upon in Nuclear Criticality Safety Evaluation (NCSE) 052 'Enrichment Cascade During Normal Operations at the Paducah Gaseous Diffusion Plant.' At 0553 hours0.0064 days <br />0.154 hours <br />9.143518e-4 weeks <br />2.104165e-4 months <br /> on 4-23-04, when responding to alarms on Cell 6 in Building C-310, the second bank of motors could not be shut down using the manual motor trip system. Operators opened the Transformer Secondary Breaker (TSB) as an alternate means to shut down the motors. The manual motor trip system is credited to mitigate/minimize the consequences or extent of a Hot Metal Reaction (HMR).
PGDP Problem Report No, ATRC-04-2299; PGDP Event Report No. PAD-2004-17; Event Worksheet [NRC Event Number]: # 40805, Responsible Division: Operations. SAFETY SIGNIFICANCE OF EVENTS: Minimal. There are multiple methods capable of shutting down equipment suspected of undergoing a HMR. The compressor motors were shut down using one of these methods. The shutdown was accomplished within 2 minutes. POTENTIAL CRITICALITY PATHWAYS INVOLVED (BRIEF SCENARIOS) OF HOW CRITICALITY COULD OCCUR: In order for a criticality to occur, the equipment would have had to be involved In the initiating event of a HMR. There were no indications of a HMR. Additionally, the HMR event would need to have occurred with a significant inventory of UF6 present. The event was in the purge cascade having UF6 concentrations in the ppm range. Therefore, there is no credible pathway to criticality for this incident. CONTROLLED PARAMETERS (MASS, MODERATION. GEOMETRY, CONCENTRATION, ETC): This scenario is singly contingent based on moderation control. ESTIMATED AMOUNT, ENRICHMENT, FORM OF LICENSED MATERIAL (INCLUDE PROCESS LIMIT AND % WORST CASE CRITICAL MASS): The event was in the purge cascade having UF6 concentrations in the ppm range at an enrichment of less than [DELETED] wt % 235U. NUCLEAR CRITICALITY SAFETY CONTROL(S) OR CONTROL SYSTEM(S) AND DESCRIPTION OF THE FAILURES OR DEFICIENCIES: This scenario is singly contingent based on moderation control. The scenario indicates that it is unlikely for a significant HMR to occur resulting in a cooler/cascade breach with subsequent sprinkler activation based on historical operations. The manual motor trip system is credited to mitigate/minimize the consequences or extent of a HMR. The credited trip failed to perform its intended function. Although the credited trip failed, alternative methods were used to shutdown the cell, thereby satisfying the intent of the administrative portion of the control. Also, no HMR, cell breach, or sprinkler activation occurred. Although the SRI failed, the moderation parameter was maintained. CORRECTIVE ACTIONS TO RESTORE SAFETY SYSTEMS AND WHEN EACH WAS IMPLEMENTED: The cell was shut down using alternate means within 2 minutes. The manual motor trip system was declared inoperable at 0700 on 4-23-04 and repaired. The NRC Resident Inspector has been notified of this event. |
| Where | |
|---|---|
| Paducah Gaseous Diffusion Plant Paducah, Kentucky (NRC Region 2) | |
| License number: | GDP-1 |
| Reporting | |
| Response | |
| Time - Person (Reporting Time:+1157.73 h48.239 days <br />6.891 weeks <br />1.586 months <br />) | |
| Opened: | Calvin Pittman 16:37 Jun 10, 2004 |
| NRC Officer: | Gerry Waig |
| Last Updated: | Jun 10, 2004 |
| 40805 - 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 | |