ENS 40641
ENS Event | |
|---|---|
19:30 Apr 4, 2004 | |
| Title | 24-Hour Nrc Bulletin 91-01 Loss of Criticality Control Notification |
| Event Description | At 1430, on 04-04-04 the Plant Shift Superintendent was notified of a violation of Nuclear Criticality Safety (NCS) control in the C-333 process building. While preparing for start up of the C-333 #1 High Speed Purge and Evacuation (P & E) pump, operations discovered that the delta pressure (DP) alarm instrument line to the RCW supply was unattached and the isolation valve was closed. With the RCW instrument line not attached, both DP alarms for this pump were not functional and therefore not able to perform their safety function, violating a safety related item (SRI) in NCSE 039. The SRI requires that both DP alarms be functional while the P & E is isolated from the cascade. The purpose of the SRI Is to alert the operator to take actions within a 28-hour timeframe to prevent wet R-114 from leaking into the process gas system. The DP alarms had been nonfunctional for more than 28 hours3.240741e-4 days <br />0.00778 hours <br />4.62963e-5 weeks <br />1.0654e-5 months <br /> when discovered. Both DP alarms were put back in service and the R-114 sampled and found dry within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> of discovery, therefore, re-establishing double contingency.
The Senior NRC Resident Inspector has been notified of this event. PGDP Problem Report No, ATR-04-1342; PGDP Event Report No. PAD-2004-09; Event Worksheet #40641 Responsible Division: Operations SAFETY SIGNIFICANCE OF EVENTS: While the R-114 was demonstrated to be dry, both DP alarms relied on for double contingency were disabled without the knowledge of the operators. POTENTIAL CRITICALITY PATHWAYS INVOLVED: In order for a criticality to occur, an unsafe mass uranium deposit would have to be present in the process gas system, an R-114 leak to the process gas system would have to occur, the R-114 would have to contain an unacceptable amount of moisture ( i.e., greater than 10 kg of water) and moderate the deposit. CONTROLLED PARAMETERS (MASS, MODERATION, G5OMETRY, CONCENTRATION, ETC): Double contingency is maintained by implementing two controls on moderation. ESTIMATED AMOUNT, ENRICHMENT, FORM OF LICENSED MATERIAL: No known mass of licensed material exists in the #1 High Speed Purge and Evacuation pump. 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 the DP switch alarming to alert the operator to take action to either verify the R-114 is dry or to isolate the RCW and remove the R-114 from the system in order to prevent water from leaking into the process gas system. This DP alarm was not maintained as functional. The DP alarm was put back in service and the R-114 was sampled and found to be dry. The SRI was not maintained and the control was violated but the process condition was maintained. The second leg of double contingency is based on the independent DP switch alarming to alert the operator to take action to either verify the R-114 is dry or to isolate the RCW and remove the R-114 from the system in order to prevent water from leaking into the process gas system. The independent DP alarm was not maintained as functional. The independent DP alarm was put back in service and the R-114 was sampled and found to be dry. The SRI was not maintained and the control was violated but the process condition was maintained. This re-established double contingency. CORRECTIVE ACTIONS TO RESTORE SAFETY SYSTEMS AND WHEN EACH WAS IMPLEMENTED: Both DP switches were returned to service and the R-114 was sampled and found to be dry on 04-04-04 at 1655.
Subsequent assay sample analysis of the Purge and Evacuation pump system indicates the system is non-fissile. The PGDP notified the NRC Resident Inspector. Notified NMSS (Torres) and R2DO (Ernstes) |
| Where | |
|---|---|
| Paducah Gaseous Diffusion Plant Paducah, Kentucky (NRC Region 2) | |
| License number: | GDP-1 |
| Reporting | |
| Response | |
| Time - Person (Reporting Time:+6.17 h0.257 days <br />0.0367 weeks <br />0.00845 months <br />) | |
| Opened: | Kevin Beasley 01:40 Apr 5, 2004 |
| NRC Officer: | Mike Ripley |
| Last Updated: | Apr 29, 2004 |
| 40641 - 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 | |