ENS 41020
ENS Event | |
|---|---|
18:45 Sep 4, 2004 | |
| Title | Violation of Nuclear Criticality Safety Control in the Process Building |
| Event Description | At 1345 [CDT], on 09-04-04 the Plant Shift Superintendent was notified of a violation of Nuclear Criticality Safety (NCS) control in the C-337 process building. During Inspection of the RCW (Recirculating Cooling Water) line to the RCW/ R114 Differential Pressure alarm switches (DP switches) for the C-337 #5 Low Speed P&E (Purge and Evacuation) Pump, Instrument Maintenance discovered that the instrument line boss was plugged. This condition rendered both Independent DP switches incapable of performing their intended safety, violating an SRI (Safety Related Item) in Nuclear Criticality Safety Evaluation (NCSE) 039. The SRI requires that both DP alarms are to be functional while the P&E pump is Isolated from the cascade process system. The purpose of the SRI is to alert an operator to take actions within a 28 hour3.240741e-4 days <br />0.00778 hours <br />4.62963e-5 weeks <br />1.0654e-5 months <br /> timeframe to prevent high moisture R-114 from leaking into the process gas system. The DP alarms had likely 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. Clarity of the Instrument line boss was subsequently re-established and both DP alarms were returned to service. The R-114 was sampled and determined to be dry (low moisture content) within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> of discovery, thereby re-establishing double contingency.
SAFETY SIGNIFICANCE OF EVENTS: While the R-114 was demonstrated to be dry, both OF alarms relied on for double contingency were disabled without the knowledge of the operators. CONTROLLED PARAMETERS: Double contingency Is maintained by Implementing two controls on moderation. 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 within four hours time of discovery. PGDP Problem Report No. ATR-04-3602; PGDP Event Report No. PAD-2004-22 The Senior 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:+2.73 h0.114 days <br />0.0162 weeks <br />0.00374 months <br />) | |
| Opened: | Eric Walker 21:29 Sep 4, 2004 |
| NRC Officer: | Arlon Costa |
| Last Updated: | Sep 4, 2004 |
| 41020 - 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 | |