Event Notification Report for September 07, 2003
U.S. Nuclear Regulatory Commission
Operations Center
EVENT REPORTS FOR
09/06/2003 - 09/07/2003
EVENT NUMBERS
40139
Fuel Cycle Facility
Event Number: 40139
Facility: PADUCAH GASEOUS DIFFUSION PLANT
Region: 3 State: KY
Unit: [] [] []
RX Type: URANIUM ENRICHMENT FACILITY
Comments: 2 DEMOCRACY CENTER
6903 ROCKLEDGE DRIVE
BETHESDA, MD 20817 (301)564-3200
NRC Notified By: THOMAS WHITE
HQ OPS Officer: RICH LAURA
Region: 3 State: KY
Unit: [] [] []
RX Type: URANIUM ENRICHMENT FACILITY
Comments: 2 DEMOCRACY CENTER
6903 ROCKLEDGE DRIVE
BETHESDA, MD 20817 (301)564-3200
NRC Notified By: THOMAS WHITE
HQ OPS Officer: RICH LAURA
Notification Date: 09/07/2003
Notification Time: 18:15 [ET]
Event Date: 09/07/2003
Event Time: 07:50 [CDT]
Last Update Date: 09/07/2003
Notification Time: 18:15 [ET]
Event Date: 09/07/2003
Event Time: 07:50 [CDT]
Last Update Date: 09/07/2003
Emergency Class: NON EMERGENCY
10 CFR Section:
10 CFR Section:
Person (Organization):
RONALD GARDNER (R3)
JANET SCHLUETER (NMSS)
TIM MCGINTY (IRO)
RONALD GARDNER (R3)
JANET SCHLUETER (NMSS)
TIM MCGINTY (IRO)
24 HOUR REPORT ON CRITICALITY CONTROLS DEGRADATION AT PADUCAH
"At 0750 on 9/7/03, it was discovered that the Recirculating Cooling Water (RCW) Supply valve for C333 Unit 6 Cell 2 was not positioned correctly for the current condition of the cell, in violation of NCSA CAS-011. On 9/3/03, the cell was in a fluorinating environment with the Odd R-114 system drained and evacuated for leak repairs, Odd RCW valves closed, the Even R-114 system was not drained with the Even RCW valves open satisfying the conditions of CAS-002. It was determined that the cell needed to have a UF6 negative obtained for maintenance work. The UF6 negative was initiated without closing the Even RCW Supply valve, tagging both the Supply and Return valve, and without performing the independent checks for valve position, which violates NCSA CAS-002. Once the UF6 negative was obtained, the cell transitioned to NCSA CAS-011 without satisfying the RCW isolation controls of that NCSA. Both RCW isolation controls require that the RCW Supply valve be tagged closed and that the RCW Return valve be tagged open and both valves independently verified to be positioned correctly. The NRC Senior Resident Inspector has been notified of this event.
"SAFETY SIGNIFICANCE OF EVENTS: Since the process condition (lack of moisture in the coolant, and therefore in the process gas system) was maintained, the safety significance of this incident is low.
"POTENTIAL CRITICALITY PATHWAYS INVOLVED (BRIEF SCENARIO OF NOW CRITICALITY OF HOW CRITICALITY COULD OCCUR): Once the fluorinating environment is removed from a process cell, moisture that may leak into the process gas system could potentially moderate any uranium that may be present. Sufficient water would have to leak into the process gas system and moderate a critical mass of uranium.
"CONTROLLED PARAMETERS (MASS, MODERATION, GEOMETRY, CONCENTRATION, ETC
Double contingency is maintained by implementing two controls on mass.
"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 ensuring that a coolant condenser leak will not introduce RCW (moderator) into the process gas side of a cell through the coolant. This is accomplished by either maintaining a fluorinating environment in the cell or by restricting /isolating the RCW supply prior to removing the fluorinating environment. This restriction/isolation is accomplished by either removing a supply spool piece or closing and tagging the manual supply valve and tagging open the return valve. Neither of these two RCW alignments was maintained. The second leg of double contingency is based on an independent verification of the RCW alignment relied upon for the first leg of double contingency. The independent verification was not performed. Therefore, this control was lost, Since double contingency is based on two controls on one parameter, double contingency was not maintained.
"CORRECTIVE ACTIONS TO RESTORE SAFETY SYSTEMS AND WHEN EACH WAS IMPLEMPNTED: At 1010 on 9-7-03, the Even RCW Supply valve was tagged closed, the Odd RCW Return valve was tagged open, and both valves were independently verified. The coolant moisture content was checked and was less than minimum detectible moisture. These actions have placed the system back in compliance with NCSA CAS-011."
"At 0750 on 9/7/03, it was discovered that the Recirculating Cooling Water (RCW) Supply valve for C333 Unit 6 Cell 2 was not positioned correctly for the current condition of the cell, in violation of NCSA CAS-011. On 9/3/03, the cell was in a fluorinating environment with the Odd R-114 system drained and evacuated for leak repairs, Odd RCW valves closed, the Even R-114 system was not drained with the Even RCW valves open satisfying the conditions of CAS-002. It was determined that the cell needed to have a UF6 negative obtained for maintenance work. The UF6 negative was initiated without closing the Even RCW Supply valve, tagging both the Supply and Return valve, and without performing the independent checks for valve position, which violates NCSA CAS-002. Once the UF6 negative was obtained, the cell transitioned to NCSA CAS-011 without satisfying the RCW isolation controls of that NCSA. Both RCW isolation controls require that the RCW Supply valve be tagged closed and that the RCW Return valve be tagged open and both valves independently verified to be positioned correctly. The NRC Senior Resident Inspector has been notified of this event.
"SAFETY SIGNIFICANCE OF EVENTS: Since the process condition (lack of moisture in the coolant, and therefore in the process gas system) was maintained, the safety significance of this incident is low.
"POTENTIAL CRITICALITY PATHWAYS INVOLVED (BRIEF SCENARIO OF NOW CRITICALITY OF HOW CRITICALITY COULD OCCUR): Once the fluorinating environment is removed from a process cell, moisture that may leak into the process gas system could potentially moderate any uranium that may be present. Sufficient water would have to leak into the process gas system and moderate a critical mass of uranium.
"CONTROLLED PARAMETERS (MASS, MODERATION, GEOMETRY, CONCENTRATION, ETC
Double contingency is maintained by implementing two controls on mass.
"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 ensuring that a coolant condenser leak will not introduce RCW (moderator) into the process gas side of a cell through the coolant. This is accomplished by either maintaining a fluorinating environment in the cell or by restricting /isolating the RCW supply prior to removing the fluorinating environment. This restriction/isolation is accomplished by either removing a supply spool piece or closing and tagging the manual supply valve and tagging open the return valve. Neither of these two RCW alignments was maintained. The second leg of double contingency is based on an independent verification of the RCW alignment relied upon for the first leg of double contingency. The independent verification was not performed. Therefore, this control was lost, Since double contingency is based on two controls on one parameter, double contingency was not maintained.
"CORRECTIVE ACTIONS TO RESTORE SAFETY SYSTEMS AND WHEN EACH WAS IMPLEMPNTED: At 1010 on 9-7-03, the Even RCW Supply valve was tagged closed, the Odd RCW Return valve was tagged open, and both valves were independently verified. The coolant moisture content was checked and was less than minimum detectible moisture. These actions have placed the system back in compliance with NCSA CAS-011."