Event Notification Report for August 29, 2002
U.S. Nuclear Regulatory Commission
Operations Center
EVENT REPORTS FOR
08/28/2002 - 08/29/2002
EVENT NUMBERS
39157
Fuel Cycle Facility
Event Number: 39157
Facility: GLOBAL NUCLEAR FUEL - AMERICAS
Region: 2 State: NC
Unit: [] [] []
RX Type: URANIUM FUEL FABRICATION
Comments: LEU CONVERSION (UF6 TO UO2)
LEU FABRICATION
LWR COMMERICAL FUEL
NRC Notified By: LON PAULSON
HQ OPS Officer: JOHN MacKINNON
Region: 2 State: NC
Unit: [] [] []
RX Type: URANIUM FUEL FABRICATION
Comments: LEU CONVERSION (UF6 TO UO2)
LEU FABRICATION
LWR COMMERICAL FUEL
NRC Notified By: LON PAULSON
HQ OPS Officer: JOHN MacKINNON
Notification Date: 08/29/2002
Notification Time: 09:49 [ET]
Event Date: 08/29/2002
Event Time: 00:00 [EDT]
Last Update Date: 08/29/2002
Notification Time: 09:49 [ET]
Event Date: 08/29/2002
Event Time: 00:00 [EDT]
Last Update Date: 08/29/2002
Emergency Class: NON EMERGENCY
10 CFR Section:
10 CFR Section:
Person (Organization):
STEPHEN CAHILL (R2)
DON COOL (NMSS)
STEPHEN CAHILL (R2)
DON COOL (NMSS)
LOSS OF GEOMETRY CONTROL
NRC BULLETIN 24 HOUR NOTIFICATION
"At approximately 4:30 p.m. on August 28, 2002, two (2) rod storage cabinets were determined to have empty stainless steel trays missing from behind the "nuclear safety blank" position in the rod storage cabinet. The stainless steel tray is included in the model used to analyze the configuration and required as part of the geometry control for the rod storage cabinets. The missing stainless steel structure in the two affected rod storage cabinets constitutes a loss of geometry control.
"The independent control on moderation remained intact, thus no unsafe condition existed.
"A total of fifteen (15) rod storage cabinets are used in bundle assembly. The remaining 13 cabinets were confirmed to contain the empty stainless steel rod tray behind the nuclear safety blank positions.
"The geometry control was re-established at 6:30 p.m. by re-installation of the required empty trays within 4-hours of discovery. This condition is reported pursuant to NRC bulletin 91-01 (within 24 hours) due to a loss of geometry control. Implementation of additional corrective actions is pending completion of incident investigation.
"SAFETY SIGNIFICANCE OF EVENTS:
"Low safety significance - rod trays limited to [...] rods; moderation control remained intact.
"POTENTIAL CRITICAL PATHWAYS INVOLVED ((BRIEF SCENARIO(S) OF HOW CRITICALITY COULD OCCUR)):
"Multiple failure modes required before a criticality accident could occur.
"CONTROLLED PARAMETERS (MASS, MODERATION, GEOMETRY, CONCENTRATION, ETC.):
"Geometry and moderation.
"ESTIMATED AMOUNT, ENRICHMENT, FORM OF LICENSED MATERIAL (INCLUDE PROCESS LIMIT AND % WORST BASE CRITICAL MASS):
"Only two (2) rod storage cabinets impacted: the first cabinet contained only 5 loaded and 13 empty authorized storage locations. The second cabinet contained only 2 loaded and 16 empty authorized storage locations. The critical safety analysis for the affected rod storage cabinet models [..] rods per tray. Operational procedures limit each tray to [...] rods maximum. The rod storage cabinet analysis conservatively assumes each tray under full water moderation, optimal interunit H2O, full water reflection conditions, for 5% enriched UO2 rods.
"NUCLEAR CRITICALITY SAFETY CONTROL(S) OR CONTROL SYSTEM(S) AND DESCRIPTION OF THE FAILURES OR DEFICIENCIES:
"The geometry control provided by rod storage cabinet design incorporates 304SS rod trays, including 304SS empty trays structure located behind the nuclear safety blank positions.
"CORRECTIVE ACTIONS TO RESTORE SAFETY SYSTEMS AND WHEN EACH WAS IMPLEMENTED:
"Storage of additional loaded rod trays was suspended. Geometry control was restored by re-installing the required empty stainless steel rod trays behind the nuclear safety blank positions. This activity was completed at 6:30 p.m. on 5/28/02
"Investigation of event and evaluation of additional corrective actions pending."
Licensee will notify NRC Region 2 of this event notification.
NRC BULLETIN 24 HOUR NOTIFICATION
"At approximately 4:30 p.m. on August 28, 2002, two (2) rod storage cabinets were determined to have empty stainless steel trays missing from behind the "nuclear safety blank" position in the rod storage cabinet. The stainless steel tray is included in the model used to analyze the configuration and required as part of the geometry control for the rod storage cabinets. The missing stainless steel structure in the two affected rod storage cabinets constitutes a loss of geometry control.
"The independent control on moderation remained intact, thus no unsafe condition existed.
"A total of fifteen (15) rod storage cabinets are used in bundle assembly. The remaining 13 cabinets were confirmed to contain the empty stainless steel rod tray behind the nuclear safety blank positions.
"The geometry control was re-established at 6:30 p.m. by re-installation of the required empty trays within 4-hours of discovery. This condition is reported pursuant to NRC bulletin 91-01 (within 24 hours) due to a loss of geometry control. Implementation of additional corrective actions is pending completion of incident investigation.
"SAFETY SIGNIFICANCE OF EVENTS:
"Low safety significance - rod trays limited to [...] rods; moderation control remained intact.
"POTENTIAL CRITICAL PATHWAYS INVOLVED ((BRIEF SCENARIO(S) OF HOW CRITICALITY COULD OCCUR)):
"Multiple failure modes required before a criticality accident could occur.
"CONTROLLED PARAMETERS (MASS, MODERATION, GEOMETRY, CONCENTRATION, ETC.):
"Geometry and moderation.
"ESTIMATED AMOUNT, ENRICHMENT, FORM OF LICENSED MATERIAL (INCLUDE PROCESS LIMIT AND % WORST BASE CRITICAL MASS):
"Only two (2) rod storage cabinets impacted: the first cabinet contained only 5 loaded and 13 empty authorized storage locations. The second cabinet contained only 2 loaded and 16 empty authorized storage locations. The critical safety analysis for the affected rod storage cabinet models [..] rods per tray. Operational procedures limit each tray to [...] rods maximum. The rod storage cabinet analysis conservatively assumes each tray under full water moderation, optimal interunit H2O, full water reflection conditions, for 5% enriched UO2 rods.
"NUCLEAR CRITICALITY SAFETY CONTROL(S) OR CONTROL SYSTEM(S) AND DESCRIPTION OF THE FAILURES OR DEFICIENCIES:
"The geometry control provided by rod storage cabinet design incorporates 304SS rod trays, including 304SS empty trays structure located behind the nuclear safety blank positions.
"CORRECTIVE ACTIONS TO RESTORE SAFETY SYSTEMS AND WHEN EACH WAS IMPLEMENTED:
"Storage of additional loaded rod trays was suspended. Geometry control was restored by re-installing the required empty stainless steel rod trays behind the nuclear safety blank positions. This activity was completed at 6:30 p.m. on 5/28/02
"Investigation of event and evaluation of additional corrective actions pending."
Licensee will notify NRC Region 2 of this event notification.