Event Notification Report for October 16, 2001
U.S. Nuclear Regulatory Commission
Operations Center
EVENT REPORTS FOR
10/15/2001 - 10/16/2001
EVENT NUMBERS
38395
Fuel Cycle Facility
Event Number: 38395
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: FANGIE JONES
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: FANGIE JONES
Notification Date: 10/16/2001
Notification Time: 16:18 [ET]
Event Date: 10/16/2001
Event Time: 00:00 [EDT]
Last Update Date: 10/16/2001
Notification Time: 16:18 [ET]
Event Date: 10/16/2001
Event Time: 00:00 [EDT]
Last Update Date: 10/16/2001
Emergency Class: NON EMERGENCY
10 CFR Section:
10 CFR Section:
Person (Organization):
DOUGLAS COLLINS (R2)
JOHN HICKEY (NMSS)
DOUGLAS COLLINS (R2)
JOHN HICKEY (NMSS)
NRC BULLETIN 91-01 REPORT - 24 HOUR
The following is from a faxed report:
At approximately 1630 on October 15, 2001 following an automatic shutdown of Dry Conversion Process Line 2, a higher than normal moisture analytical result was identified on Line 2A powder outlet cooling hopper. Manual moisture sample results indicated free moisture content in the U02 powder averaged 1.2% which is above the operational limit of 0.4% but well below the safety limit of 11 .2%.
The associated outlet hatch valve control valve seats were subsequently determined to be leaking, leading to material with a higher than normal moisture content in the cooling hopper. The associated active engineered control (AEC) interlocks functioned as designed, the cooling hoppers were isolated, and the conversion process was automatically shutdown, thus no unsafe condition existed.
The affected material has been transferred to favorable geometry containers per procedure.
Controls were reestablished within 4 hours by proper function of the redundant dewpoint probe interlocks and automatic system shutdown. This event is reported pursuant to NRC Bulletin 91-01 (within 24 hours) due to loss of one of two independent moderation controls. Line 2 conversion remains shutdown pending investigation and implementation of corrective actions.
SAFETY SIGNIFICANCE OF EVENTS:
Low safety significance - actual moisture content averaged 1.2% (12,200 ppm H20) within the established uniform moderation limit of 11.2% for (112,000 ppm H20) for the cooling hopper.
POTENTIAL CRITICALITY PATHWAYS INVOLVED (BRIEF SCENARIO(S) OF HOW CRITICALITY COULD OCCUR):
Multiple failure modes required before a criticality accident could occur.
CONTROLLED PARAMETER(S) (MASS. MODERATION. GEOMETRY. CONCENTRATION. ETC):
Moderation
ESTIMATED AMOUNT, ENRICHMENT, FORM OF LICENSED MATERIAL (INCLUDE PROCESS LIMIT AND % WORST CASE CRITICAL MASS):
Net U02 inside cooling hopper A was ~50 kgs (4.95 % enriched) with 1.22% H20 (12,200 ppm H20).
Uniform moderation limit for cooling hopper is 11.2% (112,000 ppm H20) assuming 5% enriched U02.
NUCLEAR CRITICALITY SAFETY CONTROL(S) OR CONTROL SYSTEM(S) AND DESCRIPTION OF THE FAILURES OR DEFICIENCIES:
Upstream moderation control on outlet hatch control system partially failed due to valve seat.
CORRECTIVE ACTIONS TO RESTORE SAFETY SYSTEMS AND WHEN EACH WAS IMPLEMENTED:
1. Conversion Line 2 shutdown.
2. Outlet hatch valve being replaced.
3. Investigation and implementation of additional corrective actions pending.
The licensee intends to notify the local and state authorities and NRC Region 2 (David Ayres)
The following is from a faxed report:
At approximately 1630 on October 15, 2001 following an automatic shutdown of Dry Conversion Process Line 2, a higher than normal moisture analytical result was identified on Line 2A powder outlet cooling hopper. Manual moisture sample results indicated free moisture content in the U02 powder averaged 1.2% which is above the operational limit of 0.4% but well below the safety limit of 11 .2%.
The associated outlet hatch valve control valve seats were subsequently determined to be leaking, leading to material with a higher than normal moisture content in the cooling hopper. The associated active engineered control (AEC) interlocks functioned as designed, the cooling hoppers were isolated, and the conversion process was automatically shutdown, thus no unsafe condition existed.
The affected material has been transferred to favorable geometry containers per procedure.
Controls were reestablished within 4 hours by proper function of the redundant dewpoint probe interlocks and automatic system shutdown. This event is reported pursuant to NRC Bulletin 91-01 (within 24 hours) due to loss of one of two independent moderation controls. Line 2 conversion remains shutdown pending investigation and implementation of corrective actions.
SAFETY SIGNIFICANCE OF EVENTS:
Low safety significance - actual moisture content averaged 1.2% (12,200 ppm H20) within the established uniform moderation limit of 11.2% for (112,000 ppm H20) for the cooling hopper.
POTENTIAL CRITICALITY PATHWAYS INVOLVED (BRIEF SCENARIO(S) OF HOW CRITICALITY COULD OCCUR):
Multiple failure modes required before a criticality accident could occur.
CONTROLLED PARAMETER(S) (MASS. MODERATION. GEOMETRY. CONCENTRATION. ETC):
Moderation
ESTIMATED AMOUNT, ENRICHMENT, FORM OF LICENSED MATERIAL (INCLUDE PROCESS LIMIT AND % WORST CASE CRITICAL MASS):
Net U02 inside cooling hopper A was ~50 kgs (4.95 % enriched) with 1.22% H20 (12,200 ppm H20).
Uniform moderation limit for cooling hopper is 11.2% (112,000 ppm H20) assuming 5% enriched U02.
NUCLEAR CRITICALITY SAFETY CONTROL(S) OR CONTROL SYSTEM(S) AND DESCRIPTION OF THE FAILURES OR DEFICIENCIES:
Upstream moderation control on outlet hatch control system partially failed due to valve seat.
CORRECTIVE ACTIONS TO RESTORE SAFETY SYSTEMS AND WHEN EACH WAS IMPLEMENTED:
1. Conversion Line 2 shutdown.
2. Outlet hatch valve being replaced.
3. Investigation and implementation of additional corrective actions pending.
The licensee intends to notify the local and state authorities and NRC Region 2 (David Ayres)