Event Notification Report for April 10, 2000
U.S. Nuclear Regulatory Commission
Operations Center
EVENT REPORTS FOR
04/09/2000 - 04/10/2000
Fuel Cycle Facility
Event Number: 36879
Facility: PORTSMOUTH GASEOUS DIFFUSION PLANT
Region: 3 State: OH
Unit: [] [] []
RX Type: URANIUM ENRICHMENT FACILITY
Comments: 2 DEMOCRACY CENTER
6903 ROCKLEDGE DRIVE
BETHESDA, MD 20817 (301)564-3200
NRC Notified By: RICK LARSON
HQ OPS Officer: DOUG WEAVER
Region: 3 State: OH
Unit: [] [] []
RX Type: URANIUM ENRICHMENT FACILITY
Comments: 2 DEMOCRACY CENTER
6903 ROCKLEDGE DRIVE
BETHESDA, MD 20817 (301)564-3200
NRC Notified By: RICK LARSON
HQ OPS Officer: DOUG WEAVER
Notification Date: 04/10/2000
Notification Time: 20:57 [ET]
Event Date: 04/10/2000
Event Time: 14:00 [EDT]
Last Update Date: 04/10/2000
Notification Time: 20:57 [ET]
Event Date: 04/10/2000
Event Time: 14:00 [EDT]
Last Update Date: 04/10/2000
Emergency Class: NON EMERGENCY
10 CFR Section:
10 CFR Section:
Person (Organization):
PATRICK HILAND (R3)
JOHN HICKEY (NMSS)
PATRICK HILAND (R3)
JOHN HICKEY (NMSS)
NRC BULLETIN 91-01, 24 HOUR REPORT
"AT 1400 HOURS ON APRIL 10, 2000, X-710 LABORATORY PERSONNEL WERE CONDUCTING A SELF ASSESSMENT REVIEW OF NCSA-710-025.A00 (HANDLING AND STORAGE OF SAMPLES FROM ES&H ANALYTICAL LABS) WHEN THEY DISCOVERED THAT REQUIREMENT #4 (SPACING) WAS NOT BEING MAINTAINED IN A SPECIFIED STORAGE AREA WITHIN THE FACILITY. REQUIREMENT #4 STATES: 'A
MINIMUM SPACING OF TWO FEET SHALL BE MAINTAINED BETWEEN GROUPS OF SAMPLES, EXCLUDING EXEMPTED SAMPLES.' THE FACT THAT THIS REQUIREMENT WAS NOT BEING MAINTAINED RESULTED IN A LOSS OF ONE CONTROL (SPACING). THIS CONSTITUTES A LOSS OF CONTROL 'A' (SPACING) AS IDENTIFIED IN THE DOUBLE CONTINGENCY MATRIX A/B.7.1. CONTROL 'B' (MASS + VOLUME + ENRICHMENT) WAS MAINTAINED THROUGHOUT THIS EVENT.
"AT THE DIRECTION OF THE PLANT SHIFT SUPERINTENDENT, THE REQUIREMENTS FOR AN ANOMALOUS CONDITION WERE ESTABLISHED PER PLANT PROCEDURES. AT 1630 HOURS ON 04/10/2000, DOUBLE CONTINGENCY CONTROLS WERE REESTABLISHED (SPACING) UNDER THE DIRECTION OF ONSCENE NUCLEAR CRITICALITY SAFETY PERSONNEL.
"AT THE DIRECTION OF THE PLANT SHIFT SUPERINTENDENT, THE X-710 MANAGEMENT STAFF WILL CONDUCT BRIEFINGS WITH THE RESPECTIVE PERSONNEL TO PREVENT RECURRENCE."
THE LICENSEE NOTIFIED THE NRC RESIDENT INSPECTOR.
SAFETY SIGNIFICANCE OF EVENT:
The safety significance of this event is very low. The group involved contained a maximum of 82 grams of U235
which is less than 11% of minimum sub-critical mass at 100% enrichment. Groups of samples with or > or += 500 ppm U235 are supposed to be controlled in separate safe mass groups spaced apart from the samples with < 500 ppm U235. In this event two groups were not spaced as required.
POTENTIAL CRITICALITY PATHWAYS INVOLVED BRIEF SCENARIO(S) OF HOW CRITICALITY COULD OCCUR):
Additional mass would be required and/or additional spacing violations would be required before a criticality would be possible. A mass of 760 grams U235 of sub-critical with optimum moderation, optimum geometry, and reflection according to ANSI/ANS-8.1
CONTROLLED PARAMETERS (MASS, MODERATION, GEOMETRY, CONCENTRATION, ETC.):
Mass and spacing were the controlled parameters. The spacing control was lost when the group of samples containing the > or = 500 ppm U235 sample was stored too close to a group of samples with < 500 ppm U235.
ESTIMATED AMOUNT, ENRICHMENT, FORM OF LICENSED ,MATERIAL (INCLUDE PROCESS LIMIT AND % WORST CASE OF CRITICAL MASS):
The amount of material is approximately 82 grams U235 based on a very conservative estimate for U235 mass. This represents 11% of the minimum sub-critical mass.
NUCLEAR CRITICALITY SAFETY CONTROL(S) OR CONTROL SYSTEM(S) AND DESCRIPTION OF THE FAILURES OR DEFICIENCIES:
Mass and spacing are the applicable controls. The spacing control was lost when two sample groups were stored without the required 24" minimum spacing.
CORRECTIVE ACTIONS TO RESTORE SAFETY SYSTEM AND WHEN EACH WAS IMPLEMENTED:
Under the direction of the Nuclear Criticality Safety Staff control was re-established (spacing) at 1630 hours. Plant Shift Superintendent directed facility management to conduct crew briefings prior to restart of operations.
"AT 1400 HOURS ON APRIL 10, 2000, X-710 LABORATORY PERSONNEL WERE CONDUCTING A SELF ASSESSMENT REVIEW OF NCSA-710-025.A00 (HANDLING AND STORAGE OF SAMPLES FROM ES&H ANALYTICAL LABS) WHEN THEY DISCOVERED THAT REQUIREMENT #4 (SPACING) WAS NOT BEING MAINTAINED IN A SPECIFIED STORAGE AREA WITHIN THE FACILITY. REQUIREMENT #4 STATES: 'A
MINIMUM SPACING OF TWO FEET SHALL BE MAINTAINED BETWEEN GROUPS OF SAMPLES, EXCLUDING EXEMPTED SAMPLES.' THE FACT THAT THIS REQUIREMENT WAS NOT BEING MAINTAINED RESULTED IN A LOSS OF ONE CONTROL (SPACING). THIS CONSTITUTES A LOSS OF CONTROL 'A' (SPACING) AS IDENTIFIED IN THE DOUBLE CONTINGENCY MATRIX A/B.7.1. CONTROL 'B' (MASS + VOLUME + ENRICHMENT) WAS MAINTAINED THROUGHOUT THIS EVENT.
"AT THE DIRECTION OF THE PLANT SHIFT SUPERINTENDENT, THE REQUIREMENTS FOR AN ANOMALOUS CONDITION WERE ESTABLISHED PER PLANT PROCEDURES. AT 1630 HOURS ON 04/10/2000, DOUBLE CONTINGENCY CONTROLS WERE REESTABLISHED (SPACING) UNDER THE DIRECTION OF ONSCENE NUCLEAR CRITICALITY SAFETY PERSONNEL.
"AT THE DIRECTION OF THE PLANT SHIFT SUPERINTENDENT, THE X-710 MANAGEMENT STAFF WILL CONDUCT BRIEFINGS WITH THE RESPECTIVE PERSONNEL TO PREVENT RECURRENCE."
THE LICENSEE NOTIFIED THE NRC RESIDENT INSPECTOR.
SAFETY SIGNIFICANCE OF EVENT:
The safety significance of this event is very low. The group involved contained a maximum of 82 grams of U235
which is less than 11% of minimum sub-critical mass at 100% enrichment. Groups of samples with or > or += 500 ppm U235 are supposed to be controlled in separate safe mass groups spaced apart from the samples with < 500 ppm U235. In this event two groups were not spaced as required.
POTENTIAL CRITICALITY PATHWAYS INVOLVED BRIEF SCENARIO(S) OF HOW CRITICALITY COULD OCCUR):
Additional mass would be required and/or additional spacing violations would be required before a criticality would be possible. A mass of 760 grams U235 of sub-critical with optimum moderation, optimum geometry, and reflection according to ANSI/ANS-8.1
CONTROLLED PARAMETERS (MASS, MODERATION, GEOMETRY, CONCENTRATION, ETC.):
Mass and spacing were the controlled parameters. The spacing control was lost when the group of samples containing the > or = 500 ppm U235 sample was stored too close to a group of samples with < 500 ppm U235.
ESTIMATED AMOUNT, ENRICHMENT, FORM OF LICENSED ,MATERIAL (INCLUDE PROCESS LIMIT AND % WORST CASE OF CRITICAL MASS):
The amount of material is approximately 82 grams U235 based on a very conservative estimate for U235 mass. This represents 11% of the minimum sub-critical mass.
NUCLEAR CRITICALITY SAFETY CONTROL(S) OR CONTROL SYSTEM(S) AND DESCRIPTION OF THE FAILURES OR DEFICIENCIES:
Mass and spacing are the applicable controls. The spacing control was lost when two sample groups were stored without the required 24" minimum spacing.
CORRECTIVE ACTIONS TO RESTORE SAFETY SYSTEM AND WHEN EACH WAS IMPLEMENTED:
Under the direction of the Nuclear Criticality Safety Staff control was re-established (spacing) at 1630 hours. Plant Shift Superintendent directed facility management to conduct crew briefings prior to restart of operations.
Fuel Cycle Facility
Event Number: 36880
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: CALVIN PITTMAN
HQ OPS Officer: DOUG WEAVER
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: CALVIN PITTMAN
HQ OPS Officer: DOUG WEAVER
Notification Date: 04/10/2000
Notification Time: 21:03 [ET]
Event Date: 04/10/2000
Event Time: 09:47 [CDT]
Last Update Date: 04/10/2000
Notification Time: 21:03 [ET]
Event Date: 04/10/2000
Event Time: 09:47 [CDT]
Last Update Date: 04/10/2000
Emergency Class: NON EMERGENCY
10 CFR Section:
76.120(c)(2)(ii) - EQUIP DISABLED/FAILS
10 CFR Section:
76.120(c)(2)(ii) - EQUIP DISABLED/FAILS
Person (Organization):
PATRICK HILAND (R3)
JOHN HICKEY (NMSS)
PATRICK HILAND (R3)
JOHN HICKEY (NMSS)
SAFETY EQUIPMENT FAILURE (CRITICALITY ALARM SYSTEM TROUBLE)
"At 0947 CDT on 04/10/00, the Plant Shift Superintendent was informed of a trouble alarm on the C-337A Criticality Accident Alarm System (CAAS) cluster. Investigation of trouble alarm revealed that all three modules on the 'N' CAAS cluster were in a 'Fault' condition. With all three modules in this condition, the system was unable to perform its intended safety function, rendering the system inoperable. The system is required to be operable according to TSR 2.2.4.3 for the current mode of operation in twelve rad areas covered by CAAS systems. Overlapping coverage for the C-337A facility was provided by the C-337 'X' and 'V' CAAS clusters. However, the C-360/C-337 tie line CAAS coverage is provided by the 'N' cluster. The system was inoperable for approximately seven minutes until it could be reset per procedure. A portion of the C-337/C-360 tie line was without CAAS coverage as required by TSR 2.2.4.3 during the time of cluster inoperability."
The NRC Senior Resident Inspector has been notified of this event.
(Refer to event #36934 for an event discovered during investigation of this issue.)
"At 0947 CDT on 04/10/00, the Plant Shift Superintendent was informed of a trouble alarm on the C-337A Criticality Accident Alarm System (CAAS) cluster. Investigation of trouble alarm revealed that all three modules on the 'N' CAAS cluster were in a 'Fault' condition. With all three modules in this condition, the system was unable to perform its intended safety function, rendering the system inoperable. The system is required to be operable according to TSR 2.2.4.3 for the current mode of operation in twelve rad areas covered by CAAS systems. Overlapping coverage for the C-337A facility was provided by the C-337 'X' and 'V' CAAS clusters. However, the C-360/C-337 tie line CAAS coverage is provided by the 'N' cluster. The system was inoperable for approximately seven minutes until it could be reset per procedure. A portion of the C-337/C-360 tie line was without CAAS coverage as required by TSR 2.2.4.3 during the time of cluster inoperability."
The NRC Senior Resident Inspector has been notified of this event.
(Refer to event #36934 for an event discovered during investigation of this issue.)