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Event Notification Report for March 26, 2007

U.S. Nuclear Regulatory Commission
Operations Center

Event Reports For
03/22/2007 - 03/26/2007

** EVENT NUMBERS **


42165

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Fuel Cycle Facility Event Number: 42165
Facility: PADUCAH GASEOUS DIFFUSION PLANT
RX Type: URANIUM ENRICHMENT FACILITY
Comments: 2 DEMOCRACY CENTER
                   6903 ROCKLEDGE DRIVE
                   BETHESDA, MD 20817 (301)564-3200
Region: 2
City: PADUCAH State: KY
County: McCRACKEN
License #: GDP-1
Agreement: Y
Docket: 0707001
NRC Notified By: KEVIN BEASLEY
HQ OPS Officer: BILL HUFFMAN
Notification Date: 11/22/2005
Notification Time: 15:54 [ET]
Event Date: 11/22/2005
Event Time: 12:05 [CST]
Last Update Date: 03/23/2007
Emergency Class: NON EMERGENCY
10 CFR Section:
RESPONSE-BULLETIN
Person (Organization):
KERRY LANDIS (R2)
SCOTT FLANDERS (NMSS)

Event Text

IMPROPER CRITICALITY SPACING FOR WASTE DRUM

"At 1205 CST, on 11-22-05 the Plant Shift Superintendent was notified that during waste drum remediation activities, a drum was discovered that was in violation of one leg of double contingency. Drum #39666W has been determined to contain up to (deleted) g (grams) U235 exceeding the allowed (deleted) gram limit for NCS Spacing Exempt drums. This drum was previously located in an NCS (Nuclear Criticality Safety) Spacing Exempt storage area in violation of NCSA WMO-001 requirements. The drum was moved to the C-335 storage area under an approved Remediation Guide which established a safety basis for the movement of drums that had been roped off and posted per earlier direction. This drum is currently stored in a Temporary Fissile Storage Area maintaining a minimum 2 foot edge-to-edge spacing under NCSA WMO-001, which maintains double contingency."

SAFETY SIGNIFICANCE OF EVENTS

"While the (deleted) gram U235 limit was exceeded for this drum; DAC-832-2A1280-0001 demonstrates that drums containing less than (deleted) grams U235 in an NCS Spacing Exempt array are subcritical. The storage area is roped off and posted to prevent the addition of fissile material to the area; therefore another upset would be required before a criticality is possible."

POTENTIAL CRITICALITY PATHWAYS INVOLVED (BRIEF SCENARIO(S) OF HOW CRITICALITY COULD OCCUR)

"This drum is currently stored in the Temporary Fissile Storage Area under NCSA WMO-001, meeting double contingency. In order for a criticality to occur, two independent, unlikely, and concurrent events would have to occur."

CONTROLLED PARAMETERS (MASS, MODERATION, GEOMETRY, CONCENTRATION, ETC.)

"Double contingency is maintained by implementing two controls on mass."

ESTIMATED AMOUNT, ENRICHMENT, FORM OF LICENSED MATERIAL (INCLUDE PROCESS LIMIT AND % WORST CASE CRITICAL MASS)

"The drum has been determined to contain (deleted) grams U235. Calculations performed demonstrate that drums containing less than (deleted) grams U235 each, in an NCS Spacing Exempt array are subcritical."

NUCLEAR CRITICALITY SAFETY CONTROL(S) OR CONTROL SYSTEM(S) AND DESCRIPTION OF THE FAILURES OR DEFICIENCIES

"Although the drum contains greater than the WMO-001 limit of (deleted) grams U235 for NCS Spacing Exempt drums, it has been shown to be less than (deleted) grams U235 based on independent sample results. Calculations performed demonstrate that drums containing less than (deleted) grams U235 each, in an NCS Spacing Exempt array, are subcritical. Therefore, an additional process upset (i.e., spacing upset) would be necessary in order to have a criticality. Therefore, while the drum contained greater than (deleted) grams U235 in the spacing exempt array, the array has been shown to be subcritical for drums containing less than (deleted) grams U235 thus maintaining one leg of double contingency."

CORRECTIVE ACTIONS TO RESTORE SAFETY SYSTEMS AND WHEN EACH WAS IMPLEMENTED

"At the time of discovery, the drum was being stored according to NCS approved spacing controls. The drum will continue to be handled according to approved controls until the U235 mass can be reduced to meet the NCS Spacing Exempt criteria per NCSA WMO-001.

The NRC Senior Resident Inspector has been notified of this event."
See Related Event Report #40700.

* * * UPDATE 1802 EST ON 2/13/06 FROM K. BEASLEY TO S. SANDIN * * *

"At 1100 [CST], on 02-13-06 the Plant Shift Superintendent was notified that two additional waste drums were discovered that exceed the allowed [deleted] gram limit for NCS Spacing Exempt drums and had previously been located in an NCS Spacing Exempt storage area in violation of NCSA WMO-001. The drums are currently stored in a Temporary Fissile Storage Area under NCSA WMO-001, which maintains double contingency.

"The NRC Senior Resident Inspector has been notified of this event."

Notified R2DO(Ayres) and NMSS (Camper).

* * * UPDATE ON 3/20/06 AT 1859 EST FROM B. WALLACE TO HUFFMAN * * *

"At 1430, on 03-20-06, the Plant Shift Superintendent was notified that an additional waste drum has been discovered that exceeds the allowed (deleted) gram limit for NCS Spacing Exempt drums and had previously been located in an NCS Spacing Exempt storage area in violation of NCSA WMO-001. The drums are currently stored in a Temporary Fissile Storage Area under NCSA WMO-001, which maintains double contingency.

"The additional drum was determined to contain (deleted) grams U235. Calculations performed demonstrate that drums containing less than (deleted) grams U235 each, in an NCS Spacing Exempt array are subcritical."

The licensee notified the NRC Resident Inspector. R2DO (Ernstes) and NMSS EO (Pierson) notified.

* * * UPDATE ON 4/20/06 AT 1750 EDT FROM B. WALLACE TO HUFFMAN * * *

" At 1130, on 04-20-06 the Plant Shift Superintendent was notified that an additional waste drum has been discovered that exceeds the allowed (deleted) gram limit for NCS Spacing Exempt drums and had previously been located in an NCS Spacing Exempt storage area in violation of NCSA WMO-001. The drums are currently stored in a Temporary Fissile Storage Area under NCSA WMO-001, which maintains double contingency.

"The additional drum (#41663) was determined to contain (deleted) grams of U235."

The licensee notified the NRC Resident Inspector. R2DO (Lesser) and NMSS EO (Janosko) notified.

* * * UPDATE ON 4/21/06 AT 2040 EDT FROM WALKER TO HUFFMAN * * *

"At 1333, on 4-21-06 the Plant Shift Superintendent was notified that seven additional waste drums had been discovered that exceed the allowed (deleted) gram limit for NCS Spacing Exempt drums and had previously been located in an NCS Spacing Exempt storage area in violation of NCSA WMO-001. The drums are currently stored in a Temporary Fissile Storage Area under NCSA WMO-001, which maintains double contingency.

"Seven additional drums (41160W,41161W,41162W,41158W,41159W,40605W.41681W) were determined to contain in excess of the (deleted) gram limit of U235 but less than the (deleted) gram safety limit."

The licensee notified the NRC Resident Inspector. R2DO (Lesser) and NMSS EO (Janosko) notified.

* * * UPDATE ON 4/28/06 AT 1802 EDT FROM WALKER TO A. COSTA * * *

"At 1430, on 04-28-06 the Plant Shift Superintendent was notified that an additional waste drum has been discovered that exceeds the allowed [DELETED] gram limit for NCS Spacing Exempt drums and had previously been located in an NCS Spacing Exempt storage area in violation of NCSA WMO-001. The drum is currently stored in a Temporary Fissile Storage Area under NCSA WMO-001, which maintains double contingency.

"[This] one additional drum, # 43170W was determined to contain in excess of the [DELETED] gram limit of U235 but less than the [DELETED] gram safety limit."

The licensee notified the NRC Resident Inspector. Notified R2DO (Landis) and NMSS EO (Giitter).

* * * UPDATE ON 10/11/06 AT 1551 EDT FROM WALLACE TO HUFFMAN * * *

At 0900, on 10-11-06 the Plant Shift Superintendent was notified that an additional waste drum (#41470W) has been discovered that exceeds the allowed limit (but less than the safety limit) for NCS Spacing Exempt drums and had previously been located in an NCS Spacing Exempt storage area in violation of NCSA WMO-001. The drum is currently stored in a Temporary Fissile Storage Area under NCSA WMO-001, which maintains double contingency.

The licensee notified the NRC Resident Inspector. Notified R2DO (Decker) and NMSS EO (Essig).

* * * UPDATE ON 10/24/06 AT 1130 EDT FROM K. A. BEASLEY TO MACKINNON * * *


At 1000, on 10/24/06 the Plant Shift Superintendent was notified that an additional waste drum has been discovered that exceeds the allowed [Deleted] gram limit for NCS Spacing Exempt drums and had previously been located in an NCS Spacing Exempt storage area in violation of NCSA WMO-001. The drum is currently stored in a Temporary Fissile Storage Area under NCSA WMO-001, which maintains double contingency.

The NRC Senior Resident Inspector has been notified of this event. Notified R2DO (Brain Bonser) and NMSS (Sandra Wastler).


* * * UPDATE ON 12/08/06 AT 1604 EST FROM K. A. BEASLEY TO KOZAL * * *

At 1140 on 12/08/06 the Plant Shift Superintendent was notified that an additional waste drum (42171W) has been discovered that exceeds the allowed [Deleted] gram limit for NCS Spacing Exempt drums and had previously been located in an NCS Spacing Exempt storage area in violation of NSCA WMO-001. The drum is currently stored in a Temporary Fissile Storage Area under NCSA WMO-001, which maintains double contingency.

The licensee notified the NRC Resident Inspector. Notified R2RDO (Lesser) and NMSS EO (Janosko).

* * * UPDATE ON 12/18/06 AT 1250 EST FROM B. W. WALLACE TO KOZAL * * *

At 1250 on 12/18/06 the Plant Shift Superintendent was notified that 4 additional waste drums (39639W, 42118W, 42488W, & 43521W) had been discovered that exceeds the allowed [Deleted] gram limit for NCS Spacing Exempt drums and had previously been located in an NCS Spacing Exempt storage area in violation of NSCA WMO-001. The drum is currently stored in a Temporary Fissile Storage Area under NCSA WMO-001, which maintains double contingency.

The licensee notified the NRC Resident Inspector. Notified R2RDO (Moorman) and NMSS EO (Ruland).

* * * UPDATE ON 3/23/07 AT 1602 EDT FROM C. PITTMAN TO JOE O'HARA * * *

"At 1345 on 3/23/07 the Plant Shift Superintendent was notified that an additional waste drum (43561W) had been discovered that exceeds the allowed [Deleted] gram limit for NCS Spacing Exempt drums and had previously been located in an NCS Spacing Exempt storage area in violation of NSCA WMO-001. The drum is currently stored in a Temporary Fissile Storage Area under NCSA WMO-001, which maintains double contingency."

The licensee notified the NRC Resident Inspector. Notified R2RDO (Lesser) and FSME EO (Brach).

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