Report of Loss of Criticality Safety Control

["Fill, John (DHS-DDWEM)" <JFill@DHS.CA.GOV>]

April 4, 2002

PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE -- PNO-IV-02-019

This preliminary notification constitutes EARLY notice of events of POSSIBLE

safety or public interest significance. The information is as initially

received without verification or evaluation, and is basically all that is

known by the Region IV staff on this date.



Facility

Framatome ANP, Inc.

2101 Horn Rapids Road

Richland, WA 99352

Docket No.: 07001257

License No.: SNM-1227



Licensee Emergency Classification

Notification of Unusual Event

Alert

Site Area Emergency

General Emergency

X Not Applicable



SUBJECT: Report of Loss of Criticality Safety Control (Bulletin 91-01

Report)



DESCRIPTION:

On April 3, 2002, the licensee reported the loss of a criticality control

(neutron absorbing poison) on a 45 gallon drum of UO2 powder in the UO2

processing building on April 2, 2002. The 24 hour report was made pursuant

to Bulletin 91-01. The filled drum contained 250 kg of powder from floor

sweepings and dried grinder sludge that was to be reprocessed. Criticality

control parameters for this process were 1) moderation (moisture content

less than 1 weight percent); and 2) neutron absorber such that 5 percent

enriched powder would remain subcritical if moderation control was lost. The

average enrichment of the powder in the affected drum was 2.7 percent with a

maximum enrichment of 3.2 percent for a 5 gallon sub lot. Moisture content

of the powder was less than 0.2 weight percent and was verified by two

operators using lab analysis. The drums used for this operation are normally

fitted with a bolted-in insert (spider assembly) with stainless steel rods

containing a neutron absorbing poison. The drum in question did not have the

poison insert because it was one of three drums designated for disposal due

to end of life wear. The spider assembly had been removed in preparation for

crushing. Following removal of the poison insert, the drum was not properly

segregated and controlled such that it was inadvertently reused in the

powder drumming process. The operator failed to perform the required visual

check of the drum interior prior to filling the drum. The same operator did

notice the missing assembly when he moved the drum to another station for

fitting with a tumbler lid.



According to the licensee, a criticality in the affected drum could

theoretically be possible only had the moisture content been over ten times

the process limit, or over fifty times the actual moisture content of the

affected drum. Further analysis is necessary to determine the actual

potential for criticality. In this case, one administrative control remained

in effect to prevent moderator from being introduced into the drum. The NRC

considers this a significant event because of the reliance placed on the

poison fixtures to maintain adequate subcritical margin, the multiple

failures resulting in loss of an engineered control and a critical mass of

fissile material being placed in a critical volume. 



The licensee has initiated an incident investigation board and has

implemented the following interim corrective measures: 1) The powder in the

affected drum has been removed and placed in a safe configuration; 2) All

drums that did not contain the neutron absorbing spider were tagged, removed

from the area and destroyed; and 3) Drum disassembly and blend make-up

operations have been suspended pending completion of procedure revisions and

training. Additional corrective actions are being evaluated. The NRC has

informed the licensee that they will be expected to review corrective

actions with NRC before drum disassembly and blend make-up operations

resume.



NRC plans to followup on this event during a special inspection scheduled

for April 15, 2002. That inspection will include a review of the actual

potential for criticality under the circumstances encountered.



Region IV received notification of this occurrence by telephone call from

the licensee at 1pm on April 3, 2002.



This information has been discussed with the licensee and is current as of

4:00 p.m. (CST), April 3, 2002. Region IV has notified NMSS, OSTP, OPA and

OEDO. The State of Washington has been notified.



CONTACTS: D. Blair Spitzberg

(817) 860-8191





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