Event Notification Report for July 02, 2001

NRC BULLETIN 91-01 RESPONSE - FAILURE TO MAINTAIN THE DOUBLE CONTINGENCY (24-Hour Report)

The following text is a portion of a facsimile received from Paducah:

"At 1000, on 07/02/01, the Plant Shift Superintendent (PSS) was notified that while approving a cylinder for wash on the C-400 Cylinder Wash stand, an incorrect cylinder number was both entered and independently verified on the UF6 Cylinder Wash Facility Data Sheet violating NCSA 400-002. As a result of these actions, an unapproved cylinder was washed. NCSA 400-002 required the cylinder number be independently verified to be correct on the approval data sheet. The cylinder number is used to prevent misidentification of cylinders. Since the cylinder washed had an unverified UF6 heel (mass control) and independent verification of the cylinder to be washed was incorrectly performed (assay control), double contingency was not maintained."

"SAFETY SIGNIFICANCE OF EVENTS: Independent verification required to ensure the correct cylinder be washed was not performed correctly."

"POTENTIAL CRITICALITY PATHWAYS INVOLVED (BRIEF SCENARIO(S) OF HOW CRITICALITY COULD OCCUR: In order for a criticality to be possible, a cylinder containing a critical mass of enriched uranium would need to be washed. The cylinder incorrectly washed had an assay <1.0 WT %235U."

"CONTROLLED PARAMETERS (MASS, MODERATION, GEOMETRY, CONCENTRATION, ETC.): [The] two process conditions relied on for double contingency for this scenario are assay and mass."

"ESTIMATED AMOUNT ENRICHMENT, FORM OF LICENSED MATERIAL (INCLUDE PROCESS LIMIT AND % WORST CASE CRITICAL MASS): The cylinder washed was <1.0 WT %235U."

"NUCLEAR CRITICALITY SAFETY CONTROL(S) OR CONTROL SYSTEM(S) AND DESCRIPTION OF THE FAILURES OR DEFICIENCIES: The first leg of double contingency is based on the assay not exceeding 2.0 WT %235U. The cylinder intended for wash and the cylinder actually washed were both 4BHX cylinders, which are limited to a maximum enrichment of 1.0%. While the control was violated, the process condition was maintained."

"The second leg of double contingency is based on the heel mass not exceeding 72 pounds. The cylinder actually washed has an unverified heel weight. Therefore, this control was violated, and this leg of double contingency was lost."

"Since the process parameter for mass was not independently verified prior to washing the cylinder, double contingency was not maintained."

"CORRECTIVE ACTIONS TO RESTORE SAFETY SYSTEMS AND WHEN EACH WAS IMPLEMENTED: This condition was identified while reviewing completed cylinder work records. There is no action that can be performed to resolve this condition and bring the process back into compliance since the cylinder activity has been completed."

Paducah personnel notified the NRC resident inspector.

* * * UPDATED AT 1535 EDT ON 7/10/01 BY W. F. CAGE TO FANGIE JONES * * *

"Nuclear Regulatory Affairs has reviewed the basis for the event report against the NCS reporting position and determined that the NCS violation although serious did not cause either of the two NCS process conditions (assay <2 wt.% or heel mass of 72 pounds) analyzed in NCSA 400-002 to change or to be exceeded. The assay of the material in the cylinder was 0.71 wt. % and the heel mass was 11 pounds. Under the reporting criteria, reporting would only be warranted when the double contingency principal has been violated, but the process conditions cited for double contingency were maintained, i.e., not exceeded. Thus, the double contingency principal, as defined in the SAR and ANSI 8.1 was not violated and the incident is not reportable.

Paducah personnel notified the NRC resident inspector. The R3DO (David Hills) and NMSS (Don Cool) were notified.