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At 1106 CDT, on 10/06/2010 the Plant Shift … At 1106 CDT, on 10/06/2010 the Plant Shift Superintendent was notified that the independent verification of cylinder cool down time had not been completed on the following Uranium Hexafluoride (UF6) Cylinders: PP5436, PP5453, PP5389, PP5435, PP5388, PP5424, PP5459, and PP5443 in accordance with NCSA GEN-003.</br>NCSA GEN-003 requires that prior to movement of a cylinder from a liquid UF6 cylinder handling area it shall be determined, independently verified, and documented that the required cooling time has passed. The purpose of this requirement is to ensure the cylinder does not contain liquid UF6 before it is moved from a liquid handling area. Upon discovery of the violation, it was determined that the cylinders had, in fact, met the required cool down period prior to movement; however, the independent verification had not been completed.</br>Since this independent verification was not completed, double contingency was not maintained. Therefore, this is being reported to the NRC as a 24-hour Event Report in accordance with NRC BL 91-01 Supplement 1.</br>SAFETY SIGNIFICANCE OF EVENTS</br>Although an NCSA control was violated, cylinder integrity was maintained.</br>POTENTIAL CRITICALITY PATHWAYS (BRIEF SCENARIO(S) OF HOW CRITICALITY COULD OCCUR)</br>A solid UF6 cylinder would have to have been breached and sufficient moderator entered the cylinder in order to support a criticality.</br>ESTIMATED AMOUNT, ENRICHMENT, FORM OF MATERIAL (INCLUDE PROCESS LIMIT AND % WORST CASE CRITICAL MASS)</br>The assay of any material involved is less than or equal to 5.5 wt. % U235. The cylinders involved were 10 ton cylinders.</br>NUCLEAR CRITICALITY SAFETY CONTROL(S) OR CONTROL SYSTEM(S) AND DESCRIPTION OF THE FAILURES OR DEFICIENCIES</br>Double contingency is maintained by implementing two independent controls on one parameter (moderation).</br>The first leg of double contingency relies on it being unlikely that industrial grade cranes, forklifts, and cylinder haulers would drop an ANSI N14.1 designed cylinder in such a way that it would be breached. This moderation control was maintained.</br>The second leg of double contingency relies on independent verification that the required cool down time has passed, prior to moving a cylinder from a liquid cylinder handling area. This control helps ensure that the cylinder does not contain liquid UF6 prior to movement. The independent verification was not performed or documented. Therefore, this moderation control was violated. Upon discovery of the violation, it was determined that the cylinders had, in fact, met the required cool down period prior to movement.</br>Double contingency relies on two independent controls on the same parameter. Since one of the two independent controls on moderation was violated, double contingency was not maintained; however, the moderation parameter was maintained.</br>CORRECTIVE ACTIONS TO RESTORE SAFETY SYSTEMS AND WHEN EACH WAS IMPLEMENTED</br>The cool down times for the identified cylinders have been independently verified thus bringing them back into compliance with double contingency.</br>The NRC Resident Inspector has been notified of this event.Inspector has been notified of this event.
16:06:00, 6 October 2010 +
46,312 +
21:40:00, 6 October 2010 +
16:06:00, 6 October 2010 +
At 1106 CDT, on 10/06/2010 the Plant Shift … At 1106 CDT, on 10/06/2010 the Plant Shift Superintendent was notified that the independent verification of cylinder cool down time had not been completed on the following Uranium Hexafluoride (UF6) Cylinders: PP5436, PP5453, PP5389, PP5435, PP5388, PP5424, PP5459, and PP5443 in accordance with NCSA GEN-003.</br>NCSA GEN-003 requires that prior to movement of a cylinder from a liquid UF6 cylinder handling area it shall be determined, independently verified, and documented that the required cooling time has passed. The purpose of this requirement is to ensure the cylinder does not contain liquid UF6 before it is moved from a liquid handling area. Upon discovery of the violation, it was determined that the cylinders had, in fact, met the required cool down period prior to movement; however, the independent verification had not been completed.</br>Since this independent verification was not completed, double contingency was not maintained. Therefore, this is being reported to the NRC as a 24-hour Event Report in accordance with NRC BL 91-01 Supplement 1.</br>SAFETY SIGNIFICANCE OF EVENTS</br>Although an NCSA control was violated, cylinder integrity was maintained.</br>POTENTIAL CRITICALITY PATHWAYS (BRIEF SCENARIO(S) OF HOW CRITICALITY COULD OCCUR)</br>A solid UF6 cylinder would have to have been breached and sufficient moderator entered the cylinder in order to support a criticality.</br>ESTIMATED AMOUNT, ENRICHMENT, FORM OF MATERIAL (INCLUDE PROCESS LIMIT AND % WORST CASE CRITICAL MASS)</br>The assay of any material involved is less than or equal to 5.5 wt. % U235. The cylinders involved were 10 ton cylinders.</br>NUCLEAR CRITICALITY SAFETY CONTROL(S) OR CONTROL SYSTEM(S) AND DESCRIPTION OF THE FAILURES OR DEFICIENCIES</br>Double contingency is maintained by implementing two independent controls on one parameter (moderation).</br>The first leg of double contingency relies on it being unlikely that industrial grade cranes, forklifts, and cylinder haulers would drop an ANSI N14.1 designed cylinder in such a way that it would be breached. This moderation control was maintained.</br>The second leg of double contingency relies on independent verification that the required cool down time has passed, prior to moving a cylinder from a liquid cylinder handling area. This control helps ensure that the cylinder does not contain liquid UF6 prior to movement. The independent verification was not performed or documented. Therefore, this moderation control was violated. Upon discovery of the violation, it was determined that the cylinders had, in fact, met the required cool down period prior to movement.</br>Double contingency relies on two independent controls on the same parameter. Since one of the two independent controls on moderation was violated, double contingency was not maintained; however, the moderation parameter was maintained.</br>CORRECTIVE ACTIONS TO RESTORE SAFETY SYSTEMS AND WHEN EACH WAS IMPLEMENTED</br>The cool down times for the identified cylinders have been independently verified thus bringing them back into compliance with double contingency.</br>The NRC Resident Inspector has been notified of this event.Inspector has been notified of this event.
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0.232 d (5.57 hours, 0.0332 weeks, 0.00763 months) +
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