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At 1410, on 3/26/08 the Plant Shift Superi … At 1410, on 3/26/08 the Plant Shift Superintendent was notified that a violation of a nuclear criticality safety approval (NCSA) had occurred. During a review of pre-removal NDA (Non destructive assessment) inspection in C-337 for the unit 3 cell 10 stage 2 converter inspection port, it was discovered that the NDA was performed on the wrong side of the converter (measurement taken on the east side of the converter, and the access hole was cut in the west side). The pre-removal NDA inspection was improperly performed resulting in a violation of NCSA GEN-10. The purpose of the requirement is to determine the initial handling category of the equipment.</br>Two independent post removal NDA measurements were performed on the adjacent system and two independent visual inspections were performed on the removed item that demonstrated the item and adjacent system were each UH (uncomplicated handling). The results indicate the equipment was properly classified as UH based on the resulting mass.</br>SAFETY SIGNIFICANCE OF EVENTS: Although a leg for double contingency was lost, the correct equipment handling category was used. Additionally, an independent verification of no visible uranium present on the removed item has been successfully performed in accordance with applicable procedures to NCS Exempt the item.</br>POTENTIAL CRITICALITY PATHWAYS INVOLVED (BRIEF SCENARIO(S) OF HOW CRIT!CALITY COULD OCCUR): The equipment contained less than a safe mass of uranium and the equipment was covered to prevent exposure to a moderator. The uranium mass would have had to exceed a critical mass. The equipment would then need to be exposed to sufficient moderator in order for a criticality to be possible.</br>CONTROLLED PARAMETERS (MASS, MODERATION, GEOMETRY CONCENTRATION, ETC.): The process condition relied on for double contingency for this scenario is mass.</br>ESTIMATED AMOUNT, ENRICHMENT, FORM OF LICENSED MATERIAL (INCLUDE PROCESS LIMIT AND % WORST CASE CRITICAL MASS): The NDA measurement indicated less than 674 grams at 1.6679 wt% U-235.</br>NUCLEAR CRITICALITY SAFETY CONTROL(S) OR CONTROL SYSTEM(S) AND DESCRIPTION OF THE FAILURES OR DEFICIENCIES: The first leg of double contingency relies on mass. Prior to opening the system a pre-removal NDA is required to be performed to initially classify the handling category of the equipment. Since the pre-removal NDA was performed on the wrong side of the equipment potentially resulting in an improper handling categorization, this control was violated. The second leg of double contingency is based on mass by performing a post-removal NDA of the removed equipment and adjacent system within 24 hours to verify the handling category. This control was not violated.</br>CORRECTIVE ACTIONS TO RESTORE SAFETY SYSTEMS AND WHEN EACH WAS IMPLEMENTED: On 3/26/08, a second post removal NDA was completed on the adjacent system and a second visual inspection was performed on the removed item in order to verify the handling category is UH and re-establish double contingency.</br>The NRC Senior Resident Inspector has been notified of this event. PGDP Problem Report No. ATRC-08-0906; PGDP Event Report No. PAD-2008-0808-0906; PGDP Event Report No. PAD-2008-08
19:57:00, 26 March 2008 +
44,100 +
23:04:00, 26 March 2008 +
19:57:00, 26 March 2008 +
At 1410, on 3/26/08 the Plant Shift Superi … At 1410, on 3/26/08 the Plant Shift Superintendent was notified that a violation of a nuclear criticality safety approval (NCSA) had occurred. During a review of pre-removal NDA (Non destructive assessment) inspection in C-337 for the unit 3 cell 10 stage 2 converter inspection port, it was discovered that the NDA was performed on the wrong side of the converter (measurement taken on the east side of the converter, and the access hole was cut in the west side). The pre-removal NDA inspection was improperly performed resulting in a violation of NCSA GEN-10. The purpose of the requirement is to determine the initial handling category of the equipment.</br>Two independent post removal NDA measurements were performed on the adjacent system and two independent visual inspections were performed on the removed item that demonstrated the item and adjacent system were each UH (uncomplicated handling). The results indicate the equipment was properly classified as UH based on the resulting mass.</br>SAFETY SIGNIFICANCE OF EVENTS: Although a leg for double contingency was lost, the correct equipment handling category was used. Additionally, an independent verification of no visible uranium present on the removed item has been successfully performed in accordance with applicable procedures to NCS Exempt the item.</br>POTENTIAL CRITICALITY PATHWAYS INVOLVED (BRIEF SCENARIO(S) OF HOW CRIT!CALITY COULD OCCUR): The equipment contained less than a safe mass of uranium and the equipment was covered to prevent exposure to a moderator. The uranium mass would have had to exceed a critical mass. The equipment would then need to be exposed to sufficient moderator in order for a criticality to be possible.</br>CONTROLLED PARAMETERS (MASS, MODERATION, GEOMETRY CONCENTRATION, ETC.): The process condition relied on for double contingency for this scenario is mass.</br>ESTIMATED AMOUNT, ENRICHMENT, FORM OF LICENSED MATERIAL (INCLUDE PROCESS LIMIT AND % WORST CASE CRITICAL MASS): The NDA measurement indicated less than 674 grams at 1.6679 wt% U-235.</br>NUCLEAR CRITICALITY SAFETY CONTROL(S) OR CONTROL SYSTEM(S) AND DESCRIPTION OF THE FAILURES OR DEFICIENCIES: The first leg of double contingency relies on mass. Prior to opening the system a pre-removal NDA is required to be performed to initially classify the handling category of the equipment. Since the pre-removal NDA was performed on the wrong side of the equipment potentially resulting in an improper handling categorization, this control was violated. The second leg of double contingency is based on mass by performing a post-removal NDA of the removed equipment and adjacent system within 24 hours to verify the handling category. This control was not violated.</br>CORRECTIVE ACTIONS TO RESTORE SAFETY SYSTEMS AND WHEN EACH WAS IMPLEMENTED: On 3/26/08, a second post removal NDA was completed on the adjacent system and a second visual inspection was performed on the removed item in order to verify the handling category is UH and re-establish double contingency.</br>The NRC Senior Resident Inspector has been notified of this event. PGDP Problem Report No. ATRC-08-0906; PGDP Event Report No. PAD-2008-0808-0906; PGDP Event Report No. PAD-2008-08
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00:00:00, 26 March 2008 +
GDP-1 +
Modification date"Modification date" is a predefined property that corresponds to the date of the last modification of a subject and is provided by <a rel="nofollow" class="external text" href="https://www.semantic-mediawiki.org/wiki/Help:Special_properties">Semantic MediaWiki</a>.
23:29:59, 24 November 2018 +
23:04:00, 26 March 2008 +
0.13 d (3.12 hours, 0.0186 weeks, 0.00427 months) +
19:57:00, 26 March 2008 +
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