ENS 43397
ENS Event | |
|---|---|
23:40 May 31, 2007 | |
| Title | One Hour Report Notification: Combustible Material Exceeding Item Relied on for Safety (Irofs) Limits Found |
| Event Description | BACKGROUND:
AREVA NP Richland routinely stores unmoderated uranium oxide powder ( < 1.0 wt.% moisture and < 1.0 wt.% moisture equivalent of approved additives) in metal 45-gallon drums with neutron absorbing inserts in warehouse #6. Metal 5-gallon pails containing no more than 18 kg of powder placed 4 per 25 inch X 25 inch metal pallet are also allowed to be stored in this warehouse in the same locations authorized to store 45-gallon drums. The option to storage of 5-gallon buckets in warehouse 6 is only occasionally used. EVENT DESCRIPTION: On May 31, 2007 at approximately 1640 PDT, a member of the AREVA safety staff completed a calculation to determine the volume of combustible material present in wooden pallets being used to store empty 45-gallon drum in the aisle between storage locations in warehouse 6. The presence of 27 wooden pallets had been observed during a previous walkthrough of the SNM storage warehouse. The volume of combustible material present in these pallets was about 56 [cubic feet]. The definition of failure of the administrative IROFS that restricts the amount of combustible material in this area is 54 [cubic feet]. Currently the only SNM storage containers present in warehouse 6 are 45-gallon drums with neutron absorbing inserts. When these 45-gallon drums are stored in this area accidental nuclear criticality remains 'highly unlikely' even when the IROFS limiting the presence of combustible material fails. However, if the restriction on the amount of combustible material fails and uranium oxide powder is stored in 5-gallon containers in this warehouse only a single IROFS would be present and accidental criticality does not remain highly unlikely. SAFETY SIGNIFICANCE OF EVENT: The safety significance of this condition is low because an accidental nuclear criticality for the as-found condition (only 45-gallon drums are currently being used to store uranium oxide powder) is still highly unlikely. Note: The condition being reported is only a potential but authorized plant condition. Furthermore, the municipal fire department works closely with the AREVA emergency response organization (ERO) when they respond to plant abnormal events and emergencies. The NCS organization is an integral part of the ERO and participates in the decision making during such events if NCS concerns exist. There have been no known fires in this warehouse during its existence of over 20 years. POTENTIAL CRITICALITY PATHWAYS INVOLVED (BRIEF SCENARIO(S) OF HOW CRITICALITY COULD OCCUR): Criticality could potentially occur during firefighting if the SNM in storage looses geometry control coincident with moderation. CONTROLLED PARAMETERS (MASS, MODERATION, GEOMETRY, CONCENTRATION, ETC.): The process parameters controlled in the various storage warehouses include geometry, mass, moderation and neutron absorbers depending upon the storage configuration. NUCLEAR CRITICALITY SAFETY CONTROL(S) OR CONTROL SYSTEM(S) AND DESCRIPTION OF THE FAILURES OR DEFICIENCIES: Plant-wide fire controls are established to ensure that large fires that would require the intervention by the municipal fire department are highly unlikely. This assures that the potential NCS concerns relative to fire-fighting with water are compliant with regulatory requirements. CORRECTIVE ACTIONS TO RESTORE SAFETY SYSTEMS AND WHEN EACH WAS IMPLEMENTED: After discovery of the deficiency, the combustible material was removed from the warehouse. The material is currently compliant with the above listed requirements. |
| Where | |
|---|---|
| Areva Np Inc Richland Richland, Washington (NRC Region 2) | |
| License number: | SNM-1227 |
| Reporting | |
| Part 70 App A (A)(5) | |
| Time - Person (Reporting Time:+-0.3 h-0.0125 days <br />-0.00179 weeks <br />-4.1094e-4 months <br />) | |
| Opened: | Calvin Manning 23:22 May 31, 2007 |
| NRC Officer: | Pete Snyder |
| Last Updated: | May 31, 2007 |
| 43397 - NRC Website | |
Areva Np Inc Richland with Part 70 App A (A)(5) | |
WEEKMONTHYEARENS 494752013-10-27T17:55:00027 October 2013 17:55:00
[Table view]Part 70 App A (A)(5) Failure of a Steam Supply Vacuum Breaker ENS 492792013-08-14T05:30:00014 August 2013 05:30:00 Part 70 App A (A)(5) Valve Failed to Close as Required on Low Temperature Interlock ENS 473602011-10-20T16:10:00020 October 2011 16:10:00 Part 70 App A (A)(5) One Hour Report Due to a Failed Item Relied on for Safety ENS 433972007-05-31T23:40:00031 May 2007 23:40:00 Part 70 App A (A)(5) One Hour Report Notification: Combustible Material Exceeding Item Relied on for Safety (Irofs) Limits Found 2013-08-14T05:30:00 | |