ENS 44521
ENS Event | |
|---|---|
14:20 Sep 25, 2008 | |
| Title | 24 Hour Notification of the Discovery That a Spark Arrestor for Hepa Filter Fire Control Was Not Installed |
| Event Description | Event Description
At 0720 hours0.00833 days <br />0.2 hours <br />0.00119 weeks <br />2.7396e-4 months <br /> on 9/25/2008, the Engineer responsible for the HVAC system informed a member of the EHS&L ISA Staff that the K-3 ventilation system did not have one of the two required wire-mesh spark arrestors, which we believe had never been installed. Safety Significance The safety significance of this condition is low. The missing wire-mesh spark arrestor is one of the components of IROFS [Item Relied On For Safety] 4530, which is one of two IROFS associated with an intermediate consequence environmental release as defined in 10CFR 70.61. The initiating event for this accident sequence includes failure of IROFS 4502 (control of combustible material and ignition sources) and a resulting fire that destroys a primary HEPA filter. This initiating event is listed as a 100-year event in the facility ISA. IROFS 4530 is expected to prevent a significant radiological release if the initiating event, a small fire that destroys a primary filter, occurs thereby challenging the integrity of the final bank of HEPA filters. The components of IROFS 4530 include HEPA filters which meet the resistance to heated air and spot flame resistance requirements of sections FC-5150 and 5160 respectively of ASME AG-1, and wire-mesh spark arrestors between the primary and final HEPA filters. ASME AG-1 section FC-5150 requires filters meeting this design criterion to be exposed to air heated to 700 +/- 50 degrees for not less than 5 minutes without catching fire. Section FC-5160 requires filters meeting this design criterion to have the frame, filter media, filter pack, and sealing materials exposed to a 2.5 inch blue flame (1750 +/- 50 degrees F) for not less than 5 minutes without sustaining combustion. In addition, if these IROFS are not available to perform their function, the enabling condition needed for an intermediate environmental consequence event is more than a total of 116 kg of uranium be present in the primary and final HEPA filters involved in the postulated fire. The uranium is conservatively assumed to be relatively higher activity blended low-enriched uranium (BLEU), i.e. high enriched uranium blended down to 5% 235U or less. The likelihood of all the uranium on the filters being BLEU material is low. Since 1995, primary HEPA filters in the K-3 system have been replaced over 1,600 times. Of these, only 6 have contained more than 2 kg of U. The highest contained about 2.7 kg. Immediate Corrective Actions The differential pressures of the HEPA filters in the K-3 system were verified to be in acceptable ranges, indicating normal loading. A fire-watch was instituted to further limit potential ignition sources and to assure minimal amounts of combustible materials are used near, or in areas serviced by, the K-3 system. Wire-mesh to be used in fabricating a spark arrestor has been ordered for expedited installation. Planned Actions A wire-mesh spark arrestor is expected to be installed Saturday, October 4. |
| Where | |
|---|---|
| Areva Np Inc Richland Richland, Washington (NRC Region 2) | |
| License number: | SNM-1227 |
| Reporting | |
| Part 70 App A (B)(2) | |
| Time - Person (Reporting Time:+5.72 h0.238 days <br />0.034 weeks <br />0.00784 months <br />) | |
| Opened: | Alvin Manning 20:03 Sep 25, 2008 |
| NRC Officer: | Bill Huffman |
| Last Updated: | Sep 25, 2008 |
| 44521 - NRC Website | |
Areva Np Inc Richland with Part 70 App A (B)(2) | |
WEEKMONTHYEARENS 524332016-12-13T23:00:00013 December 2016 23:00:00
[Table view]Part 70 App A (B)(2) Non-Performance of Administrative Item Relied on for Safety ENS 464472010-12-02T15:15:0002 December 2010 15:15:00 Part 70 App A (B)(2) Uranium Concentration Greater than Expected in Gas Stripper System Following an Acid Wash ENS 445212008-09-25T14:20:00025 September 2008 14:20:00 Part 70 App A (B)(2) 24 Hour Notification of the Discovery That a Spark Arrestor for Hepa Filter Fire Control Was Not Installed 2016-12-13T23:00:00 | |