On September 30, 2009 at approximately 1910 (PDT) an Air Balance Tech at AREVA NP's Richland fuel fabrication plant discovered that the primary and secondary
HEPA filters servicing the ammonium diuranate (ADU) area showed visible signs of deterioration. The apparent deterioration is being reported in accordance with
10CFR70.50.b.2.
The K32A HEPA filters were examined at approximately 1910 PDT on September 30, 2009 based on a request to follow up on some observations the previous day of a dusting of powder and very low contamination downstream of the filters. Air flow was diverted to HEPA filters in a parallel upper housing in order to check the filters in the lower housing. Investigation showed apparent deterioration, cracked creases, of both the primary and final HEPA's.
At approximately 2030 PDT the same day EHS&L personnel were informed of the event. The only processes running at the time were the Mop Water Furnace and Cylinder Wash. EHS&L ordered that these be shut down. Air monitor samples were pulled on the K-32A system. Air monitoring samples showed negligible release levels. A Health Safety Technician survey of the downstream side of the final HEPA housing of K-32A revealed no contamination.
Potential dose to a member of the public and the effect on the environment are essentially negligible. External conditions are not known to have affected the event.
A Corrective Action Report was written on October 1, 2009. The cause of the apparent deterioration is under active investigation. Steps to prevent recurrence will be developed as appropriate.
The licensee stated that records indicate that the primary filter was changed out in August and the final filter was changed out in March.
The licensee will notify the State and the NRC regional contact.