|UNUSUAL BUILDUP OF MATERIAL IN ALUMINUM CENTRIFUGE AREA |
"During the unloading of centrifuges in the Building 333 U-Aluminum centrifuge area, a crusty buildup of material (~1/8" thick) was observed on the inside of the centrifuge 'jacket' that contains the centrifuge bowl. The buildup was also observed on the underside of the centrifuge lid ('cake pan'). This level of material buildup was unusual and had not been previously observed. It should be noted that some dusting or spattering had been previously observed. The system is designed with drains on the bottom that are designed to prevent the accumulation of liquid within the centrifuge 'jacket'. There is also a requirement to inspect the 'jacket' when solution is observed draining from the overflows. This was considered an unanalyzed or improperly analyzed condition because the mechanism for buildup of this extent was not considered in the safety analysis (i.e. there was no indication of buildup provided by the overflows).
"The following corrective actions were taken: 1) operations in the affected area were suspended; 2) the area was posted to maintain the integrity of the as-found conditions; 3) the area was inspected by safety personnel; 4) the issue was entered into the internal Problem Identification, Resolution, and Correction System (PIRCS); 5) an Unusual Incident Evaluation was performed; 6) calculations were performed with bounding conditions; 7) photographs were taken of the equipment; 8) the system was scanned to determine U-235 mass (~46 grams U-235); 9) material samples were taken and delivered to the laboratory for analysis; and 10) an investigation has been initiated."
There were no control or control system failures. There were no actual or potential safety consequences to workers, the public, or the environment. No degradations or failures have been identified. The system is currently in a safe and stable condition. An investigation has been initiated.
The licensee has notified the NRC Resident Inspector.