The UUSA [URENCO USA] facility
CAAS [Criticality Accident and Alarm System] exists to detect and alarm in the unlikely event of a criticality accident, as required by 10 CFR 70.24, Criticality accident requirements. This monitoring system will be temporarily disabled during planned corrective maintenance activities for approximately thirty minutes, commencing at approximately 0730 MDT, on Saturday, September 15th, 2018. This activity will affect the
CAAS in the Separations Building Module (
SBM) 1001/1002 and the Cylinder Receipt and Dispatch Building (CRDB). The
CAAS in the remaining portions of the facility will be unaffected.
Essential personnel will remain inside the controlled access area during the maintenance activities. The populated areas of the facility will be limited to the Security Alarm Station, Operations Control Room, and the Maintenance Area housing the CAAS control cabinets in the Technical Services Building (TSB) where technicians will be needed for this work evolution. CAAS coverage of these populated areas will be provided during the maintenance activity by temporary criticality detection equipment.
Compensatory measures will be implemented in accordance with section 3.1.5 of the UUSA Integrated Safety Analysis (ISA) Summary. These measures including evacuation of non-essential personnel from the areas of concern and the Immediate Evacuation Zone (IEZ) before removing the equipment from service, limiting access into facility, and restricting Special Nuclear Material (SNM) movement will be implemented until CAAS coverage is verified operational.
UUSA will notify the NRC when CAAS coverage is returned to normal operation. Radiation surveys will be conducted prior to re-entry to confirm acceptable conditions in the area.
The licensee has notified the NRC Project Manager.
- * * UPDATE FROM WYATT PADGETT TO HOWIE CROUCH AT 1139 EDT ON 9/15/18 * * *
The Criticality Accident and Alarm System was returned to service at 0930 MDT after the completion of the scheduled maintenance. During the maintenance period, no abnormal radiation readings were observed.
Notified R2DO (Ernstes).