Design of Systems for Continuous Accountability Measurements at the Y-12 National Security Complex

A new effort has begun at the Y-12 National Security Complex to focus on providing continuous inventory measurements on processes where the quantities of HEU vary with time. System design methodology includes the selection and placement of radiation detectors and other sensors; such as liquid flow meters, level monitors and weight sensors. Factors that influence these designs are the geometry of the system, the accessibility of the system, and the environmental conditions surrounding the system. Environmental considerations include the operating temperatures with variations, background radiation with variations and other atmospheric conditions. Any sensors installed in the system must not degrade criticality safety and must not introduce other safety hazards. The accountability systems must not introduce operational problems, but may ease the difficulty of operations in cases where systems are shut down to conduct regular inventories. Modeling tools are used to estimate the effectiveness of the inventory systems during the design phase.