Year
2010
Abstract
The IAEA devotes substantial resources to verifying declarations associated with UF6 cylinder movements at uranium enrichment plants. Part of this effort is devoted to applying and removing seals for UF6 cylinder valves, which is the primary method for certifying containment. The seals used tend to be the venerable wire-loop-type seals that require nearly one hundred percent post- mortem evaluations to confirm no prior tampering. A conceptual design for a valve seal specifically designed for these UF6 cylinders has been developed at the Oak Ridge National Laboratory. This valve seal unit would replace the existing valve and detect when the valve is opened and closed. The valve seal will be scalable for use on process valves throughout the facility. A tamper switch will also be included to indicate if the entire unit has been removed from the valve. The size and shape of the unit will not cause it to extrude excessively reducing the likelihood of damage during handling and transport. Another important feature of this unit is its reusability, which is reliant on the durability of its electronics, power supply, and seal body. To accommodate these features, the valve seal unit is powered by a battery, which is the only component that needs regular replacement. Utilizing an improved method of sealing cylinder valves will reduce the burden regarding seal application and post mortem inspections on the IAEA inspectors, while also increasing the amount of process knowledge available to the inspector. This paper further discusses the mechanical design and basic sensors of the valve seal unit.