Assessing gamma radiation dose distribution: Extremities versus whole body in mixed oxide fuel fabrication

Assessment of radiation dose to the occupational worker is made to determine compliance with the dose limits/constraints, to guide decisions on the level of control of exposure, and to help identify actions to be taken to reduce exposure. Plutonium-based mixed oxide (MOX) fuel fabrication (FF) processes are carried out within glove boxes (GBs) considering the radiotoxicity of plutonium. Although partial to complete automation has been introduced in the processes of MOX FF, there are some actions that require manual work in GBs. Owing to the proximity of the hands of operators to MOX when work in GBs is being carried out, the hands are more susceptible to external exposure than other parts of the body. At FF, the whole-body exposure due to gamma is controlled by providing composite shielding on the front panel of most of the GBs and the use of shielded aprons. Despite this, external dose to the extremities (hands and feet) remains a critical issue due to nonuniform radiation field on the GB surfaces and the gauntlets worn by the workers. To ascertain the issue of extremities’ dose monitoring and its control at MOX FF, a correlation is established between the external gamma dose to the whole body and extremities.