Radiation exposure control in back end of nuclear fuel cycle facilities

Fuel Reprocessing Plant and Waste Immobilization Plant for management of high level liquid waste, generated during reprocessing, form part of the back end of Nuclear Fuel Cycle. Both the plants handle annually several million curie of fission products in easily dispersible form. There is potential for significant external exposure and internal contamination to plant workers during plant operations, associated maintenance works and also during outages for carrying out repairs/modifications inside cells where process equipment handling/storing radioactive materials are installed. In view of handling of fissile material (Pu) in a reprocessing plant, special attention has to be paid to ensure that a condition for self sustaining nuclear fission chain reaction (criticality) does not arise even under foreseeable maloperation conditions. The reprocessing plant and Waste Immobilization plant have several engineered safety features such as shielding, ventilation, containment, remote operation etc. These features aim at reducing exposure to plant personnel and keeping the release of radioactive materials to environment below the limits specified in Technical Specifications of the plant. Execution of a comprehensive radiological surveillance programme which includes area monitoring, personal monitoring, effluent monitoring and investigative surveys in connection with safety related unusual occurrences, plays very important role in ensuring radiation safety of plant personnel and the environment. This together with training in radiation safety to plant workers helps reduce 'radiation phobia' in some workers. The paper describes radiological safety considerations and radiological surveillance programme (giving specific examples where required) that is being implemented in reprocessing plants and Waste Immobilization Plants in India. (author)