Project n.4: local strategies for decontamination

The efficiencies of a great number of techniques for decontamination or dose reduction in contaminated areas have been investigated by several teams of E.C. and CIS scientists (ECP4 project). Modelling, laboratory and field experiments, and a return from experience from the area contaminated by the Chernobyl accident allowed to assess radiological efficiencies and requirements for the operation of numerous practical solutions. Then those data were supplemented with data on cost and waste generation in order to elaborate all the information for the optimisation of decontamination strategies. Results are presented for about 70 techniques. However, a technique cannot be compared to another from a generic point of view. Rather it is designed for a specific target and the best technology depends on the objectives. It has been decided to implement decision analyses on case studies and the local conditions and objectives have been investigated. Individual doses ranged from 1 to 5 mSv, with the contrasted contributions of internal and external doses. The desire to restore a normal activity in a partially depopulated settlement and concerns about the recent increase in internal doses were typical incentives for action. The decision aiding analysis illustrated that actions can be usually recommended. Results are outlined. (authors)