Radiological criteria for restroation of land

摘要

The development of nuclear facilities, the conduct of weapons tests and a number of accidents have given rise to varying degrees of radioactive contamination of land and buildings. Guidance on radiological criteria for the recovery phase following accidents and for the remediation of contaminated land has been developed by the International Commission on Radiological Protection and by the international agencies which produced the International Basic Safety Standards. The interventions used to avert doses to affected groups and to restore land to allow a return to normal living conditions are relocation, restrictions on food and water, cleanup of contaminated areas and facilities, and actions to reduce the uptake of radionuclides in foodstuffs. A generic intervention level for relocation/resettlement is a dose of the order of 10 mSv/a, or a lifetime dose approaching 1 Sv. There is now extensive experience and information on methods of cleanup and decontamination and on measures for reducing the uptake of radionuclides into foodstuffs. Where remediation is carried out to allow alternative land uses in decommissioned facilities or sites that were subject to regulatory controls while in operation, doses to critical groups should be controlled as they are for practices. In other cases, the choice of basic approach to remediation may not be clear, or it may be unacceptable to society to have differing cleanup end points dependent on the particular approach taken. It has been proposed that dose constraints be established as part of the optimization procedure in such situations.