Radiation protection standards and monitoring in the event of an accident at a nuclear facility

To regulate and limit irradiation of the population in the event of a nuclear accident, two levels of radiation exposure have been established. Depending on the level of exposure either emergency measures, including evacuation, or limited measures taking account of particular situation and local conditions, may be implemented. Evacuation of the population outside the 30 km zone was carried out after the Chernobyl accident and a wide range of protection arrangements were applied in adjacent areas. Temporary permissible contamination levels of the main types of foodstuff were established, including the admissible contamination levels of environmental objects (roads, clothes, ets.) and radioactive products monitored after the Chernobyl NPP accident. For effective protection, these levels must constantly be decreased. Emergency workers involved in dealing with the consequences of a serious radiation accident as a rule should not be exposed at doses exceeding the maximum permissible dose (1 MPD). As an exception, exposure of 2 MPD up to 5 MPD may be tolerated if it is followed up and compensated for under constant medical supervision. Other standards and limits should apply to the irradiation of a person under reproductive age. For men the dose accumulated by the age of 30 years should not exceed 12 MPD, for women aged up to 40 years planned heightened exposure should be forbidden. To diminish the occupational exposure of the personnel in the allocation of work in the area of the accident, the possibility of identifying zones with different levels of exposure should be considered, with appropriate health measures for each. Monitoring and radiation control are becoming increasingly important, as is the setting of standards for triggering emergency actions. As the Chernobyl accident has shown, this control should provide for continuous collection of information on the dynamics of the radiation situation over a wide area, including the monitoring of exposure to personnel. (author). 3 refs, 3 tabs