Evaluation method for effective dose equivalent in internal exposure

According to the recommendation of the ICRP Publ. 30, Fuji Electric has developed a method of evaluating internal exposure of radiation-area workers as an effective dose equivalent in a specific period for the purpose of radiation management in nuclear power plants and others. This method is to evaluate a derived approximation with a personal computer. By numerical processing with a large-capacity computer, we evaluated the applicability of this approximation method with regard to some nuclides. The result showed that sufficient accuracy for practical use could be obtained with appropriate evaluation periods, for example, about three days for the class D such as 137Cs and about three months for the class Y such as 60Co. (author)