Development of dose evaluation method for confirmation of completion of decommissioning, 1; Development of radioactivity distribution evaluation combined with scoping survey and sampling measurement

Shimada, Taro ; Nabekura, Nobuhide*; Miwa, Kazuji ; Takeda, Seiji 

It is necessary for confirmation of completion of decommissioning of nuclear facilities to comply with dose criteria for public using the land after site release, based on the radioactivity distribution at the land of the site. We are developing a methodology of public dose evaluation based on the survey results of evaluation of the radioactivity distribution. In this report, the external drift kriging method combined with scoping survey and sampling measurement were applied to 1km square area, and a cross validation method was applied to validate the evaluated distribution. Index of Mean Absolute Error is appropriate to evaluate the difference between evaluation and measurement. In addition, upper limit of 95% single side confidence interval for the evaluation of non-measured point was suggested to input for dose evaluation.