Evaluation of activated nuclides for Fugen Nuclear Power Station's decommissioning

The density and amount of radioactive nuclides in equipment or concrete including the reactor core need to be evaluated for the decommissioning of the Fugen Nuclear Power Station. To prepare for decommissioning, measurement and evaluation of the neutron flux density have been executed mainly during the reactor operation, because neutron flux density is measured under that condition. Activation evaluation is mainly executed by the calculation method, and the results are checked by the sampling measurements. All of the equipments is divided into three parts, inner core part, shielding part, outer shielding part. The neutron flux distribution of two former parts can be evaluated by calculation, but the last part cannot; it is evaluated by measuring the activation foil for many points. These evaluation methods are checked by a small number of sampling measurements. (author)