Evaluation of the Activated Radioactivity of Turbine Equipments in BWR

<jats:p>The activated radioactivity of turbine equipments irradiated by neutron originating from 17N in the main stream is evaluated for an introduction of clearance system to boiling-water reactor (BWR) plant. The 17N, main neutron source is generated by 17O(n, p)17N reaction in the core region. The evaluation results clarified that the activated radioactivity of the turbine equipment is extremely small comparing to the clearance level. The feature of the evaluation is as follows. (1) Actual radioactive concentration of the 17N in the main steam in Hamaoka nuclear power station unit 5 (Hamaoka-5) which is an advanced boiling-water reactor (ABWR) was measured with solid-state track detector (SSTD). The 17N concentration is used for the neutron transport calculation as initial neutron sources. (2) The turbine equipments were modeled as two-dimensional geometry for DORT code. (3) Activation cross-sections for major nuclides subject to the clearance evaluation were based on JENDL3.3 on 175 energy group structure (VITAMIN-J). (4) Minor nuclides subject to the clearance evaluation were calculated with ORIGEN-S code.</jats:p>