A shutdown dose rates analysis of the Korean fusion demonstration reactor using MCNP5 mesh-based R2S approach

Abstract

In the fusion reactor, lots of high energy neutrons are produced by the nuclear fusion reaction, which produces unstable nuclides emitting gamma rays in various components of fusion energy systems. So, estimation of shut down dose rate in such facilities is very important to check if the dose rates are below the radiational safety limits. Generally, two computational analysis schemes of the cell-based Rigorous-2-Step (R2S) method and the Direct-1-Step (D1S) method have been used widely in evaluating the shutdown dose rates. In this work, the mesh-based R2S method is automated with in-house auxiliary programs for our practical applications. This mesh-based R2S procedure was applied to the Korean fusion demonstration reactor (K-DEMO) facility. From the analysis for K-DEMO, it was shown that the automated mesh-based R2S procedure gives much higher computational efficiencies in terms of FOM than the cell-based R2S method and gives higher shutdown dose rates than the cell-based R2S and D1S method.