Neutronics design analyses of fusion power reactors based on a novel integral approach

A novel integral approach was applied for the nuclear design analyses performed for the European DEMO Conceptual Study including, for the first time, the automatic generation of analysis models for Monte Carlo calculations from available CAD geometry data by the new McCad conversion tool. Starting from neutronics pre-analyses to define the radial reactor build, a generic neutronics CAD model of the DEMO reactor was constructed serving as basis for the generation of DEMO reactor models employing the HCLL (Helium Cooled Lithium Lead) and HCPB (Helium Cooled Pebble Bed) blankets for the tritium breeding and the power production. The HCLL and HCPB DEMO reactor models were converted to the MCNP geometry representation by the newly developed McCad software tool. The nuclear analyses performed on the basis of MCNP Monte Carlo calculations using the converted models showed that both DEMO reactor variants could satisfy the requirements for a sufficient shielding and tritium breeding performance. As a major outcome of this work it is concluded that the newly established integral approach for neutronics analyses, including the automatic generation of analysis geometry models by McCad, is mature for applications to reactor design analyses and studies.