Development of CAD-to-MCNP Model Conversion System and Its Application to ITER

We developed a conversion system from three-dimensional computer-aided design (CAD) drawing data to MCNP geometry input data. This system consists of programs of "void creation" and "conversion into MCNP input data." By using this system, it is possible to convert large and complicated CAD drawing data such as a fusion reactor into MCNP geometry input data. We applied this system to ITER CAD drawing data and created MCNP input data for ITER nuclear analysis. We calculated the neutron flux and nuclear heating using this input data. The calculation results agreed well with those by the other parties participating in this ITER research and development.