High Fidelity Monte Carlo for Fusion Neutronics

The High Fidelity Monte Carlo for fusion neutronics project HIFIMC aims at providing the computational resources for the development, testing and application of advanced modeling and simulation techniques as required for the design and optimization of upcoming fusion reactors like ITER, DEMO, HELIAS and related research facilities like IFMIF or DONES. Large-scale simulations are required to provide high fidelity results to assess the performance of such facilities. These include numerous time consuming Monte Carlo simulations for describing the transport of particles (neutrons and gammas) through the complex and heterogeneous geometry. The main computational tool for such application is the MCNP Monte Carlo code, developed at LANL, US, and the coupled transport-activation tool R2Smesh, developed at KIT. Several concurrent research topics have been conducted and are reported here. Further development of R2Smesh on enhancing performance and studies on convergence issues in meshing of the activation responses are required to qualify the tools for many large nuclear performance and radiation shielding applications in fusion devices. Verification and validation of alternative codes, like GEANT 4, developed at CERN, CH, are supporting these efforts. Applications to port systems in ITER (next step fusion reactor under construction in France), breeding blankets in DEMO (Demonstration fusion reactor), full reactor of HELIAS (Helical-Axis Advanced Stellarator) and irradiation test systems of IFMIF/DONES (International Fusion Material Irradiation Facility/DEMO-oriented neutron source) are presented. It is shown that the tools on high-performance computing platforms are capable to tackle the challenging problems of radiation shielding and activation in complex geometries involving both deep penetration and radiation streaming.