Development of the Advanced Neutronic Analysis Model for the K-DEMO With MCNP Code

Neutronic assessment is the important foundation of Korean fusion demonstration reactor (K-DEMO) study. Previously, preliminary neutronic calculations using a simplified model have been performed [1], and optimized structure of blanket module and shield material has been derived. Based on the previous calculation results, the advanced K-DEMO neutronic analysis model has been developed to perform more accurate and reliable neutronic assessments with the detailed configuration of vacuum vessel (VV), toroidal field (TF) coil, blanket, and shield. The advanced K-DEMO neutronic analysis model was imported into the integrated interface program by the help of Monte Carlo automatic modeling system to produce input files for the Monte Carlo neutron photon transport code analyses. The neutronic calculation on neutron wall loading (NWL) distribution, tritium breeding ratio (TBR), and nuclear heating in tokamak components was conducted for the newly developed advanced K-DEMO neutronic analysis model. In the NWL calculation, the peak was indicated at the inboard (IB) and the outboard (OB) blanket first wall with the value of 3.81 and 3.93 MW/m2. The different types of models by changing gaps between the blanket modules and the thickness of separated borated steel shield blocks are calculated to check global TBR and the shield performance. The global TBR of 1.017 was achieved with the 49.7and 76.2-cm-thick IB and OB blanket modules. The model with 1-cm-thick assembly gap between blanket modules, 22-cm-thick IB shield, 50-cm-thick OB shield, and 34-cm-thick divertor shield are considered as a reasonable shield model with the total nuclear heating in 16 TF coils and VV of 9 and 32 kW.