Neutronic Analysis for The Radial Direction Heterogeneous Core Configuration of GFR with Thorium Fuel

Abstract A neutronic analysis has been carried out for the radial direction heterogeneous core configuration in GFR with thorium nitride fuel to obtain the most optimal heterogeneous design has k eff > 1 and excess reactivity below one percent. Neutronic analysis was performed using openMC version 0.13.2 based on open-source Monte Carlo simulation with ENDF/B-VII.1 data library. The first calculation is benchmarking openMC and SRAC where the largest error is 2.49% is caused by different data library. SRAC data library is JENDL 4.0. The second calculation is a homogeneous core configuration with 5% to 15% uranium-U233 fuel variation, the stability lies at 8% for the reference of heterogeneous core configuration. The heterogeneous core configuration was performed with three types of fuel percentage and five different geometry variations. Optimum design for geometry F1:F2:F3 = 1 ring:4 rings:1 ring using fuel type F1:F2:F3 = 6.5%:8%:9.5%. Optimum design for geometry F1:F2:F3 = 2 rings:2 rings:2 rings using fuel type F1:F2:F3 = 7.5%:8%:8.5%. Optimum design for geometry F1:F2:F3= 1 ring:2 rings:3 rings using fuel type F1:F2:F3=7%:8%:9%. Optimum design for geometry F1:F2:F3= 1 ring:3 rings:2 rings using fuel type F1:F2:F3 = 7.5%:8%:8.5%. Optimum design for geometry F1:F2:F3 = 1 ring:1 ring: 4 rings using fuel type F1:F2:F3 = 7.5%:8%:8.5%. The most optimum design among the other five designs is the F1:F2:F3 = 2 rings:2 rings:2 rings geometry design because it has a maximum k eff of 1.00999 and excess reactivity of 0.99%. This design is carried out for an extended burn-up 15 years and still stable with the characteristics of the neutron flux and fission rate in this design decrease with burn-up time. Fission product in this design also decreased according to the purpose of the generation IV reactor is the prevention of nuclear weapons.