Time-Dependent Neutronic and Burn-up Analyses of in a Thorium-Based ADS cooled with Various Coolants

This study presents the investigation of thorium utilization in an ADS with Lead-Bismuth Eutectic (LBE) target. To effectively burn thorium, the ThO2 fuel rods cylindrically prepared, and cladded with SiC, are mixed with 233UO2 at volumetric ratio of 1%. These fuel rods are placed in the fuel zone in hexagonal arrangement. Three different coolant cases, helium (He) gas, light water (H2O) and heavy water (D2O), are individually examined for cooling of fuel zone. The volumetric percentages of fuel, clad and coolant are 60%, 10% and 30%, respectively. The LBE-target is bombarded by protons amplified to 1000 MeV in linear accelerator (LINAC) which in turn releases 29-30 high-energetic neutrons per proton via the spallation reactions. Proton beam power is assumed as 20 MW corresponding to 1.24828·1017 protons per second. The steady-state neutronic and subsequent time-dependent burn calculations are performed by using MCNPX 2.7 with LA150 library and CINDER computer codes, respectively. The ADSs can be operated under subcritical mode until the value of keff increases to 0.980-0.985. Subject to this constraint of keff, the maximum operation times are determined as 184, 825 and 2215 days and at end of these times, the values of gain (G) increase up to 17.362, 12.909 and 9.100, in the cases of H2O, D2O and He coolants, respectively.