Investigation of neutronic potential of a moderated (D-T) fusion driven hybrid reactor fueled with thorium to breed fissile fuel for LWRs

The potential of a moderated hybrid reactor fueled with ThC2 or ThF4 is inv estigated by a PF (plant factor) 75% under a first wall fusion neutron curr ent load of 5 MW/m(2) LWR (Light Water Reactor) fuel rods containing ThC2 o r ThF4 are replaced in the fissile fuel zone of the hybrid reactor. It is c onsidered that gas (He or CO2), or flibe (Li2BeF4), or natural lithium is t he coolant. The behaviour of the neutronic potential is observed for four y ears. At the end of the operation period, the Cumulative Fissile Fuel Enric hment (CFFE) values varied between 3.55 and 7% depending on the fuel and co olant type. Calculations show that the best neutronic performance is obtain ed with Flibe, followed by air and natural lithium coolants. After 48 month s, the maximum CFFE value is 7% in the ThF4 fuel and flibe coolant mode, an d the lowest CFFE value 3.55% is in the ThC2 fuel and natural lithium coola nt mode. Consequently, these enrichments would be sufficient for LWRs. The Tritium Breeding Ratio (TBR) values are greater than 1.05 for all investiga ted natural lithium coolant modes, and the investigated hybrid reactor is s elf-sufficient in the tritium required for the D,T fusion driver in these m odes during the operation period. The blanket energy multiplication factor M, varies between 2.45 and 3.68 depending on the type of fuel and coolant a t the end of the operation period. At the same time, the peak-to-average fi ssion power density ratio decreases by similar to 25%. The lowest radial ne utron leakage out of the blanket is in the blanket with the flibe coolant m odes. (C) 1999 Elsevier Science Ltd. All rights reserved.