Evaluation on transmutation performance of minor actinides with high-flux BWR

The performance of high-¯ux BWR (HFBWR) for burning and/or transmutation (B/T) treatment of minor actinides (MA) and long-lived ®ssion products (LLFP) was discussed herein for estimating an advanced waste disposal with partitioning and transmutation (P&T). The concept of high-¯ux B/T reactor was based on a current 33 GWt-BWR, to transmute the mass of long-lived transuranium (TRU) to short-lived ®ssion products (SLFP). The nuclide selected for B/T treatment was MA (Np-237, Am-241, and Am-243) included in the dis- charged fuel of LWR. The performance of B/T treatment of MA was evaluated by a new function, i.e. [F/T ratio], de®ned by the ratio of the ®ssion rate to the transmutation rate in the core, at an arbitrary burn-up, due to all MA nuclides. According to the results, HFBWR could burn and/or transmute MA nuclides with higher ®ssion rate than BWR, but the ®ssion rate did not increase proportionally to the ¯ux increment, due to the higher rate of neutron adsorption. The higher B/T fraction of MA would result in the higher B/T capacity, and will reduce the units of HFBWR needed for the treatment of a constant mass of MA. In addition, HFBWR had a merit of higher mass transmutation compared to the reference BWR, under the same mass loading of MA