Neutronics of LBE target-cooled ADS for MA transmutation: Japan

Purpose and goal: JAEA's reference design of ADS is a tank type 800 MWth subcritical reactor to transmute about 250 kg of minor actinides annually. A lead-bismuth eutectic (LBE) is used as both the primary coolant and the spallation target. A superconducting linear accelerator (SC-LINAC), whose proton energy and maximum current are 1.5 GeV and 20 mA (30 MW), is connected to produce spallation neutrons. The (MA, Pu) N fuel diluted by ZrN is used in the subcritical core. Because the relatively high power peaking factor will be observed at the burnup stage of low HII value, where the influence of the spallation neutrons is strong, Pu is added at the beginning of the first burnup cycle to mitigate the rapid increase of the burnup reactivity