Design of transition cores of RSG GAS (MPR-30) with higher loading silicide fuel

A procedure of designing transition cores to achieve the equilibrium silicide core of RSG GAS with higher fuel loading of 300 g U/fuel element (FE) (meat density of 3.55 g U/cm3) has been proposed. In the proposed procedure, the EOC excess reactivity of each transition core is minimized in order to satisfy the safety design limit of one-stuck-rod sub-criticality margin while keeping the maximum of radial power peaking factor below the allowable value. Under the design procedure, the initial fuel loadings are increased gradually in two steps, i.e. from 250 to 275 g U/FE followed by 275–300 g U/FE. The analysis results show that all transition cores can satisfy all design requirements and safety limits. We concluded that the obtained transition core design should be adopted into the future core conversion program of RSG GAS. The targeted silicide core can be achieved practically in at least 24 transition cores.