Zaki Su'ud; cmail:szaki@fi.itb.ac.id. In this study the characteristic andprospect of very small size (10-20MWe) nuclear power reactors based on liquid Pb-Bicoolant and nitride fuel are investigated Theproposed design uses internal blanket tominimize excess reactivity during reactor operation. The reactor core is divided intoseveral region and adjusted to optimized reactivity swing, power peaking and coolantdensity coefficient of reactivity. As usualfor liquid Pb and Pb-Bi core, the design is alsoadjusted to minimize pressure drop and maximize natural circulation component. In thepresent study we used balanced core to optimize nelltronicperformance. U\'ing higher.filel volume fraction we can overcome solution of low power density problem usuallyappearfor velY small nuclear power reactors.
