抄録
Core burn-up calculation was performed and result shows that the excess reactivity can be suppressed by either soluble boron or control rods in addition to the burnable poison. The necessary condition for uniform doping was determined. The graphite spacer, height of 25 cm, needs to be placed between ingots to allow neutron current into both top and bottom of the ingots. The ingot height is necessary to be limited by 20 cm.
