Development of package-reactor (2). Feasibility design for nuclear power generation system

Feasibility design of Package-Reactor with a thermal output of 50MWt has been performed. Several key designs have been investigated taking into account both PWR and BWR technologies. The reactor has three or seven nuclear cassettes. Each cassette includes a steam generator and a riser. The pressure tube of the cassette is the pressure boundary for the core cooling system with a pressure of 15.5MPa. The core is cooled by natural circulation with two-phase flow of light water. The core inlet and outlet temperatures are 340degC and 345degC respectively and the average void fraction at the core top is about 50%. The height and the outer diameter of the cassette are respectively about 10m and about 0.7m. The design target of the cycle length is five years by using UO2 fuel with an enrichment of 5wt%. Burnable absorber loaded in the core of each cassette gives a very small reactivity swing with burnup. This phenomenon leads to reactivity control free reactor. (author)