An innovative concept of a sodium-cooled reactor (the Advanced Loop-Type Fast Reactor) to pursue high economic competitiveness has been developed.

Measures to reduce cost adopted in the design are compact design of reactor structure, shortening of piping, reduction of loop number, and integration of components. These design measures are expected to be realized by introducing some innovative technologies (12Cr steel with high strength, advanced elevated temperature structural design standards, three-dimensional seismic isolation, and recriticality free technology), which have the potential to be put to practical use by 2015, and by taking into account the desirable characteristics of sodium coolant (operability in a low-pressure system and excellent heat transfer characteristics).

By drastically decreasing the amount of materials through these measures, it is expected that the construction cost will be reduced to below 200 000 yen/kW(electric), i.e., below two-thirds times that of light water reactors at present. The potential to realize this plant concept has been obtained through evaluations of major design issues concerning safety, structural integrity, and thermal hydraulics.