Underground location of nuclear power stations

In Japan where the population is dense and the land is narrow, the conventional location of nuclear power stations on the ground will become very difficult sooner or later. At this time, it is very important to establish the new location method such as underground location, Quaternary ground location and offshore location as the method of expanding the location for nuclear power stations from the viewpoint of the long term demand and supply of electric power. As for underground location, the technology of constructing an underground cavity has been already fostered basically by the construction of large scale cavities for underground pumping-up power stations in the last 20 years. In France, Norway and Sweden, there are the examples of the construction of underground nuclear power stations. In this way, the opportunity of the underground location and construction of nuclear power stations seems to be sufficiently heightened, and the basic research has been carried out also in the Central Research Institute of Electric Power Industry. In this paper, as to underground nuclear power stations as one of the forms of utilizing underground space, the concept, the advantage in aseismatic capability, the safety at the time of a supposed accident, and the economical efficiency are discussed. (Kako, I.)