[en] The isolation period of high level radioactive waste from human biotope is some ten thousand years or more. Especially, many crustal movement zones are located in our country, so that very careful measures should be taken. Isolation of high level radioactive waste in lithosphere needs to confirm good isolation site. Boring is a chief method to determine the location conditions for radioactive waste. In order to study crack of rock and behavior of groundwater, high density of drilling must be necessary. However, high density drilling should be avoided. In place of it, a geophysical exploration is an ideal method, one of non-destructive inspection. It is important for many countries to establish the technologies to determine the conditions of crack and groundwater by this method. A large amount of data about the contact condition of radionuclide and minerals, pH, oxidative-reduction potential and temperature are needed. (S.Y.)