Abstract: A method of restraining a diffusion of tritium and an apparatus for same are disclosed. The method includes the step of disposing a hydrogen-absorbing metal in a tritium passage in a direction of diffusion of tritium so that the hydrogen-absorbing metal absorbs tritium to be diffused. The apparatus includes a hydrogen-absorbing metal surrounding a device of a fast breeder reactor. The tritium to be diffused can be readily captured. An arrangement of capturing the tritium permeating the device is simplified in the present invention.

Abstract: Of the components making up the pump, one part including the bearing is removably assembled into the other part so that the bearing is received in the other part. This structure allows easy removal of the first part of the pump components from the second part for disassembly and for maintenance and inspection of the pump. The pump can also be reassembled with ease by inserting the first part into the other part.

Abstract: This invention relates to a cold trap for collecting impurities from liquid, which comprises a mesh screen and a spacer mesh having higher strength and wider mesh holes than that of the mesh screen interposed between the windings of the mesh screen. According to the present invention, since the spacer mesh supports the mesh screen over the whole surface thereof so that the mesh screen is protected free from break or deformation, the stiffness and collecting efficiency of the mesh section can be maintained prolongedly.

Abstract: An electrically conductive metal is arranged within a passage for sodium having leaked, and the temperature change of the electrically conductive metal attributed to the heat of vaporization of which the sodium mist deprives the electrically conductive metal upon contact with the latter and subsequent vaporization is detected. The temperature change of the electrically conductive metal is detected in the form of a change in the current or voltage conducting property, and current corresponding to the temperature change is fed back to the electrically conductive metal. The change of the conducting property is taken out as a pulse signal, and a value proportional to the weight of a sodium mist particle is detected from the magnitude of the signal. Further, a value proportional to the weight of the whole mist is detected by the pulse height analysis. The leakage of the sodium is decided by comparing the value of the weight of the whole mist with a predetermined value.