Hitachi, Ltd.

Hitachi-ge Nuclear Energy, Ltd.

Tetsuo Fukasawa

Fumio Kawamura

Naohito Uetake

Kiyomi Funabashi

Akira Sasahira

Yoshihiro Ozawa

Makoto Kikuchi

Takehiko Kitamori

Hideo Yusa

Takashi Nishi

Haruo Fujimori

Kazumichi Suzuki

Masanori Takahashi

Mamoru Kamoshida

Toshio Takagi

Megumu Urata

Youji Shibata

Hajime Iba

Ietsugu Sekine

Masaharu Ohtsuka

Haruo Hasimoto

Most part of an amount of uranium contained in the spent nuclear fuel is removed by making fluorine or a fluorochemical act on the spent nuclear fuel to convert the uranium into UF, and the uranium is purified through a simple method of distilling the UFtogether with a absorbent. After removing the most part of the amount of uranium, the remaining nuclear fuel material is dissolved and then transferred to an extraction process to recover plutonium. By doing so, a small sized dry process can be employed as a uranium purification process. Since the nuclear fuel material is dissolved and extracted after removing most part of an amount of uranium, a volume of processing solution can be reduced and the machine installation scale can be made small. Accordingly, the reprocessing facility can be extremely downsized.

Method of reprocessing spent nuclear fuel

Cations and anions contained as impurities in a spent organic solvent can be removed by an alkaline aqueous solution passing through inside of hydrophobic porous membrane such as hollow fibers for capturing anions and by an acidic aqueous solution passing through inside of hydrophobic porous membrane such as hollow fibers for capturing cations at the same time so as to regenerate the organic solvent. An apparatus suitable for removing cations and anions simultaneously from the spent organic solvent is also provided.

Process and apparatus for regenerating spent reprocessing extraction

A dissolved substance contained in a solution is oxidized or reduced by adding a particulate semiconductor photocatalyst and a water-soluble electron acceptor or donor for the particulate semiconductor photocatalyst to a solution containing a dissolved substance, and irradiating the particulate semiconductor photocatalyst in the solution with an electromagnetic wave having an energy high enough to excite the particulate semiconductor photocatalyst, or by adding a particulate semiconductor photocatalyst and a water-soluble electron acceptor or donor for the particulate semiconductor photocatalyst to a solution containing a dissolved substance and irradiating the particulate semiconductor photocatalyst in the solution with an electromagnetic wave having an energy high enough to excite the particulate semiconductor photocatalyst and having a wavelength outside the absorption wavelength region of a precursor substance capable of producing an oxidation or reduction reaction-inhibiting substance, whereby (1) ions or complexes are converted to simple substances or to ions or compounds with different valencies, and (2) simple substances, ions, complexes or other compounds are separated and recovered or removed by utilizing its actions and effects.

Process and apparatus for oxidizing or reducing dissolved substance

A method of solidifying radioactive waste wherein radioactive solid waste of a predetermined shape are embedded in a solidifying material which has a modulus of elasticity that is equal to, or smaller than, the modulus of elasticity of said waste, to provide a solidified body. The modulus of elasticity of the solidifying material is adjusted to be equal to, or smaller than, that of the radioactive solid waste, in order to prevent stress concentrations at the boundaries between the solidifying material and the radioactive solid waste, particularly on the solidifying material side thereof. The invention makes it possible to prepare a solidified body with a desired durability and safety factor.

Method of solidifying radioactive solid waste

Method for solidifying radioactive waste

A solid radioactive waste can be solidified by a process comprising packing a solid radioactive waste in a container, adding to the container an aqueous solution comprising an alkali silicate, a hardening agent and a fluidity-improving agent for the aqueous solution and conducting the solidification of the alkali silicate, the resulting solidified radioactive waste being excellent in weather resistance, showing no cracks and having sufficient strength.

Process for solidifying radioactive waste

An apparatus for separating solid matters having a rotor of a double-basket construction consisting of a centrifugal filtering basket which is secured in a basket which effects the separation relying upon the difference in specific gravity. A pipe is so arranged as to supply the liquid to be treated into the centrifugal filtering basket, and scoop pipes are arrayed near the side surfaces of the two baskets.

Apparatus for separating solid matters

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Hitachi, Japan

Tetsuo Fukasawa