Hitachi, Ltd.

The Tokyo Electric Power Company, Incorporated

Hitachi-ge Nuclear Energy, Ltd.

Akira Sasahira

Tetsuo Fukasawa

Hiroaki Kobayashi

Fumio Kawamura

Takehiko Kitamori

Hideo Yusa

Takashi Nishi

Haruo Fujimori

Kazumichi Suzuki

Masanori Takahashi

Kenji Noshita

Mamoru Kamoshida

Yoshihiro Ozawa

Keita Okuyama

Osamu Amano

Masakatsu Aoi

Kuniyoshi Hoshino

Youji Shibata

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

A subterranean environment evaluating apparatus and method, which measure, e.g., the geologic distribution coefficient in a subterranean environments using, e.g., a pit formed by boring. The subterranean environment evaluating apparatus comprises a geologic evaluation sensor, a pump, an analyzer, a PC, a data transmitter, etc., and it is disposed in the pit formed underground by boring. The geologic evaluation sensor is disposed to form a thin layer channel defined by the surface of a rock bed. Groundwater mixed with a tracer is caused to flow through the sensor, and the analyzer measures a change of tracer concentration in the groundwater between before and after contact of the groundwater with the rock bed. The PC determines a breakthrough curve from the change of tracer concentration, thereby calculating the distribution coefficient (Kd) between the rock bed and the groundwater and the effective diffusion coefficient of the rock bed.

Apparatus and method for evaluating subterranean environments

It is an object to increase a reprocessing speed of spent nuclear fuel and to obtain uranium having a high purity and a plutonium mixture reusable as it is at a low cost through a simple procedure. The spent nuclear fuelis subjected to fluorination using fluorinein a fluorination step, and as a result, uranium, a mixture of uranium and plutonium and a fission product are separated and recovered independently of one another. The plutonium fluoride volatilized in the fluorination is recovered along with a fixing agent and then passed through an oxidative conversion step, thereby recovering a mixture of uranium and plutonium oxides. Since the uranium can be recovered in a high purity, it is managed very easily when reused or saved. Further, since the uranium and plutonium are recovered as a mixture thereof, fuel reproduction cost is decreased and prevention of proliferation is strengthened.

Method for reprocessing spent nuclear fuel

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

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Hitachi, Japan

Akira Sasahira