According to an embodiment, a nuclear fuel material recovery method of recovering a nuclear fuel material containing thorium metal by reprocessing an oxide of a nuclear fuel material containing thorium oxide in a spent fuel is provided. The method has: a first electrolytic reduction step of electrolytically reducing thorium oxide in a first molten salt of alkaline-earth metal halide; a first reduction product washing step of washing a reduction product; and a main electrolytic separation step of separating the reduction product. The first molten salt further contains alkali metal halide, and contains at least one out of a group consisting of calcium chloride, magnesium chloride, calcium fluoride and magnesium fluoride. The method may further has a second electrolytic reduction step of electrolytically reducing uranium oxide, plutonium oxide, and minor actinoid oxide in a second molten salt of alkali metal halide.

A processes for recycling uranium that has been used for the production of molybdenum-99 involves irradiating a solution of uranium suitable for forming fission products including molybdenum-99, conditioning the irradiated solution to one suitable for inducing the formation of crystals of uranyl nitrate hydrates, then forming the crystals and a supernatant and then separating the crystals from the supernatant, thus using the crystals as a source of uranium for recycle. Molybdenum-99 is recovered from the supernatant using an adsorbent such as alumina. Another process involves irradiation of a solid target comprising uranium, forming an acidic solution from the irradiated target suitable for inducing the formation of crystals of uranyl nitrate hydrates, then forming the crystals and a supernatant and then separating the crystals from the supernatant, thus using the crystals as a source of uranium for recycle. Molybdenum-99 is recovered from the supernatant using an adsorbent such as alumina.

A processes for recycling uranium that has been used for the production of molybdenum-99 involves irradiating a solution of uranium suitable for forming fission products including molybdenum-99, conditioning the irradiated solution to one suitable for inducing the formation of crystals of uranyl nitrate hydrates, then forming the crystals and a supernatant and then separating the crystals from the supernatant, thus using the crystals as a source of uranium for recycle. Molybdenum-99 is recovered from the supernatant using an adsorbent such as alumina. Another process involves irradiation of a solid target comprising uranium, forming an acidic solution from the irradiated target suitable for inducing the formation of crystals of uranyl nitrate hydrates, then forming the crystals and a supernatant and then separating the crystals from the supernatant, thus using the crystals as a source of uranium for recycle. Molybdenum-99 is recovered from the supernatant using an adsorbent such as alumina.

A process for controlling the dissolution of a metal in an acid bath is described. The metal may comprise aluminum and the acid bath may contain a metal catalyst that causes the metal to dissolve. In order to control the rate of dissolution, the metal can be contacted with a cathodic member. In one embodiment, the process can be completely stopped even without removing the metal from the acid bath. The cathodic member provides anodic protection to the metal. In one embodiment, the cathodic member is made from a nickel-chromium-based alloy.

A process for controlling the dissolution of a metal in an acid bath is described. The metal may comprise aluminum and the acid bath may contain a metal catalyst that causes the metal to dissolve. In order to control the rate of dissolution, the metal can be contacted with a cathodic member. In one embodiment, the process can be completely stopped even without removing the metal from the acid bath. The cathodic member provides anodic protection to the metal. In one embodiment, the cathodic member is made from a nickel-chromium-based alloy.

A process for minimizing waste and maximizing utilization of uranium involves recovering uranium from an irradiated solid target after separating the medical isotope product, molybdenum-99, produced from the irradiated target. The process includes irradiating a solid target comprising uranium to produce fission products comprising molybdenum-99, and thereafter dissolving the target and conditioning the solution to prepare an aqueous nitric acid solution containing irradiated uranium. The acidic solution is then contacted with a solid sorbent whereby molybdenum-99 remains adsorbed to the sorbent for subsequent recovery. The uranium passes through the sorbent. The concentrations of acid and uranium are then adjusted to concentrations suitable for crystallization of uranyl nitrate hydrates. After inducing the crystallization, the uranyl nitrate hydrates are separated from a supernatant. The process results in the purification of uranyl nitrate hydrates from fission products and other contaminants. The uranium is therefore available for reuse, storage, or disposal.

A process for minimizing waste and maximizing utilization of uranium involves recovering uranium from an irradiated solid target after separating the medical isotope product, molybdenum-99, produced from the irradiated target. The process includes irradiating a solid target comprising uranium to produce fission products comprising molybdenum-99, and thereafter dissolving the target and conditioning the solution to prepare an aqueous nitric acid solution containing irradiated uranium. The acidic solution is then contacted with a solid sorbent whereby molybdenum-99 remains adsorbed to the sorbent for subsequent recovery. The uranium passes through the sorbent. The concentrations of acid and uranium are then adjusted to concentrations suitable for crystallization of uranyl nitrate hydrates. After inducing the crystallization, the uranyl nitrate hydrates are separated from a supernatant. The process results in the purification of uranyl nitrate hydrates from fission products and other contaminants. The uranium is therefore available for reuse, storage, or disposal.

The invention concerns an apparatus and a method for treating radioactive material (36), in particular for cleaning radioactive contaminated water. The apparatus comprises a process chamber (10) with a combustion zone (12) for generating an oxygen rich gas (34) and an oxidation zone (14), which is arranged to receive the oxygen rich gas (34) from the combustion zone (12). The process chamber (10) further comprises a feed opening (16) for feeding the radioactive material (36) into the oxidation zone (14) and the process chamber (10) is configured to use the oxygen rich gas (34) for oxidizing the radioactive material (36) to obtain oxidized material (38). The apparatus further comprises a separation device (50) operationally connected to an outlet of the process chamber (10) and configured to at least partly separate the oxidized material (38) into a gaseous fluid (56) and a non.sup.− gaseous residue (58). This way a greatly reduced volume of the radioactive material (36) is achieved, enabling safe and efficient handling and/or compact and space-saving disposal of the radioactive material (36).

A nuclear fuel powder production plant comprises a conversion installation (2) for the conversion of uranium hexafluoride (UF.sub.6) into uranium dioxide (UO.sub.2) having a hydrolysis reactor (4) for the conversion of UF.sub.6 into uranium oxyfluoride powder (UO.sub.2F.sub.2) and a pyrohydrolysis furnace (6) for converting the UO.sub.2F.sub.2 powder into UO.sub.2 powder. The nuclear fuel powder production plant also includes a packaging unit (20) for the UO.sub.2 powder comprising a filling station (22) having a chamber (26) for receiving a container (24) to be filled, a filling duct (28) supplied from the furnace (6) and a suction system (32) comprising a suction ring (34) disposed at the outlet (30) of the filling duct (28) for sucking an annular air flow (A) around a stream (P) of UO.sub.2 powder falling from the outlet (30) from the filling duct (28) into the container (24).

An installation for the conversion of uranium hexafluoride (UF.sub.6) to uranium dioxide (UO.sub.2) comprises a hydrolysis reactor (4) for the conversion of UF.sub.6 into uranium oxyfluoride powder (UO.sub.2F.sub.2), a pyrohydrolysis furnace (6) for converting the UO.sub.2F.sub.2 powder supplied by the reactor (4) into UO.sub.2 powder, a supply device (8) comprising reagent injection ducts (10) for the injection of UF.sub.6, water vapor or H.sub.2, and a control system (16) designed to control the supply device (8) so as to supply at least one of the reagent injection ducts (10) with a neutral gas during a shut-down or start-up phase of the conversion installation.