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.

A single integrated system for recycling used nuclear fuel (UNF) emerging from a reactor has a decladding vessel separating fuel pellets from nuclear fuel rods via oxidation to produce U.sub.3O.sub.8. A fluorination vessel is coupled to the decladding vessel to remove hexafluorides from the U.sub.3O.sub.8 produced by the decladding vessel. An electrowinning vessel is coupled to the fluorination vessel removing plutonium and actinides via electrowinning.

A conversion process for converting uranium hexafluoride into uranium dioxide includes the steps of hydrolysis of UF6 to uranium oxyfluoride (UO.sub.2F.sub.2) in a hydrolysis reactor (4) by reaction between gaseous UF6 and dry water vapour injected into the reactor (4), pyrohydrolysis of UO.sub.2F.sub.2 to UO.sub.2 in a pyrohydrolysis furnace (6) by reacting UO.sub.2F.sub.2 with dry steam and gaseous hydrogen (H.sub.2) injected into the furnace (6), extracting excess gas in the reactor (4) via a collecting device (50) comprising several filters (52), periodically cleaning the filters (52) by injecting a neutral gas into the filters (52) from the outside to the inside of the reactor (4) to remove powder stuck on the filters (52), and measuring the relative pressure in the reactor (4). The conversion method further includes carrying out point cleaning of the filters (52) when the relative pressure in the reactor (4) exceeds a predetermined point cleaning threshold.

Systems and methods for injecting a carbonate-based sacrificial material into a nuclear reactor containment for containment of molten corium in severe nuclear reactor accidents are disclosed. Molten corium can be quickly cooled and solidified by the endothermic decomposition of the sacrificial material.

Systems and methods for injecting a carbonate-based sacrificial material into a nuclear reactor containment for containment of molten corium in severe nuclear reactor accidents are disclosed. Molten corium can be quickly cooled and solidified by the endothermic decomposition of the sacrificial material.

A method of direct oxide reduction includes forming a molten salt electrolyte in an electrochemical cell, disposing at least one metal oxide in the electrochemical cell, disposing a counter electrode comprising a material selected from the group consisting of osmium, ruthenium, rhodium, iridium, palladium, platinum, silver, gold, lithium iridate, lithium ruthenate, a lithium rhodate, a lithium tin oxygen compound, a lithium manganese compound, strontium ruthenium ternary compounds, calcium iridate, strontium iridate, calcium platinate, strontium platinate, magnesium ruthenate, magnesium iridate, sodium ruthenate, sodium iridate, potassium iridate, and potassium ruthenate in the electrochemical cell, and applying a current between the counter electrode and the at least one metal oxide to reduce the at least one metal oxide. Related methods of direct oxide reduction and related electrochemical cells are also disclosed.

A method of direct oxide reduction includes forming a molten salt electrolyte in an electrochemical cell, disposing at least one metal oxide in the electrochemical cell, disposing a counter electrode comprising a material selected from the group consisting of osmium, ruthenium, rhodium, iridium, palladium, platinum, silver, gold, lithium iridate, lithium ruthenate, a lithium rhodate, a lithium tin oxygen compound, a lithium manganese compound, strontium ruthenium ternary compounds, calcium iridate, strontium iridate, calcium platinate, strontium platinate, magnesium ruthenate, magnesium iridate, sodium ruthenate, sodium iridate, potassium iridate, and potassium ruthenate in the electrochemical cell, and applying a current between the counter electrode and the at least one metal oxide to reduce the at least one metal oxide. Related methods of direct oxide reduction and related electrochemical cells are also disclosed.

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.2F2) and a pyrohydrolysis furnace (6) for converting the UO.sub.2F2 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).

A single integrated system for recycling used nuclear fuel (UNF) emerging from a reactor has a decladding vessel separating fuel pellets from nuclear fuel rods via oxidation to produce U.sub.3O.sub.8. A fluorination vessel is coupled to the decladding vessel to remove hexafluorides from the U.sub.3O.sub.8 produced by the decladding vessel. An electrowinning vessel is coupled to the fluorination vessel removing plutonium and actinides via electrowinning.