Method and facility for converting uranium hexafluoride into uranium dioxide

A conversion installation for converting uranium hexafluoride (UF6) to uranium dioxide (UO2), the conversion installation comprising:

• a hydrolysis reactor for the conversion of UF6 to uranium oxyfluoride (UO2F2) by reaction between gaseous UF6 and dry water vapor injected into the reactor;
• a pyrohydrolysis furnace for the conversion of UO2F2 to UO2 by reaction of UO2F2 with dry water vapor and hydrogen gas (H2) injected into the furnace;
• a capture device for capturing and extracting of excess gas in the reactor, the capture device comprising several filters;
• an unclogging device configured for unclogging of the filters by injecting a neutral gas into the filters from the outside to the inside of the reactor to remove a powder stuck on the filters;
• a pressure sensor configured for measuring a pressure inside the hydrolysis reactor;
• and
• a control system configured to shut down the conversion installation if the relative pressure in the hydrolysis reactor exceeds a predetermined safety threshold,
• the unclogging device configured to:
• periodically unclog the filters by injecting a neutral gas into the filters from an outside to an inside of the hydrolysis reactor to remove the powder stuck on the filters;
• and
• implement a punctual unclogging of the filters when a relative pressure in the hydrolysis reactor exceeds a predetermined punctual unclogging threshold,
• wherein the punctual unclogging threshold is set in a range of 100 mbar below the safety threshold.