Patent ID: 7666370

Claim:
A process of recycling sodium salt in a wet reprocessing process of a spent nuclear fuel, comprising: a neutralization step in which a nitric acid liquid waste or an off-gas having nitric acid dissolved therein which is produced through a wet reprocessing process comprising a dissolution step for dissolving a spent nuclear fuel in nitric acid is neutralized by adding or contacting one or more sodium salts selected from the group consisting of sodium hydroxide, sodium hydrogencarbonate and sodium carbonate to or with the nitric acid liquid waste or the off-gas, thereby yielding a sodium nitrate liquid waste; a sodium nitrate-decomposition step in which the sodium nitrate liquid waste obtained in the neutralization step is reductively decomposed with a reducing agent, thereby decomposing sodium nitrate into a nitrogen gas and the sodium salt(s); and a recycle step for recycling the sodium salt(s) produced in the sodium nitrate-decomposition step into the neutralization step or the wet reprocessing process, wherein the reductive decomposition in the sodium nitrate-decomposition step is carried out by reductive decomposition using a reducing agent and a catalyst or by reductive decomposition using a reducing agent under supercritical conditions where water serves as a supercritical fluid.