Abstract

This briquette for vitrifying radioactive waste includes a powdery vitrifying material and a binder, wherein the binder includes an inorganic borate compound.

IPC Classes  ?

• G21F 9/16 - Processing by fixation in stable solid media
• G21F 9/30 - Processing

Abstract

The present disclosure relates to a process for recycling a sodium salt by decomposition of a sodium nitride liquid waste, 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 the nitrate liquid waste or the off-gas to or with at least one sodium salt selected from the group consisting of sodium hydroxide, sodium hydrogencarbonate and sodium carbonate, thereby yielding a sodium nitrate liquid waste; a sodium nitrate-decomposition step in which the sodium nitrate liquid waste is reductively decomposed with a reducing agent, thereby decomposing sodium nitrate into a nitrogen gas and the sodium salt; and a recycle step for recycling the sodium salt into the neutralization step or wet reprocessing process.

IPC Classes  ?

• B01D 11/00 - Solvent extraction
• G21F 9/00 - Treating radioactively contaminated materialDecontamination arrangements therefor
• G21F 9/16 - Processing by fixation in stable solid media
• G21F 9/20 - Disposal of liquid waste

Abstract

Disclosed is a system for recycling of a sodium salt by decomposition of a sodium nitride liquid waste. The system comprises: a neutralizing step in which a nitrate liquid waste or an off-gas having nitric acid dissolved therein which is produced through a wet reprocessing process comprising dissolving a used nuclear fuel in nitric acid is neutralized by adding or contacting the nitrate liquid waste or the off-gas to or with at least one sodium salt selected from sodium hydroxide, sodium bicarbonate and sodium carbonate, thereby yielding a sodium nitrate liquid waste; a sodium nitrate-decomposing step in which the sodium nitrate liquid waste is reductively decomposed with a reducing agent, thereby decomposing sodium nitrate into a nitrogen gas and the sodium salt; and a step of recycling the sodium salt into the neutralizing step or wet reprocessing process. The sodium nitrate liquid waste obtained in the neutralizing step may be condensed by evaporation to give a concentrated sodium nitrate liquid waste, and the condensed sodium nitrate liquid waste may be reductively decomposed in the sodium nitrate-decomposing step.

IPC Classes  ?

• G21F 9/06 - Processing
• G21C 19/46 - Aqueous processes