Journal of Nuclear Fuel Cycle and Waste Technology

Thermal decomposition and stabilization characteristics of the solid cake after the dissolution of nitrate of the lagoon sludge was investigated. Most of the nitrates were dissolved in the water and removed to the filtrate, but small amount of nitrates, calcium carbonate and uranium were remained in the solid cake. The solid cake was thermally decomposed in the muffle furnace at 900 ℃ for 5 hours. Uranium, which is in the lagoon 1, was stabilized with NaNO3 decomposition to Na2O · 2UO3 form. For the lagoon 2, it is confirmed that CaO, which was created by thermal decomposition of the Ca(NO3)2 and CaCO3, was transferred to Ca(OH)2 in the air with water. Because it is known that Ca(OH)2 is stable material, further additives did not need to the stabilization of the thermal decomposition of the lagoons.

Keywords

uranium conversion,thermal decomposition nitrate,sludge,stabilization