Encapsulation of radioactive stainless-steel corrosion products sludge in aluminum using hot isostatic pressing process and treatment suitability assessment

Sludge powder with stainless-steel corrosion products generated from the long-term contaminated-waste fluid tank of a nuclear power plant was compressed into a cylindrical shape by a hydraulic press at room temperature. The cylindrical sludge was wrapped in molten Al in a carbon crucible and cooled and hardened at room temperature. Subsequently, the encapsulated sludge was heated and compressed by the hot isostatic pressing (HIP) process. The Al capsule was melted and separated from the cylindrical solidified sludge. In solidified sludge, the leachability indices of Co, Fe, Cr, and Ni were 17.5 +/- 0.0736, 13.4 +/- 0.0952, 11.2 +/- 0.0952, and 16.9 +/- 0.0739, respectively. This satisfies Korea's criterion for the disposal of solidified radioactive waste, which is a leachability index of more than 6.