Study on treatment of intermediate level waste

Intermediate level liquid waste (ILW) stored in tanks at Kalpakkam is alkaline in nature and is treated by ion exchange process. Prior to ion exchange, ILW is pre-treated first with HNO₃ to destroy the carbonate complexes of actinides and later with NaOH to precipitate out the actinides. The resultant actinide free supernatant is passed through ion exchanger specific to remove Cs activity. ILW is converted into a low volume of high level waste (HLW) and large volume of low level waste (LLW). During carbonate destruction step of ILW, an insoluble (in most of the acids) gelatinous precipitate was formed unlike the treatment of usual acidic ILW. The modified procedure for the treatment was established and can be adopted for plant operation. (author)