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  • 1 Kalpakkam Reprocessing Plant, Bhabha Atomic Research Centre Facilities, Kalpakkam, 603102 India
  • 2 Department of Chemical Engineering, Indian Institute of Technology, Roorkee, 247667 India
  • 3 Reprocessing R&D Division, Indira Gandhi Centre for Atomic Research, Kalpakkam, 603102 India
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Abstract  

Study of runaway reaction between tri-n-butyl phosphate (TBP) and nitric acid resulting in red-oil formation (and related problems) in the process evaporators of reprocessing plants has been a major safety concern since last 50 years. Thermal decomposition of nitrated TBP results in rapid pressurization and in close-vent condition it may lead to failure of process vessel and containment. Thermal decomposition of nitrated TBP is reported in the literature but corresponding studies for alternate PUREX/UREX solvent tri-iso-amyl phosphate (TiAP) are not available. In this work, comparative study of the thermal decomposition of nitrated solvents (TBP as well as TiAP) under adiabatic conditions in a sealed autoclave is presented. Experimental results indicate much lesser pressurization in the case of TiAP as compared to TBP.