Thermal Analysis of Vacuum Distillation Chamber in Pyroprocessing Facility

D. Sujish, S. Agarwal, B. Muralidharan, B.K. Sharma, V. Suresh Kumar, B. Prabhakara Reddy, G. Ravisankar, K. Nagarajan, C.A. Babu, and P. Kalyanasundaram
Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamil Nadu, India

Non aqueous metal fuel reprocessing involves electrochemical deposition of spent metallic fuel on the cathode of an electrolytic cell. Apart from metal fuel, the cathode deposit would also contain occluded molten salts and liquid cathode. Subsequent purification and consolidation of these heavy metals is conducted in a vacuum retort. Here the cathode deposits are charged into graphite crucible and heated by induction to 900oC and 1300oC at 0.1 mm Hg pressure to distill off liquid cathode and salts respectively. The steady state temperature profile during vacuum distillation of cathode deposits was obtained by a thermal analysis of the vacuum distillation vessel. It was carried out using COMSOL. A transient analysis was also done to determine the heating time for a particular frequency and current in the induction coils. This paper highlights the important temperature profiles at steady state which would be helpful in the final mechanical design of the various components. This also gives the time required for heating the crucible to about 1300oC by induction.