Sequence showing radioactive iodine extraction process at chemist's bench at Chalk River power plant: MS of chemist manipulating florence flasks near lead brick wall separating man from radioactive appartus. CU of rubber gloved hand turning knob on lead brick wall. HACS of liquid boiling in flask, then stopping; various pipes and valves visible around boiler flask. MS and MCS of laboratory man seated in front of complex equipment in laboratory, writing down data. CS of other laboratory technician adjusting suspended glass tube on complex equipment. LACU of rubber gloved hand adjusting glass tube, liquid bubbling down.