PROBLEMS OF REMOVAL AND CONTAINMENT OF HIGH-LEVEL RADIOACTIVE POLONIUM FROM ACCELERATOR-DRIVEN TRANSMUTATION SYSTEM USING LIQUID LEAD-BISMUTH TARGET

摘要

The channels of polonium nuclide formation in lead-bismuth target irradiated by high energy protons and secondary neutrons are considered. Under off blanket condition the activity of 200{sup left}Po ÷ 210{sup left}Po, as well as the fission and spallation product activity are calculated for 15 MW target after 1 year operation. Polonium separation methods, including removal using alkaline extraction, vacuum sublimation, and so-called carrier method are analyzed. The engineering design for experimental apparatus to test polonium removal and containment using alkaline extraction using tellurium as a chemical analog of polonium is developed. The necessary degree of polonium removal to keep concentration below levels appropriate to meet the US and Russia safety standards is estimated. Comparative analysis of alkaline extraction and vacuum sublimation techniques from the viewpoint to achieve the necessary removal depth is carried out.