RADIOLOGICAL AND ENVIRONMENTAL ASPECTS OF TH-U FUEL-CYCLE FACILITIES

The comparatively higher level of thorium reserves and the absence of long lived actinides of environmental concern offer real advantages fo r utilization of thorium in nuclear reactors. While use of uranium is likely to continue for some more time in view of investments already m ade, a shift to thorium eventually is an imperative necessity. It is i n fact inevitable for a country like India. The paper presents a detai led comparative analysis of occupational radiation exposures as well a s environmental releases. Different stages such as mining,fuel fabrica tion, reactor operation, spent fuel storage and reprocessing are consi dered. The factors that need to be taken into account include among ot hers, the relatively lower occupational exposures and environmental re leases in sodium cooled fast reactors compared to LWRs, the occurrence of thorium as surface deposits obviating the need for deep mining as in the case of uranium and the special dose reduction measures that ne ed to be devised to minimize occupational exposures due to daughter pr oducts of U-232 present in U-233 during fuel fabrication operations. I f once through mode of fuel cycle is to be adopted, thorium oxide mate rials are likely to be more enduring than would be the case with urani um. (C) 1997 Published by Elsevier Science Ltd.