Required Removal Rates for Kr-85 in the Future

概要

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Krypton-85 is a radioactive noble gas with a long half-life, and its release to the environment results in global contamination. The concentration of 85Kr in the atmosphere is gradually increasing today, and it will reach the order of 104 pCi/m3 by the year 2000 if this nuclide is continued to be released without removal. The release will likely be restricted in the future under international control, though the dose rates due to 85Kr absorption based on the ICRP recommendation is at present being reevaluated on account of its appearing to be excessively high. In this paper, the removal rates required for 85Kr are estimated to cover several decades, using the linear programming method, with a selection of given constraints specifying different criteria for limiting atmospheric pollution, and based on an assumed program for nuclear electricity power generation and construction of reprocessing plants. Some parameters contained in the objective function are difficult to fix, particularly the equipment and operating costs and the penalty for absorbed dose rate, but some results are given as indication, with these parameters tentatively assumed. As an example, adopting the constraint to limit to 108 Ci the accumulation in atmosphere of 85Kr released from reprocessing plants in Japan should require the removal of 80...90% of effluent 85Kr at the reprocessing plants by the year 1990 at the latest.
一般社団法人日本原子力学会の論文