Safe Handling and Reduction of Low-Level Radioactive Waste from Radioisotope-Handling Facilities of Universities.

在大学的许多高级科学研究中，放射性同位素经常被用作不可避免的工具。大部分同位素在使用后回收，必须支付高昂的费用转交给日本放射性同位素协会进行处理，或者必须根据《防止放射性同位素等引起的辐射危害法》将其储存在大学的废物处理设施中，即使放射性水平很低。在这项研究中，我们与国立大学放射性同位素中心的研究人员合作，研究了改善在大学设施中处置的这种低水平放射性废物的安全处理，以及根据法律通过几种方法减少废物量的问题。对活性极低的可燃性废弃物如纸、布、塑料等进行了燃烧、低温灰化、干馏等减容试验，并对放射性同位素在不同处理条件下的行为进行了研究。初步达到了提高效率、防止扩散和安全回收同位素的目的。经国家科技局批准，研究了5种放射核素（H-3、C-14、P-32、S-35、Ca-45）测量后液体闪烁体鸡尾酒溶液的燃烧情况。在不同的燃烧条件下，研究了这些化合物在燃烧过程中和燃烧后的行为，在废气和处理水中的分布和化学形态，以及在炉内的剩余分数。所得结果为高浓度液体闪烁混合液的安全燃烧提供了指导。通过沉淀、吸收、离子交换和蒸馏等方法从液态有机和/或无机废物溶液中去除放射性同位素，以及通过几种洗涤方法重新使用使用过的放射性同位素装置，研究了降低废物溶液中的放射性或减少体积的其他可能性。少

Radioisotopes are often used as inevitable tools in many advanced scientific researches at universities. Most of the isotope is recovered after the use and must be transferred to Japan Radioisotope Association for disposal with paying the high cost or must be stored in the waste disposal facilities in the universities by the Law Concerning Prevention from Radiation Hazards due to Radioisotopes, etc. even at very low level radioactivity. In this research, were studied the improvement of safe handling of such low level radioactive waste disposed at university facilities and the reduction of the waste volume by several methods following the Law by cooperation of the researchers belonging to the Radioisotope Centers of the National Universities.Combustible waste such as paper, cloth and plastics with extremely low level activities were tested to reduce the volume by combustion, low temperature ashing, or dry distilllation, and the behaviors of radioisotopes during the treatment under vaiou … More s conditions were studied. The improvement of efficiency and the prevention of dispersion and the safe recovering of isotopes were preliminarily achieved.Combustion of the liquid scintillator cocktail solution after the measurement of 5 kind betaray emitting nuclides (H-3, C-14, P-32, S-35, Ca-45) were investigated under the permission of Science and Technology Agency. The behaviors of these unclides during and after the combustion, their distribution and chemical forms in the exhausted gas and treated water, their remaining fraction in the furnace were investigated under the various combusting conditions. The obtained results gave the guideline for the safe combustion of higher concentration liquid scintillation cocktail.Other possibilities of the reduction of the radioactivity in the waste solution or reduction of the volume were studied by the removal of radioisotopes from liquid organic and/or inorganic waste solutions by precipitation, absorption, ion-exchange, and distilllation, etc. and by the re-use of the radioisotope-used apparatus by several kind washing methods. Less