低放固体废物核素活度浓度上限值的推导

Derivation of activity concentration upper limits for low level solid radioactive wastes

介绍了近地表处置设施在300a监护期前及其以后的任何时间,公众个人及闯入者通过各种途径的受照剂量分别小于剂量限值时所要求的低放固体废物核素活度浓度上限值的推导方法及过程。以我国放射性废物近地表处置的基本安全要求为前提,并以遥田处置场和北龙处置场为对象,分析处置设施关闭后各景象的核素迁移过程和照射途径,建立各景象核素迁移的概念模型、数学模型,并计算各景象对人类产生的照射剂量。假设核素活度浓度与剂量之间呈线性关系,推导满足剂量准则下各景象各放射性核素的活度浓度上限值,选择最小的上限值,从而确定出低放固体废物各核素活度浓度上限值的量级。

A derivation method and process of activity concentration upper limits are introduced in this paper. It is for low level solid radioactive wastes at any time before and after the three-hundred-year surveillance period in near surface disposal facilities when their radiation doses are less than the dose limits for individual public or intruders through various exposure pathways. Taking Yaotian disposal site and Beilong disposal site as reference sites, the radionuclide transfer processes and exposure pathways of various scenarios following the closure of disposal facilities are analyzed based on basic safety requirements for near surface disposal of radioactive wastes. Their conceptual model and mathematical model of radionuclide transfer are established, and effective doses to human from various scenarios are calculated. Under the assumption of a linear relationship between activity concentration and dose rate, the activity concentration upper limits of various scenarios are derived for each radionuclide meeting dose criteria. The smallest upper limit is selected to determine the magnitude of upper limits of activity concentration for each radionuclide in low level solid radioactive wastes.