低、中放射性固体废物岩洞处置场辐射环境影响研究

Radiation impact of low and medium level radioactive waste cavern disposal sites on the environment

低、中放射性固体废物处置场正常关闭后,放射性核素在处置单元内释放,经工程屏障和岩石圈迁移并进入生物圈可能会对公众造成辐射影响。结合我国某低中放岩洞处置场的隧洞布置、处置工艺、回填层特征、防排水系统等工程设计,以及场址水文地质条件和土地利用等环境特征,开展核素在地下水中的迁移模拟,分析并给出核素通过大气、地表水、食物链等途径对周围环境的影响。研究结果表明,岩洞处置场正常关闭后在自然条件下对公众的辐射影响是较小的,^(60)Co、^(90)Sr和^(137)Cs等半衰期较短的易吸附性核素迁移有限且衰变减少,^(129)I、^(14)C、^(99)Tc等寿命较长且较难吸附性核素应进一步被关注。

After the normal closure of low and medium level radioactive solid waste disposal sites,radionuclides release in the disposal unit,then migrate through engineering barriers and the lithosphere,and finally enter the biosphere and produce radiation effects on the public.According to the cavern layout,disposal process,backfill characteristics,waterproof and drainage system design of the LLW disposal,as well as the hydrogeological condition and the land use of the site,we simulated the migration of nuclides in groundwater environment and analyzed the effects of nuclides on the surrounding environment through the atmosphere,surface water,and food chain.The results show that the radiation effect on the public is small under the natural condition after the normal closure of the site,and that the absorbable nuclides with short half-lives such as ^(60)Co、^(90)Sr and ^(137)Cs migrates slowly and decay quickly,and that the nuclides such as ^(129)I,^(14)C,99Tc should be paid more attention.