低中放废物处置场核素经地下水迁移对环境影响预测

Environmental impact prediction of radionuclides migration through groundwater at a repository with Low-Intermediate Level Radioactive Waste

研究了我国某民用低中放固体废物处置场核素迁移的途径,对核素在地下水中的迁移进行了详细分析与计算.假定正常释放或一次降水量达到600mm,处置场底浸泡一个月,存在6m的包气带时,对该处置场处置的7种核素进行预测,结果表明,包气带是延迟核素迁移的主要屏障,在500年内,可以使60Co、137Cs、90Sr、63Ni等核素延迟,其中239Pu降低6个数量级,但不能延迟3H和14C的迁移.穿过包气带进入含水层中的核素将在泉水或地表水体中出露,据此计算居民饮用含污染物的泉水或海产品所致的各年龄组的剂量.结果是该处置场对关键居民组的影响远低于国家对处置场的管理限值和该处置场的管理目标.

The radionuclides migration at a domestic repository with Low\|Intermediate Level Radioactive Waste is studied.The migration in groundwater is analyzed and computed in detail.Under presumption of normal releasing,or the bottom of the repository has been marinated for one month with precipitation reaching 600?mm once and existing a 6?m aerated zone, a prediction for 7 radionuclides is conducted.It shows that the aerated zone is the primary barrier for migration.The migration for radionuclides 60 Co, 137 Cs, 90 Sr, 63 Ni,etc.will be retarded in it within 500 years. The concentration of 239 Pu will be decreased by amount of 6 orders.Only 3H and 14 C can migrate through the aerated zone. The radionuclides that passed through the aerated zone and entered the aquifer will exist in spring, stream and sea. Based on this,the intake dose by residents in different age groups resulting from drinking contaminated spring water and eating seafood is calculated.The results show that the impact of the repository to the key resident group is lower than the limit in national repository regulation standard. This complies with the repository management target.