核环境地下水评价源项模型及浓度计算

结合美国地下核试验场公开资料,分析了地下核爆炸的源项核素特征,在源项释放和核素迁移过程概化的基础上,建立以水力释放和玻璃体浸出为主要机制的源项释放浓度计算模式,对3H、90Sr和239Pu释放到地下水的浓度进行了理论计算。结果表明:3H、90Sr和239Pu向地下水的释放是一个连续、缓慢的过程,就核素释放浓度曲线递减程度而言,3H>90Sr>239Pu,但浓度并不是短期内显著降低。在地下水污染安全评价中,应重视源强及其持续时间的分析,以使环境模型能更为合理地反映核素迁移行为。

Source Term Model and Concentration Calculation for Groundwater Evaluation of Radioactive Environment

Combined with the public information of some United States underground nuclear tests,a source term release concentration mode mainly concerning hydraulic action and leaching rate is built,which is based on the analysis of radionuclide source term in underground nuclear explosion and the conceptualization of source term release and radionuclide migra tion process.Then a theoretical concentration calculation of 3H、90Sr and 239Pu is made.The result indicates that radionuclide release process is consecutive and slow.The rank of concentration change is 3H>90Sr>239Pu.But the concentration change in short period is indistinct.It is suggested that attentions should be paid on the strength and pulse time of source term in the safety assessment of groundwater pollution,in order to make the environment model to reflect the behavior of radionuclide transport reasonably.