【摘要】 从1997年6月25日到2000年7月11日在中国辐射防护研究院试验场,在天然降雨和人工喷淋(15 mm/d)两种条件下,在包气带黄土中进行了237Np,238Pu,241Am和90Sr在中国膨润土和日本膨润土中迁移的野外试验。试块由膨润土和砂子以质量比为15∶85组成,试块大小为150 mm×150 mm。试验结果表明,在两种条件下,核素在两种膨润土试块中分布状态和变化趋势相似,238Pu和241Am在3 a内没有明显移动,237Np和90Sr在天然降雨条件下,分布曲线有所展宽;在人工喷淋条件下经1 106 d后,237Np和90Sr在试块内分别向下迁移1.5 mm和2.0 mm,呈现出扩散为主的迁移。更多还原

【Abstract】 Under natural and artificial rainfall conditions,field tests of ²³⁷Np,²³⁸Pu,²⁴¹Am and ⁹⁰Sr migration in bentonite from China and Japan at aerated zone were conducted in the field test site of China Institute for Radiation Protection during the period from June 25,1997 to July 11,2000.The specimen with the dimension of 150mm×150mm is composed of（bentonite） and sand（bentonite∶sand=15∶85（wt））.Tests show that radionuclide distribution and migration trend in two types of specimen are similar under both natural and artificial rainfall conditions.²³⁸Pu and ²⁴¹Am have not remarkable movement under two rainfall conditions in three years.Under natural rainfall condition,concentration peak of ²³⁷Np and ⁹⁰Sr in specimen show to be widen.²³⁷Np and ⁹⁰Sr move down wards 1.5mm and 2.0mm in specimen separately after 1106d under artificial rainfall condition.This indicates that nuclide movement in bentonite/sand is dominated by diffusion.更多还原