~(60)Co、~(85)Sr和~(134)Cs在非饱和黄土中迁移特征研究

经过2年的野外核素示踪试验、实验室柱试验、批实验以及数值模拟，获得^60Co、^85Sr和^134Cs在非饱和黄土中迁移特征如下：（1）非饱和黄土上述核素具有很强的吸附作用，经2年的试验，^85Sr的浓度峰位在天然条件下迁移不到2cm，喷淋条件下迁移13cm；^60Co和^134Cs在天然和喷淋条件下迁移甚微。（2）^85Sr在喷淋条件下迁移出现两个浓度峰。（3）^60Co、^85Sr和^134Cs迁移“快成份”在环境的安全评价中不容忽视。（4）在含水量和入渗水量很低时，扩散对核素迁移起主导作用。(5)水入渗量对^85Sr迁移速度和横向扩散无明显影响。（6）静态法测定的Kd值比野外求得的值大。（7）核素在非饱和黄土中的延迟系数Rd不是常数。

Characteristic of 60Co,85Sr and 134Cs migration in unsaturated loess

By in\|situ field test of tracer nuclide migration,indoor soil column test,batch test and numerical modeling for two years the characteristic of 60 Co, 85 Sr and 134 Cs migration in unsaturated loess are revealed as follows:(1) Unsaturated loess possesses strong sorptivity.The concentration peak of 85 Sr migrated less than 2?cm under natural condition and 13?cm under sprinkling condition while 60 Co and 134 Cs migrated little both under natural condition and sprinkling codition;(2) There are two concentration peaks for 85 Sr migration under sprinkling condition;(3) The part of facter migrated 60 Co, 85 Sr and 134 Cs which migrate faster can not be neglected in environmental safety assessment;(4) Diffusion plays a dominant role in radionuclide migration under low water content and small intensity of infiltration;(5) Infiltration does not influence 85 Sr migration rate and transverse diffusion significantly;(6) K d obtained by static test is greater than that obtained by field test;(7) Retardation factor R d for radionuclide nigration in unsaturated loess in not a constant.