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主要介绍在包气带黄土、含水层黄土和工程屏障材料(膨润土、水泥、变质水泥、砂浆粉)中,237Np2、38Pu2、41Am和90Sr迁移的野外试验、实验室模拟实验及工程屏障材料性能测定、黄土对核素吸附特性、化学形态等研究结果。在天然和喷淋两种条件下,237Np2、38Pu和241Am在包气带、含水层和工程屏障材料的野外试验中三年时间基本未移动。喷淋条件下,野外试验中90Sr通过石英砂示踪源层其质心位置1 079 d向下迁移2.7 cm,在示踪源层外6 cm处黄土中90Sr浓度峰在1 215 d向下迁移13 cm左右。在包气带模拟实验中,90Sr2、37Np2、38Pu和241Am在1号柱中经1 073 d分别向下迁移9.8 cm、3.25 cm、0.5 cm和0.25 cm。在含水层模拟实验中,经970.5 d,90Sr2、37Np2、38Pu和241Am分别迁移16 cm,4 cm、0.2 cm和0.2 cm。野外对比试验验证,在包气带中核素通过踪源层黄土载体向下迁移的距离是通过石英砂载体的3.6倍多。在完全相同条件下,Br迁移速度比3H略快。包气带石英砂示踪源层处,核素浓度分布出现低谷现象。CIRP试验场地下水中,237Np以离子态(V、V1价)存在为主,238Pu主要由以Ⅳ价离子态存在2。37Np不易形成真胶体。工程屏障材料、HA和FA的存在对核素化学形态有影响。
The field experiments, laboratory simulation experiments and engineering barrier material properties of 237Np2, 38Pu2, 41Am and 90Sr migration in aerated loess, aquifer loess and engineering barrier materials (bentonite, cement, metamorphic cement and mortar powder) , Loess on the nuclide adsorption characteristics, chemical forms and other research results. In both natural and spray conditions, 237Np2, 38Pu, and 241Am remained virtually unchanged for three years in field trials with aerated zones, aquifers and engineering barrier materials. Spray conditions, field experiments 90Sr quartz sand through the source layer of its centroid position of 1079d downward migration of 2.7 cm, 6cm in the tracer source layer of loess 90Sr concentration peak in the 1121 d downward migration 13 cm or so. In the simulated experiment of gas-banding, 90Sr2, 37Np2, 38Pu and 241Am migrated down 9.8 cm, 3.25 cm, 0.5 cm and 0.25 cm respectively in the No.1 column by 1 073 d. In the aquifer simulation experiments, 16 cm, 4 cm, 0.2 cm and 0.2 cm were transported by 970.5 days, 90Sr2, 37Np2, 38Pu and 241Am, respectively. In field experiments, it was verified that the distance that the radionuclides migrated downward through the source layer loess carrier in the aeration zone was over 3.6 times that of the quartz sand carrier. Under exactly the same conditions, Br migrates slightly faster than 3H. At the source layer of gas-bearing quartz sand tracer, the nuclide concentration distribution appears trough phenomenon. At the CIRP test site, 237Np mainly existed in the ionic state (V, V1 valence), while 238Pu did not form true colloids due to the presence of the IV valence state 2.37Np. The presence of engineering barrier materials, HA and FA has an impact on the chemical forms of the nuclides.