^(237)Np、^(238)Pu、^(241)Am和^(90)Sr近地表迁移行为及含超铀核素中低放废物处置安全评价方法研究  

Near-surface migration behavior of ^(237)Np,^(238)Pu,^(241)Am and ^(90)Sr in relation to the method study on safety assessment of the disposal of low and intermediate level waste containing transuranic nuclides

作　　者：李书绅[1] 王志明[1] 李祯堂 赵英杰[1] 郭择德[1] 郭亮天[1] 王金生[1] 范智文[1] 宋建新[1] 安永锋[1] 

机构地区：[1]中国辐射防护研究院,山西太原030006

出　　处：《核科学与工程》2005年第4期330-346,共17页Nuclear Science and Engineering

摘　　要：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。This paper presents the research results on the field and laboratory tests of ^237Np, ^238Pu, ^241Am and ^90Sr migration, the determination of engineering barrier materials performance, and the nuclide-by-loess adsorption properties and their chemical speciation, which were conducted aerated zone loess and aquifer loess and engineering barrier materials made of bentonite, cement, degraded cement and mortar. Under both natural and sprinkling conditions, movement has hardly been found of ^237Np, ^23SPu, and ^241 Am in aerated zone, aquifer and engineering barrier materials in a three-year period. Under the sprinkling condition, a 2.7 cm downward movement of ^90 Sr from the mass center of quartz sand trace layer was observed in the fieldwork in a 1 079 d period, with a about 13 cm downward movement of its concentration peak in the loess at a distance of about 6 cm from the trace layer within the 1 215 d period. In the aerated zone test, ^90Sr, ^237Np, ^238Pu, and ^241Am in Column 1, after 1 073 d, migrated downward 9.8 cm, 3.25 cm, 0.5 cm and 0.25 cm, respectively. In aquifer simulation test, they migrated downward, after 950.5 d, 16 cm, 4 cm, 0.2 cm and 0.2 cm, respectively. The field contrast test performed within the aerated loess zone demonstrates that nuclides move downward through the loess （of field） carrier of trace source layer at a faster rate than in the quartz sand carrier by a factor of about 3.6. Under the same condition, Br migrates somewhat faster than ^3 H. The phenomena of low valley were found in the nuclide concentration distribution over the quartz sand trace source layer. In the groundwater at CIRP Field Test Site, ^237 Np with ion speciation and the valence of Ⅴ or Ⅵ dominate in their existence while ^238Pu with ion speciation and the va lence of Ⅳ is dominant. ^237 Np is not apt to form collide. The existence of engineering barrier materials, humic acid （HA） and fumic acid （FA） has the influence upon chemical speciation of nuclides.

关 键 词：包气带 含水层 工程屏障材料 野外试验 模拟实验 吸附 

分 类 号：TL942.2[核科学技术—辐射防护及环境保护]