Canadian Nuclear Laboratories, Reactor Chemistry and Corrosion Branch, 286 Plant Road, Chalk River, ON K0J 1J0, Canada.
Canadian Nuclear Laboratories, Reactor Chemistry and Corrosion Branch, 286 Plant Road, Chalk River, ON K0J 1J0, Canada.
J Environ Radioact. 2018 Oct;193-194:57-67. doi: 10.1016/j.jenvrad.2018.08.013. Epub 2018 Sep 5.
This paper summarizes the results of the decontamination of the infrastructure materials concrete, limestone, brick and asphalt contaminated with Co, Sr, Cs and Am. The paper focuses on the effect of differences in substrate properties and of the pH of the radionuclide solution used for surface contamination on adsorption or ion exchange of the radionuclides and how these factors affect the decontamination effectiveness. A six-component chemical formulation was used and a process effectiveness of up to 76% was obtained depending on the substrate and radionuclide. Asphalt was the easiest material to decontaminate because of its more hydrophobic nature. Concrete and limestone (and to some extent brick) were less effectively decontaminated as their porous surfaces allowed penetration of radionuclides into water-filled pores in the substrate facilitating adsorption or ion exchange and making them difficult to remove. Brick was the most difficult material to decontaminate because the major component of brick is clay which retains most mono- and divalent ions. The removal of Co, Sr and Cs from the surfaces of concrete, limestone and brick increased when the pH of the radionuclide solutions was moderately acidic to neutral compared to when they were highly acidic. The variability in the test results was similar to that observed in other studies using other decontamination methods, attributed to the inhomogeneity of the substrates used and considered representative of real infrastructure materials.
本文总结了受 Co、Sr、Cs 和 Am 污染的基础设施材料混凝土、石灰石、砖和沥青的去污结果。本文重点研究了基底性质的差异和用于表面污染的放射性核素溶液的 pH 值对放射性核素吸附或离子交换的影响，以及这些因素如何影响去污效果。使用了一种六组分化学配方，根据基底和放射性核素的不同，获得了高达 76%的工艺有效性。由于其疏水性更强，沥青是最容易去污的材料。混凝土和石灰石（在某种程度上还有砖）的去污效果较差，因为其多孔表面允许放射性核素渗透到基底充满水的孔隙中，从而促进了吸附或离子交换，使其难以去除。砖是最难去污的材料，因为砖的主要成分是粘土，它保留了大多数单价和二价离子。与高度酸性相比，当放射性核素溶液的 pH 值为中等到中性时，从混凝土、石灰石和砖表面去除 Co、Sr 和 Cs 的效果增加。与使用其他去污方法的其他研究中观察到的结果相似，这种可变性归因于使用的基底不均匀性，并被认为代表了实际的基础设施材料。
