Chemical Stabilization of Hanford Tank Residual Waste
Chemical Stabilization of Hanford Tank Residual Waste
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汉福德罐残余废物的化学稳定
DOI：
10.1016/j.jnucmat.2013.10.060
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发表时间：
2014
影响因子：
3.1
通讯作者：
Edward J. Mausolf
中科院分区：
文献类型：
--
作者：
K. Cantrell;W. Um;B. Williams;M. Bowden;B. Gartman;W. Lukens;E. Buck;Edward J. Mausolf
测试了三种不同的化学处理方法稳定汉福德C-202罐残余废物的能力，以减少污染物（特别是Tc、Cr和U）的释放。所测试的三种处理方法是石灰添加[Ca(OH)2]，基于化学键合磷酸盐陶瓷的原位陶瓷废物形式，以及亚铁/针铁矿处理。这些方法依赖于不溶性污染物的形成（石灰添加和陶粒）和化学还原，然后共沉淀（亚铁/针铁矿掺入处理）。结果表明，与未经处理的模拟灌浆孔隙水相比，处理后的储罐残余废物中铀的释放量显著减少。所有三种处理方法都将可浸出铀浓度降低了三个数量级以上。就铀和锝而言，其释放浓度远低于所测废物各自的最大污染物水平。对于槽C-202残余废物，铬释放浓度高于MCL，但相对于未经处理的槽废物显著降低。这种创新方法有可能彻底改变汉福德的储罐回收过程，允许在储罐中留下更大量的残余废物，同时提供可接受的低水平的污染物释放风险，从而保护环境和人类健康。这种方法可以使DOE通过简化检索和关闭操作实现显著的成本节约。
Three different chemical treatment methods were tested for their ability to stabilize residual waste from Hanford tank C-202 for reducing contaminant release (Tc, Cr, and U in particular). The three treatment methods tested were lime addition [Ca(OH)2], an in situ Ceramicrete waste form based on chemically bonded phosphate ceramics, and a ferrous iron/goethite treatment. These approaches rely on formation of insoluble forms of the contaminants of concern (lime addition and Ceramicrete) and chemical reduction followed by co-precipitation (ferrous iron/goethite incorporation treatment). The results have demonstrated that release of uranium from tank residual wastes can be dramatically reduced after treatment compared to contact with simulated grout porewater without treatment. All three treatments methods reduced the leachable uranium concentrations by well over three orders of magnitude. In the case of uranium and technetium, released concentrations were well below their respective Maximum Contaminant Levels (MCLs) for the wastes tested. For tank C-202 residual waste, chromium release concentrations were above the MCL but were considerably reduced relative to untreated tank waste.This innovative approach has the potential to revolutionize Hanford’s tank retrieval process, by allowing larger volumes of residual waste to be left in tanks while providing an acceptably low level of risk with respect to contaminant release that is protective of the environment and human health. Such an approach could enable DOE to realize significant cost savings through streamlined retrieval and closure operations.