Abstract Cementitious materials are included in many geological disposal facilities for radioactive wastes, including the UK candidate backfill material Nirex Reference Vault Backfill (NRVB). As part of an ongoing programme of work to assess NRVB performance, 1-D reactive-transport models have been constructed to simulate reaction with different illustrative groundwater compositions. Variant cases were also produced to explore the effect of model assumptions on the predicted behaviour of the backfill. Depending on groundwater composition, cement alteration pathways included: carbonation; external sulphate attack; chloride attack; the formation of magnesium-rich solids; and the precipitation of secondary aluminosilicate minerals. In general, the models suggest that the pore space in backfill associated with radioactive waste disposal systems is likely to become clogged (to some degree) over time close to backfill-rock interfaces resulting in a reduction in capacity for solute transport. However, the models do not include all relevant process couplings which is potentially, an area for further work.

中文翻译：

---

用于放射性废物处置的水泥回填的反应运输建模

摘要 许多放射性废物地质处置设施中都包含胶结材料，包括英国候选回填材料 Nirex Reference Vault Backfill (NRVB)。作为正在进行的评估 NRVB 性能工作计划的一部分，已经构建了 1-D 反应输运模型来模拟与不同说明性地下水成分的反应。还产生了变体案例来探索模型假设对回填预测行为的影响。根据地下水成分，水泥蚀变途径包括：碳化；外部硫酸盐侵蚀；氯化物侵蚀；富镁固体的形成；以及次生铝硅酸盐矿物的沉淀。一般来说，这些模型表明，与放射性废物处理系统相关的回填土中的孔隙空间随着时间的推移可能会（在某种程度上）堵塞回填土-岩石界面附近，从而导致溶质运输能力下降。然而，这些模型并不包括所有相关的过程耦合，这可能是一个需要进一步工作的领域。