ABSTRACT The gas production of wasteforms is a major safety concern for encapsulating active nuclear wastes. For geopolymers and cements, the H2 produced by radiolytic processes is a key factor because of the large amount of water present in their porous structure. Herein, the gas composition evolution around geopolymers was monitored online under 60Co gamma irradiation. The transient evolution of the hydrogen release yield was measured for samples with different formulations. Its evolution and the final values are consistent with the presence of a pseudo-first-order chemical reaction consuming hydrogen in the samples. The results show that this phenomenon can significantly reduce the hydrogen source term of geopolymer wasteform provided their diffusion coefficient remains low. Lower hydrogen production rates and faster kinetics were observed with geopolymer formulations in which pore water pH was higher. Besides hydrogen release, a steady oxygen consumption was observed for all geopolymer samples. The oxygen consumption rates are proportional to the diffusion coefficients estimated in the modelization of hydrogen recombination by a pseudo-first-order reaction.

中文翻译：

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伽马辐照下地质聚合物周围大气的在线测量

摘要 废物形式的气体产生是封装活性核废物的主要安全问题。对于地质聚合物和水泥，辐射分解过程产生的 H2 是一个关键因素，因为它们的多孔结构中存在大量的水。在此，在 60Co 伽马辐射下在线监测地质聚合物周围的气体成分演化。对不同配方的样品测量了氢释放产率的瞬态演变。它的演变和最终值与样品中消耗氢的伪一级化学反应的存在一致。结果表明，这种现象可以显着减少地质聚合物废物形式的氢源项，只要它们的扩散系数保持较低。在孔隙水 pH 值较高的地质聚合物配方中观察到较低的产氢速率和较快的动力学。除了氢气释放外，所有地质聚合物样品均观察到稳定的耗氧量。耗氧率与在模拟一级反应的氢复合模型中估计的扩散系数成正比。