The release of radiolysis gas is a concern that may restrict the use of cement materials to condition intermediate level radioactive waste. Indeed, water naturally present in cement materials produces hydrogen gas (which can be explosive/flammable under some conditions) when it is exposed to ionizing radiation.

The primary goal of the MATRICE (MAterials Resistant to Irradiation based on Cement) project is to identify and define formulations of cement materials in order to minimize the quantities of hydrogen gas released by radiolysis. The first approach is the minimization of water amount in standard Portland materials (calcium silicate-based cements) by addition of specific compounds (superplasticizers) to enable the preparation of wasteform. The second approach is to use “alternative” cement such as calcium sulfoaluminate cement. This cement was expected to release less hydrogen because the quantity of water needed for cement hydration is higher than Portland and moreover, their hydrates differ from those of hydrated calcium silicate mostly encountered in Portland based materials.

Based on gamma irradiations with a⁶⁰Co source, the results obtained demonstrate that the first approach is efficient but yet limited because the production of hydrogen of Portland pastes is about proportional to the total amount of water present in the materials. Thus, a tremendous drop of hydrogen production cannot be reach because rheological constraint does not allow a huge reduction of water, even with efficient superplasticizers. The second approach using calcium sulfoaluminate cements as an alternative binder provides results that are quite similar to Portland cement concerning the production of hydrogen under gamma irradiation.

放射分解气体的释放是一个问题，可能会限制使用水泥材料来处理中等水平的放射性废物。确实，水泥材料中自然存在的水在暴露于电离辐射中时会产生氢气（在某些条件下可能会爆炸/燃烧）。

MATRICE（基于水泥的耐辐射材料）项目的主要目标是识别和定义水泥材料的配方，以最大程度地减少辐射分解释放的氢气量。第一种方法是通过添加特定的化合物（高效减水剂）来使标准波特兰材料（硅酸钙基水泥）中的水量最小化，以制备废料。第二种方法是使用“替代”水泥，例如硫铝酸钙水泥。预计该水泥释放的氢较少，因为水泥水合所需的水量高于波特兰，而且其水合物不同于波特兰基材料中最常见的水合硅酸钙。

基于⁶⁰ Co源的伽马射线辐照，获得的结果表明第一种方法是有效的，但由于波特兰糊剂的氢产生量与材料中存在的水总量成正比而受到限制。因此，由于流变学的限制，即使使用高效的高效减水剂，也无法大量减少水的含量，因此无法实现氢产量的大幅下降。使用硫铝酸钙水泥作为替代粘合剂的第二种方法提供的结果与波特兰水泥在γ辐射下产生氢的结果非常相似。