Inducing the resumption of alteration in UK radioactive watse glasses

放射性废玻璃的初始溶解速率相当快，但在与水接触的前1 - 28天内，其溶解速率降低约一千倍。这种溶解速率降低到所谓的残余速率，与溶解的热力学驱动力的降低以及形成抑制向未改变的玻璃表面和从未改变的玻璃表面运输的改变层对玻璃表面的保护作用有关。英国放射性废玻璃处置中剩余的主要不确定性之一是可能发生所谓的恢复改造现象。当玻璃溶解以接近初始溶解速率的速率恢复时，在国际（和组成不同的）玻璃配方中偶尔会在长时间尺度上观察到该过程，初始溶解速率将显著影响处置的安全情况。该项目的主要目标将是：通过用沸石播种恢复来人工诱导该过程，使表面重新结构并改变往返于玻璃表面的运输，同时通过从溶液中去除溶解的物质来增加溶解的热力学驱动力。在联合王国的处置方案中，要确定恢复的机制及其可能性，就需要使用XRD、SEM、TEM、NMR等分析技术对改变的表面进行详细表征，并使用同位素特定质谱法对溶液浓度和溶解速率进行分析。

The initial dissolution rate of radioactive waste glasses is quite rapid, but reduces by approximately a factor of one thousand over the first 1 - 28 days of contact with water. This reduction in dissolution rate, to what is known as the residual rate, is associated with a reduction in the thermodynamic driving force for dissolution and the protective effect on the glass surface of the formation of an altered layer that inhibits transport to and from the unaltered glass surface. One of the major remaining uncertainties in the disposal of UK radioactive waste glass is the potential for a phenomenon known as resumption of alteration to occur. This process is occasionally observed at long time scales in international (and compositionally different) glass formulations when the glass dissolution resumes at rates approaching the initial dissolution rate, a rate that would substantially affect the safety case for disposal. The main objectives of the project will be: To artificially induce the process by seeding the resumption with zeolites that cause the surface to re-structure and alter the transport to and from the glass surface and also simultaneously increase the thermodynamic driving force for dissolution by removing dissolved species form solution. The determination of the mechanism of resumption and its likelihood in the UK disposal scenario will require a detailed characterisation of the altered surface with analytical techniques such a as XRD, SEM, TEM, NMR as well as analysis of the solution concentrations and dissolution rates with isotope specific mass spectrometry.