Inducing the resumption of alteration in UK radioactive watse glasses

促使英国放射性水玻璃恢复改造

• 批准号: 2608121
• 金额: --
• 依托单位: University of Cambridge
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2021
• 资助国家: 英国
• 起止时间: 2021 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2608121
• 关键词: Inducing; resumption; alteration; UK; radioactive

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.

放射性废玻璃的初始溶解速率相当快，但在与水接触的最初 1 - 28 天内溶解速率降低了大约一千倍。这种溶解速率的降低，即所谓的残留速率，与溶解的热力学驱动力的降低以及形成变质层对玻璃表面的保护作用有关，变质层抑制了往返于未变质玻璃表面的传输。英国放射性废玻璃处置中剩下的主要不确定因素之一是可能发生一种称为恢复改变的现象。当玻璃溶解以接近初始溶解速率的速率恢复时，在国际（且成分不同）玻璃配方中偶尔会在长时间范围内观察到这一过程，该速率将极大地影响处置的安全情况。该项目的主要目标是：通过用沸石播种恢复来人为诱导该过程，从而导致表面重组并改变玻璃表面的传输，同时通过去除溶液中的溶解物质来增加溶解的热力学驱动力。要确定英国处置方案中的恢复机制及其可能性，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分析溶液浓度和溶解速率。