STFC-ISIS-9 Growth of crystalline samples for encasing nuclear materials
04 Feb 2019







We encounter radiation everywhere, with natural sources varying from cosmic radiation to the decay of isotopes in terrestrial rocks. A variety of radiation sources are created and used in science and technology, notably in nuclear power stations. The energy of emitted particles often has a two-fold effect. On the one hand the surrounding material is heated, which can be used to generate electricity. On the other hand, this energy damages these materials and degrades their important properties (mechanical, thermal, transport and so on) to the point that a material might lose the properties for which it was selected in the first place. This issue is particularly important in the processing and safe immobilization of nuclear waste, and constitutes one of the pressing issues that modern society faces. At present nuclear materials from reactors are stored temporarily, however this is risky and expensive, and a large stockpile of old waste already exists. A long-term solution involves their chemical insertion into another material that is strongly inert, that would in turn be stored in geologically stable underground deposits. The timescales for this storage are hard to comprehend – millions of years (for reference, the Egyptian pyramids are only a few thousand years old!). Finding materials that are chemically stable, even when radiation-damaged, is therefore a major challenge. This project is to discover if it is possible to make single crystals of the inert host material, zirconolite, at the crystal growth lab run in collaboration between University College London and STFC. Natural (geological) crystals exist, but are usually mixed up with pieces of rock and are hence unsuitable for performing the precise experiments for which crystals are essential. Such precise experiments, which have never been possible due to the lack of “clean" crystal samples, can then be compared to results obtained from the latest computational methods, to confirm the accuracy of the calculations and to give confidence that they can then be used to predict the physical properties many thousands of years in the future.​

The student who works on this project will learn a variety of transferrable skills in both physics and chemistry laboratory techniques, gaining working familiarity with numerous pieces of solid state chemistry apparatus, as well as physical characterisation methods like specific heat and x-ray diffraction. There will also be opportunities to participate in the wider scientific life of the facility and to learn about the research conducted at RAL, through participation in group meetings, seminars, etc.

Supervisor: Russell, Ewings,​