The use of nuclear power presents numerous challenges with safety and radioactive waste management key considerations. An area of nuclear research of particular importance in the UK is the field of nuclear decommissioning and radioactive waste management. As a nation, we have accumulated radioactive waste from a variety of sources including nuclear power stations and the use of radio-active materials in medicine, industry and research which needs to be disposed of in a safe and secure manner.
Diamond provides specialist analytical techniques for the atomic to microscale characterisation of materials relevant to all stages of the nuclear fuel cycle.
Fuels and Decommissioning
Interaction with the Environment
To be fully effective, the cladding encapsulating nuclear fuel
must be highly resistant to radiation damage, be relatively
transparent to thermal neutrons, have effective corrosion
resistance and good mechanical properties. Zirconium alloys are well suited to these needs and have therefore to date been the most favoured material for fuel cladding. Commonly used alloys such as Zircaloy-2, Zircaloy-4, M5TM and ZIRLOTM also include small amounts of iron which has been shown to increase corrosion resistance.
In March 2011 a major earthquake hit Japan’s East coast. Although the six nuclear reactors at the Fukushima Daiichi Nuclear Power Plant (FDNPP) were robust enough to survive the seismic effects, the subsequent 15 metre tsunami had devastating effects, causing a power failure and loss of core cooling. Rising heat within the reactor cores caused the fuel rods to overheat and partially melt down, and radioactive material was released into the surrounding area.Read more...
Uranium (U) metal, attached to Magnox cladding and removed from spent fuel prior to reprocessing, is a key component of the UK’s intermediate level waste (ILW). It is encapsulated in grout and sealed within stainless steel canisters in preparation for interim storage and eventual disposal. Understanding corrosion processes that may occur in these U-containing waste canisters is critical to ensuring the safe long term containment of this ILW (>100 years).Read more...
One key problem facing the nuclear industry is how to store spent nuclear fuel safely in the long term. Any deep geological repository will be built to last many thousands of years, and there is the very real potential that the stored spent fuel will come into contact with groundwater. The predominant component of nuclear fuel is uranium dioxide (UO2), which is insoluble in water. However, the residual radioactivity of the fission daughter products, and of the fuel itself, cause the radiolytic splitting of water into highly oxidising species. These products then cause the dissolution of the fuel with the subsequent release of fission products into the environment.Read more...
Management and disposal of higher activity radioactive wastes is a significant issue across the developed world as many countries with a history of nuclear power generation and military activities seek long term solutions for these materials. The most common disposal choice is containment within a deep geological disposal facility (GDF). To remain effective over the long term, the design of a GDF must limit the mobility and migration of radionuclides.Read more...
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