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The proposed research will develop generic knowledge in the field of decommissioning engineering that can be used to solve problems associated with nuclear decommissioning. The work will be carried out under the auspices of the Dalton Institute of the University of Manchester and thus a multi-disciplinary approach to the research will be facilitated. Existing nuclear facilities (eg. Magnox, AGR Station, Reprocessing plant, medical waste) present significant challenges with respect to waste management and decommissioning. The research programme will expand and enhance the skill base in nuclear engineering and science in order to meet these challenges. Additionally, the research will provide valuable information for use in future generations of nuclear facilities so as to reduce decommissioning and waste management problems.The impact of the new Chair appointment will be enhanced by interactions with the already established links with industry and in particular with BNFL. Furthermore, the appointee will contribute to the training of research scientists, in an area of research where the demands of industry substantially exceed the availability of individuals with appropriate expertise.

We propose to carry out fundamental mathematical research into efficient methods for problems with uncertain parameters and apply them to radioactive waste disposal.The UK Government's policy on nuclear power states that it is a proven low-carbon technology for generating electricity and should form part of the UK's future energy supply. Energy companies will be allowed to build new nuclear power stations provided sufficient progress is made on the radioactive waste issue. In common with other nations, geological disposal is the UK's preferred option for dealing with radioactive waste in the long term. Making a safety case for geological disposal is a major scientific undertaking. National and international research programmes have produced a good understanding of the mechanisms by which radionuclides might return to the human environment and of their consequences once there. One of the outstanding challenges is how to deal with the uncertainties inherent in geological systems and in the evolution of a repository over long time periods and this is at the heart of the proposed research.The main mechanism whereby radionuclides might return to the environment, in the event that they escape from the repository, is transport by groundwater flowing in rocks underground. The mathematical equations that model this flow are well understood, but in order to solve them and to predict the transport of radionuclides the permeability and porosity of the rocks must be specified everywhere around the repository. It is only feasible to measure these quantities at relatively few locations. The values elsewhere have to be inferred and this, inevitably, gives rise to uncertainty. In early performance assessments, relatively rudimentary approaches to treating these uncertainties were used, primarily due to the computational cost. Since then, there have been considerable advances in computer hardware and in the mathematical field of uncertainty quantification. One of the most common approaches to quantify uncertainty is to use probabilistic techniques. This means that the coefficients within the flow equations will be modelled as random fields, leading to partial differential equations with random coefficients (stochastic PDEs), and solving these is much harder and more computationally demanding than their deterministic equivalents. Many fast converging techniques for stochastic PDEs have recently emerged, which are applicable when the uncertainty can be approximated well with a small number of stochastic parameters. However, evidence from field data is such that in repository safety cases much larger numbers of stochastic parameters will be required to capture the uncertainty in the system. Only Monte Carlo (MC) sampling and averaging methods are currently feasible in this case, and the relatively slow rate of convergence of these methods is a major issue.In the work proposed here we will develop and analyse a new and exciting approach to accelerate the convergence of MC simulations for stochastic PDEs. The multilevel MC approach combines multigrid ideas for deterministic PDEs with the classical MC method. The dramatic savings in computational cost which we predict for this approach stem from the fact that most of the work can be done on computationally cheap coarse spatial grids. Only very few samples have to be computed on finer grids to obtain the necessary spatial accuracy. This method has already been applied (by one of the PIs), with great success, to stochastic ordinary differential equations in mathematical finance. In this project we will extend the technique to PDEs, developing the analysis of the method required, and apply the technique to realistic models of groundwater flow relevant to radioactive waste repository assessments. The potential impact for future work on radioactive waste disposal and also for other areas where uncertainty quantification plays a major role (e.g. carbon capture and storage) is considerable.

Shortly after lunch on the 11th March 2011, a 15 m high tsunami triggered by the magnitude 9.0 Great Tohoku earthquake engulfed the Fukushima Daiichi Nuclear Power Plant (FDNPP) - crippling the site, its essential surrounding infrastructure and the multiple safety layers the provided emergency reactor core cooling. Resulting from this absence of sustained core cooling provision, over the following days and in response to critical temperatures and pressures within the reactors, seawater was injected as a final resort to provide emergency core cooling. However, this desperate effort was insufficient, and temperatures rose in each of the reactor pressure vessels (RPVs) to in-excess of 2,000C; causing the uranium contained within the nuclear fuel assemblies to melt (partially or fully) and corrode vertically downwards through the RPV, into base of the primary containment vessel (PCV) - as well as coating the internal volume of the extensive PCV. In the UK, the Sellafield site includes the first commercial power-generating station (Calder Hall, with four Magnox reactors) and the plutonium-producing Windscale Piles 1 and 2, that fuelled the UK's original nuclear weapons programme. The haste to assemble led to little planning for end-of-life retirement, waste management and post-operational decommissioning, meaning that such facilities still present high hazards. The hazard removal challenges at Sellafield are, however, not unique in the UK, with the large number of Magnox stations also embarking on "accelerated decommissioning" ahead of long-term "care and maintenance". Many of the most pressing and complex decommissioning challenges across the NDA estate concern the decontamination of radiologically contaminated surfaces, with numerous methods having been considered to address this, and laser cleaning emerging as the promising candidate. Laser ablation (or "laser cleaning") is an emerging decommissioning tool for the international nuclear industry to rapidly decontaminate surface-fixed radioactive materials, having recently been identified as a "promising technique" for use across the UK NDA Estate. It is particularly attractive for nuclear decommissioning as it is not only non-contact, but also produces much smaller volumes of secondary solid and aqueous wastes than alternative physical and chemical methods. However, some fundamental challenges remain which prevent widespread implementation of the technique: - The ablative nature of the technique can generate localised atmospheric contamination. - Waste collection and disposal are complicated due to the airborne particulate nature of the ablated, radioactive material. - Additional 'before' and 'after' characterisation surveys are necessary to plan the decontamination activities and assess the quality of laser cleaning. This timely, cross-disciplinary, and impactful proposal addresses these and other challenges by developing novel particulate containment and collection strategies, integrated with innovative optical characterisation, for planning and assessing cleaning activities. In this way, it will reduce the burden, risks and overheads of laser cleaning, leading to its broader international utilisation. This would be particularly applicable at FDNPP, but also at Sellafield and other legacy nuclear sites in the UK. We will use knowledge from the laboratory assessments to make a prototype fibre coupled, 'OptiClean' system for integration onto our LBR-SuperDroid, as developed for the NNUF programme. The platform consists of a SuperDroid HD2, a large tracked robotic platform, with a KUKA LBR IIWA 14 robotic manipulator mounted on the top. Its tracked nature allows for remote doorway-scale accesses with additional stair-climbing capabilities whilst the LBR is a seven degrees of-freedom robotic manipulator with force feedback sensing for human-safe interaction.

Nuclear cultural heritage is a fast-growing field in many European countries due to nuclear decommissioning and its impact on local communities, and the challenge of safeguarding nuclear waste and protecting future generations. However, it is unclear and contested what constitutes nuclear cultural heritage and how it can benefit different social groups. There is a risk that valuable tangible and intangible forms of nuclear cultural heritage will be lost and that social inequalities might be perpetuated in the process. NuSPACES will collaborate with different stakeholders to document and examine the creation of nuclear cultural heritage in three countries, the UK, Sweden and Lithuania and to shape a new agenda for research and practice in this field. It will explore, first, the ways in which different social groups at local communities, nuclear industries and national cultural organisations engage in creating museum expositions and heritage sites in the process of selective preservation of their nuclear past. Second, it will explore the role that nuclear cultural heritage can play in the process of decommissioning nuclear objects, for instance, providing new categories and types of materials to be preserved in the archives that are being assembled to inform future management of nuclear waste depositories. Third, it will contribute to the internationalisation of local and national nuclear cultural heritage-making activities by establishing a platform where stakeholders will be able to share their experience and shape future agenda for research and practice in the field in conversation with academic researchers. NuSPACES will result in new empirical data, academic publications, workshops and will produce a report containing policy guidelines on nuclear cultural heritage.