UTGARD LAB PHASE II: A SIMFUEL FABRICATION & CHARACTERISATION FACILITY

英国目前约16%的电力来自核裂变，这在我们的低碳电力中占很大比例。为了让这种情况继续下去，为了让我们的能源使用按照计划脱碳，未来将需要新的核电站。英国作为核裂变先驱的历史留下了乏核燃料（SNF）储存的遗产，预计在国家先进气冷反应堆（AGR）舰队和Sizewell轻水反应堆（LWR）的寿命期间将增长到6200 teU的UO 2燃料。如果新的建造达到目前的预计能力，这将导致进一步产生约16，000 teU的基于二氧化铀的轻水堆乏燃料。根据各个核国家的政策，SNF要么进行再加工，要么在地质处置设施（GDFs）中进行处置。开发先进、更安全的后处理循环或安全的湿/干储存、回收和随后交付给GDF，需要详细了解在与这些活动相关的条件下SNF的演变和行为。在英国，真实的SNF产生的非常高的辐射场禁止他们在所有的研究，但由塞拉菲尔德或NNL操作的一些专门的“热室”。解决这一问题的一种方法是研究模拟的SNF（SIMFUEL），该模拟SNF（SIMFUEL）由例如具有与真实的SNF相同的微观结构的特别制备的UO 2（贫化）芯块组成，其中添加化学成分以模拟反应堆中形成的钚和裂变产物。大量SIMFUEL成分的现成可用性将加速和增强对SNF中不同相的相对作用的理解以及对关键燃料行为的机械理解。目前，SIMFUEL在英国的制造仅在NNL进行，这再次造成了准入问题。因此，该提案的愿景是建立一个SIMFUEL制造和表征的大学设施-该设施将在英国HEI景观中独一无二，并通过向外部用户提供开放访问，将有助于推动和加速英国SNF研究。考虑到英国目前AGR和LWR中使用的燃料以及新建造LWR中使用的燃料，我们的重点将放在氧化物SIMFUEL上-尽管着眼于未来的燃料循环，这将包括MOX和ThO 2基燃料。因此，拟议的设施将启动、支持和实现以下主题的研究：主题1：开发新的先进烧结路线，用于制造具有孔隙率、裂变产物负载和缺陷微观结构的SIMFUEL，这些孔隙率、裂变产物负载和缺陷微观结构更好地模拟真实的SNF。主题2：对这些先进的SIMFUEL以及使用传统陶瓷加工技术制备的SIMFUEL的性能进行研究，在与燃料循环后端相关的一系列条件下，包括湿/干临时储存、地质处置和新的后处理路线，潜在的学术用户包括与SNF的基本物理、化学和材料特性及其储存、回收和处置有关的任何人。这不仅包括以退役/处置为重点的EPSRC TRANSCEND联盟和BEIS资助的回收和废物管理国家核创新计划，还包括在这一领域工作的核CDT学生。在工业方面，我们已与RWM有限公司、NNL及塞拉菲尔德取得协议，他们希望以比目前更灵活的方式委托制造样品。拥有这样一个国家设施将不仅对英国用户而且对来自海外的裂变研究合作者都是一个巨大的推动者，因为一些国际实验室报告说，很难获得SIMFUEL样品，这些样品可以快速生产和交付，并且在一系列组成中反复通知正在进行的研究计划。

The UK currently derives ~16% of its electricity from nuclear fission which constitutes a significant proportion of our low-carbon power. For this to continue, and for our energy use to be decarbonised as is planned, new nuclear plant will be needed well into the future. The UK's history as a nuclear fission pioneer has left a legacy of spent nuclear fuel (SNF) in storage that is projected to grow to 6200 teU of UO2-based fuel over the lifetime of the national Advanced Gas cooled Reactor (AGR) fleet and the Light Water Reactor (LWR) at Sizewell. If new build is implemented to current projected capacity, this will lead to a further ~16,000 teU of UO2-based spent LWR fuel.Depending on the policies of individual nuclear nations, SNF is either reprocessed or destined to be disposed of in Geologic Disposal Facilities (GDFs). Development of advanced, safer reprocessing cycles or safe wet/dry storage, retrieval and subsequent consignment to GDF requires a detailed understanding of the evolution and behaviour of SNF under conditions relevant to those activities. In the UK, the very high radiation fields arising from real SNF prohibits their study in all but a few specialised "hot cells" operated by Sellafield or NNL. This access is necessarily resource constrained, so impeding the advancing of knowledge in key areas of SNF research.One way to obviate this problem is to work on simulated SNF (SIMFUELs) consisting of e.g. specially prepared UO2 (depleted) pellets with the same microstructures expected for real SNF with chemical components added to simulate plutonium and fission products formed in-reactor. Ready availability of a wide range of SIMFUEL compositions would both accelerate and enhance understanding of the relative roles of different phases in SNF and mechanistic understanding of key fuel behaviours. Currently, SIMFUEL fabrication in the UK is only conducted at NNL, which again presents access issues. Thus, the vision for this proposal is to establish a university facility for SIMFUEL fabrication & characterisation - a facility that will be unique within the UK HEI landscape and, by offering open access to external users, will serve to drive and accelerate UK SNF research. Reflecting the fuel used in the UK's current AGRs & LWR, and to be used in new build LWRs, our focus will be on oxide SIMFUELs - although, with an eye to future fuel cycles, this will include MOX and ThO2-based fuels. The proposed facility will therefore initiate, support and enable research in the following themes:Theme 1: The development of new, advanced sintering routes for the fabrication of SIMFUELs with porosities, fission product loadings, and defect microstructures that better simulate those of real SNF.Theme 2: Study of the behaviour of these advanced SIMFUELs, as well as those prepared using conventional ceramic processing techniques, under a range of conditions relevant to the back end of the fuel cycle - including wet/dry interim storage, geologic disposal and new reprocessing routes.Potential academic users include any concerned with the fundamental physical, chemical and materials properties of SNF, its storage, recycle and disposal. This includes not only the decommissioning / disposal focussed EPSRC TRANSCEND Consortium and the BEIS-funded National Nuclear Innovation Programme in Recycle and Waste management, but also those nuclear CDT students working in this area. Industrially, we have already sequestered interest from RWM Ltd, NNL and Sellafield who would wish to commission the fabrication of samples on a more flexible basis than currently available. To have such a national facility will be a great enabler not only for UK users but also for fission research collaborators from overseas as some international laboratories report great difficulty in getting access to SIMFUEL samples that can be produced & delivered quickly and in a range of compositions iteratively informed by on-going research programmes.