Field Assisted Sintering of Nuclear Fuel Simulants

英国先进气冷堆（AGR）的预期剩余寿命将产生约5,000吨AGR乏核燃料（SNF）。英国核退役管理局（NDA）管理AGR SNF的首选方案是临时储存-目前在塞拉菲尔德现场的池塘中-在托运到储存库ca之前。2075. AGR燃料棒由密封在钢包壳管内的二氧化铀芯块组成。在反应堆内，一些包壳可能会受到池内腐蚀的影响，可能导致穿墙包壳失效。这可能会导致SNF对池塘水的污染以及颗粒本身的粒间腐蚀，从而导致颗粒完整性的丧失。因此，已经提出了向干燥储存的过渡-包括干燥湿储存的SNF。这可能会带来更多未知的风险，在实施之前必须了解这些风险。与这一理解相关的主要知识差距包括：1。从机理上了解在没有辐射场和特别是有辐射场的情况下，暴露于积水中的湿储存乏二氧化铀燃料芯块是如何腐蚀的;对燃料芯块可能的干燥过程的机械理解，同样在存在和不存在辐射场的情况下-但特别是在具有失效包壳的湿-干过渡燃料中，并且可能受到池内腐蚀过程的影响。

The expected remaining lifetime of the UK's Advanced Gas-cooled Reactors (AGRs) will result in the generation of ~5,000t of AGR Spent Nuclear Fuel (SNF). The UK Nuclear Decommissioning Authority's (NDA's) preferred option for managing AGR SNF is interim storage - currently in ponds at the Sellafield site - prior to consignment to repository ca. 2075. AGR fuel pins consist of UO2 pellets sealed inside steel cladding tubes. Whilst in-reactor, some of the cladding can be rendered susceptible to in-pond corrosion, potentially leading to through-wall cladding failure. This may result in pondwater contamination by the SNF and inter-granular corrosion of the pellets themselves with loss of pellet integrity. Consequently, a transition to dry storage has been proposed - including the drying of wet stored SNF. This may carry further unknown risks which must be understood before implementation. Key knowledge gaps relating to this understanding include:1. A mechanistic understanding of how pondwater-exposed wet-stored spent UO2 fuel pellets corrode in both the absence and, especially, the presence of a radiation field; and 2. A mechanistic understanding of the possible drying processes of fuel pellets, again both in the presence and absence of radiation fields - but especially in wet-to-dry transitioned fuel with failed cladding and that may have been subject to in-pond corrosion processes.