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5000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Sellafield场址的池塘中，然后在2075年左右运往储存库。AGR燃料销由密封在钢包壳管内的UO2颗粒组成。在反应堆中，一些包层容易受到池内腐蚀，可能导致穿壁包层失效。这可能导致池塘水被SNF污染，颗粒本身的颗粒间腐蚀，失去颗粒的完整性。因此，已经提出了向干燥储存的过渡-包括干燥湿储存的SNF。这可能会带来更多的未知风险，在实施之前必须了解这些风险。与这种理解相关的主要知识缺口包括：1。在没有辐射场的情况下，特别是在存在辐射场的情况下，对暴露在池塘中的湿式储存乏氧燃料颗粒如何腐蚀的机理理解；和2。对燃料颗粒可能干燥过程的机理理解，同样包括在存在和不存在辐射场的情况下，但特别是在包层失效的湿到干过渡燃料中，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.