Back-end fuel-cycle strategies in uncertain 'Generation-IV' futures: Effective scenarios towards sustainable nuclear energy futures

With nuclear energy anyhow a necessary part of a sustainable and affordable energy future worldwide, intra-nuclear options to further improve the sustainable performance of nuclear energy have been researched and some developed since the early days of nuclear energy. These especially address the back-end of the nuclear fuel cycle given the management of spent fuel (SF) being a socio-politically sensitive topic translating into technical-economic challenges for many of the back-end fuel cycle options. Especially in those countries with a large legacy of SF from the past decades of nuclear energy use, these SF-inventories become an increasing challenge. For small(er) nuclear power plant (NPP) parks, such a SF-inventory is even more challenging as the prime option to dispose of this SF in geological disposal facility (GDF) may become overly costly. These situations influence the acceptance of nuclear energy as sustainable energy source while nuclear newcomer countries watch which new SF-management options may become available in due time and well before such challenges may also pose to them. Though, SF-management does not have to be a "bottleneck" to nuclear energy use now nor in the future. Various SF-management options have been researched, some developed and some even industrialised. There"s been expectations during the last 30 years that so-called "Generation-IV" systems or even more advanced "Generation-X" (partitioning & transmutation (P&T)) systems would become online by around the 2030s and able to resolve many of the challenges of such SF-management. Today, these expectations largely remain prospects for post-2050 with exception for some countries continuously advancing towards such advanced nuclear energy systems. Though, while the role of nuclear energy and thus its prospects in light of sustainable energy is today high on the agenda and will have to be clarified during the 2020s, a proper solution-oriented and responsible and above-all timely SF-management will need to go along and be realised by mid-century. This paper overviews which back-end fuel cycle strategies may construe such proper solution-oriented SF-management aligned to nuclear energy"s role within the uncertain prospect to evolve soon towards "Generation-IV" systems. (author)