利用聚变中子规模化生产核电池α辐射源
Scalable production of nuclear battery alpha emitters using fusion neutrons
AI总结：
该研究提出利用氘氚聚变产生的14 MeV中子，可规模化生产高能量密度的α辐射源核电池燃料，具备防扩散特性，能支撑千瓦至兆瓦级核电池，为高能量密度电源提供新方案。
AI中文摘要：
由α衰变供能的核电池已成功部署超60年，全球每年$^{238}$Pu的供应量为千克级。研究表明，单台氘氚聚变装置产生的14 MeV中子每年可生产多达吨级的三类核电池α辐射源燃料：拥有全新生产路径的燃料（$^{236}$Pu、$^{227}$Ac、$^{210}$Pb）、此前曾被提出但因原料稀缺而无法规模化的燃料（$^{232}$U、$^{228}$Th），以及已成熟应用的$^{238}$Pu。通过OpenMC对托卡马克包层中锕系通道的模拟，每1 GW·yr聚变能量可产出：11至57 kg的$^{236}$Pu，其衰变链在一个世纪内每克释放18 GJ能量，最终衰变为稳定的$^{208}$Pb，同时可产出多达5.2吨的副产物$^{238}$Pu；从钍中可产出多达1.4吨的$^{231}$Pa，若以$^{231}$Pa为原料，可产出约15吨的$^{232}$U或约122 kg的$^{210}$Pb，$^{227}$Ac的产量为每吨$^{231}$Pa每年21克。中子俘获还可将$^{241}$Am升级为$^{242}$Cm/$^{242m}$Am/$^{241}$Am/$^{238}$Pu的混合物，其功率密度可提升10倍。$^{236}$Pu和$^{232}$U还具备防扩散特性：$^{237}$Np、$^{232}$Th和$^{231}$Pa的通道产物具有自保护特性，钚因$^{236}$Pu和$^{238}$Pu的衰变热以及$^{208}$Tl产生的2.6 MeV γ射线而受保护，铀则因$^{232}$U而受保护。这些燃料中的多数（$^{236}$Pu、$^{232}$U、$^{228}$Th、$^{227}$Ac）的功率和能量密度比当前的α辐射源高一个数量级，在与人类航天相关的功率下，当功率超过几百瓦时，$^{227}$Ac和$^{210}$Pb衰变链所需的屏蔽质量少于$^{238}$Pu或$^{241}$Am。因此，聚变中子可实现千瓦至兆瓦级的核电池，为需要极高能量密度的电源开辟新可能。
英文摘要：
Nuclear batteries powered by alpha decay have been deployed successfully for over 60 years, on a worldwide $^{238}$Pu supply of kilograms per year. We show that the 14 MeV neutrons of a single deuterium-tritium fusion plant can produce alpha emitter battery fuels up to tons per year, in three classes: fuels with completely new production pathways ($^{236}$Pu, $^{227}$Ac, $^{210}$Pb), fuels previously proposed whose scarce feedstock the same pathways now breed at scale ($^{232}$U, $^{228}$Th), and the established $^{238}$Pu. OpenMC simulations of actinide channels in a tokamak blanket give, per GW yr of fusion: 11 to 57 kg of $^{236}$Pu, whose chain releases 18 GJ per gram over a century, ending at stable $^{208}$Pb, plus up to 5.2 t of co-product $^{238}$Pu; up to 1.4 t of $^{231}$Pa from thorium, and, from channel with $^{231}$Pa feedstock, up to $\sim$15 t of $^{232}$U or $\sim$122 kg of $^{210}$Pb, with $^{227}$Ac produced at 21 g/yr per tonne of $^{231}$Pa. Neutron capture also upgrades $^{241}$Am to a $^{242}$Cm/$^{242m}$Am/$^{241}$Am/$^{238}$Pu blend with up to 10 times higher power density. The same $^{236}$Pu and $^{232}$U also serve as proliferation safeguards: the $^{237}$Np, $^{232}$Th, and $^{231}$Pa channel products are self-protecting, the plutonium by $^{236}$Pu and $^{238}$Pu decay heat and the 2.6 MeV gammas from $^{208}$Tl content, and similarly the uranium from its $^{232}$U. Many of these fuels ($^{236}$Pu, $^{232}$U, $^{228}$Th, $^{227}$Ac) have an order of magnitude higher power and energy density than current alpha emitters, and at human spaceflight-relevant doses the $^{227}$Ac and $^{210}$Pb chains need less shield mass than $^{238}$Pu or $^{241}$Am above a few hundred watts. Fusion neutrons could therefore enable nuclear batteries at the kilowatt to megawatt scale and unlock new possibilities for power sources requiring exceptionally high energy density.
