Thorium Fuel Cycle as a Promising Energy Source in and after 21st Century

1.钍燃料反应堆设计研究：(1)核数据：测量了18 MeV中子U-233和Th-232双微分截面裂变的质量产额和中子谱。(2)反应堆设计研究：设计了用于长寿寿命的少元素转化的熔盐反应堆、装载Th-232的快堆、用于生产U-233的三种类型的热堆、熔盐动力反应堆富士和迷你富士以及加速器增殖堆。(3)在库卡进行了载钍堆芯的临界实验，并与计算结果进行了比较。(4)初步研究了14 MeV中子在Th和Thoria中的输运。2.钍燃料及其他反应堆材料的研究：(1)钍燃料，研制了U-Th-Ti-Zr合金，并对其吸氢性能进行了测试。得到了氧在ThO2-UO&lt；2+x&gt；中氧的化学扩散系数。观察到了氧化钍燃料的高燃耗行为。(2)熔盐研究：测定了镍、铬在LiF-BeF_2熔体中残留水分的腐蚀行为，以及辐系元素和裂变产物在LiF-BeF_2熔体中的扩散系数，Y在LiCl-KCl-NaCl熔体中的电化学行为，以及T在LiF-BeF_2熔体中的释放速率。(3)铀浓缩：发现了化学交换铀浓缩过程中的异常同位素效应。(4)后处理：研究了从有机膦酸硝酸盐溶液中萃取Th、U及部分金属。3.钍循环辐射安全研究：研制了一台被动积分型钍(Thoron)监测仪，并对某市的Thoron和氡(^&lt；220&gt；Rn)进行了测量。

1. Design studies of thorium fueled reactors: (1) Nuclear data; mass yield and neutron spectrum of the fission of U-233 and double differential cross section of Th-232 for 18 MeV neutrons were measured. (2) Reactor design studies; molten salt reactors for transmutation of long-lived minor actinides, fast reactors loading Th-232, three types of thermal reactors for U-233 production, molten salt power reactors named FUJI and mini-FUJI and accelerator breeders were designed. (3) Critical experiment of thorium loaded cores was carried out at KUCA and the result is compared with calculation. (4) Preliminary study of 14 MeV neutron transport in thorium and in thoria was done at KUCA. 2. Studies of thorium fuels and other reactor materials: (1) Thorium fuels; U-Th-Ti-Zr alloy was newly made and its hydrogen absorption properties were measured. The chemical diffusion coefficients of oxygen in ThO_2-UO_<2+x>was obtained. High burnup behavior of thorium oxide fuels was observed. (2) Molten salt studies; corrosion of Ni and Cr by residual moisture in molten LiF-BeF_2, diffusion coefficient of actinides and fission products in molten LiF-BeF_2, electrochemical behavior of Y in molten LiCl-KCl-Nacl and release rate of T from molten LiF-BeF_2 were measured. (3) Uranium enrichment; Anomalous isotope effects in chemical exchange uranium enrichment process was discovered. (4) Reprocessing; Solvent extraction of Th, U and some metals from nitrate solution of organophosphinic acid was investigated. 3. Study of radiation safety in thorium cycle: A passive integrating thoron(^<222>Rn) monitor was developed and was applied to measure thoron and radon(^<220>Rn) in a city.