α decay half-lives are calculated using the Q_α values obtained by Semi-empirical Shell Model in the framework of the Unified Fission Model (UFM) with the Coulomb repulsion,nuclear attraction due to proximity potent...α decay half-lives are calculated using the Q_α values obtained by Semi-empirical Shell Model in the framework of the Unified Fission Model (UFM) with the Coulomb repulsion,nuclear attraction due to proximity potential, and rotational energy due to angular momentum transfer of α particle.In addition,the calculated and experimental half-lives of 425 nuclei are compared to check the validity of the model applied on α decay.The calculated half-lives of α decay are in good agreement with the experimental data.Finally,some useful predications on the α decay half-lives are provided for future experiments.展开更多
钍铀燃料循环以其优异的物理和化学特性,受到核能界的广泛关注。本文利用单群的点燃耗计算程序ORIGEN,分别研究了钍燃料在沸水堆(Boiling Water Reactor,BWR)、压水堆(Pressurized Water Reactor,PWR)和加拿大重水铀反应堆(Canada Deute...钍铀燃料循环以其优异的物理和化学特性,受到核能界的广泛关注。本文利用单群的点燃耗计算程序ORIGEN,分别研究了钍燃料在沸水堆(Boiling Water Reactor,BWR)、压水堆(Pressurized Water Reactor,PWR)和加拿大重水铀反应堆(Canada Deuterium Oxide Uranium,CANDU,又称坎杜堆)能谱中辐照时,232Th、233Th、233Pa、233U等核素生成量随中子注量率和中子能谱的变化规律,并探索了多次"辐照-冷却"循环对钍铀转化率的影响。计算结果表明,能谱相同时,233Th和233Pa存量的最大值与注量率有关;233U存量的最大值与注量率无关,大概在注量(注量率×时间)为4×1016 n·cm-2左右;注量率相同时,能谱越硬,233U存量的最大值越大。采取循环"辐照-冷却"可以提高233Th-233U的转化率,对于相同的总辐照时间,每次循环周期内的辐照时间越短,相对于总辐照时间相同的单次辐照,转化率增量提高越明显;当总辐照时间超过两个月时,循环辐照对转化率增量的作用较小,与单次辐照不冷却相比,转化率相对增量不超过1倍。展开更多
基金Supported by the Natural Science Foundation of China under Grant Nos.10775061,10875152,10875151,and 10975064the Fundamental Research Fund for Physics and Mathematic of Lanzhou University(LZULL200805)+2 种基金the Fundamental Research Funds for the Central Universities(lzujbky-2009-21)the Knowledge Innovation Project of the Chinese Academy of Sciences under Grant Nos.KJCX2-SW-N17,KJCX3-SW-N02Major State Basic Research Development Program under Grant No.2007CB815000
文摘α decay half-lives are calculated using the Q_α values obtained by Semi-empirical Shell Model in the framework of the Unified Fission Model (UFM) with the Coulomb repulsion,nuclear attraction due to proximity potential, and rotational energy due to angular momentum transfer of α particle.In addition,the calculated and experimental half-lives of 425 nuclei are compared to check the validity of the model applied on α decay.The calculated half-lives of α decay are in good agreement with the experimental data.Finally,some useful predications on the α decay half-lives are provided for future experiments.
基金Supported by the National Natural Science Foundation of China under Grant No 10775061, the Fundamental Research Fund for Physics and Mathematics of Lanzhou University （LZULL200805）, the Knowledge Innovation Project of Chinese Academy of Sciences under Grant No KJCX-SYW-N02, the National Basic Research Program of China under Grant No 2007CB815004.
文摘钍铀燃料循环以其优异的物理和化学特性,受到核能界的广泛关注。本文利用单群的点燃耗计算程序ORIGEN,分别研究了钍燃料在沸水堆(Boiling Water Reactor,BWR)、压水堆(Pressurized Water Reactor,PWR)和加拿大重水铀反应堆(Canada Deuterium Oxide Uranium,CANDU,又称坎杜堆)能谱中辐照时,232Th、233Th、233Pa、233U等核素生成量随中子注量率和中子能谱的变化规律,并探索了多次"辐照-冷却"循环对钍铀转化率的影响。计算结果表明,能谱相同时,233Th和233Pa存量的最大值与注量率有关;233U存量的最大值与注量率无关,大概在注量(注量率×时间)为4×1016 n·cm-2左右;注量率相同时,能谱越硬,233U存量的最大值越大。采取循环"辐照-冷却"可以提高233Th-233U的转化率,对于相同的总辐照时间,每次循环周期内的辐照时间越短,相对于总辐照时间相同的单次辐照,转化率增量提高越明显;当总辐照时间超过两个月时,循环辐照对转化率增量的作用较小,与单次辐照不冷却相比,转化率相对增量不超过1倍。
