TOPAZ-II反应堆是使用固体金属氢化物为慢化剂的微型空间堆,常用的慢化剂材料是氢化锆。近年来,由于金属钇的制造成本降低,氢化钇逐渐成为TOPAZ-II反应堆慢化剂材料的新选择。使用MCNP程序对TOPAZ-II反应堆进行功率分布计算,分别研究氢...TOPAZ-II反应堆是使用固体金属氢化物为慢化剂的微型空间堆,常用的慢化剂材料是氢化锆。近年来,由于金属钇的制造成本降低,氢化钇逐渐成为TOPAZ-II反应堆慢化剂材料的新选择。使用MCNP程序对TOPAZ-II反应堆进行功率分布计算,分别研究氢化锆和氢化钇在不同条件下对反应堆功率的影响。计算结果表明:改变金属氢化物慢化剂的氢含量和温度参数时,堆芯径向功率峰因子的变化趋势决定了功率不均匀系数的变化趋势;慢化剂的氢含量和温度参数的改变会导致堆芯热中子分布发生变化,进而影响反应堆功率分布,低能热中子占中子群份额越高,堆芯径向功率峰因子越小;慢化剂周围的CO2气体环境导致氢损失速率较小,对反应堆功率分布的影响很小;两种慢化剂呈正温度效应,氢化钇的温度系数比氢化锆的温度系数小,且以氢化钇为慢化剂的反应堆keff更高。The TOPAZ-II reactor is a micro-space reactor that uses solid metal hydride as the moderator, with zirconium hydride being the commonly used moderator material. In recent years, the reduced manufacturing cost of yttrium has led to yttrium hydride gradually becoming a new choice of moderator material for the TOPAZ-II reactor. The MCNP program was used to calculate the power distribution of the TOPAZ-II reactor and research the influence of zirconium hydride and yttrium hydride on the reactor power under different conditions. The calculation results show that the trend of the variation in radial power peak factor determines the trend of the variation in power inhomogeneous coefficient when changing the hydrogen content and temperature parameters of the metal hydride moderator. Changes in hydrogen content and temperature parameters of the moderator can cause changes in the thermal neutron distribution in the core, thereby affecting the reactor power distribution. The higher the proportion of low-energy thermal neutrons in the neutron group, the smaller the radial power peak factor in reaction core. The CO2 gas environment surrounding the moderator causes a lower rate of hydrogen loss, resulting in minimal impact on the reactor power distribution. Both moderators exhibit positive temperature effects, with the temperature coefficient of hydrogenated yttrium being smaller than that of hydrogenated zirconium, and the keff of the reactor with hydrogenated yttrium as the moderator is higher.展开更多
基于密度泛函理论,对氧化铟锡(Indium Tin Oxide,ITO)表面负载单原子Y模型的表面性能进行了第一性原理计算.根据表面能计算结果可知,单原子Y最稳定负载位置为空位(H),即确定了ITO负载单原子钇(Single-atom Y supported on ITO,Y/ITO)稳...基于密度泛函理论,对氧化铟锡(Indium Tin Oxide,ITO)表面负载单原子Y模型的表面性能进行了第一性原理计算.根据表面能计算结果可知,单原子Y最稳定负载位置为空位(H),即确定了ITO负载单原子钇(Single-atom Y supported on ITO,Y/ITO)稳定模型.对ITO和Y/ITO表面吸附气体分子(NO和CO)模型的吸附性能进行了第一性原理计算.根据对比ITO和Y/ITO表面的吸附能和态密度计算结果可知,单原子钇负载提高了ITO表面的稳定性和吸附性能.根据对比Y/ITO表面吸附NO和CO气体分子的吸附能和态密度计算结果可知,NO和CO气体分子吸附均为自发行为,过程放热.且NO气体分子更容易吸附在Y/ITO表面,即Y/ITO对NO气体分子更敏感.展开更多
文摘TOPAZ-II反应堆是使用固体金属氢化物为慢化剂的微型空间堆,常用的慢化剂材料是氢化锆。近年来,由于金属钇的制造成本降低,氢化钇逐渐成为TOPAZ-II反应堆慢化剂材料的新选择。使用MCNP程序对TOPAZ-II反应堆进行功率分布计算,分别研究氢化锆和氢化钇在不同条件下对反应堆功率的影响。计算结果表明:改变金属氢化物慢化剂的氢含量和温度参数时,堆芯径向功率峰因子的变化趋势决定了功率不均匀系数的变化趋势;慢化剂的氢含量和温度参数的改变会导致堆芯热中子分布发生变化,进而影响反应堆功率分布,低能热中子占中子群份额越高,堆芯径向功率峰因子越小;慢化剂周围的CO2气体环境导致氢损失速率较小,对反应堆功率分布的影响很小;两种慢化剂呈正温度效应,氢化钇的温度系数比氢化锆的温度系数小,且以氢化钇为慢化剂的反应堆keff更高。The TOPAZ-II reactor is a micro-space reactor that uses solid metal hydride as the moderator, with zirconium hydride being the commonly used moderator material. In recent years, the reduced manufacturing cost of yttrium has led to yttrium hydride gradually becoming a new choice of moderator material for the TOPAZ-II reactor. The MCNP program was used to calculate the power distribution of the TOPAZ-II reactor and research the influence of zirconium hydride and yttrium hydride on the reactor power under different conditions. The calculation results show that the trend of the variation in radial power peak factor determines the trend of the variation in power inhomogeneous coefficient when changing the hydrogen content and temperature parameters of the metal hydride moderator. Changes in hydrogen content and temperature parameters of the moderator can cause changes in the thermal neutron distribution in the core, thereby affecting the reactor power distribution. The higher the proportion of low-energy thermal neutrons in the neutron group, the smaller the radial power peak factor in reaction core. The CO2 gas environment surrounding the moderator causes a lower rate of hydrogen loss, resulting in minimal impact on the reactor power distribution. Both moderators exhibit positive temperature effects, with the temperature coefficient of hydrogenated yttrium being smaller than that of hydrogenated zirconium, and the keff of the reactor with hydrogenated yttrium as the moderator is higher.
文摘基于密度泛函理论,对氧化铟锡(Indium Tin Oxide,ITO)表面负载单原子Y模型的表面性能进行了第一性原理计算.根据表面能计算结果可知,单原子Y最稳定负载位置为空位(H),即确定了ITO负载单原子钇(Single-atom Y supported on ITO,Y/ITO)稳定模型.对ITO和Y/ITO表面吸附气体分子(NO和CO)模型的吸附性能进行了第一性原理计算.根据对比ITO和Y/ITO表面的吸附能和态密度计算结果可知,单原子钇负载提高了ITO表面的稳定性和吸附性能.根据对比Y/ITO表面吸附NO和CO气体分子的吸附能和态密度计算结果可知,NO和CO气体分子吸附均为自发行为,过程放热.且NO气体分子更容易吸附在Y/ITO表面,即Y/ITO对NO气体分子更敏感.
