可控中子源中子-伽马测井仪中屏蔽结构的优化

本文设计了一种使用遗传算法调用蒙特卡罗计算软件MCNP的方案,用以优化设计中子-伽马测井仪中的屏蔽结构。以D-D聚变中子源和BGO探测器为研究对象,以最小化探测器内的辐照本底为优化目标,设计出了3种不同厚度的屏蔽结构。模拟结果表明,这些屏蔽结构具有优异的屏蔽性能,可有效地降低探测器中的辐射本底。     

γ射线无损检测炮弹体内炸药密度

讨论了各方有关参数对测定炮弹体炸药密度的影响，借助于向炮弹壳体内注入水的工艺过程，等效物理吸收厚度概念及γ射线透射－注水法无损检测弹体炸药密度公式，测定了弹体内充填琐材料时的密度值。     

利用视电阻率测井参数计算含水层渗透系数的探讨

通过对库捷尔太地区八道湾组含水层岩石渗透系数进行取样测试,并对视电阻率测井参数(ρ)与岩石渗透系数(Κ)的关系进行了研究,得出了岩石视电阻率与渗透系数关系散点图,由此建立了利用视电阻率测井参数确定岩石渗透系数的相关方程及关系曲线图;利用曲线图法和相关方程法确定的渗透系数与水文孔抽水试验计算的渗透系数进行了对比,其结果基本一致。     

高温气冷堆内含硼碳材料吸湿特性与扩散系数研究

高温气冷堆（HTGR）是世界上首座具有第四代核电特征的堆型,堆内装载了大量石墨和碳作为结构材料和燃料元件基体。碳素材料是一种多孔材料,常温下吸附空气中的水分等杂质。高温气冷堆的初装堆除湿过程和事故后除湿过程,由水分扩散性能决定。通过含硼碳（BC）材料动态吸湿实验得到水分质量变化曲线,将其与模拟结果拟合得到材料中水分的有效扩散系数D_e＝7.30×10^-10 m²/s。通过吸湿实验得到湿度和温度对平衡吸湿量的影响。环境湿度越高,平衡吸湿量越大,二者近似呈线性关系;温度越高,平衡吸湿量越小。     

用修正淬透性系数法对反应堆压力容器锻件RTNDT数值的预估

分析反应堆压力容器(RPV)锻件制造过程中关键化学元素含量及基准无塑性转变温度(RTNDT)数值,通过引入修正淬透性系数,建立了反映RTNDT变化规律的修正淬透性系数函数表达式,并给出了实例验证,结果表明,通过本文建立的修正淬透性系数函数式可以比较精确地预估RPV锻件的RTNDT值。     

Analysis of Experiment on Temperature Coefficient of Reactivity in Light-Water-Moderated and Heavy- Water-Reflected Cylindrical Core Loaded with Highly-Enriched-Uranium or Medium-Enriched-Uranium Fuel

An analysis was performed for the temperature coefficient of reactivity measured in the six types of light-water-moderated and heavy-water-reflected cylindrical cores containing highly-enriched-uranium (HEU) or medium-enriched-uranium (MEU) fuel, which was constructed in the Kyoto University Critical Assembly (KUCA). The purpose of the present analysis was to reveal a mechanism why a light-water region existed in the core contributes to a large positive temperature effect on reactivity. Therefore, based on the assessment of the computational method to calculate the temperature coefficient of reactivity in a multi-region type core, studies were carried out to examine each effect of three physical processes (Doppler broadening, thermal expansion and thermal neutron spectral shift) on the temperature coefficient and to separate each contribution of the multi-regions to this physical quantity. The measured temperature coefficients were approximately simulated by the calculations using the SRAC code system. The Doppler broadening caused a slightly negative effect in the MEU cores and the thermal expansion a negative effect in all the cores, whereas the thermal neutron spectral shift caused a large positive effect in all the cores. The temperature effect on reactivity in the fuel region was negative, while that in the light-water region existed in the core was positive because of the decrease in neutron absorption due to the thermal expansion and the spectral shift effects, and it became positive in the present core where large light-water regions existed in the core.