10MW高温气冷实验堆(HTR-10)燃耗测量系统控制方案的改进

基于10MW高温气冷实验堆(HTR-10)的FCA系统及CFC系统的设计原理及运行规程,在不改变FCA系统原有设备部件的前提下,对FCA系统运行逻辑关系进行了优化,改进了原燃耗测量程序,实现了燃耗测量过程的自动运行及测量结果的自动建库.在此基础上,设计了CFC系统与FCA系统PLC的通信协议,实现了燃耗测量流程与控制系统的实时数据通信.上述改进的结果使得燃料装卸流程不再需要另设运行班组,提高了效率,将人为操作的步骤最少化,降低了误操作的可能性.     

云南东川泥石流沟与非泥石流沟~(137)Cs示踪法物源研究

运用1 37Cs示踪法调查云南东川小江流域 6条泥石流沟、6条非泥石流沟和主河的泥沙来源。泥沙主要来源于冲沟侵蚀和滑坡崩塌堆积、坡耕地和草地。坡耕地和草地表层土壤1 37Cs平均含量分别为 0 9Bq m2 和1 98Bq m2 ,冲沟沟壁和滑坡崩塌堆积土体1 37Cs。作者通过 3种源地土体1 37Cs含量的比较 ,分析了细粒泥沙(<0 0 1mm)的来源。 6条泥石流沟冲沟侵蚀和重力侵蚀 (滑坡崩塌 )的相对产沙量变化于 90 2 %～ 1 0 0 % ,平均值为 95 1 % ,6条非泥石流沟的相对产沙量变化于 74 5 %～ 83 3% ,平均值为 78 9%。小江主河为 81 4 %。     

鄱阳湖湖底沉积物放射性水平

本文报道了1985年鄱阳湖湖底沉积物放射性水平的调查结果。沉积物中 U、Th、~(226)Ra、~(40)(?)和~(137)Cs 的比活度分别为64.8、67.9,58.9、676.1和3.5Bq/kg;用~(137)Cs 测龄方法作了沉积物泥芯垂直深度的年代定位,由此得知1985—1958年对应深度沉积物中 U、Th、~(226)Ra 和~(40)K 的比活度与1957—1930年对应深度沉积物比较无显著性差异;U、Th 和~(226)Ra 的浓集因予分别为5.2×10~413.9×10~4和4.8×10~4L/kg。     

射线料位计的故障及维护

介绍济源钢铁公司炼铁厂射线料位计的常见故障、解决方向和维护措施。     

Determination of Linear Attenuation Coefficients of Materials by Using Timing Method

Abstract

In this work, gamma-ray linear attenuation coefficients of aluminum (Al) and lead (Pb) materials were determined by using timing method. The used setup is different from the conventional ones. The goal of the presented setup is the fact that it is used the timing technique. The detection system is composed of a 3″ × 3″ NaI(Tl) inorganic scintillation detector and related equipment together with ¹³⁷Cs and ⁶⁰Co radioactive sources. Obtained results are in good agreement with each other.     

Improving the MCA Spectra of BC‐400 Plastic Scintillation Detectors at Room Temperature

Abstract

In the presented work, the leading edge timing and constant fraction discrimination timing techniques were applied to beta rays emitted from a ¹³⁷Cs radioactive source through the developed spectrometers in order to improve the beta energy spectrum of the source. The energy spectra, with and without the techniques, were obtained with a BC‐400 plastic scintillation detector. The obtained spectra were compared with each other for the elimination of spurious pulses, which rise from background, backscattering, scattering, and any radiations other than the source, on the multichannel analyzer output.     

Study of relation between the gamma flux buildup factors and source geometry by M-C simulation

This paper is to achieve a gamma-ray source with the lowest rate of buildup factor, which is of great importance in medical, industrial and agricultural sciences.The flux buildup factor of gamma rays is calculated by the MCNP code for point, linear, surface and volume sources with shield layers of lead, iron and aluminum. The results show that for the high Z shielding material, the flux buildup factor of coaxial cylindrical sources is the lowest(1.6–2.3)of all sources, while for low Z shielding materials, the coaxial disk surface sources have smaller buildup factor(1.45–1.6).     

Measurement of Thermal Neutron Cross Section of 137Cs(n, γ)138Cs Reaction

A calculational model for a modified diffusion coefficient has been developed to incorporate the neutron streaming effect in heterogeneous low-density channels accurately into diffusion theory calculations. The model uses a supercell, and the axial and radial diffusion coefficients of the heterogeneous inner cell are so defined that they can reproduce Benoist's axial and radial diffusion coefficients of the supercell when the diffusion coefficient of the outer cell is given as 1/3 Σ_tr . In the case of the axial diffusion coefficient, the axial buckling effect is taken into account by modifying the neutron path length within the streaming channel in calculating the collision probabilities. This model has been applied to an RZ fast reactor Core model with a gas expansion module (GEM). By using the axial diffusion coefficient obtained with the presented model, calculational error of GEM worth was reduced to less than 1/7 compared to the formula of Rowlands and Eaton.     

Liquid-Liquid Extractions of Microamounts of 137Cs and 85Sr with Chlorinated Dicarbollide and Crown Ethers into Mixed Dodecanenitrile/n-dodecane Nonpolar Diluent

New methods of extraction of ¹³⁷Cs and ⁸⁵Sr into solvent mixture of dodecanenitrile with n-dodecane in the presence of various crown ethers and chlorinated dicarbollide are described. This is the first time when extraction with chlorinated dicarbollide anion was accomplished into a judiciously chosen nonpolar solvent. The theoretical reasoning leading to the choice of such nonpolar solvent is outlined. New crown ethers with laterally branched alkyl chain were synthesized and tested. These, when the same crown moiety is compared, are more effective for Sr²⁺ extraction than the commonly used DC18C6 (18C6 ring moiety), but less effective for Cs⁺ extraction compared with DB21C7 (21C7 moiety). The systems may be used both in analytical applications and, hopefully, after further development, as well in a nuclear reprocessing industry.