Solvent Extraction Calculation Model for Purex Process in Pulsed Sieve Plate Column

A new calculation code PULCO has been developed to simulate the Purex extraction process in a pulsed column. The model for the PULCO code is based on the mass transfer taking place at the interface between dispersed drops and continuous phase fluid. The following physical quantities of the moving drop are included in the model for each period of drop motion in a pulsed column:

1. Mass transfer coefficient from liquid drop to continuous phase

2. Diameter and velocity of moving drop in the pulsed column

3. Holdup of dispersed and continuous phases in the pulsed column

4. Longitudinal dispersion coefficient in the pulsed column.

To establish the validity of the PULCO code, experiments were performed using a 50 mm diameter pulsed column which had a sieve plate section height of 2 m and plates spaced 50 mm apart. The experiments were performed by CY tests with use of unirradiated U and Pu. The experimental concentration profiles fitted well with the calculated concentration profiles.     

Consideration on Effective Diffusivity of Strontium in Granite

Abstract

Diffusive behavior of strontium and certain kinds of divalent cations in Inada granite were studied by a through-diffusion method. In order to examine the effect of sorption onto overall diffusive behavior, two kinds of solutions were used: 0.1M KCl solution and deionized water. The effective diffusion coefficient (D_e ) and rock capacity factor (a) were (2.0–3.6) xl0–¹³ m²/s and less than 0.022 in 0.1M KCl solution and (0.32–1.7) x 10 ^?13m²/s and 1.5–2.4 in deionized water respectively. The D_e , and α in deionized water were much larger than those in 0.1M KCl solution. These results are well explained by taking into account the diffusion of sorbed ion or the surface diffusion. In support of this mechanism, most D_e , values of Sr reported for various rocks are found proportional to the sorptivity ( _ρR_d )-In the case that the sorptivity is low, D_e of Sr depends on porosity like that of nonsorbed iodide. The effective diffusion coefficient of Sr in rocks was well explained by taking into account pore and surface diffusion and was expressed as D_e=2.1 xl0^?10 _? ^1.3+3.5xl0″^?12 _ρR_d . The effective diffusion coefficient of divalent cations in the granite was found proportional to their diffusion coefficients in bulk solution.     

不同60Coγ剂量率下10位双极D/A转换器的总剂量效应

为探索电离辐射对数模混合电路的影响,对国产10位双极D/A转换器在60Coγ射线不同剂量率辐照下的电离辐射效应及退火特性进行研究。结果表明：D/A转换器对辐照剂量率十分敏感,在大剂量率辐照时,电路功能正常,各功能参数变化较小;在低剂量率辐照下,各参数变化显著,电路功能出现异常,表现出明显的低剂量率损伤增强效应。最后,结合空间电荷模型对其电离辐射损伤机理进行了初步探讨。     

环形通道内液态铅铋合金流动换热特性实验研究

通过对环形通道内液态铅铋合金的流动换热特性进行实验研究,得到了气泡泵注气对液态金属流动的影响,并拟合出环形通道内液态铅铋合金的摩擦系数关系式和换热特性关系式。结果表明：采用气泡泵注气能有效提升铅铋合金的质量流速;相同Reynolds数下环形通道内液态铅铋合金的摩擦系数大于由布拉休斯公式计算得到的摩擦系数;液态铅铋合金对流换热过程中,导热项占主导地位,并且Nusselt数随Peclet数的增大而增大。     

RWM-B放射性水连续监测系统

核设施液态流出物的监测是鉴别核设施生产运行是否处于正常状况不可缺少的有力措施，也是评价核设施辐射安全的重要手段。本工作涉及RWM-B放射性水连续监测仪的研制。该监测系统采用高气压氙气电离室作为探测器，以8051单片计算机作为控制主机，电路上采用弱电流测量方法。如果5min 报告1次数据结果，取95%置信度，在普通天然本底条件下，探测下限则可达到2644Bq/m³。     

中温SOFC密封玻璃热稳定性研究

研究了一种热稳定性好的中温固体氧化物燃料电池密封玻璃. 研究表明, 此密封玻璃的热膨胀系数(室温～631℃)为9.8×10^-6/K, 与8YSZ电解质的热膨胀系数10.0×10^-6/K(室温～631℃)接近, 并且在700℃热处理300h后, 该密封玻璃的热膨胀系数几乎没有变化. 粘度实验表明, 玻璃在700℃下具有足够的刚性, 适合于运行温度在700℃左右SOFC的密封. 化学相容性的研究显示, 在700℃下与8YSZ反应300h后没有发现显著的界面反应.     

可伐合金与无氧铜复合材料的研制

采用外皮为可伐合金(4J29)内芯为无氧 Cu(UT_1),经热加工、冷加工和扩散退火等工艺复合制成的复合材料。Cu 芯是圆形的,复合界面形成固溶体并牢固地结合在一起。轴向平均线膨胀系数α_(20)—400℃=(4.9-5.5)×10~(-6)/℃。外径为1.5mm,内芯径为0.6mm 复合线,其电阻率ρ=8.3×10~(-8)Ω·m;复合界面漏气率小于6.67×10~(-8)Pa·L/S。     

Hierarchical Spatially Varying Coefficient Process Model

The spatially varying coefficient process model is a nonstationary approach to explaining spatial heterogen-eity by allowing coefficients to vary across space. In this article, we develop a methodology for generalizing this model to accommodate geographically hierarchical data. This article considers two-level hierarchical structures and allow for the coefficients of both low-level and high-level units to vary over space. We assume that the spatially varying low-level coefficients follow the multivariate Gaussian process, and the spatially varying high-level coefficients follow the multivariate simultaneous autoregressive model that we develop by extending the standard simultaneous autoregressive model to incorporate multivariate data. We apply the proposed model to transaction data of houses sold in 2014 in a part of the city of Los Angeles. The results show that the proposed model predicts housing prices and fits the data effectively.     

简化位移法正则方程的一种方法

本文将超静定结构中的结点转角和位移进行了重新组合,建立了新的位移弯矩系统,使得位移法正则方程为之简化,这个问题有一定的实际意义。     

光面爆破在卡鲁玛尾水隧洞开挖中的改进与应用

在乌干达卡鲁玛尾水隧洞8#支洞Ⅲ类围岩开挖中,为了解决光面爆破施工中用的25mm细药卷短缺、绑扎光面爆破药串用的竹片无法买到等问题,采用了经过加工的32mm常规药卷,调整了光面爆破孔内装药结构和装药方法,并在选用常规周边光面爆破孔孔距条件下,适当减小光面爆破层厚度,将周边光面爆破孔密集系数提高到1.25~1.43。爆破实践表明:通过一系列改进,即便在只有最常见的32mm常规药卷和导爆索条件下,仍能取得良好的光面爆破效果。这一改进简化了光面爆破药串加工工序,减少了光面爆破层脱落需要克服的阻力,减轻了爆破对洞周被保留岩体的伤害。