数字X射线图像综合校正方法研究

基于CCD-镜头耦合X射线数字成像系统的输出图像往往会产生信息畸变.针对图像中的CCD暗电流噪声和图像不均匀性,本文提出了相应的校正方法.针对系统特有的散点噪声,本文通过建立噪声模型提出了改进型均值滤波算法(IMF).最后,本文总结了X射线数字图像综合校正方法,对像质计图像进行的校正获得了令人满意的图像质量.     

基于网格计数的停机剂量率计算方法研究

本文根据严格二步法的计算理论,研究了基于网格计数的停机剂量率计算方法,设计并实现了基于网格计数的停机剂量率计算程序。该程序能够支持圆柱坐标下的网格计算。本文使用源子程序进行复杂源描述。为了加快计算速度,本文采用了多节点和多线程等技术。本文利用国际热核聚变实验堆(ITER)停堆剂量基准实验ITER-T426进行测试,计算结果与实验值吻合良好,证明了该方法和程序的正确性和可用性。     

2005年全国放射源事故评估分析

本文对国内2005年放射源辐射事故进行了概括与分析,事故发生频度与往年相比有所下降,表明国家放射性同位素与射线装置实行统一监管初见成效.本文也对事故的应对措施进行了归纳总结,分析了监管中存在的问题,提出了工作建议.     

退役源项刍议

本文论述了退役源项在核设施退役中的重要性,定义了什么是退役源项.本文主要从退役源项计算的内容和时间两方面对退役源项的计算进行分析,没有涉及具体的计算方法.由于退役方式的不同将导致退役源项的特征有很大的差异,因此本文就退役方式对退役源项的影响做了详细的分析.     

发展大容量核电站——兼谈EPR较N4的改进

本文介绍了世界大容量核电站发展趋势。法国的N4和欧洲EPR是当前世界大容量核电站的代表,本文对N4和EPR的总体要求,系统和设备,安全系统设置等进行了重点比较并对我国发展大容量核电站提出了看法。     

“第二核纪元”与核动力堆发展前景

本文分析了核能在许多发达国家与发展中国家内衰落的历史根源。本文认为,目前动力堆设计中忽视内在安全准则,导致系统过于复杂化,从而造成经济规模过大,投资过高与建造周期过长等一系列弱点。本文进一步对各国提出的第二代改进堆型作了综合评价,并提出我国核动力堆发展的技术路线。     

X射线光栅相衬成像中保留源光栅的探测器校正方法

本文提出了一种X射线光栅相衬成像探测器校正方法,该方法无需移除靠近光源的源光栅,而是将其与光源作为一个整体参与增益校正。在基于几何投影的光栅相衬成像系统上,开展了利用传统的探测器校正与本文提出的探测器校正方法的对比实验,两种方法获得了一致的结果。实验结果表明,本文方法大幅简化了实验操作流程,提高了系统的稳定性,对于实现X射线相衬成像的临床应用有一定的推进意义。     

β反散射镀(涂)层测厚的理论公式及其实验检验

本文以β吸收实验规律为基础,推导了β测厚的计算公式,与实验值比较,结果令人满意。本文还根据对实验数据及公式参数的分析,得出了常用β源的测厚范围,介绍了基体校正的基本原理。     

大屏幕显示系统在先进核电厂人机接口系统中的应用

通过对法规标准的分析研究,本文详细阐述了大屏幕显示系统在先进核电厂人机接口系统中的功能,并基于工程应用给出了主要的显示信息。本文结果对后续先进核电厂大屏幕显示系统设计有一定的指导意义。     

β衰变型自给能堆芯中子探测器灵敏度K因子研究（第一篇：理论分析、计算模型及计算结果）

本文对β衰变型自给能堆芯中子探测器灵敏度K因子进行了较全面、深入、系统的研究,建立了热中子灵敏度K因子、超热共振中子灵敏度K因子、中子场全谱中子灵敏度K因子的完整理论体系,给出了计算这些K因子的数学模型及公式,并提供了各K因子的计算结果,论证了探测器的轻水堆K因子与重水堆K因子的关系。通过与其他文献发表的灵敏度K因子进行比较,验证了本文提出的灵敏度K因子理论模型是科学的,本文给出的灵敏度K因子计算结果是可信的。     

R&D progress of high power ion source on EAST-NBI

The neutral beam injector(NBI) system was designed and developed mainly for the plasma heating on the Experimental Advanced Superconducting Tokamak(EAST). The high power ion source is the key part of the NBI. A hot cathode ion source was used on the EAST-NBI. The ion source was conditioned on the ion source test bed with hydrogen gas and achieved the designed parameters. The deuterium gas was used when it moved to the EAST-NBI. The main performance of the ion source on EAST is presented in this paper. The highest beam power of 4.5 MW in NBI-1 and 2.75 MW in NBI-2 was achieved. The total neutral beam power is about 4.5 MW. The long pulse beam of 100 s is injected into the EAST plasma too.     

熔融池氧化物层自然对流的数值模拟

本文以BALI试验段为对象建模,对其中有内热源的湍流自然对流流体进行了二维数值模拟。模拟工况的瑞利数Ra高达10¹²～10¹⁵。流体的湍流运动用大涡模拟模型来捕捉。通过对下边界局部热流密度的面积加权积分,计算了三维下边界换热量。结果表明,Ra对流场、温度场与下边界局部热流密度分布均有显著影响。计算所得上下边界的Ra-Nu关系与试验结果符合较好。对不同物理机理导致的下边界热流密度分布规律进行了分析。     

离心力对旋叶式分离器壁面液膜界面不稳定性的影响

本文对旋转流场条件下离心力对旋叶式分离器壁面液膜界面不稳定性的影响规律进行了理论研究。首先利用势函数对汽液两相的动量方程和连续方程进行线性化处理。然后通过对无黏条件下液膜界面的受力分析,获得汽液界面的动力学边界条件和运动学边界条件,结合线性化方程组建立液膜界面波的色散方程。根据力平衡原理获得了液膜运动规律,并结合色散方程建立了界面不稳定发生的判定准则关系式。基于所获得的理论模型编写计算程序,对界面稳定性进行计算分析。研究发现,旋转流场条件下的离心力能够抑制旋叶式分离器壁面液膜界面不稳定的发生。     

基于MicroTCA的EPICS控制系统研究

本文介绍了现代加速器控制系统的发展趋势,针对未来加速器控制系统的高数据传输率、低延时的要求,研究了基于MicroTCA技术的EPICS控制系统,开发了基于EPICS平台的、具有完整功能的MicroTCA样机系统。此系统包括硬件搭建、Linux系统设备驱动开发、基于EPICS的设备支持层和实时数据库。此外,本文采用CSS开发了功能完备的OPI,且对该系统的性能进行了测试,为该系统的实际应用打下了基础。     

核电厂辅助给水系统水箱抗震分析研究

本文针对成熟M310堆型核电厂储液容器辅助给水系统(ASG)水箱,根据ASCE 4—98,采用基于壳模型的有限元法以及两种不同的地震输入,完成了抗震分析,并依据RCC-M规范J篇进行了地震屈曲评价。结果表明,ASG水箱原设计存在一定的地震屈曲风险。在此基础上本文对ASG水箱的结构设计分析给出了建议。     

Development of Parallel Coupling System between Three-Dimensional Nodal Kinetic Code ENTREE and Two-Fluid Plant Simulator TRAC/BF1

The high-speed three-dimensional neutron kinetic code ENTRÉE was developed based on the polynomial and semi-analytical nonlinear iterative nodal methods (PNLM and SANLM) with also introducing the discontinuity factor. In order to enhance the efficiency of transient calculation, the nonlinear correction-coupling coefficients are intermittently updated based on the changing rate of core state variables. By giving the analytical form for two-node problem matrix elements, the additional computing time in SANLM was minimized. A fast algorithm was developed for the multi table macro-cross section rebuilding process. The reactivity component model was implemented based on the variation of the neutron production and destruction terms. The code was coupled with the two-fluid thermal hydraulic plant simulator TRAC/BF1 through PVM or MPI protocols. Two codes are executed in parallel with exchanging the feedback parameters explicitly. Based on the LMW PWR transient benchmark, it was shown that both PNLM and SANLM spend less than 20% excess computing time in comparison with the coarse mesh finite difference method (CFDM). The implementation of the discontinuity factor was verified based on the DVP problem. Adequacy and parallel efficiency of the coupling system TRAC/BF1-ENTREE was demonstrated based on the BWR cold water injection transient proposed by NEA/CRP.     

水基磁性流体竖直加热棒下的池沸腾传热实验研究

研究了磁性微粒浓度、外加磁场对水基磁性流体在竖直加热棒加热情况下的沸腾传热影响;实验结果显示,磁性微粒浓度和外加磁场对磁性流体的沸腾换热有很大影响：对于中低浓度的磁性流体,存在一个最优的磁粒浓度,在该浓度下沸腾传热的强化效果最显著,施加磁场时,该结论仍然成立。施加磁场能强化磁性流体的沸腾传热。     

Influence of Transverse Magnetic Field on Heat Transport Characteristics of Potassium Heat Pipe

The influence of a transverse magnetic field on the heat transport characteristics of a potassium heat pipe was experimentally studied in the range of field strength 0~0.6 T. The wick was constituted of a multilayer mesh screen, and the adiabatic section, to which the magnetic field was applied, was made up of a concentric double-wall rectangular tube, with the inner wall completely separating the vapor and liquid flows.

The magnetic field was applied perpendicularly to the heat pipe, upon which the axial temperature distribution of the heat pipe was observed to be affected, and the heat transport rate to be reduced with increasing field strength.

The effect of the magnetic field on the heat transport rate is analyzed in terms of the liquid pumping ability of the wick and of the magnetohydrodynamic (MHD) effect on the liquid flow through the wick. The MHD effect on the flow through wick is shown to be expressible by a formula similar to that for flow between parallel plates.

The heat transport rate measured in magnetic field are compared with values calculated assuming that the wick pumping ability was not influenced by the magnetic field but that it was the MHD effect on the liquid flow through the wick that affected the heat transport. The calculated results well explained the experimental data.     

Flow Profile Measurements of Gas in a Rotating Cylinder

An azimuthal flow of the gas motion in a rotating cylinder induced by the forced source-sink flow was measured using the laser Doppler anemometer in connection with the development of a gas centrifuge for ²³⁵U enrichment. The cylinder, held vertically, was driven in the air at an angular velocity of 10 π rad/sec. The air to which paraffin mist was added as the light scattering particles was fed into the cylinder through the inlet slit provided on the upper end plate at the relative radius of 0.43 and withdrawn through the outlet slit on the lower end plate at the relative radius of 1.0. The Ekman number E was approximately 5.6 × 10^?5 in this experiment. The Ekman layer on the upper end plate was so thin that it was not observed, and that on the lower end plate was not either. The Stewartson E ^1/4 layers on the side wall and at the feed radius were clearly observed and their profiles were quite similar to the result of the linear theory except the inviscid core region. The discrepancy in this region should be attributed to the fact that the Stewartson layers on the side wall and at the feed radius were thick enough to overlap each other.