γ射线技术在测量旋风分离器内颗粒浓度分布上的应用

在实验室循环流化床装置上用γ射线技术对直径Φ260 mm旋风分离器内的FCC催化剂颗粒浓度进行了测量。首先,在轴对称假设的条件下建立旋风分离器内径向颗粒浓度分布模型,然后根据所测实验数据重构出浓度分布图像。重构结果较为真实地反映了旋风分离器内颗粒浓度场的分布规律,且突出了近壁面高浓度梯度的特点。与光纤法的测量结果对比表明,两者在浓度分布的形态和数值上基本吻合,说明了γ射线技术测量流场可行性和可靠性。     

X-ray fluorescent computer tomography with synchrotron radiation

This paper describes the possibility of a quantitative calculation of the distribution of a nonradioactive element within a selected cross section with nondestructive methods with the help of X-ray fluorescent tomography (XFCT). In order to increase measurement sensitivity, the use of a lamellar collimator was avoided. One of the main problems for the quantitative determination of concentration was absorption of the stimulating synchrotron ray as well as re-absorption of the emitted fluorescent light. The absorption coefficients required for a consideration of the absorption processes have been determined with two absorption tomograms. The algebraic reconstruction technique (ART) and the maximum likelihood method with expectation maximization (MLEM) were used for the reconstruction of the chemical element to be classified, with close consideration of the absorption phenomenon. The experiments were undertaken at the bending-magnet beamline, CEMO, at the laboratory for synchrotron radiation in Hamburg, HASYLAB (4.5 GeV) (100 mA). The photon intensity flux was approximately 10/sup 9/ photons/mm/sup 2//s. The concentration of iodine was calculated with phantoms and an untreated, dissected human thyroid gland with the help of a calibration curve. The total error related to the reconstructed mean value amounts to 20%. One can find at least an iodide concentration of 0.6 mmol/l in this experimental setup.     

13C同位素的分离工艺设计与实验研究

本文综述了在¹³C同位素的分离研究中建立“数值模拟+实验研究”的工程化研究方法,完成了一氧化碳低温精馏法分离稳定性同位素¹³C的计算机辅助设计,以及低温精馏工程实验研究。通过CO低温精馏单塔实验测定了¹³C同位素分离体系的基础参数;利用计算机辅助设计了¹³C分离二塔级联工艺,并得到了级联装置的优化参数;通过低温精馏分离¹³C二塔级联实验,对优化设计结果进行检验。研究结果表明,课题建立的“数值模拟+实验研究”相结合的工程研究方法可靠,在¹³C同位素分离中得到了实际应用;课题建立的研究方法提高了¹³C同位素分离的设计水平、降低了实验成本、提高了研发效率,为¹³C同位素分离工业化生产装置的设计提供了可靠的技术方法。     

BSRF高灵敏度衍射增强成像系统搭建

作为一种重要的相位衬度成像方法,衍射增强成像(Diffraction Enhanced Imaging,DEI)是利用晶体的角度选择特性探测样品引起的X射线角度变化来获得样品衬度图像。晶体摇摆曲线是衍射增强成像装置的重要特征,理论上晶体的摇摆曲线越窄,则衍射增强成像灵敏度越高,所获得的图像衬度也会越好。在北京同步辐射装置(Beijing Synchrotron Radiation Facility,BSRF)4W1A成像实验站现有Si(111)晶体DEI装置的基础上,通过选用高精度转台并对晶体采取减少加工应力残余和降低安装夹持应力的措施,设计研制了基于Si(400)和Si(333)晶体的高灵敏度DEI实验装置,并利用标准样品和实际生物样品进行了实验验证。系统摇摆曲线测试及成像结果表明,所研制的成像装置可以开展二维和三维成像实验且具有更高的成像灵敏度。     

Soft X-ray ptychography method at SSRF

Ptychography is a diffraction-based X-ray microscopy technique in which an extended sample is scanned by a coherent beam with overlapped illuminated areas and complex transmission function of the sample is obtained by applying iterative phase retrieval algorithms to the diffraction patterns recorded at each scanned position.It permits quantitatively imaging of non-crystalline specimens at a resolution limited only by the X-ray wavelength and the maximal scattering angle detected.In this paper,the development of soft X-ray ptychography method at the BL08U1A beamline of Shanghai Synchrotron Radiation Facility is presented.The experimental setup,experimental parameters selection criteria,and post-experimental data analyzing procedures are presented in detail with a prospect of high-resolution image reconstruction in real time.The performance of this newly implemented method is demonstrated through the measurements of a resolution test pattern and two real samples:Pt-Co alloy nanoparticles and a breast cancer cell.The results indicate that strong scattering specimens can be reconstructed to sub-20 nm resolution,while a sub-25 nm resolution for biological specimens can be achieved.     

Liquid radwaste concentration by evaporation from porous plates

The possibility of concentrating liquid radwastes by evaporation from the surface of porous plates is examined. It is shown by means of tests of a laboratory setup and an experimental stand that liquid radwastes can be concentrated to salt content 319 g/liter at a temperature far below the evaporation temperature of water and with specific energy consumption 20 times lower that the specific heat of vaporization of water. The results of the tests of the experimental setup with capacity up to 43 kg/h with respect to the evaporated water are described; this setup has been incorporated in the EKO mobile modular water purification complex used at the MosNPO Radon for reprocessing radioactive water from various organizations. Translated from Atomnaya énergiya, Vol. 106, No. 4, pp. 210–214, April, 2009.     

Physical Startup of the LEPTA Accumulator

The LEPTA setup (Low Energy Particle Torroidal Accumulator) is being constructed at the Joint Institute of Nuclear Research. The main purpose of this setup is to generate intense fluxes of positronium ions and perform experiments in positronium physics. The main component of the setup is the low-energy positron accumulator with a electronic cooling system. A special feature of the accumulator is that it uses a longitudinal magnetic field to focus a circulating beam. The physical startup of the accumulator was performed in September 2004. The results of the adjustment of the main components of the accumulator, the method for obtaining a circulating beam, and the first results of measurements of its parameters are presented.__________Translated from Atomnaya Energiya, Vol. 98, No. 3, pp. 225–233, March, 2005.     

Characterization and applications of a new tabletop confocal micro X-ray fluorescence setup

A tabletop confocal three-dimensional micro X-ray fluorescence (3D micro-XRF) setup was designed, based on polycapillary X-ray optics and a micro-focus X-ray source. This confocal setup consists of a polycapillary full lens to focus the incident beam and a polycapillary half lens to collect the X-ray fluorescence. The confocal volume was proved to be ellipsoidal. The full-width at half maximum (FWHM) of the confocal volume in three directions were measured with a “knife edge” scan method to obtain the spatial resolution of the confocal setup. The structure of multilayer samples was studied using the depth scan technique.     

Detection of Explosives by Neutron-Radiation Analysis

The possibility of using in practice the analytical methods of computational efficiency and minimization of the directed discrepancy in the algorithm of the working program for a setup for detecting explosives by neutron-radiation analysis is discussed. The captured-radiation spectra, which are recorded on a model of a real setup, and the computed response functions for -ray energies 6 and 10.9 MeV taking account of the energy resolution of the detector are presented. The possibility of applying these methods to the problem of detecting explosives is briefly described. Difficulties arising in the practical implementation of the methods are noted.__________Translated from Atomnaya Energiya, Vol. 98, No. 3, pp. 220–225, March, 2005.     

临界事故报警系统仪表剂量计算方法研究

本文对临界安全基准实验国际评价中的迷宫实验进行了详细建模和验证计算,使用三维蒙特卡洛程序,采用两步法对中子探测器的读数进行了预测,并与实验结果进行了比较分析,统计了所有448个实验测点的计算偏差分布。通过总结临界事故报警系统在实际应用时位置选择和阈值设定的步骤,评价了本文所验证内容在上述过程中的作用。本文所开展的临界事故报警系统仪表剂量计算方法研究是临界事故报警系统设置中一项基础工作,可以为实际应用提供计算精度的参考数据,也可以应用于中子屏蔽设施的评价工作。     

On-line reconstruction of in-core power distribution by harmonics expansion method

Fixed in-core detectors are most suitable in real-time response to in-core power distributions in pressurized water reactors (PWRs). In this paper, a harmonics expansion method is used to reconstruct the in-core power distribution of a PWR on-line. In this method, the in-core power distribution is expanded by the harmonics of one reference case. The expansion coefficients are calculated using signals provided by fixed in-core detectors. To conserve computing time and improve reconstruction precision, a harmonics data library containing the harmonics of different reference cases is constructed. Upon reconstruction of the in-core power distribution on-line, the two closest reference cases are searched from the harmonics data library to produce expanded harmonics by interpolation. The Unit 1 reactor of DayaBay Nuclear Power Plant (DayaBay NPP) in China is considered for verification. The maximum relative error between the measurement and reconstruction results is less than 5.5%, and the computing time is about 0.53 s for a single reconstruction, indicating that this method is suitable for the on-line monitoring of PWRs.     

Accurate quantification resulting from precise beam monitoring and calibration

PIXE investigations in Heidelberg utilize very different target types for which analogous standards are very rarely available. Standardless quantitative measurements are therefore the preferred method. This asks for precise beam monitoring and accurate calibration of the setup for the conversion from X-ray counts to concentrations. It will be shown that our beam monitor enables us to measure beam currents down to 1 pA with a precision of ≈ 0.5%.

The computer code GUPIX which we use to quantify our results offers the possibility to use a calibration function H(E) rather than one constant only. H(E) has been measured, leading to an overall accuracy for quantification of 5% even for trace elements.     

工业CT图像的三维重建

工业CT图像三维重建是近年来工业CT技术研究的热点之一,将二维断层图像数据直接堆垒起来,结合阈值分割、线性内插等方法,获得了直观性较好的三维工业CT图像。通过对重建图像进行旋转、截取等操作,获得了不同方向、不同部位的三维图形。这种简单、快速的重建方法对更复杂的工业CT图像三维重建具有重要的指导意义。     

基于制备型气相色谱的氙氡分离技术研究

放射性氙同位素探测对监视全面禁止核试验条约（CTBT）的履行具有重要意义;同时在核设施安全运行、环境辐射监测及核事故应急监测中意义重大。氡的子体,包括²¹⁴Bi和²¹⁴Pb会严重干扰放射性氙同位素的活度测量,在氙测量前必须将氡去除,为此开展了制备型气相色谱分离氙氡技术研究。本文研究建立了一套制备型气相色谱系统实验平台,采用氙标准样品,考察了实验平台的氙制备性能;自制了氙氡混合源,测试了氡去污因子。结果表明：建立的实验平台和基于该平台的氙氡分离与氙制备的实验方法实用高效：对氙的制备量不小于11.5 mL（@STP）;制备样品中氙的体积比浓度和氙回收效率分别不小于80%和95%;氡去污因子大于10⁵,满足CTBT大气放射性氙监测技术要求。     

Single-purpose electronuclear installation using natural uranium as fuel

The results of investigations of the parameters of an electronuclear setup, operating on solid fuel, for producing useful power are presented. The objective of the investigations is to show the attractiveness and practical possibility of producing a safe (subcritical) setup for producing energy with unlimited fuel resources. The setup contains an accelerator, two targets, and two blankets. The fissioning isotopes accumulate in one blanket, supplied with natural uranium. Actually, his blanket performs the function of enrichment for the uranium-plutonium fuel cycle in modern nuclear power. Power is generated mainly in the other blanket, which is supplied with fuel assemblies that are extracted from the first blanket. In contrast to reactors operating on natural uranium, in an electronuclear setup a high degree of fuel burnup can be achieved by converting part of the generated energy into neutrons. 1 figure, 9 references. State Science Center of the Russian Federation—Institute of Theoretical and Experimental Physics. Translated from Atomnaya énergiya, Vol. 87, No. 3, pp. 199–204, September, 1999.     

用激光束测试和标定气体径迹探测器

近年来利用激光束产生的电离径迹对径迹探测器进行测试、标定和监测已成为一种强有力的通用方法。本文介绍这种方法的基本原理、实验装置以及它的若干应用。     

Probability analysis of the safety of the second energy module of the leningrad nuclear power plant

A special international program was undertaken to estimate the safety of the second power unit at the Leningrad Nuclear Power Plant after reconstruction and the effectiveness of the new safety measures introduced. The analysis is based on the IAEA method, modified for RBMK reactors. The calculations employ a full-scale model of the risk of the power unit and the initial data for a 10-year operating period. After reconstruction, the frequency of serious accidents with core damage is 1.4·10⁻⁵ per reactor-year and is acceptable in terms of the OPB-88/97 requirements. The influence of reconstruction is considerable: according to the estimates, the risk is reduced by a factor of more than 100. The results of the analysis permit suggestions regarding further increase in safety and reduction in cost of the reconstruction without increasing the risk of accident. Scientific-Research and Design Institute of Power Engineering. Translated from Atomnaya énergiya, Vol. 87, No. 2, pp. 113–117, August, 1999.     

The simultaneous neutron and photon interrogation method for fissile and non-fissile element separation in radioactive waste drums

Measuring -emitters such as (^{234,235,236,238}U, ^{238,239,240,242,244}Pu, ²³⁷Np, ^241,243Am, …), in solid radioactive waste allows us to quantify the -activity in a drum and then to classify it. The simultaneous photon and neutron interrogation experiment (SIMPHONIE) method dealt with in this paper, combines both active neutron interrogation and induced photofission interrogation techniques simultaneously. Its purpose is to quantify fissile (²³⁵U, ^239,241Pu, …) and non-fissile (^236,238U, ^238,240Pu, …) elements separately in only one measurement. This paper presents the principle of the method, the experimental setup, and the first experimental results obtained using the DGA/ETCA Linac and MiniLinatron pulsed linear electron accelerators located at Arcueil, France. First studies were carried out with U and Pu bare samples.     

2D/1D耦合的堆芯实测功率分布快速重构研究

针对三代核电压水堆在线监测系统需要快速准确进行实测3D功率重构的需求,本文提出了一种2D/1D耦合的3D功率重构方法。首先采用耦合系数法对探测器层的功率进行了2D实测功率重构;其次针对每个组件,采用二次样条函数拟合方法进行了轴向1D实测功率重构,最后得到了全堆3D实测功率分布。该方法计算流程简单,占用内存少。针对华龙一号开展的4个典型例题的数值验证结果表明,该方法具备很高的精度,满足三代核电在线监测系统实测功率重构对精度和速度的要求。     

Verification and validation of the flux reconstruction method for CANDU® applications

In this paper, we propose a new method for the cell local flux reconstruction for CANDU® applications. The method is based on the modulation method where the core local mesh flux is reconstructed by modulating the form function with an interpolated cell mesh flux along with an appropriate normalization technique. The reconstruction method was adapted to the diffusion finite difference method. In this paper we present: (a) the flux reconstruction method, (b) the verification of this method using two benchmarking problems and (c) its validation using the ZED-2 data generated from the defueled channel experiments.