最新刊期
      卷 42 ， 期 7 ， 2019

        SYNCHROTRON RADIATION TECHNOLOGY AND APPLICATIONS

      • “在核反应领域，科学家们通过共沉淀法制备了铈掺杂的U3O8混合氧化物样品，利用XRD和XAFS技术研究了其局域结构，为理解乏燃料性状提供新见解。”
        CAO Hanjie,BAO Hongliang,YU Haisheng,HUANG Yuying,WANG Jianqiang
        Vol. 42, Issue 7, (2019) DOI: 10.11889/j.0253-3219.2019.hjs.42.070101
        摘要：BackgroundCerium is one of the important products of the mixed oxide (MOX) reaction, and CeO2 forms U1-xCexO2 solid solution with UO2. In the post-treatment of spent fuel, UO2 may be oxidized to U3O8 resulting in an increase in spent fuel volume. The structure and volume of spent fuel are concerned with the solubility, valence and electronic structure of uranium-cerium solid solutions.PurposeThis paper aims to study the local structure of Ce-substituted U3O8 by X-ray absorption fine structure (XAFS) technique.MethodsFirst of all, (U1-yCey)3O8-δ (y=0, 0.05, 0.20) mixed oxides were prepared by coprecipitation method. Then, powder X-ray diffraction (XRD) and X-ray absorption fine spectroscopy (XAFS) characterizations at U L3 edge and Ce K edge have been undertaken to study the chemical changes of uranium-cerium oxides.ResultsThe XRD data shows that the Ce-substituted U3O8 has the P62¯m space group which is different with α-U3O8. The U L3-edge X-ray absorption near edge structure (XANES) data of Ce-substituted U3O8 shows a slight increase in the uranium average valance. The X-ray absorption near edge structure (EXAFS) data shows that the neighboring atoms of Ce cations are far away from those of U cations.ConclusionsThe Ce cations replaced the U site in U3O8, and the U3O8 sample was changed from the original C2mm to P62¯m space group. The lattice volume was increased and the local structure around U cation was changed by adjusting the atomic distance and increasing the valence of U.  
        关键词：Synchrotron radiation X-ray absorption fine structure;Cerium doping;Uranium oxide;Local structure   
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        发布时间：2024-10-25

        ACCELERATOR, RAY TECHNOLOGY AND APPLICATIONS

      • “在材料科学领域，研究者利用慢正电子技术，探究了低活化铁素体/马氏体钢在H+辐照下的损伤机理。研究发现，随着辐照剂量的增加，材料中空位型缺陷浓度上升，且缺陷尺寸增大。”
        ZHANG Zihan,SONG Ligang,JIN Shuoxue,CAO Xingzhong,SUN Jianrong,HONG Zhiyuan,LI Xiaoyan,LI Jinyu,YAN Qingzhi,WANG Baoyi
        Vol. 42, Issue 7, (2019) DOI: 10.11889/j.0253-3219.2019.hjs.42.070201
        摘要：BackgroundRAFM steel is a good candidate structural material and is widely accepted today as a fusion reactor core material.PurposeThis study aims to investigate the radiation damage mechanism of reduced activation ferritic/martensitic (RAFM) steel, the vacancy-type defects and their effects on the material structure of RAFM steel irradiated by H+ were probed by slow positron beam.MethodsThe experimental sample was RAFM steel based on Fe-9wt.% Cr. H+ ion beam energy was 100 keV whilst the dose was set to be 1×1015 cm-2, 1×1016 cm-2, 1×1017 cm-2, respectively, for irradiation experiments.ResultsThe results of slow positron beam Doppler broadening measurement were available. The S parameter increased with the increase of dose, and the W parameter shows the opposite trend. The main irradiation area of the material was 142~348 nm, there were a large number of defects in this range, the irradiation mainly produced vacancy-type defects, most of which were hydrogen-vacancy complex defects. The concentration of irradiation defects increased with the H+ doses.ConclusionsThe size of the vacancy-type defect changes with the dose increase. When the irradiation dose reaches 1017 cm-2, the slope of the S-W curve changed, so the type of irradiation defects varies significantly, and the defects of larger size were occurred.  
        关键词：RAFM steel;H+ irradiation;Slow positron beam;Vacancy-type defects   
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        发布时间：2024-10-25
      • “在全面禁止核试验条约放射性核素检测领域，专家提出了基于判断限的γ峰筛选方法，结合二阶导数寻峰法，显著提高了HPGe γ能谱中弱γ峰的准确检出率。”
        ZHANG Xinjun,WANG Shilian,JIA Huaimao,LI Qi,SHI Jianfang,FAN Yuanqing,ZHAO Yungang
        Vol. 42, Issue 7, (2019) DOI: 10.11889/j.0253-3219.2019.hjs.42.070202
        摘要：BackgroundRadionuclide monitoring is critical to determine whether a suspicious nuclear event detected is a nuclear explosion test. Trace released radionuclides will be transported in the atmosphere, their decay and dilution induce that comprehensive nuclear-test-ban treaty (CTBT) relevant radionuclide monitoring belongs to the ultra-low level radioactive monitoring. The weak γ peaks of CTBT relevant radionuclides are interfered by the complex high environment radioactivity background.PurposeThis study aims to search accurately the weak γ peaks of CTBT relevant radionuclides in γ spectra of aerosol samples from CTBT radionuclide stations.MethodsA screening method for γ peaks based on the critical level was proposed to detect weak γ peaks immerged in high environmental radioactive background. Combining the second derivative peak finding method, accurate detection for γ peaks was achieved. Finally, verification was performed on HPGe γ spectra from CTBT radionuclide stations.ResultsThe identification rate of γ peaks by using proposed method is 97.4% and the error identification rate of γ peaks can be reduced from 274% to 10.4%.ConclusionThe high sensitivity screening method for γ peaks based on the critical level can improve the accurate detection rate of the weak γ peaks.  
        关键词：CTBT;γ peak;Critical level;Screening method   
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        发布时间：2024-10-25
      • “在CMOS器件抗辐射领域，专家采用蒙特卡罗方法分析了器件吸收剂量与标称辐照剂量的差异，评估了次级电子不平衡对器件敏感区吸收剂量和电离总剂量效应的影响程度，为提高器件抗辐射水平提供解决方案。”
        WANG Yuankun,WANG Qian,WANG Tao,LIU Jing
        Vol. 42, Issue 7, (2019) DOI: 10.11889/j.0253-3219.2019.hjs.42.070203
        摘要：BackgroundAbsorbed dose is the most important physical quantity in the study of radiation effect. In the total ionizing dose experiment of 60Co gamma ray, the secondary electron equilibrium condition is not satisfied in the sensitive area of a thinner device. The actual absorbed dose could be less than the irradiation dose measured by the same dosimeter.PurposeThis study aims to analyze and evaluate the influence extent of secondary electron imbalance on the absorbed dose and total ionizing dose of the sensitive layer of the device.MethodsBy studying the total ionizing dose effect with 60Co γ-rays on complementary metal oxide semiconductor (CMOS) device "CC4069 inverters", the difference between the absorbed doses of the sensitive layer of CC4069 inverters and the nominal irradiation dose measured by the dosimeter was calculated by Monte Carlo simulation. Combined with the measurement of the threshold voltage of the irradiation sensitive parameter of CC4069 inverter, the relationship between the threshold voltage drift of positive channel metal oxide semiconductor (PMOS) and negative channel metal oxide semiconductor (NMOS) under different bias conditions and the nominal irradiation dose and absorbed dose corrected by Monte Carlo simulation were analyzed and compared.ResultsThe results show that the absorbed dose of the device sensitive layer is only 83.52% of the nominal irradiation dose.ConclusionThe radiation test under the condition of secondary electron non-equilibrium will affect the evaluation of radiation hardening of device, and the radiation hardening of the device is overestimated by 16.5%.  
        关键词：Total ionizing dose effect;Secondary electron equilibrium;Absorbed dose;Monte Carlo simulation   
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        发布时间：2024-10-25

        NUCLEAR CHEMISTRY, RADIOCHEMISTRY, RADIOPHARMACEUTICALS AND NUCLEAR MEDICINE

      • “最新研究利用阳离子交换技术，成功去除废水中的银胶体，为生态环境保护提供新方案。”
        GU Enxi,FU Lingxiao,WANG Huan
        Vol. 42, Issue 7, (2019) DOI: 10.11889/j.0253-3219.2019.hjs.42.070301
        摘要：BackgroundAg colloids is a hazard to the environment, but little attention has been paid to the research on its removal from waste water.PurposeThis study aims to make a Fe3+ modified resin for removing Ag colloids from aqueous solution, and to investigate its adsorption behavior on Ag colloids.MethodsThe adsorption behavior of Ag colloids on the modified resin was studied by dynamic tests, and it was used as a function of pH value, adsorbent dosage, adsorption time and initial concentration. Both the X-ray fluorescence (XRF) and the X-ray photoelectric spectroscopy (XPS) were employed to test the effect of this approach.ResultsIn the batch adsorption experiment of Ag colloids, under neutral conditions, the removal efficient of Ag in 20×10-6 solution of modified resin of 6.67 mg∙mL-1 was up to 92.5%, and the adsorption process reached dynamic equilibrium in 6 h.ConclusionsThe adsorption process agreed to the typical Langmuir model and the pseudo-second-order kinetic model. XRF result showed that Na+ existing in the D001 resin was totally exchanged by the Fe3+. XPS analysis indicated that the modified resin was decorated to Ag+, Fe3+ and Fe2+ after absorbing the Ag collide solution. Apparently, Ag was oxidized to Ag+ and Fe3+ was reduced to Fe2+ in the adsorption process, which implied that the adsorption mechanism was ion exchange.  
        关键词：Ag colloid;Redox adsorption;Loading Fe3+;Modified resin   
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        发布时间：2024-10-25

        NUCLEAR ELECTRONICS AND INSTRUMENTATION

      • “在中子散射等领域，PTI-204型稻草管探测器展现出巨大潜力，其γ射线甄别率可达约10-8，热中子探测效率约为20%。”
        ZENG Jun,XIANG Qingpei,ZHANG Yingzeng,ZE Rende,XIANG Yongchun,HAO Fanhua
        Vol. 42, Issue 7, (2019) DOI: 10.11889/j.0253-3219.2019.hjs.42.070401
        摘要：BackgroundBoron-coated straw detector is a new type of 3He replacement neuron detector, which can be used for large-area low-energy neutron detection in the field of neutron scattering, arms control, and neutron interrogation.PurposeThis study aims to obtain the thermal neutron detection performance of boron-coated straw detector with strong γ radiation background.MethodsThe PTI-204 boron-coated straw detector was taken for study the influence of discrimination threshold to neutron counting against the gamma counting. Both the detection efficiency of γ-ray and thermal neutron were measured with standard radiation sources of 137Cs and 252Cf.ResultsThe results indicated that the gamma-ray resolution of the PTI-204 detector is up to ~10-8, and the thermal neutron detection efficiency is about 20%.ConclusionsThe performances of the boron-coated straw detector indicated that it was a good choice for replacing of the expensive 3He tube for neutron detection.  
        关键词：Boron-coated straw;Neutron detection efficiency;γ-ray discrimination   
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        发布时间：2024-10-25
      • “核脉冲信号滤波成形电路研究取得新进展，专家推导了基于数字极零相消、数字Sallen-Key的成形递推函数，分析了滤波性能和幅频响应特性，为核脉冲信号极零相消、滤波成形参数的最优化选取提供解决方案。”
        ZHANG Huaiqiang,YAN Miaomiao,LIU Jinyang
        Vol. 42, Issue 7, (2019) DOI: 10.11889/j.0253-3219.2019.hjs.42.070402
        摘要：BackgroundFilter shaping of pulsed signals is used to change the pulse shape and increase the system signal-to-noise ratio for better performance in a nuclear spectrometer system.PurposeThis study aims at digitalization of filter shaping circuit for nuclear pulse signal.MethodsBased on the principle of digital pole-zero cancellation and digital Sallen-Key in the time domain, the shape recursive function was derived, and the transfer function of them in the Z domain was obtained respectively. The filtering performance and amplitude-frequency response characteristics in the frequency domain were analyzed. Then the digital pole-zero cancellation and digital Gaussian shaping recursive function model are used to realize the simulated nuclear pulse signal processing with different parameters. Furthermore, 55Fe and 137Cs radioactive sources were measured with the Si-PIN detector and NaI detector respectively, obtained nuclear pulse signals were processed by the digital pole-zero cancellation and digital Gaussian shaping processing with different parameters. [Results andConclusion] The results in both the time domain and the frequency domain show the efficiency of proposed digitalization approaches of filter shaping circuit for nuclear pulse signal. These approaches can be applied to the optimization of the pole-zero cancellation and filter shaping parameters of nuclear pulse signals.  
        关键词：Nuclear pulse signal;Digital Sallen-Key;Digital pole-zero cancellation;Frequency response   
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        发布时间：2024-10-25
      • “在高能物理探测领域，研究人员建立了基于μ子径迹直线拟合模型的迭代芯片位置校正算法，为解决硅像素芯片拼接误差问题提供解决方案。”
        WANG Hongkai,XU Chong,ZHAO Chuanqi,ZUO Jiaxu,HAN Jingru
        Vol. 42, Issue 7, (2019) DOI: 10.11889/j.0253-3219.2019.hjs.42.070403
        摘要：BackgroundBenefit by the position resolution at the micro-meter level and the extremely high detection efficiency, complementary metal oxide semiconductor (CMOS) pixel sensors were widely used for particle tracking. Pixel sensors have the ability to be assembled on a large scale and can be applied to muon radiography.PurposeThis study aims to improve the position deviations of the sensors to be less than ten microns to prevent deterioration of the position accuracy for multi-layer muon radiography.MethodsFirst of all, an iterative position correction method was established based on cosmic muon tracks fitted by straight line model. Then a muon radiography prototype consisting of 8 physical layers was simulated by using GEANT4 with 4 pixel sensors on each physical layer. Finally, artificial deviation in the x-y plane and rotation angle θ along z axis for all the sensors were introduced to simulate and correcte position deviations of the sensors.ResultsThe results show that the precision of position correction is less than 5 μm.ConclusionThe proposed chip position correction method can be used to correct the real position of the chip with high accuracy.  
        关键词：Pixel sensor;Position resolution;Track reconstruction;Position correction   
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        发布时间：2024-10-25

        NUCLEAR ENERGY SCIENCE AND ENGINEERING

      • “据最新研究，秦山核电基地大气中氚化水、氢、甲烷浓度呈季节性变化，随距离增加而降低。”
        XU Qingsong,QIN Lailai,XIA Zhenghai,DAI Zhongqin,LIU Wei,PAN Taijun
        Vol. 42, Issue 7, (2019) DOI: 10.11889/j.0253-3219.2019.hjs.42.070601
        摘要：BackgroundThe harmfulness of tritium to environment and human life is not only related to the activity of tritium, but also to the chemical forms of tritium. Qinshan nuclear power plants base is one of the largest tritium-processed areas in China, but little attention has been paid to the distribution of atmospheric multi-forms tritium in this area.PurposeThis study aims to investigate the distribution characteristics of atmospheric multiform tritium in the vicinity of Qinshan nuclear power plants.MethodsSamples of tritium in different forms around the vicinity of Qinshan nuclear power plants in different years and seasons were collected and measured using instruments independently developed by Shanghai Institute of Applied Physics.The temporal and spatial distribution characteristics of HTO concentration and the seasonal discharge of three forms of atmospheric trituim were both discussed.ResultsThe results showed that three chemical forms of atmospheric tritium existed in the vicinity of Qinshan nuclear power plants. The average concentration of HTO (tritiated water) in the atmosphere is 78.24~8 324.16 mBq∙m-3; the concentrations of HT (tritiated hydrogen) and CH3T (tritiated methane) in the sampling period were 15.35~2 763.12 mBq∙m-3 and 5.68~163.96 mBq∙m-3, respectively.ConclusionThe concentration of HTO in the atmospheric increased with the time of operation of the nuclear power plant and decreased gradually with the increase of the distance from the heavy water reactor; the concentration of HTO and HT presented apparent seasonal distribution: high in summer and low in winter; however the concentration of CH3T showed no obvious seasonal variations.  
        关键词：HTO;HT;CH3T;Concentration;Qinshan nuclear power plants base   
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      • “在第四代核能系统领域，专家对373 MW熔盐堆非能动余热排出系统进行了优化设计研究，提出了初步设计方案，并基于FLUENT仿真结果对核心部件换热元件进行了分析优化。”
        HUANG Wanjue,XU Bo,ZHOU Chong,ZOU Yang,XU Hongjie
        Vol. 42, Issue 7, (2019) DOI: 10.11889/j.0253-3219.2019.hjs.42.070602
        摘要：BackgroundThe molten salt reactor is one of the candidates for the fourth generation advanced nuclear energy system. It has the characteristics of good economy, high safety and flexible fuel cycle. The passive decay heat removal system for the fuel drain tank is the key of passive safety system of the molten salt reactor.PurposeThis study aims to optimize the design of the passive decay heat removal system for the 373 MW molten salt reactor.MethodsFirst of all, the design scheme of the passive decay heat removal system for the molten salt reactor experiment (MSRE) was taken as case application, calculation results of application by using the MATLAB program were compared with that of thermal-hydraulic analysis software FLUENT. Both of them were verified as the passive decay heat removal system design and analysis software for molten salt reactor. Then, in the case of the 373 MW molten salt reactor, the preliminary design scheme of the passive decay heat removal system for the fuel drain tank was proposed. Finally, a series of analysis and optimization of the core component - the bayonet cooling tubes were conducted on the basis of the simulation results of FLUENT. [Results andConclusion] The results show that the bayonet cooling tubes arranged at 95.0 mm square spacing value can achieve maximum economic efficiency under the premise that the maximum wall temperature of the heat exchanger does not exceed the safety limit of 977.4 K, and the decrease of the air gap has a little effect on system.  
        关键词：Molten salt reactor;Fuel drain tank;Passive decay heat removal system;Bayonet cooling tube;Air gap   
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        发布时间：2024-10-25
      • “在熔盐堆领域，专家针对2 MW液态燃料钍基熔盐堆提出多种停堆方式，为熔盐堆停堆方式提供技术储备和理论参考。”
        YU Shihe,LIU Yafen,YANG Pu,JI Ruimin,ZHU Guifeng,ZHOU Bo,KANG Xuzhong,YAN Rui,ZOU Yang,LAN Bing
        Vol. 42, Issue 7, (2019) DOI: 10.11889/j.0253-3219.2019.hjs.42.070603
        摘要：BackgroundReactivity control design is one of the main contents of reactor neutronics design. Molten fluoride mixture was used as fuel in molten salt reactor (MSR). Due to the particularity of nuclear fuel, molten salt reactor is different from traditional solid fuel reactor in reactor design.PurposeThis study aims at feasibility analysis of shutdown modes with emphasis on the standby scheme.MethodsThe shutdown modes includes discharging fuel salt, injecting neutron poison into the core tube, changing the composition of fuel salts, changing the number of graphite cells. The 2 MW thorium molten salt reactor-liquid fuel (TMSR-LF1) model was taken as the reference reactor, and the calculation was completed by using Monte Carlo N particle transport code (MCNP).ResultsThe analysis results show that injection of neutron poison into the core tube was a good alternative to shutdown the reactor when the control rod cannot be inserted into the core. The adjustable composition of fuel salts was the characteristic of MSR itself, thus, adding BF3, LiF-BeF2-ZrF4, LiF-ThF4 to fuel salts was a good way to adjust the reactivity. Changing the number of graphite cells could also shutdown the reactor.ConclusionThe analysis of this study can provide technical reserves and theoretical reference for the shutdown modes of molten salt reactor.  
        关键词：Molten salt reactor;TMSR;Shutdown modes;Reactivity   
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      • “在镍基合金压力容器焊接部位裂纹安全评估领域，专家采用失效评估图方法，考虑焊接残余应力影响，为含缺陷压力容器失效应力计算提供参考。”
        LYU Liushuai,ZHANG Xiaochun,SU Bo,LI Chaowen,WANG Naxiu
        Vol. 42, Issue 7, (2019) DOI: 10.11889/j.0253-3219.2019.hjs.42.070604
        摘要：BackgroundResidual stress in girth weld and failure stress of reactor vessel are very important in structural integrity assessment regardless the structural material.PurposeThis study aims to evaluate the safety of internal surface cracks in welding parts of nickel-based alloy pressure vessels.MethodsFirst of all, based on the British structural integrity assessment standard BS7910(2013), the failure assessment method of failure assessment diagram (FAD) was adopted, and the finite element analysis (FEA)methodwas employed to carry out numerical simulation of V groove and X groove multilayer and multiple girth butt welding of pressure vessel respectively. The distribution of welding residual stresses was then obtained. In addition, the residual stress curve of V groove butt welding was compared with that of BS7910(2013) standard. Secondly, the formula of BS7910(2013) 1-FAC curve was deduced. Finally, considering the influence of residual stress, stress concentration and plastic failure factor, the failure stress of semi-elliptic crack in the axial direction was predicted.ResultsThe results show that the distribution of residual stress directly affects the calculation results. When the conditions remain unchanged, the calculation result of failure stress decreases with the increase of the ratio of crack depth (c) and crack half length (a). When c/a takes the same value, failure stress decreases with the increase of a.ConclusionsThe prediction method of welding residual stress and failure stress can provide some reference for the calculation of failure stress of pressure vessels and pipeline in the future.  
        关键词：Girth butt weld;Weld simulation;Residual stress;BS7910;FAD;Failure stress   
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      • “在熔盐堆热工水力学领域，专家利用Fluent软件对TMSR-LF堆芯流场进行数值模拟，提出了分步式改进方案，有效优化了流量分布，为工程优化设计提供参考。”
        LI Qingyuan,XU Bo,ZHOU Chong,ZOU Yang,XU Hongjie
        Vol. 42, Issue 7, (2019) DOI: 10.11889/j.0253-3219.2019.hjs.42.070605
        摘要：BackgroundFlow rate distribution design is one of the main contents of the thermal hydraulics study of molten salt reactor, because the flow rate distribution among all salt channels directly determines the location and peak value of local hotspots, which seriously affects the safety and reliability of the reactor operation.PurposeThis study aims to improve the uniformity of mass flow rate distribution among salt channels of 373 MW molten salt reactor named TMSR-LF2 (Thorium Based Molten Salt Reactor - Liquid Fuel).MethodFirst of all, the computational fluid dynamics program Fluent 15.0 was employ to is numerically simulate core flow field. Then the uniformity of structure optimization of upper plenum and lower plenum from several thermal-hydraulics characteristics were concluded according to the simulation output. Finally, several step-by-step improvement schemes were proposed.ResultThe schemes of inserting the cylindrical baffle plate can effectively suppress the eddy within the lower plenum and eliminate the radial inhomogeneity of the flow rate. Increasing the height of the upper plenum can balance the pressure drop of inner and outer channels on the radial direction to improve the flow rate uniformity. Reducing the radius of the inner channels on the metal support plate will bring about a platform area of flow rate among inner salt channels and the overall trend will be more gentle.ConclusionThe modification results showed that the improvement methods mentioned above has important reference value for the further optimization design of MSR-LF.  
        关键词：MSR-LF;Flow rate distribution;Structure optimization;Computational fluid dynamics (CFD)   
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        发布时间：2024-10-25
      • “中国聚变工程实验堆负离子源中性束系统验证样机辐射屏蔽研究，为确保工作人员辐射安全提供解决方案。”
        LI Mengting,HU Chundong,XIE Yahong,CHEN Yuqing,WU Bin
        Vol. 42, Issue 7, (2019) DOI: 10.11889/j.0253-3219.2019.hjs.42.070606
        摘要：BackgroundChina fusion engineering test reactor (CFETR) negative ion based neutral beam injection system (NNBI) prototype was designed for hydrogen beam operation. When the NNBI prototype works, the energetic particles collide with the solid targets of the prototype structural material during production and transmission to produce bremsstrahlung. When the CFETR NNBI prototype is designed to operate with a beam energy of 200 keV and beam current of 20 A, the dose rate outside the vacuum wall is higher than the limit dose rates of general worker radiation (10 μSv∙h-1).PurposeThis study aims to reduce the radiation dose rate of the CFETR NNBI with hydrogen beam energy of 200 keV.MethodsThe radiation dose of the prototype was simulated by the radiation shielding theory. The shielding design scheme of sinking the prototype with lead plate was put forward and evaluated.ResultsWhen the CFETR NNBI is placed underground and shielding layer on the top, the outside dose rate at 1 m from vacuum wall (with 2 cm thickness) of ion source (200 keV, 20 A) is below the limit.ConclusionThe design scheme can meet the radiation safety standards when the CFETR NNBI prototype operated with radiation shielding.  
        关键词：CFETR neutral beam test facility;Radiation dose;Radiation shielding   
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