最新刊期
      卷 39 ， 期 2 ， 2016
      • Baixin ZHANG,Tong ZHANG,Jianhui CHEN,Bo LIU,Dong WANG
        Vol. 39, Issue 2, Article number: 020101(2016) DOI: 10.11889/j.0253-3219.2016.hjs.39.020101
        摘要：Background:Optimization of free-electron laser (FEL) facilities is of great significance to achieve radiations of high-quality, e.g. higher brilliance, purer spectrum. In addition, these properties are affected by various parameters, e.g. the electron trajectory along the accelerator and undulator, the beam envelope or beta function, which could be changed by tuning the correctors and quadrupoles.Purpose:This study aims to find a set of suitable parameters to optimize the radiation power.Methods:The genetic algorithm (GA) is applied to investigation of the FEL power optimization with respect to the focus-defocus-focus (FODO) lattice configuration between the undulator segmentations. A friendly graphical user interface (GUI) is designed for deployment of the software.Results:The preliminary study of the machine optimization shows that it is efficient to find good pair of FODO lattice to get power high enough even if it is not globally optimized.Conclusion:This application of genetic algorithm for optimization design of free electron laser is efficient and stable based on many experiments of multi-variable optimization problems, and it is helpful to the future application to the genuine FEL machine optimization.  
        关键词：Real-coded;Genetic algorithm;Free-electron laser   
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        发布时间：2021-05-24
      • Dan YANG,Haidong LI,Jidong ZHANG
        Vol. 39, Issue 2, Article number: 020102(2016) DOI: 10.11889/j.0253-3219.2016.hjs.39.020102
        摘要：Background:Thermal annealing will enhance the performance of diketopyrrolopyrrole-containing oligothiophene (SMDPPEH) based solar cells. However, its mechanism is unclear.Purpose:We investigated the variation of SMDPPEH thin film during the thermal annealing.Methods:The SMDPPEH thin film was spin-coated from chlorobenzene solution and characterized by ultraviolet-visible spectrophotometry (UV-VIS) absorption spectra and grazing incidence X-ray diffraction (GIXRD).Results:The absorption maximum (λmax) peaks of the annealed SMDPPEH thin film were at 100℃ and above blue-shifted. The GIXRD results exhibited that the intensities of (100) diffraction peaks were enhanced with increasing annealing temperatures and there was a small change in shape from dot to arc when annealing temperature was equal to or higher than 100℃ for SMDPPEH thin film.Conclusion:These results indicate that a phase transition is present in SMDPPEH when the annealing temperature is up to 100℃ and the crystallinity of all the films improved with the increase of annealing temperature.  
        关键词：SMDPPEH thin film;Phase transition;Thermal annealing   
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        发布时间：2021-05-24
      • Yi CHEN,Yang WU,Jian WANG
        Vol. 39, Issue 2, Article number: 020201(2016) DOI: 10.11889/j.0253-3219.2016.hjs.39.020201
        摘要：Background:Conventional neutron radiography is an absorption contrast imaging method which is based on wave character. When neutron wavefront traverses the inspected sample, the variations of the thickness, material and neutron refractive index of the sample bring different phasic difference, which would cause a change in a shape of a neutron wavefront, and the aberrancewavefront interference behind the sample leads to enhancement of the image sharpness.Purpose:The aim is to validate thermal neutron to carry out phase contrast imaging.Methods:Numerical simulation of neutron edge enhancement imaging is processed by MATLAB based on reflection theory and experiment is carried out at a reactor using polychromatic thermal neutron beam line.Results:The thermal neutron phase contrast imaging can be realized in CMRR (Chinese Mianyang Research Reactor) neutron radiography device when theL/Dis 2 000 and the distance of sample between scintillator is 60 cm.Conclusion:Both the simulation and experiment results show that a properL/Dcondition would cause image enhancement at the edge of aluminum materials and the monochromatic neutron source is not necessary. The effect is related toL/Dand the distance between sample and scintillator.  
        关键词：Neutron;Phase contrast imaging;Simulation;Experiment   
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        发布时间：2021-05-24
      • Tiannan YE,Hanzhou LIU,Siqi YAN,Wenjuan CHANG,Wenhui FAN,Xiao YU,Wanxin WEN
        Vol. 39, Issue 2, Article number: 020202(2016) DOI: 10.11889/j.0253-3219.2016.hjs.39.020202
        摘要：Background:Hydrogel has been widely applied to drug delivery, tissue engineering, water treatment, water retention and separation, etc. Mechanical properties of hydrogel can be improved by combining with other materials without changing its intrinsic properties. Due to the excellent properties of carbon nanotubes (CNTs) such as mechanical strength, hydrogen storage, high specific surface area, they can be applied to selective absorption or separation of hydrogen isotope. CNTs composite hydrogel may combine these excellent properties.Purpose:This study aims at a new absorbent material fabricated by irradiation-induced grafting and crosslinking two-steps method.Methods:The G-CNTs/PAAm hydrogel with Poly(acrylamide) and CNTs grafted with acrylic acid were fabricated by irradiation-induced grafting and crosslinking two-steps method. Properties of G-CNTs and CNTs were investigated by Fourier transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA), and transmission electron microscope (TEM). X-ray diffraction (XRD) and Brunauer-Emmett-Teller specific surface area (BET) were used to characterize PAAm hydrogel and G-CNTs/PAAm hydrogel. Liquid water and vaporous water absorption ability of G-CNTs/PAAm hydrogel and PAAm hydrogel were tested at room temperature.Results:Many objects and pieces appeared on the surface of G-CNTs. There were two new absorption bands at 1 726 cm-1and 1 452 cm-1in the FTIR spectra of the G-CNTs which indicates that acrylic acid has been successfully introduced onto the surface of CNTs by Co-60 irradiation grafting. According to TGA curves of CNTs and G-CNTs, grafting ratio of G-CNTs (15%) could be calculated. The gel content of G-CNTs/PAAm hydrogel and PAAm hydrogel were 95.6% and 94.7%, respectively. Compared with PAAm hydrogel, two new peaks at 26.5° and 43.2° could be found in the XRD pattern of G-CNTs/PAAm hydrogel associated with CNTs and G-CNTs. The surface area of G-CNTs/PAAm hydrogel with 30 m2·g-1was two times larger than that of PAAm hydrogel with 12 m2·g-1.Conclusion:Due to the larger surface area of G-CNTs/PAAm hydroge, better vaporous water absorption ability was shown compared with the PAAm hydrogel. Hydrophilic and dispersibility of CNTs in water have been improved and the crystal lattices of CNTs still exist after being grafted. The existence of G-CNTs improves the surface area and stables the structure of G-CNTs/PAAm hydrogel.  
        关键词：CNTs;Hydrogel;Radiation grafting;Radiation crosslinking   
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        发布时间：2021-05-24
      • Jing SUN,Wu LU,Wei DENG,Qi GUO,Xuefeng YU,Chengfa HE
        Vol. 39, Issue 2, Article number: 020203(2016) DOI: 10.11889/j.0253-3219.2016.hjs.39.020203
        摘要：Background:In the complex space environment, the regulator parameter can be changed, which is a serious threat to the reliability and security of an integrated circuit system.Purpose:This study aims at the effect of temperature on the radiation-sensitive parameters of linear regulators exposed to ionizing radiation.Methods:Ion radiation effect tests were carried out at different temperature for the three regulators of the same model produced by ON Semiconductor (ONS), National Semiconductor (NSC) and one Chinese company, respectively. The key electrical parameters of the regulator, such as output voltage, input current and line regulation, varies with total ion radiation dose range from 0 Gy to 1 000 Gy under various centigrade temperatures of 25℃, 70℃ and 100℃.Results:The damage to the output voltage and the input current of the three regulators under irradiation is enhanced with the increased temperatures. The damage to line regulation of ONS and NSC regulators under irradiation at 'elevated temperature' is smaller than that at room temperature. There was no effect of temperature observed on input current of ONS regulator and line regulation of the regulator provided by the Chinese company.Conclusion:The effect of temperature on radiation-sensitive parameters of the linear regulators mainly depends on trap charge.  
        关键词：Bipolar linear voltage regulator;Radiation effect;Irradiation temperature   
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        发布时间：2021-05-24
      • Juan ZHAO,Zhengming GAO
        Vol. 39, Issue 2, Article number: 020401(2016) DOI: 10.11889/j.0253-3219.2016.hjs.39.020401
        摘要：Background:The datum error of the gamma detection on large-mass and high security controlled radioactive materials is too large for quantitative analysis.Purpose:This study aims to accurately measure the radiation of gamma radioactive materials placed upon support body.Methods & Results:Based on the theory of particle flux parameters on the cross section of detection, the method to calculate the influence of the support body on radiation detection was simplified. Then, simulations were done to find the error distributions with Monte Carlo method when the materials were placed on the concrete ground. In order to reduce the detection error, a plate of lead was recommended to be inserted between the materials and the concrete ground. The best thickness of the lead layer was simulated and experimental verification was performed.Results:Simulation results show that if a lead layer thicker than 0.5 cm exists between the radioactive materials and the concrete ground. The relative detection error could be reduced from 22% to 15% or even the least of 10% in some particular situations.Conclusion:If a large-mass or high security controlled gamma radiator would be detected, it should be placed on a lead layer thicker than 0.5 cm in case of reducing the datum errors.  
        关键词：Support body;Radioactive material;Gamma radiation detection;Monte Carlo method   
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        发布时间：2021-05-24
      • Chuanxin ZHU,Yunfeng MOU,Pu ZHENG
        Vol. 39, Issue 2, Article number: 020402(2016) DOI: 10.11889/j.0253-3219.2016.hjs.39.020402
        摘要：Background:The gadolinium-loaded liquid scintillator detector is an important tool for particle detecting in the area of high energy physics and nuclear physics experiments.Purpose:In this work, a large-size ø30cm×30cm gadolinium-loaded liquid scintillator detector has been developed for neutron measurement. Neutron gamma discrimination and distribution of neutron capture time of gadolinium-loaded liquid scintillator were main values of detecting performance.Methods:The n-gamma discrimination of the large-size gadolinium-loaded liquid scintillator detector has been studied using a252Cf spontaneous fission neutron source by zero-crossing method. It was observed that the neutron-gamma discrimination property of large-size gadolinium-loaded liquid scintillator detector was poor. n-gamma discrimination spectra of ø30 cm×30 cm gadolinium-loaded liquid scintillator detector within 1 μs after the fission event were captured with coincidence method based on the start signal of fission fragment from252Cf fission chamber.Results:It was observed that the neutron-gamma discrimination property of large-size gadolinium-loaded liquid scintillator detector was also poor. The time distributions of neutron and gamma in the n-gamma discrimination spectra were measured by time-of-flight (TOF) technique and coincidence method. The peak time difference of neutron time distribution and gamma time distribution was 2 ns. The distribution of neutron capture time was measured for a ø30 cm×30 cm gadolinium-loaded liquid scintillator detector with coincidence method based on the start signal of fission fragment from252Cf fission chamber. The main signals of γ by neutron capture of ø30 cm×30 cm gadolinium-loaded liquid scintillator detector were in about 30 μs. The average time of neutron capture is 11 μs.Conclusion:The neutron capture time property of homemade gadolinium-loaded liquid scintillator meets the experimental requirements. For the most signal of neutron and gamma within the superposition, single peak was presented in the n-gamma discrimination spectra. Therefore, the n-gamma discrimination could not be realized. The phenomenon of the poor neutron-gamma discrimination property of ø30 cm×30 cm gadolinium-loaded liquid scintillator detector was explained clearly based on the experiments.  
        关键词：Gadolinium-loaded liquid scintillator detector;Neutron gamma discrimination;The distribution of neutron capture time   
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        发布时间：2021-05-24
      • Sheng LUO,Liang YANG,Guqing GUO,Tao GE
        Vol. 39, Issue 2, Article number: 020501(2016) DOI: 10.11889/j.0253-3219.2016.hjs.39.020501
        摘要：Background:Zr-based alloys have been widely used as nuclear materials. However, enhancement of the resistance of particle radiation, the mechanical properties, and the corrosion resistance in alloys are still required.Purpose:The aim is to develop a new Zr-based nuclear material of excellent mechanical properties and corrosion resistance.Methods:DC magnetron sputtering method was applied to preparing ZrCuNb ternary amorphous films precipitated upon the pure zirconium substrate. The structure of ZrCuNb films was characterized using scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, and high-resolution transmission electron microscope. Testing on mechanical properties such as tensile experiment was performed for both the ZrCuNb films/Zr substrate (the composite material) and the corresponding Zr metal plate. Corrosion resistance was studied using potentiodynamic polarization measurements.Results:It is found that full amorphous structure in films could be obtained microalloying Nb in ZrCu alloy, such as Zr53Cu38Nb9. In comparison with the Zr metal plate, the Zr substrate coated with Zr53Cu38Nb9film does not have higher hardness or Young's modulus, however, the composite material possesses relatively high tensile strength and in particular obviously larger plastic-strain range. The enhancement is caused by the difference in initiation mechanism of cracks between the amorphous film and Zr substrate that they propagate along different orientations. Cracks in the substrate and film interfere with each other, leading to a delayed catastrophic rupture. In addition, the composite material has a stronger corrosion resistance.Conclusion:Zr metal plate coated with ZrCuNb amorphous film is a novel composite material with excellent mechanical properties and good corrosion resistance, which has a potential application in the nuclear engineering.  
        关键词：Magnetron sputtering;ZrCuNb;Amorphous film;Mechanical properties;Corrosion resistance   
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        发布时间：2021-05-24
      • Xuemei ZHOU,Lingjie MENG,Wei LAI
        Vol. 39, Issue 2, Article number: 020601(2016) DOI: 10.11889/j.0253-3219.2016.hjs.39.020601
        摘要：Background:C/C composites coated with SiC were introduced for the irradiation measurement at high temperature in Thorium Molten Salt Reactor-Solid Fuel (TMSR-SF) due to their excellent performance as an irradiation carrier of activation foil.Purpose:This study aims at the effects of C/C composites to activation foils.Methods:Based on the characteristics and service environment of C/C composites, component test and thermos analysis were carried out by element gravimetric density (GD) and calorimeter respectively to verify whether they would have influence on the irradiation results. Neutron irradiation experiment for activation foils with/without C/C composites was performed in a horizontal radial hole of uranium zirconium hydride reactor. And the activation rates of mononuclear were calculated respectively.Results:Experimental results show that SiC coating is essential for C/C composites to enhance oxidation resistance. The activation rate of mononuclear with C/C composites was reduced slightly. When the thickness of C/C was of mm-level, the decrement of activation rate for mononuclear was less than 10%.Conclusion:C/C composites coated with SiC could be used as carrier materials for activation foils at high temperature when the carrier wall is thin. The results of irradiation could be corrected based on the measurement of C/C composites.  
        关键词：C/C composites;Neutron irradiation;Activation rate of mononuclear;TMSR-SF   
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        发布时间：2021-05-24
      • Yunpeng JIA,Zihao WANG,Junxia GENG,Yang YANG,Qiang DOU,Haixia CONG,Qingnuan LI,Haiying FU
        Vol. 39, Issue 2, Article number: 020602(2016) DOI: 10.11889/j.0253-3219.2016.hjs.39.020602
        摘要：Background:The removal of CsF, a major fission product in molten salt reactor, on a regular basis is helpful for the improvement of neutron economy of the reactor.Purpose:This study aims to investigate the evaporation behavior of CsF under different experimental conditions in FLiNaK molten salt.Methods:Two different evaporation methods, namely vacuum distillation and reductive evaporation by metal lithium, were employed in this work.Results:The results from the experiments of vacuum distillation at 5 Pa revealed a linear correlation between evaporated mass of CsF and evaporation temperature. At 780℃, the CsF concentration in molten salt decreased from 1% to 0.14% upon distillation with a separation rate of 86% despite the loss of 9.5% of the carrier salt. Reductive evaporation by metal lithium was carried out at 700℃ and 1.01×105Pa. The amount of evaporated CsF increased with the increase of lithium added into the molten salt. The separation rate was 91% at a molar ratio of lithium to CsF of 120.Conclusion:Fundamental data are provided to understand the evaporation behaviors of CsF in fluoride molten salt, which could further benefit the establishment of efficient separation technique for CsF removal from spent fuel.  
        关键词：CsF;FLiNaK;Evaporation;Reductive   
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        发布时间：2021-05-24
      • Yongcai SHEN,Jia FU,Bo LYU,Bin WU,Yuejiang SHI,Yingying LI,Fudi WANG,Zhengying CUI
        Vol. 39, Issue 2, Article number: 020603(2016) DOI: 10.11889/j.0253-3219.2016.hjs.39.020603
        摘要：Background:Impurity density measurement is very important in tokamak plasma, especially for impurity behavior and transport study.Purpose:This study aims to obtain the impurity density of tokamak plasma by using passive spectroscopy diagnostics.Methods:Line emissions of impurity are measured by passive spectroscopy diagnostics, and the chord-integrated brightness profiles are obtained by multiplying the sensitivity calibration coefficients. The radial emissivity profiles corresponding to a certain number of considered magnetic surfaces can be obtained by using the version technique. Then the density profiles of impurity ions can be acquired according to the relationship of emissivity profiles and density profiles of impurity ions. And the total impurity density distribution can be calculated by the simulation of impurity transport code.Results:Experimental results on obtaining of total molybdenum density on experimental advanced superconducting tokamak (EAST) by soft X-ray and extreme ultraviolet spectrometers (XEUV) show the total measureing error is less than 10%.Conclusion:Impurity density can be measured by using spectroscopic method, combining spectroscopy diagnostics and impurity transport code.  
        关键词：Tokamak plasma;Passive spectroscopy diagnostics;Emissivity;Impurity transport;Impurity density   
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        发布时间：2021-05-24
      • Weiwei WANG,Kemei CAO,Zhanfei QI
        Vol. 39, Issue 2, Article number: 020604(2016) DOI: 10.11889/j.0253-3219.2016.hjs.39.020604
        摘要：Background:In Loss of Coolant Accidents (LOCAs), jet impact of fluid from a high energy pipe could damage insulation materials, etc. near the break into debris, which would be transported along with fluid in containment and finally deposit on sump screen to form a debris bed, impeding normal operation of Emergency Core Cooling System (ECCS). A part of the debris may bypass the screen and flow into the reactor pressure vessel, resulting in a series of effects. The issue is referred as GSI-191 (Generic Safety Issue 191) problem.Purpose:In order to solve this issue, quantity of debris generated near the break should be determined firstly.Methods:One calculation tool for jet impact Zone of Influence (ZOI) was developed independently based on ANSI/ANS 58.2-1988 standard and equivalent volume sphere model.Results:The jet outline and isobar of the Nuclear Energy Institute (NEI) test case obtained by the tool agreed well with the results of U.S NRC (United States Nuclear Regulatory Commission) and thus the duplication of the NEI test case was realized successfully. Furthermore, sensitivity analysis under different stagnation conditions was performed. Analysis results showed that, under the same stagnation pressure, increase of fluid temperature will result in the decrease of the ZOI destruction radius and debris quantity.Conclusion:So when jet impact test is performed to obtain the ZOI destruction radius, double ended guillotine break of cold leg should be selected conservatively as the limiting condition to maximum the debris quantity generated during jet impact process.  
        关键词：Jet impact;Debris;Zone of influence;LOCA   
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        发布时间：2021-05-24
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