最新刊期
      卷 41 ， 期 11 ， 2018

        LOW ENERGY ACCELERATOR, RAY AND APPLICATIONS

      • Changwang YUAN,Aimin WANG,Zhiyong DAI
        Vol. 41, Issue 11, Article number: 110202(2018) DOI: 10.11889/j.0253-3219.2018.hjs.41.110202
        摘要：Background Spectral smoothing is the basis of qualitative and quantitative analysis in X-ray fluorescence (XRF) spectra. However, most of the current spectral smoothing methods require a large number of experiments to obtain prior knowledge. PurposeThis study aims to propose a novel method to automatically denoise XRF spectra. Methods Based on Fourier transform denoising, the optimal threshold is determined by cross validation to achieve automatic noise elimination. Results Simulation results show that the relative error between the optimal threshold determined by cross validation and the actual optimal threshold is less than 30% under different signal-to-noise ratios. Conclusion Proposed cross validation Fourier transform method has the advantages of convenience compared with wavelet threshold denoising method, and preserve higher precision than that of Savitzky-Golay polynomial filter method.  
        关键词：X-ray fluorescence spectrum;Fourier transform;Cross validation;Spectral smoothing method   
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        发布时间：2021-05-19
      • Honghua PENG,Chuanhuo TU,Shuai WANG,Qiang QIN,Guifeng ZHU,Zhenghua QIAN,Xueyang LIU,Liuqing SHI,Jun CAI,Yanbo QIAO
        Vol. 41, Issue 11, Article number: 110201(2018) DOI: 10.11889/j.0253-3219.2018.hjs.41.110201
        摘要：BackgroundRadioactive aerosols monitoring is required to protect workers for radiation safety, during the operation of the nuclear facility. Purpose This paper aims to study the measuring chamber of the radioactive aerosols continuous monitor. Methods The computational fluid dynamics (CFD) codes Fluent was applied for particle transport deposition of radioactive aerosol in the measuring chamber. The transportation and deposition of aerosol particles were simulated and analyzed by the discrete phase model (DPM). Transportation and deposition affected by the size, velocity and flow space of the particles were investigated. Results Under certain conditions, the larger the particle flow rate and the smaller the particle size, the higher penetration rate of the chamber to the filter papers for measurement can be obtained. Meanwhile, when the kinetic diameter of aerosol particles between 1~2 μm, the inlet flow rate between 1.85~3.18 m·s-1, the penetration rate of particles were about 80%~60%. ConclusionThe simulation results provide the reference and foundation for radioactive aerosol transportation and deposition, treatment and detection which related to the subsequent project.  
        关键词：Radioactive aerosol;Computational fluid mechanics;Transport and deposition simulation;Gas-solid multiphase flow   
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        发布时间：2021-05-19
      • Penghui LYU,Di YIN,Junhui YUE,Jianshe CAO,Shujun WEI,Qinghong LAN,Yaoyao DU,Fang LIU,Yanhua LU
        Vol. 41, Issue 11, Article number: 110203(2018) DOI: 10.11889/j.0253-3219.2018.hjs.41.110203
        摘要：Background When the beam goes through the high-frequency cavity and the vacuum chamber of the accelerator, the coupled-bunch instability caused by the high-order mode and the resistive wall will limit the threshold of the beam. Purpose This study aims to control the coupled-bunch instability by design of a longitudinal or transverse feedback system. Methods The accelerator digital feedback system was designed to filter the beam signal and make a 90° phase shift by using the finite impulse response (FIR) filter to finally obtain the feedback signal. The FIR filter can be designed by using the least square fitting method and the selective FIR filter method. The difference between the two methods was studied in the transverse and the longitudinal feedback system. After optimized the selective filter method, the operational reliability and filtering effect of the FIR filter designed by using the selective filter method are analyzed deeply. Results The results show that the selective filter method is more simple and better. Conclusions Proposed method can be referenced for designing FIR filter of the feedback system.  
        关键词：Transverse feedback;Longitudinal feedback;Finite impulse response filter;The least square fitting method;Selective FIR filter method   
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        发布时间：2021-05-19

        NUCLEAR ENERGY SCIENCE AND ENGINEERING

      • Yusheng LIU,Chao XU,Guoshun YOU,Jieru AN,Shaoxin ZHUANG
        Vol. 41, Issue 11, Article number: 110603(2018) DOI: 10.11889/j.0253-3219.2018.hjs.41.110603
        摘要：Background Station blackout (SBO) accidents increasingly become the focus of research in the field of nuclear safety after Japan's Fukushima nuclear plant accident. Core decay heat under SBO condition will be transferred by natural circulation (NC) occurring in passive systems for the nuclear plants incorporated passive safety design concept such as AP1000 or CAP1400. As a result, response of safety systems will differ in accident sequence and kind between passive safety plant and traditional plant. PurposeThis study aims to identify main thermal hydraulic phenomena of passive nuclear power plants (NPPs) during SBO accident. MethodsSBO accident progress and NC phenomena of AP1000 were investigated. The event sequence and stages were obtained as a result of Relap5 simulation with the nodalization model established according to design parameters. The sensitivity analysis for injection quantity of core makeup tank (CMT) and parameter deviation of in-containment refueling water storage tank (IRWST) were also conducted in the calculation. Results The results show that multiple NC phenomena occur in loop formed by core, steam generators, passive residual heat removal heat exchanger (PRHR HX), and CMTs under accident conditions. The whole SBO accident progress of passive NPPs can be divided into three periods, namely reactor coolant system (RCS) NC process, passive core cooling system NC process and long term cooling process, based on characteristics of heat sink and parametric variation. What is more, the natural circulation rate between core and PRHR HX, pressure of RCS are both significantly affected by the injection failure of one CMT and parameter deviation of IRWST. Conclusions The NC process between core and PRHR HX plays a vital role in removal of core decay heat. The multiple NC processes occurring in passive core cooling system NC process period are unique to passive NPPs and they are worthy of research in experimental verification and code development.  
        关键词：Station blackout;Natural circulation;Passive nuclear power plant;AP1000   
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        发布时间：2021-05-19
      • Jiazeng LI,Lifeng HAN,Danqing LI,Wenbo HUANG,Limei WU,Liyuan ZHANG,Ziwei LIANG,Huihao XIA
        Vol. 41, Issue 11, Article number: 110605(2018) DOI: 10.11889/j.0253-3219.2018.hjs.41.110605
        摘要：Background The present commercial system for safety monitoring can hardly meet the complex requirements of thorium molten salt reactor (TMSR) Nuclear Energy Project's laboratory safety to deal with wide geographical coverage, distinct environmental difference, various signals, various software interfaces, etc. Purpose This study aims to build a laboratory safety monitoring system which can fulfil these requirements. Methods A laboratory safety monitoring system was developed by using Node.js, experimental physics and industrial control system (EPICS) and Hikvision video acquisition system. A function to link videos with EPICS signals was implmented. It possesses distributed structure, network distribution, well scalability and optimum economical efficiency. Results Various signals such as toxic and harmful gases, temperature and smoke, etc. are monitoring in real-time, so as to ensure the system to run efficiently and stably. Conclusion This system can be referenced for the development of security monitoring system in large-scale institutions and enterprises.  
        关键词：Distributed laboratory safety monitoring;EPICS;Node.js;Real-time Web monitoring   
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        发布时间：2021-05-19
      • Guifeng ZHU,Rui YAN,Shihe YU,Honghua PENG,Xuzhong KANG,Pu YANG,Bo ZHOU,Yang ZOU
        Vol. 41, Issue 11, Article number: 110601(2018) DOI: 10.11889/j.0253-3219.2018.hjs.41.110601
        摘要：BackgroundThe location of shim rods is one important monitoring parameter of nuclear reactor, and the shift of shim rods will affect the core physical parameters. Purpose This study aims to calculate the location of shim rods varied with burnup time in thorium molten salt reactor with solid fuel (TMSR-SF1), and analyze its effect on the spatial distribution of power density, flux and burnup. Methods A reactivity search by adjusting shim rods is coupled to conventional Monte Carlo burnup code. It is validly shown that 3 times are mostly required to realize reactivity convergence. The location of shim rods with one group scheme in TMSR-SF1 is calculated. Results Results show that shim rods are sharply moved when near to the time of xenon equilibrium and end of life, while linear changed under middle burnup time. Shim rods at the beginning are located in the upper side of half rod route, which increases the axial unevenness of power density and flux. The power peak factor and maximum flux are 17% and 12% larger than those at the end of life. Conclusions This change of power peak factor and maximum flux are accepted and it is feasible to use one group scheme of shim rods in TMSR-SF1.  
        关键词：Burnup;Shim rods;TMSR-SF1   
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        发布时间：2021-05-19
      • Jiayi XU,Xubo MA,Yixue CHEN
        Vol. 41, Issue 11, Article number: 110604(2018) DOI: 10.11889/j.0253-3219.2018.hjs.41.110604
        摘要：BackgroundThe nuclear data is the fundamental input parameter of reactor physics computation and it is also one of the significant uncertainty sources to the result of nuclear physics calculation. Usually, the cross section is measured by the integral experiment. However, the cross section obtained from the experiment is always imprecise due to numerical approximation and model simply in the experiment. Purpose This study aims to evaluate the effect caused by relative factors of cross section consistence and different covariance library in the process of uncertainty analysis. Methods The home-developed code SUACL based on statistical sampling method was developed for the uncertainty analysis, and the Three Mile Island unit 1 (TMI-1) benchmark was taken to evaluate the impact of both the initial value of cross section and the various covariance matrices. Results It is found that the larger of the cross section value, the higher uncertainty caused by it in the same degree of perturbation. Therefore, it is better to use the practical initial value of cross section. The uncertainty of infinite effective multiplication factor would be different based on different evaluated neutron data library such as ENDF/B-Ⅶ.1, JENDL4.0 and JEFF3.2. For example, the uncertainty of 238U fission cross section based on JEFF3.2 is smaller four orders of magnitude than that of ENDF/B-Ⅶ.1 and JENDL4.0. Conclusion The appropriate covariance data and precise unperturbed initial value of cross section are critical to analysis uncertainty. Both of them have great impact on the uncertainty result.  
        关键词：Uncertainty analysis;Cross section;Covariance;Nuclear data   
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        发布时间：2021-05-19
      • Zhaowei MA,Hua LI,Wei LIU,Guimin LIU,Qin ZHANG,Guo YANG,Fei WEI
        Vol. 41, Issue 11, Article number: 110602(2018) DOI: 10.11889/j.0253-3219.2018.hjs.41.110602
        摘要：Background The Venturi-type bubble generator is adopted in molten salt reactor degassing system because of its advantages of simple structure and effective production of micro-sized bubbles. Purpose This study aims to investigate the motion and breakup characteristics of bubbles in the throat and expansion section of Venturi-type bubble generator. MethodsBased on the experimental water loop, high speed camera was employed to measure the movement of bubbles. The velocity distribution of bubbles in the throat and expansion section were analyzed, and compared with water velocity distribution without gas inlet. Results Bubble motion was divided into four stages:high-speed stable motion stage; rapid change stage; stable fluctuation stage; low-speed steady motion stage. With the increase of the gas inlet diameter, the fragmentation rate of the bubble decreases, and the stability of the bubble increases in the above four stages. As the water flow increases, the areas in the second and third stages will shrink to near x=0 mm. Conclusion The fragmentation of bubbles is related to the distribution of bubbles in the throat and expansion section of Venture-type bubble generator. The higher the velocity of the bubble changes, the greater the degree of fragmentation of the bubble, and the breakup process of bubbles occurs mainly in the second stage.  
        关键词：Bubble generator;Bubble motion;Velocity distribution;Bubble breakup   
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        发布时间：2021-05-19

        NUCLEAR PHYSICS, INTERDISCIPLINARY RESEARCH

      • Shima LIU,Min LYU,Liqiang LUO,Jingyang GUO,Lihua WANG,Chunhai FAN
        Vol. 41, Issue 11, Article number: 110504(2018) DOI: 10.11889/j.0253-3219.2018.hjs.41.110504
        摘要：Background Bacteria tends to form biofilm to adapt to the unfavorable living environment. Biofilm, a three-dimensional hydrogel-like compound, is composed of bacteria adhering to the substrate and its extracellular polymeric substance (EPS). Biofilm with gel-like structure has been widely used in industrial wastewater treatment, bioengineering and bio-battery. Purpose This study aims to simply and effectively regulate biofilm for practical applications. Methods Gram-positive bacteria (Bacillus subtilis) and -negative bacteria (Pseudomonas aeruginosa) were selected as model organisms to investigate the effect of different phase media (solid and liquid) on biofilm structure by rheological tests and scanning electron microscopy. Results The results showed the gel-like structure of biofilm depended on the medium phase. Compared to the liquid medium, biofilm cultured with solid medium possessed loose, thicker and stronger mechanical strength. Conclusions This study provides a simple method for regulating the structure and mechanical properties of biofilm, and also provides insight into the application of biofilm for adsorption of organic pollutants and the design of new biomaterials.  
        关键词：Medium phase;Biofilm;Microstructure;Mechanical property   
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        发布时间：2021-05-19
      • Mohan LIU,Wu LU,Jincheng JIA,Weilei SHI,Xin WANG,Xiaolong LI,Jing SUN,Qi GUO,Xue WU,Peijian ZHANG
        Vol. 41, Issue 11, Article number: 110502(2018) DOI: 10.11889/j.0253-3219.2018.hjs.41.110502
        摘要：Background As the state-of-the-art high speed bipolar complementary process, the high performance and speed analog integrated circuit making by double-polysilicon self-aligned (DPSA) technology has a wide application prospect in the extreme fields of space radio frequency (RF)/microwave communication. Purpose This study aims to investigate the response of high-and low-dose-rate irradiation on domestic double polysilicon self-aligned NPN transistors with different emitter sizes, analyze the dependence of emitter size on dose rate effect of DPSA NPN bipolar junction transistor (BJT). Methods The two different emitter size devices were irradiated to a maximum total ionizing dose level of 1 000 Gy(Si) under the high (0.5 Gy(Si)·s-1) and low (1×10-4 Gy(Si)·s-1) dose rate. The electrical parameters including Gummel characteristics and direct current gain of the devices were measured with Keithley 4200-SCS semiconductor parameter analyzer removed from the irradiation room within 20 min at room temperature before and after each specified value of accumulated dose. Results The NPN DPSA bipolar transistors have good resistance to ionizing radiation damage under high and low dose rate irradiation, and the low dose rate irradiation damage is greater than the high dose rate. Meanwhile, the smaller the perimeter area ratio of the emitter, the smaller the transistor degradation. Conclusions The DPSA NPN BJT has a great tolerance of the ionizing radiation for the application of the extreme radiation environment, and the smaller perimeter area ratio it has, the better the performance of the tolerance.  
        关键词：DPSA;NPN BJT;Emitter size;Dose rate effect   
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        发布时间：2021-05-19
      • Han XUE,Yugang MA,Hongwei WANG,Xiguang CAO,Zhendong AN,Gongtao FAN,Longxiang LIU,Haijuan FU,Yue ZHANG,Xinrong HU
        Vol. 41, Issue 11, Article number: 110503(2018) DOI: 10.11889/j.0253-3219.2018.hjs.41.110503
        摘要：Background The 151Eu neutron capture cross-section plays an important role in reactor physics and in the slow neutron capture of nuclear astrophysics. PurposeThis study aims to distinguish two isomers of 152Eu and measure neutron capture cross-section of 151Eu. MethodsThe 151Eu(n, γ) 152Eu reaction cross-sections at the neutron energies from 0.01 MeV to 20 MeV were calculated by using software TALYS-1.8 which is a mature computer code for simulating nuclear reactions in present work. The accuracy of simulation calculation program was verified and compared the theoretical data with the existing experimental data from EXFOR cross-section database and the latest neutron activation cross-section data. Results & Conclusions The results show that there is a large error in the cross-section measurement of the ground state and the first isomeric state due to the interference of the 121.78 keV energy level, whereas the theoretical values of the ground state and the second isomeric state are basically consistent with the existing experimental values.  
        关键词：TALYS-1.8;151Eu (n, γ)152Eu reaction;Cross-section   
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        发布时间：2021-05-19
      • Chenguang ZHANG,Heng AN,Shengsheng YANG,Yujun MIAO,Yuxiong XUE,Zhou CAO
        Vol. 41, Issue 11, Article number: 110501(2018) DOI: 10.11889/j.0253-3219.2018.hjs.41.110501
        摘要：Background Complementary Metal Oxide Semiconductor Active Pixel Sensor (CMOS APS) photoelectric device is widely used in satelite applications with radiation exposure. Purpose This study aims at the radiation effects of heavy ions on CMOS APS photoelectric devices and the sensitivity of single event effects. Methods The internal structure characteristics and radiation effect of CMOS APS were analyzed, and a test method based on the combination of monitoring data logic state and image "white point" was formed. Then, a single event effects simulation experiment was carried out using heavy ion accelerator. Results & Conclusion The results show that the pixel array is not disturbed when linear energy transition (LET) of heavy ion is below 9.01 MeV·cm2·mg-1, only the charge is accumulated in the pixel array. Heavy ion LET corresponding to single event upset (SEU) saturation cross section is 42.0 MeV·cm2·mg-1.  
        关键词：CMOS APS;Single event effects;Single event upset;Single event transient;Heavy ion   
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        发布时间：2021-05-19

        NUCLEAR ELECTRONICS AND INSTRUMENTATION

      • Yaqiu LI,Jiawei ZHU,Qiang SUN,Linsen YANG,Qin ZHAN,Baimao LEI
        Vol. 41, Issue 11, Article number: 110402(2018) DOI: 10.11889/j.0253-3219.2018.hjs.41.110402
        摘要：Background Neutron tube is the core component of a controllable neutron generator. There are still some gaps in reliability and stability between domestic products and foreign commercial products. Purpose This study aims to obtain the key factors which affect the reliability level of domestic neutron tube. Methods Taking certain type of pre-absorbing target sealed D-T neutron tube as the research object, a failure mode and effects analysis (FMEA) based on risk priority number (RPN) method was performed. A reliability analysis was carried out based on the results of FMEA. Results All possible failure modes as well as the cause, effect, occurrence probability and the harm extent of failure at different levels of neutron tube product were obtained. The key factors affecting the reliability level of domestic neutron tube were found out. Base on the analysis, some improvement measures in design are suggested. ConclusionThe reliability of ion sources and the target turns out to be the key factor of neutron tube's reliability. The abnormal ionization caused by cathode/anode short circuit and the loss of adsorptive helium gas capacity caused by target film oxidation are the most harmful failure modes for the neutron tube.  
        关键词：Neutron tube;Failure mode and effect analysis;Reliability analysis;Criticality analysis;Effect severity ranking   
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        发布时间：2021-05-19
      • Zaipeng XIE,Yukai DING,Jian LIANG,Yuan HE,Yongming LI
        Vol. 41, Issue 11, Article number: 110401(2018) DOI: 10.11889/j.0253-3219.2018.hjs.41.110401
        摘要：Background Arc discharge is one of the main issues of high power radio frequency (RF) cavities, which may affect the stable operation of the RF system and requires to be fast detected. Purpose This paper aims to design a diagnosis and warning system to detect the arc discharge in real-time. MethodsBased on open-source hardware and LabVIEW data acquisition software, this system was built and installed in the detector chamber inside the coupler. A redundant hardware design strategy was employed to improve the stability of the system. Results Experimental test results showed the response time was of tens of microseconds. Conclusion Design scheme and implementation proposed in this paper can be referenced for protecting high power microwave cavity.  
        关键词：High-power radio-frequency cavity;Arc discharge effect;Real-time detector;Open-source hardware;LabVIEW   
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      • Na MA,Zhiyong KE,Zhenqiang HE,Bo LI
        Vol. 41, Issue 11, Article number: 110403(2018) DOI: 10.11889/j.0253-3219.2018.hjs.41.110403
        摘要：Background The drift tube Linac (DTL) is the end of the China Spallation Neutron Source (CSNS) Linac segment and its collimation accuracy is directly related to the final performance of the Linac. Because of its long length, large number of the cavity and drift tube, and high alignment accuracy requirement, it is extremely difficult to meet requirement. Purpose This study aims to explore high precision collimation method for DTL of CSNS and analyze the accuracy of drift tube pre-alignment. Methods Accuracy is verified by external coincidence measurement, and the pre-alignment accuracy of the center hole and the end face of the drift tube in the DTL cavity can reach 0.035 mm. The long-span, full coverage of the comprehensive measurement methods and adjustment in the CSNS application are employed to achieve high precision measurement. Results Experimental results showed that the relative measurement accuracy in straight tunnel was 0.03 mm and 0.04 mm in ring tunnel. Conclusion A smooth calculation and adjustment method based on accelerator alignment proposed in this paper can be used to obtain the cavity's relative collimator precision of 0.08 mm and the drifting tubes' relative alignment accuracy of 0.03 mm, and thus the smooth adjustment between DTL cavities can be realized.  
        关键词：DTL overall measurement;Smooth calculation;Relative position accuracy   
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