最新刊期
      卷 40 ， 期 2 ， 2017

        SYNCHROTRON RADIATION TECHNOLOGY AND APPLICATIONS

      • Zhigang ZHANG,Yubin ZHAO,Kai XU,Xiang ZHENG,Zheng LI,Shenjie ZHAO,Qiang CHANG,Hongtao HOU,Jianfei LIU
        Vol. 40, Issue 2, Article number: 020101(2017) DOI: 10.11889/j.0253-3219.2017.hjs.40.020101
        摘要：Background:The most important processing is division in the algorithm for the field flatness controller on multi-cell cavity. The algorithm in conventional integer division uses multiple subtraction and shift methods to achieve the operation. A lot of clocks are consumed in the subtraction process, and the cycles consuming is not fixed on each cycle of the division. Purpose:This study aims to design a circular unrecoverable divider based on FPGA (Field-Programmable Gate Array). Methods:Improvement is taken for meliorating the program structure and optimizing the time sequences to achieve speedup of the division and same clock cycle for each conventional division. This algorithm is implemented on FPGA chip using QuartusII, simulated and verified by ModelSim toolkits. Results:The stability of field flatness is less than ±1.3% and 35 cycles for each algorithm when it applied in the controller of DLLRF (Digital Low Level Radio Frequency) for the booster of Shanghai Synchrotron Radiation Facility (SSRF). Conclusion:Control of field flatness based on FPGA for multi-cell cavity satisfies all functional requirements, overperforms the design expectations.  
        关键词：FPGA;Conventional;Divider;Field flatness control;Clock cycle   
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        发布时间：2021-05-19

        LOW ENERGY ACCELERATOR, RAY AND APPLICATIONS

      • Houjun HE,Xiaohui XU,Yongkai LU,Jianxin ZOU,Qiang WANG,Xingcai GUAN,Jiangtao ZHAO,Tieshan WANG
        Vol. 40, Issue 2, Article number: 020201(2017) DOI: 10.11889/j.0253-3219.2017.hjs.40.020201
        摘要：Background:Palladium is a very important hydrogen storage material with high hydrogen absorption capacity. It also plays an important role in the separation process of hydrogen isotopes. Purpose:The aim is to study the deposition behavior of deuterium ions in palladium. Methods:The dynamic and static concentration of deuterium in palladium was studied by means of D-D nuclear reaction induced by deuterium ion. These data were analyzed with a diffusion model. Results:The dynamic deuterium consists of free diffusing deuterium, unsteadily trapped deuterium and steadily trapped deuterium. The concentration of free diffusing deuterium and unsteadily trapped deuterium were increased with deuterium ion implantation, and then reached dynamic balance state when the deuterium was saturated, and would disappear quickly when the beam stopped. While the static deuterium concentration steadily trapped in defects were x=(0.42±0.03)%, due to defects caused by radiation damage reached saturation. Conclusion:The deposition behavior of hydrogen isotopes and its adsorption/desorption coefficient in Pd were closely related to the damage characteristics of materials and hydrogen isotope injection method.  
        关键词：Palladium foil;D-D nuclear reaction analysis;Deuterium concentration;Diffusion model   
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        发布时间：2021-05-19
      • Guangbo CAI,Liang YANG,Guqing GUO
        Vol. 40, Issue 2, Article number: 020202(2017) DOI: 10.11889/j.0253-3219.2017.hjs.40.020202
        摘要：Background:Molecular dynamic (MD) method has been widely used in simulation of particle radiation-induced micro-structure damage in materials. There is no nuclear database in MD simulation, thus, simplified processing is adopted in some initial conditions, such as primary knock-on atom (PKA) and structural model of the material. Purpose:This study aims to obtain the optimal initial conditions for MD to simulate the particle radiation-induced structural damage. Methods:GEANT4 software was applied for simulating neutron radiating Zr-based metals (Zr, Zr2Cu and Zr2Ni). The PKA spectra excited by incident neutrons were tracked and detected. Thereafter the PKA scattering angel distribution was calculated. Results:It is found that PKA energy in these three metals increases with the neutron energy, and exists a cut off value of dozens or hundreds keV. In addition, it is revealed that the PKA energy spectra in these three metals are very similar. The preferred scattering angles of PKAs were estimated. Conclusion:Damage of Zr-based metals caused by cascaded collision of PKAs with dozens or even hundreds of keV energies is significant for MD simulation. Some simplified structural models are suitable for approximating the radiation damage in alloys (such as Zr-based alloys and Fe-based alloys) via MD simulation, and estimated preferred scattering angles of PKAs is helpful for optimizing the moving direction of a PKA.  
        关键词：Structural damage;Neutron irradiation;MD;Particle transport;PKA;Nuclear materials   
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        发布时间：2021-05-19
      • Dapeng XU,Zeen YAO,Yongzhi YIN,Huyuan FENG
        Vol. 40, Issue 2, Article number: 020203(2017) DOI: 10.11889/j.0253-3219.2017.hjs.40.020203
        摘要：Background:The doses and biological effects of irradiated plants have been studied and reported widely. In the research, gamma-ray source and X-ray source was more often used than the neutron source. Although there were few studies on the plant of neutron radiation, but the research had increased in the past few years. Because neutron source is promising in such irradiation studies, it has many advantages such as strong biological effect, high mutation rate, wide variation spectrum and stable mutant. Purpose:This paper aims to explore neutron radiation biological effects of flax seed. The biological effects of different doses of neutron radiation are investigated. Methods:The dry seeds of Linum usitatissimum L. were irradiated by 252Cf fission neutrons. According to different neutron absorption doses, the biological effects of M1 and M2 generation on the morphological characters were studied during the growth period. Results:The results showed that, there were some correlations between the radiation biological effect and the neutron dose:the neutron radiation (0.24-4.33 Gy) had promotion on lateral bud growth of M1 and M2 generations of flax, and had the best promotion dose, moreover, the lower neutron dose (2.55 Gy and 4.33 Gy) had significant promotion on the plant height of M1 generation of flax. There were some differences between M1 and M2 generations of flax on the radiation biological effects:in 0.24-4.33 Gy neutron irradiation, the seedling emergence of M1 generation of flax can be promoted, however, the seedling emergence of M2 generation of flax can be inhibited during the growth stag. The plant height and the branching growth showed a similar promotion effect on M1 and M2 generations of flax, but the biological effect of M2 generation was less than that of M1 generation. Conclusion:After being irradiated by low neutron doses (0.24-4.33 Gy), M1 and M2 generations of flax show obvious biological effects. There are some certain correlations between the radiation biological effect and the neutron dose, for example the neutron absorbed dose being between 1.12 Gy and 4.33 Gy, flax appear obvious radiation biological effects during the seedling stage. The research results have positive significance for the agricultural production and breeding.  
        关键词：Biological effects;Linum usitatissimum L.;252Cf;Neutron absorption dose   
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        发布时间：2021-05-19

        NUCLEAR CHEMISTRY, RADIOCHEMISTRY, RADIOPHARMACEUTICALS AND NUCLEAR MEDICINE

      • Chenglie LIN,Jiang LI,Yi ZHOU,Yanhong SUN,Lihua WANG,Jun HU,Chunhai FAN
        Vol. 40, Issue 2, Article number: 020301(2017) DOI: 10.11889/j.0253-3219.2017.hjs.40.020501
        摘要：Background:Autophagy is a natural process in cells for self-digestion of intracellular elements, which is highly related to human health. Purpose:To better understand the relationship between autophagy and health issues like cancer, neurodegeneration and aging, we reviewed recent studies on this topic in this paper. We also reviewed some physical stimulations that have effects on health while have been verified capable to induce autophagy, including ionic radiation, physical exercise, acupuncture and massage. Results & Conclusion:We discussed the molecular mechanisms of their effects from the point of autophagy, and looked to the future of healthcare where the regulation of autophagy may be heavily involved.  
        关键词：Autophagy;Oncology;Neurodegeneration;Radiation;Acupuncture   
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        发布时间：2021-05-19

        NUCLEAR ELECTRONICS AND INSTRUMENTATION

      • Yeqiang XU,Weihong YUE
        Vol. 40, Issue 2, Article number: 020401(2017) DOI: 10.11889/j.0253-3219.2017.hjs.40.020401
        摘要：Background:Operation and decommissioning of nuclear facilities will produce radioactive waste, and different radionuclides in the waste will bring different hazards to the public and the environment. The waste would be sorted more reasonably by distinguishing different radionuclides. Yet it is still very difficult to measure directly the pure β radioactive waste in situ, though in situ γ-analytical-and α-waste-barrel measurement techniques have become more sophisticated. Purpose:The aim is to propose a scientific technique to sort the radioactive waste in situ. Methods:This study focused on the 90Sr-contaminated material in China Institute of Atomic Energy and optimized the design of the existing solid waste disposal facilities. Results:A novel technique to measure the radioactive waste 90Sr-90Y online was proposed, trying to sort the radioactive waste as optimally as possible to realize further separation of exemption waste. Conclusion:Theoretically, the exemption waste can be further sorted, and it can guide the design of radioactive waste disposal system.  
        关键词：Radioactive waste;β nuclides;90Sr;In situ measurement   
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        发布时间：2021-05-19
      • Yinyu LIU,Yudong WANG,Rong ZHOU,Chaowen YANG
        Vol. 40, Issue 2, Article number: 020402(2017) DOI: 10.11889/j.0253-3219.2017.hjs.40.020402
        摘要：BackgroundSince the 1990s, with the rapid development of various digital devices, nuclear signal digital processing has been widely used. PurposeTo enhance energy resolution of digital spectrum system of nuclear radiation measurement, appropriate filter and pulse shaping algorithm is necessary. Trapezoidal filter is widely used for its advantage of easy to use and narrow pulse width,etc. MethodsThe trapezoidal model and two kinds of trapezoidal filter algorithm based on simplified mathematical model of detector's output pulse signal are established. ResultsThe energy resolution of 137Cs spectrum has improved to 7.65% from 10.78%. ConclusionTrapezoid shaping is necessary in nuclear signal digital processing.  
        关键词：Digital spectroscopy;Pulse model;Trapezoidal shaping;FPGA implementation;Energy resolution   
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        发布时间：2021-05-19
      • Wei CHEN,Jianbin ZHOU,Fang FANG,Xu HONG,Ye LIN,Jie YU,Wei ZHOU,Yingjie MA
        Vol. 40, Issue 2, Article number: 020403(2017) DOI: 10.11889/j.0253-3219.2017.hjs.40.020403
        摘要：BackgroundIt is necessary to detect internal contamination when nuclear emergency events happened. PurposeThis study aims to develop an instrument to fast detect internal radiation contamination of large crowds. MethodsAn integrated machine capable of simultaneous detection of α and γ radiation was developed. Based on the digital energy spectrum processing technology, α-ray from nose swab is detected by using planar implanted passivated silicon (PIPS) whilst the NaI (Tl) detector is equipped to measure the γ-ray which deposits in lung of human body. ResultsThe experimental testing results show that the energy resolution of the instrument is 6.1% for 239Pu and 6.9% for 137Cs. The processing speed is no less than 10 persons per hour. ConclusionDetection speed and the energy resolution of proposed instrument satisfy the requirement of fast measuring internal radiation contamination of large crowds. It can provide reliable evidence for subsequent diagnosis.  
        关键词：Internal contamination;α-ray detection;γ-ray detection;Fast detection;Large crowds   
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        发布时间：2021-05-19
      • Hanping LI,Feng WANG,Xianyun AI
        Vol. 40, Issue 2, Article number: 020404(2017) DOI: 10.11889/j.0253-3219.2017.hjs.40.020404
        摘要：BackgroundIn gamma-ray imager, reconstruction algorithm directly affects the quality of the reconstructed image. The maximum likelihood expectation maximization (MLEM) iteration algorithm is widely used in modified uniformly redundant arrays (MURA) coded aperture for the reason of satisfactory performance of suppressing noise, improving signal noise ratio (SNR) and reducing distortion. But MLEM iteration algorithm also has shortcomings, like amplifies the noise with the increase of the iterative times. PurposeThis study aims to improve the ability of suppressing noise for MLEM iteration algorithm, and increase precision and resolution of coded aperture imaging system. MethodsBased on the de-noising method of complementary coded aperture, a correction factor α for MLEM algorithm modification is proposed to control the convergence rate of the complementary MLEM iteration algorithm. Both Monte Carlo simulation and experimental date are used to verify the effectiveness of the complementary MLEM iteration algorithm. ResultsThe results of Monte Carlo simulation and experiment prove the complementary MLEM iteration algorithm is efficient and practicable in coded aperture image. Its efficiency is related to the modifying factor α. The fitting formula of α-μt in the complementary MLEM iteration algorithm is α=-0.6+0.12421μt-0.01252(μt)2. ConclusionsThe coded aperture gamma camera is capable of imaging gamma-rays instantly. It can form radioactive 2D-map of different radionuclides. The reconstruction algorithm is important for coded aperture gamma camera. With the development of coded aperture, more and more study of algorithm modification will focus on it.  
        关键词：Coded aperture;Reconstruction of image;Suppress noise;MLEM;Monte Carlo simulation   
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        发布时间：2021-05-19

        NUCLEAR ENERGY SCIENCE AND ENGINEERING

      • Fengrui LIU,Jianping HUANG,Zhong LI,Naxiu WANG
        Vol. 40, Issue 2, Article number: 020601(2017) DOI: 10.11889/j.0253-3219.2017.hjs.40.020601
        摘要：BackgroundThe Pebble-bed Fluoride-salt-cooled High-temperature Reactor (PB-FHR) is one type of next generation IV nuclear power plants. It combines two existing technologies to create a new reactor option:graphite-matrix, coated-particle fuels developed for helium-cooled high-temperature reactors and liquid-fluoride-salt coolant used in molten salt reactors. To proceed thermal-hydraulic analysis of the core of PB-FHR such as online refuelling, randomly packed bed with different porosity is usually required firstly. PurposeIn this study, an efficient algorithm to produce randomly packed pebble bed with mono-sized spheres and variable packing factor in cylindrical containers is proposed. MethodsThe packing of the pebble bed is initially constructed by free falling of soft particles (Young's module much less than the real value) under the gravity environment using the discrete element method (DEM). During the free-falling process, different Young's modules and friction factors are used to control the overlaps of the packing. Then the packing expands with specific large Young's module and friction factor to eliminate the unrealistic large overlaps. In the expanding process, the time step is limited and the strategy of dissipating elastic energy is introduced to constrain the speed of expansion. ResultsLow friction factor in two processes tends to produce the dense packing or vice versa. The computational burden depends on the Young's module in the free-falling process significantly. ConclusionThrough adjusting the friction factor and the Young's module in the free-falling process and the friction factor in the expansion process, the packing algorithm can generate the pebble bed with wide range of porosity and higher computational efficiency.  
        关键词：PB-FHR;Pebble fuel;Packing algorithm;DEM   
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        发布时间：2021-05-19
      • Jianping JING,Bin JIA,Lei LEI,Jinsheng BI,Jiaxu ZUO,Yaning LIU,Chunming ZHANG,Dalin ZHANG
        Vol. 40, Issue 2, Article number: 020602(2017) DOI: 10.11889/j.0253-3219.2017.hjs.40.020602
        摘要：BackgroundThorium-based molten salt reactor nuclear power system project is one of the leading science and technology projects of Chinese Academy of Sciences, its strategic goal is to develop the fourth generation fission reactor nuclear power system. The core of solid fuel molten salt reactor is constructed of the random pileup of fuel graphite balls, which brings difficulties and uncertainties in the establishment of the pebble bed model for simulation analysis. PurposeThis study aims to analyze the influence of two modes of fuel ball arrangement on the core flow and heat transfer in the molten salt reactor, which are face centered cubic (FCC) and body centered cubic (BCC) arrangement mode. MethodsBased on the computational fluid dynamics (CFD) program, two computational models based on the FCC and BCC arrangement modes are established respectively. The re-normalization group (RNG) k-ε turbulence model is selected with constant velocity and temperature as the inlet boundary conditions and constant pressure as the outlet boundary condition whilst the gauge pressure is assumed to be zero. ResultsCompared to the BCC arrangement mode, the streamline under the FCC arrangement mode is more complex, the flow pressure drop is larger, the fuel ball surface temperature distribution is more uniform, and the hot spot temperature is lower. Under the FCC arrangement mode, the maximum temperature of the ball center is 1153 K, the total pressure drop is 1323 Pa; under the BCC arrangement mode, the maximum temperature of the ball center is 1155 K, the total pressure drop is 574 Pa. ConclusionThe streamlines under the FCC arrangement mode are periodically curved and the streamlines under the BCC arrangement mode are generally straight. Under FCC arrangement mode, the surface temperature distribution of a single intermediate fuel ball is more uniform and the hot spot temperature is lower, but the pressure drop from the bottom of the fuel ball to the top is larger than that of BCC arrangement mode.  
        关键词：Thorium Molten Salt Reactor-Solid Fuel (TMSR-SF);CFD;Arrangement mode;Flow and heat transfer   
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        发布时间：2021-05-19
      • Guangchao LI,Yang ZOU,Chenggang YU,Jianyou SUN,Jingen CHEN,Hongjie XU
        Vol. 40, Issue 2, Article number: 020603(2017) DOI: 10.11889/j.0253-3219.2017.hjs.40.020603
        摘要：BackgroundAs the only one of liquid fuel reactor among the six candidate reactors chosen by the Generation IV International Forum (GIF), Molten Salt Reactor (MSR) shows great potential for future nuclear energy and thorium usage, especially for Molten Salt Fast Reactor (MSFR) with characters of high Th-U Breeding Ratio (BR) and large negative Temperature Coefficient of Reactivity (TCR). PurposeTh-U breeding capacity of MSFR is expected to be further improved for more 233U production and shorter Double Time (DT), and burn-up analysis is necessary to demonstrate the breeding characters with time, as well as TCR for safety. MethodsBased on SCALE6.1, three aspects are explored including fertile in radial direction, newly added fertile in axial direction and appended graphite reflector, followed with explanations from the point of nuclide reaction rate. Furthermore, burn-up analysis is carried out with time by using the self-developed code Molten Salt Reactor Reprocessing Sequence (MSR-RS) specifically for on-line reprocessing of MSR. ResultsInitial BR of 1.17 is obtained when axial fertile is included, and about 50% of fertile salt is saved with graphite reflector. BR above 1.1 in equilibrium and DT of 36 a are achieved, and the production of 233U is about 133 kg·a-1, while TCR can be kept at about -6×10-5 K-1. ConclusionNewly added axial fertile improves the BR obviously, while about half inventory of thorium can be saved with graphite reflector. The self-developed module MSR-RS is suitable for simulating the reprocessing of MSR, and 233U production for the optimized geometry increases markedly while TCR is kept negative enough at all the running time for safety.  
        关键词：MSFR;Geometry optimization;Th-U fuel breeding   
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        发布时间：2021-05-19
      • Qi LIU,Kun XU,Mingzhun LEI,Yuntao SONG
        Vol. 40, Issue 2, Article number: 020604(2017) DOI: 10.11889/j.0253-3219.2017.hjs.40.020604
        摘要：BackgroundIn Tokamak experiment device, the 14-MeV high-energy neutrons which D-T fusion reaction releases may cause a series of problems such as material activation, high thermal loading and so on when they contact surrounding parts, so the relative neutronics calculation in the process of blanket design and optimization is particularly important. PurposeThis study aims to analyze the effect of point source, uniform source, neutron source based on L-mode, H-mode, A-mode respectively on different neutronics calculation. MethodsUsing MCNP (Monte Carlo N Particle Transport Code) program based on the Monte Carlo method the neutron transport process is simulated and the effect of different neutron source models is calculated. ResultsDifferent descriptions of neutron source models have less influence on tritium breeding ratio, but obvious effects on neutron wall loading and power density distribution. ConclusionTherefore, proper neutron source model should be applied to calculate different neutronics.  
        关键词：Monte Carlo;Neutron source;Tritium breeding ratio;Neutron wall loading;Power density   
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        发布时间：2021-05-19
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