最新刊期
      卷 45 ， 期 6 ， 2022

        SYNCHROTRON RADIATION TECHNOLOGY AND APPLICATIONS

      • “在同步辐射光束线领域，设计了双驱动四点滚柱压弯机构，通过有限元仿真分析，实现了高精度大尺寸光学镜面的非等力矩椭圆柱面压弯。”
        MA Tianyu,LU Qipeng,WANG Dazhuang,PENG Zhongqi,GONG Xuepeng,SONG Yuan
        Vol. 45, Issue 6, Article number: 060101(2022) DOI: 10.11889/j.0253-3219.2022.hjs.45.060101
        摘要：BackgroundIn order to meet the technical requirements of synchrotron radiation beamlines for related optical components, a double-drive four-point roller bending mechanism is designed.PurposeThis study aims to implement an unequal moment elliptical cylinder bending of high-precision large-size optical mirror through finite element analysis (FEA) simulation.MethodsFirst of all, a reflector with an external dimension of 1 200 mm×70 mm×50 mm was taken as the research object. Based on the object distance of 26.5 m, the image distance of 13 m and the grazing incidence angle of 2.8 mrad, the pressure applied to the bending moment was calculated according to the theoretical ellipse shape equation and the beam deformation bending moment equation. Then, the FEA software was employed to simulate and analyze the double-drive four-point bending mechanism. The focusing mirror was subjected to single-point compensation, double-point compensation, three-point compensation and four-point compensation in the presence of gravity compensation torque. Finally, the simulation compensation surface results obtained by FEA were compared with the theoretical calculation results.ResultsThe simulated application of unequal torque at both ends reduces the surface shape error from 0.81 µrad under single-point compensation to 0.075 µrad under four-point compensation, reducing 95.96% of the original error to the greatest extent. It can effectively reduce the elliptical bending surface shape error with theoretical value of 0.013 µrad, and the decreasing trend is gradually gentle.ConclusionsThis study indicates that the double drive compensated bending mechanism is feasible and effective to improve the bending accuracy of large-scale elliptical mirrors under multi-point compensation, and has important theoretical guiding role and significance for the bending technology of synchrotron radiation beamlines.  
        关键词：Bending mechanism;Elliptical cylinder;Finite element analysis;Surface error;Synchrotron radiation   
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        发布时间：2024-10-25
      • “上海软X射线自由电子激光升级改造，开发双环PI控制微波低电平系统，实现双束团模式运行，满足设计要求。”
        XU Yiming,ZHANG Junqiang,XIAO Chengcheng,FANG Wencheng
        Vol. 45, Issue 6, Article number: 060102(2022) DOI: 10.11889/j.0253-3219.2022.hjs.45.060102
        摘要：BackgroundShanghai Soft X-ray Free-electron Laser (SXFEL) is upgrading and requires to operate in double-bunch mode instead of original mode to transport uniform energy along the bunch chain.PurposeThis study aims to satisfy the requirement of double-bunch mode by designing and implementing low level radio frequency (LLRF) system to flatten the output of RF pulse compressor through amplitude modulation.MethodsBased on double PI-control loops, the LLRF control system was designed and implemented with one PI-feedback loop for keeping the long-term stability of amplitude and phase, and the additional operating-outside-LLRF PI-feedback loop for flattening the output pulse shape. Furthermore, an experimental setup, including the compressor, was built for the verification of the above method.ResultsThe 2-h continuous test results show that the double PI-control loops can flatten and keep the compressor output, and maintain the long-term stability of amplitude and phase within 0.09% and 0.1° (Root Mean Square, RMS) respectively. In addition, the algorithm can restore the flat-top output automatically when a large manual frequency offset occurs.ConclusionsThe double PI-control loop applied to the LLRF system preserves satisfactory static and dynamic behaviors, meeting the requirement of the SXFEL upgrade.  
        关键词：Low level radio frequency;RF pulse compressor;PI control;Amplitude modulation   
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        发布时间：2024-10-25

        ACCELERATOR, RAY TECHNOLOGY AND APPLICATIONS

      • “在多孔材料领域，研究人员利用正电子湮没谱学观察了SBA-15的热稳定性，发现煅烧后SBA-15表现出较好的热稳定性，电子偶素是一种非常灵敏的研究孔隙结构的探针。”
        LI Chongyang,WANG Feiyue,CHEN Zhiquan
        Vol. 45, Issue 6, Article number: 060201(2022) DOI: 10.11889/j.0253-3219.2022.hjs.45.060201
        摘要：BackgroundSince the 1990s, porous materials have been widely used in the fields of gas adsorption, electrochemistry, drug delivery, catalyst and catalyst carrier because of their excellent physical and chemical properties such as high specific surface area, high permeability, adsorption and assemblability. The application of porous materials largely depends on their macroscopic properties, especially the diversity of pore structure and the adjustability of pore size, especially, the thermal stability of SBA-15 is very important for its large-scale practical application.PurposeThis study aims to observe the thermal stability of SBA-15 by positron annihilation spectroscopy (PAS).MethodsFirst of all, ordered mesoporous silica SBA-15 were synthesized by using TEOS (tetraethyl orthosilicate) as the silicon source and P123 as the structure-directing agent. Part of the obtained SBA-15 was further calcined at 550 ℃. Then, the above two kinds of SBA-15 were heated at 100~1 000 ℃ to check the thermal stability of their pore structure. Small angle X-ray scattering (SAXS), scanning electron microscopy (SEM),high-resolution transmission electron microscopy (HRTEM), N2 adsorption/desorption and positron annihilation spectroscopy (PAS) measurements were used to study the ordered pore structure of SBA-15.ResultsPositron lifetime measurements reveal that four life components exist in both SBA-15 whilst the two longer lifetimes τ3 and τ4 correspond to the annihilation of o-Ps in the micropores and large pores of the material, respectively. With the increase of heat treatment temperature, the longest lifetime τ4 of these two kinds of synthesized silica decrease gradually, as well as the corresponding intensity I4. However, the longer life and intensity of calcined SBA-15 decrease obviously after 600 ℃. Meanwhile, the S parameter of calcined SBA-15 is in good agreement with the results of o-Ps lifetime, and the S-W curve also shows that the pore types of calcined SBA-15 nearly are unchanged during in the heat treatment process at the temperature range of 100~900 ℃.ConclusionsAll the results indicate that the synthesized SBA-15 calcined at 550 ℃ exhibits relatively better thermal stability, and positronium (Ps) is a very sensitive probe to study pore structure.  
        关键词：SBA-15;Pore structure;Positronium;Thermal stability   
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      • “在聚变反应堆中，涂层表面裂纹性能和基底粗糙度是影响涂层服役周期的关键因素。通过Abaqus模拟，分析了基底粗糙度和涂层表面裂纹之间的关系，为解决涂层服役问题提供解决方案。”
        LIU Ze,TANG Lin,SUN Fuchun,ZHANG Yafei,YU Songke,MU Xueling
        Vol. 45, Issue 6, Article number: 060202(2022) DOI: 10.11889/j.0253-3219.2022.hjs.45.060202
        摘要：BackgroundDuring the service period of the tritium barrier coating in the fusion reactor, the crack performance of the coating surface and the roughness of the substrate are the key factors restricting the service cycle of the coating.PurposeThis study aims to clarify the relationship between substrate roughness and coating surface cracks in SiC/316L stainless steel tritium barrier coating system.MethodBased on the Abaqus finite element software, SiC/316L stainless steel tritium penetration barrier system was established. Factors such as the strain energy release rate, amplitude of substrate and length position were investigated with emphasis on the relationship between substrate roughness and coating surface cracks.ResultsThe results show that the substrate roughness has a significant effect on the strain energy release rate of the coating surface cracks. When the crack is above the peak of the substrate, the strain energy release rate is the largest. When the crack is located directly above the valley, the strain energy release rate is the smallest. Compared with the smooth interface, the stress along the rough interface is suppressed, showing a decreasing trend.ConclusionsThis study reveals the influence of crack position on the driving force of crack growth.  
        关键词：SiC tritium penetration barrier;Multiple cracks on the surface;Strain energy release rate;Stress   
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        发布时间：2024-10-25
      • “最新研究显示，纳米稀土三氧化二钇/环氧树脂复合材料能有效屏蔽X/γ射线，有望替代传统含铅材料。”
        ZHENG Yulong,PAN Xinyi,XIONG Houhua,ZENG Zhengkui,DU Jifu,CHEN Zhiyuan
        Vol. 45, Issue 6, Article number: 060203(2022) DOI: 10.11889/j.0253-3219.2022.hjs.45.060203
        摘要：BackgroundTraditional shielding X/γ ray materials are generally lead or lead containing materials, which have the disadvantages of high toxicity, heavy weight, difficult molding and high price. Polymer composite materials are considered to be new materials that can effectively protect against nuclear radiation in the future. Epoxy resin (EP) as a base material has many advantages, such as corrosion resistance, good mechanical properties, strong wear resistance, excellent insulation, and stronger radiation resistance, while rare earth materials have a better shielding effect on γ-rays in the 20~88 keV energy region, and can make up for the weak absorption zone of lead.PurposeThis study aims to verify the shielding performance of nano Yttrium trioxide/epoxy resin composites (Y2O3/EP) against X/γ rays.MethodsFirst of all, Y2O3/epoxy resin radiation protection materials with different yttrium oxide contents were prepared by filling Y2O3 into EP. Then, the positron lifetime spectrum analysis combined with X-ray diffraction (XRD), scanning electron microscopy (SEM) and other methods were employed to study the microstructure of the material whilst the thermogravimetric analysis and differential scanning calorimeter (DSC) were applied to analyzing the thermal stability of the material, and Vickers hardness tester and universal tensile machine were used to test the mechanical properties of the material. Finally, the Monte Carlo N Particle Transport Code (MCNP) was applied to the simulation calculation of the radiation protection performance of the these samples.ResultsTesting results show that Y2O3 filled with epoxy resin can improve the thermal stability, hardness and Young's modulus of the composite material, but reduce the tensile strength. In the X/γ ray energy range of 20~1 332 keV, the shielding effect of 40% Y2O3/EP composite is 2%~10% of that of pure Pb under the same material thickness, and the shielding effect of 40% Y2O3/EP composite is 15%~66% of that of pure Pb under the same mass.ConclusionsAlthough the shielding effect of Y2O3/EP composite is worse than that of pure lead, it can meet the shielding requirements at X/γ low-energy radiation region with capability to replace lead or lead containing materials as radiation shielding materials.  
        关键词：Radiation protection;Composite materials;Shielding;Rare earth materials   
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        发布时间：2024-10-25

        NUCLEAR ELECTRONICS AND INSTRUMENTATION

      • “在辐射环境监测领域，专家利用峰总比不变性特点，建立了多能核素级联符合相加效应修正体系，为提高样品分析准确性提供解决方案。”
        ZHANG Lei
        Vol. 45, Issue 6, Article number: 060401(2022) DOI: 10.11889/j.0253-3219.2022.hjs.45.060401
        摘要：BackgroundIn the radiation environmental quality measurement or emergency measurement, one of the factors that influence the measurement results of γ spectrum activity is the cascade coincidence summing effect of multienergy nuclides.PurposeThis study aims to verify the accuracy of coincidence summing correction and analyze its influencing factors.Methods152Eu nuclide was taken as an example object, the peak-to-total fitting formula of the detector was obtained according to the invariance characteristics of peak-to-total ratio. Combined with the coincidence summing correction formula and the full energy peak efficiency formula, and the coincidence summing correction factors of 152Eu nuclide were calculated, and the Genie 2000 Monte Carlo program was used to correct 152Eu nuclide of the bulk samples.ResultsThe experimental results show that the relative deviation between the result and the true value is less than 6% of point source, and the relative deviation between the corrected results and the reference values is within ±4% of bulk samples. Through the linear relationship between the point source coincidence summing correction factor and the distance from the source to the detector, the minimum measurement distance with negligible coincidence summing effect can be obtained. The results of coincidence summing correction of bulk samples show that the higher the sample height is, the smaller the coincidence summing correction factor is.ConclusionsThe numerical correction method combining peak-to-total ratio invariance and decay scheme, which does not require measurement of the point source total efficiency at different locations. Compared with the Monte Carlo program method, this method does not require factory characterization of the detector, nor does the parameters of the bulk sample such as medium, density and shape after abandoning the energies with serious cascade coincidence, hence be used for the coincidence summing corrections of the environmental emergency samples. In the low energy part, the self-absorption effect has a great influence on the effective solid angle of the sample, so that affecting the coincidence summing correction factor of the sample.  
        关键词：Coincidence summing correction;γ spectrum;Peak-to-total ratio   
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      • “在空间辐射防护领域，科学家研发了一种新型能量拓展型长中子计数器，通过嵌入金属铅和铬材料，显著改善了高能响应，为辐射防护提供新方案。”
        LI Yanan,LI Taosheng,HONG Bing,GUO Haomin
        Vol. 45, Issue 6, Article number: 060402(2022) DOI: 10.11889/j.0253-3219.2022.hjs.45.060402
        摘要：BackgroundThe measurement of high-energy neutrons is becoming more and more important in the evaluation of dose caused by space neutrons and the radiation protection of particle accelerators.PurposeThe study aims to investigate the performance of an energy-extended neutron long counter.MethodsThe energy-extended neutron long counter was designed based on De Pangher type. The (n, xn) multiplication reaction between neutrons and metallic materials was utilized to improve the high-energy response of neutron long counter by adding metal chromium and lead materials into the moderator of the neutron long counter. Then, the structure of the neutron long counter was optimized by using Monte Carlo simulation to obtain the maximum value within the energy range of 1 keV~20 MeV and 1 keV~150 MeV, respectively. Finally, the effective center and energy response of the long neutron counter were measured by Am-Be neutron source and D-T neutron source in the standard radiation field.ResultsThe calculated response curve shows that the deviation of the maximum value from the average value is 12.2% in above energy range. The comparison between experimental results and the Monte Carlo simulation results shows that the theoretical calculation is consistent with the experiment within the error range.ConclusionThe upper energy limit of the long neutron counter can be extended by embedding metallic lead and chromium materials in the inner polyethylene layer of the long neutron counter.  
        关键词：Neutron long counter;Neutron multiplication;Energy extended;Fluence measurements   
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      • “在辐射环境监测领域，专家通过增加附加过滤，建立了不同能量的参考辐射质，为剂量仪表校准提供解决方案。”
        LI Mengyu,ZHAO Rui,QU Bingbing,LU Pingzhou,SONG Fei,LI Yunfei,FU Lin,WU Jinjie
        Vol. 45, Issue 6, Article number: 060403(2022) DOI: 10.11889/j.0253-3219.2022.hjs.45.060403
        摘要：BackgroundCalibration is an important way to assess the performance of radiation monitoring instruments and to ensure their accuracy and reliability for measurement.PurposeThis study aims to solve the traceability problem of dose meters at low dose rate.MethodsFirst of all, reference radiation masses of 55 kV, 70 kV, 100 kV, 170 kV, 240 kV were established and their energy spectra were measured by adding additional filtering to the X-ray radiation field. Then, the energy spectrum of each radiative mass was simulated by the EGS (Electron Gamma Shower) program to obtain the radiative mass half-value layer and the average energy. Finally, the kerma rate at the reference point was measured by using a large volume spherical ionization chamber, followed by calibration of conventional radiation environmental monitoring instruments.Results & ConclusionsThe results showed that the relative deviation between the simulated energy spectra and measured spectra does not exceed 1.6% and the dose rate decreases with more additional filtration. The established dose rates for the radiation masses ranged from 606 nGy·h-1 to 4 451 nGy·h-1 the uncertainty is 6.0% (k=2). The uncertainty of the calibration measurement results of the high-pressure ionization chamber 6150AD dose rate meter is 7.0% (k=2).  
        关键词：Low dose rate;X-ray;Energy spectrum simulation;Calibration factor;Uncertainty   
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        NUCLEAR PHYSICS, INTERDISCIPLINARY RESEARCH

      • “在中子源强度测量领域，专家采用模拟方法研究锰浴测量装置参数，建立了测量基准装置，为装置建立提供参考。”
        YANG Junkai,ZHANG Jian,WANG Pingquan,ZHANG Hui,ZHANG Yanan
        Vol. 45, Issue 6, Article number: 060501(2022) DOI: 10.11889/j.0253-3219.2022.hjs.45.060501
        摘要：BackgroundMn bath method is one of the most commonly used methods to measure the intensity of radionuclide neutron sources in the world.PurposeThis study aims to guarantee the accuracy of numerical transmission and give a reasonable parameter range during the design of manganese bath device.MethodsFirst of all, Monte Carlo N–Particle Transport Code System (MCNP) was employed to calculate the correction factors, solution concentrations and Mn-bath sphere. Then, a reference device of Mn bath measurement was setup according to the MCNP calculation results, and applied to the measurement of 12 neutron sources located in the standard of thermal neutron fluence rate with International Comparison of neutron sources.ResultsSimulation results show higher ratio of total neutron absorption and manganese neutron capture is obtained when the solution concentration is 17.3%~38.6% in which the uncertainty of neutron-escaping and section ratio is reduced, and the radius of Mn-bath sphere is 45~60 cm in which the volume specific activity of solution is increased and neutron-escaping is decreased. When the number of input particles is up to 100 000, the values of correction factors remain stable, hence the statistical fluctuation can be ignored. The international comparison of neutron sources for the measurement of 12 neutron sources indicates consistent results with the reference values within the uncertainty range.ConclusionsThe parameters range of this study provides an effective reference for the establishment of Mn bath device in the future.  
        关键词：Mn bath method;Monte Carlo simulation;Solution concentration;Radius;Parameters   
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        NUCLEAR ENERGY SCIENCE AND ENGINEERING

      • “中国发布最新核数据库CENDL-3.2，大幅提高数据种类和质量，验证了Be数据可靠性，为熔盐堆设计提供支持。”
        WU Jun,LIU Shichang,CHEN Yixue
        Vol. 45, Issue 6, Article number: 060601(2022) DOI: 10.11889/j.0253-3219.2022.hjs.45.060601
        摘要：BackgroundCENDL-3.2 was released in June 2020. Compared with CENDL-3.1, data type and quality has been greatly improved in CENDL-3.2,and most important isotopes including 235U, 238U, 239Pu, 56Fe and others have been re-evaluated and supplemented. Due to its large scattering cross section and small absorption cross section, Be is often used as one of the fuel carrier salt components of molten salt reactor (MSR). The accuracy of reaction cross section data of Be in MSR design cannot be ignored.PurposeThis study aims to examine and analyze the adaptability of the cross section data of Be in CENDL-3.2 to the calculation of MSR problems by the discrete-ordinate method.MethodsBased on CENDL-3.2,the MATXS format multi-group cross section library of 199 neutron groups and 42 photon groups was generated by NJOY, and 35 fast critical benchmarks were selected for its inspection and analysis. Then, results were compared with those of multi-group cross section library based on ENDF/B-7.1 and JENDL-4.0.ResultsThe deviation between the calculated results of the multi-group cross section library based on CENDL-3.2 and the experimental values is less than 0.5% in 26 benchmark cases which is 74.29% of total, outperform those of ENDF/B-7.1 and JENDL-4.0.ConclusionsThe results of this study indicate that the data of Be and the multi-group cross section library based on CENDL-3.2 and its processing method are reliable and can be used in the design of molten salt reactor.  
        关键词：CENDL-3.2;Multi-group cross section library;Be;Fast critical benchmark   
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      • “在核反应堆领域，研究人员模拟了锆合金表面污垢形成过程，研究了镍铁对污垢形成及硼析出的影响。结果表明，铁比镍更易沉积，形成的污垢为尖晶石结构，镍铁比升高会造成硼析出。”
        MENG Shuqi,HU Yisong,RUAN Tianming
        Vol. 45, Issue 6, Article number: 060602(2022) DOI: 10.11889/j.0253-3219.2022.hjs.45.060602
        摘要：BackgroundCorrosion products will deposit on the surfaces of PWR (pressurized water reactor) zirconium alloy to form CRUD (chalk rivers unidentified deposit), the precipitated boron will cause axial power distribution anomaly and affect the core safety.PurposeThis study aims to investigate the impact of nickel and iron on PWR zirconium alloy surface CRUD formation and boron precipitation using an artificial CRUD experiment setup.MethodThe experimental loop of high temperature and high pressure hydrodynamic circulation was utilized to carry out simulation study of CRUD formation and boron precipitation. The impact mechanism of nickel and iron on CRUD formation and boron was analyzed by X-ray photoelectric spectroscopy (XPS) and scanning electric microscope (SEM) methods. The measurement data were obtained by adjusting the injection sequence of nickel-iron and DH (dissolved hydrogen) concentrations.ResultsExperimental results show that maximum CRUD thickness are 5 μm and 15 μm, respectively, under 40 cm3·kg-1 and 0 cm3·kg-1 DH concentrations; boron mole fraction inside CRUD are 19.8%, 4.5% and 0.3%, respectively, corresponding to 1.06, 0.48 and 0.11 of nickel-iron ratios. The morphology of deposited iron is spinel whilst the morphology of the mixed nickel-iron deposit is porous.ConclusionsThese results indicate that iron is easier to deposit on the clean zirconium alloy surface, and the iron can enhance the deposition of nickel. Elevating the CRUD nickel-iron ratio could cause the boron precipitation while the relatively low nickel-iron ratio has little impact on boron precipitation.  
        关键词：PWR;Zirconium alloy;CRUD;Boron precipitation;Nickel-iron ratios   
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      • “在钍基熔盐堆领域，专家开发了基于Qt的熔盐泵试验台架控制系统，实现了3D模型显示和设备控制，为熔盐泵应用提供解决方案。”
        YU Jiali,CHEN Yongzhong,HAN Lifeng
        Vol. 45, Issue 6, Article number: 060603(2022) DOI: 10.11889/j.0253-3219.2022.hjs.45.060603
        摘要：BackgroundA low-flow high-temperature molten salt pump is developed for the thorium-based molten salt reactor (TMSR) nuclear energy project launched in 2012. Before the low-flow high-temperature molten salt pump is applied to the molten salt reactor, a large amount of experimental data is required.PurposeThis study aims to develop 3D interface of molten salt pump experiment platform control system to monitor the real-time data generated by the system.MethodsFirst of all, the Blender opensource software was used to draw the 3D model of this control system, then, Qt Creator was employed to load the model and develop the control system interface, and "sqlite" was applied to the storage of the real-time data generated by the system. Finally, experimental tests were conducted to verify its performance.ResultsExperimental results show that the display of 3D models and real-time data are achieved in the monitoring system, so do the 3D model rotation and scaling. Functionalities such as the valve switch state control, the user operation behavior and historical data recording, over-threshold alarm, etc. are realized with stability and flexibility.ConclusionsThis new technology of Qt and 3D can be applied to the development of the molten salt pump control system in the future.  
        关键词：Molten salt pump experimental platform;3D model;Experimental physics and industrial control system;Qt Creator   
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      • “新型熔盐快堆堆芯优化，提高中子经济性和安全性，实现高效99Mo同位素生产。”
        LIU Xiaolin,ZHOU Bo,ZOU Yang,YAN Rui,XU Hongjie,CHEN Liang
        Vol. 45, Issue 6, Article number: 060604(2022) DOI: 10.11889/j.0253-3219.2022.hjs.45.060604
        摘要：Background99Mo has important applications in nuclear medicine field. It can be produced in a 235U fission reactor with high yield and specific activity.PurposeThis study aims to optimize the core parameters of new type molten salt fast reactor, and then analyze the production of 99Mo based on the optimized core.MethodsThe Standardized Computer Analyses for Licensing Evaluation Version 6.1 (SCALE6.1) was used to perform the critical calculations, by analyzing the influence of geometry parameters on keff (effective proliferation factor) and temperature coefficient of reactivity, the geometry parameters of the core were determined, and then the extraction position of fuel target in the production of 99Mo was determined by analyzing the neutron energy spectrum and mean microscopic fission cross sections of 235U. Finally, the output of 99Mo in fuel target was calculated.ResultsThe results show that the keff can be increased while the coolant temperature coefficient be decreased by increasing the radius of fuel element and reducing the radius of fuel cell appropriately. When the fuel element container wall thickness is 0.1 cm, fuel element radius is 3.5 cm, fuel cell radius is 5 cm, active area radius and reflector thickness are 63 cm and 100 cm respectively, the operating life of core reaches 32 months and the temperature coefficient of reactivity is -1.615×10-5 K-1, which ensure the inherent safety of reactor core. Selecting the outermost fuel element as the fuel target for 99Mo production can increase the yield of 99Mo. The 99Mo annual output exceeds 6.25×1016 Bq and specific activity exceeds 2.77×1015 Bq∙g-1 when the extraction cycle of fuel target is 7 days.ConclusionsTherefore, the high yield and purity of 99Mo can be obtained by producing 99Mo in the new type molten salt fast reactor.  
        关键词：New type molten salt fast reactor;99Mo radioisotope;Reactivity temperature coefficient   
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      • “氦氙冷却反应堆采用一体化布雷顿循环系统，小型化、轻量化优势明显。专家分析了其严重事故频率，为核电源PSA分析提供参考。”
        WU Jianhui,ZHOU Jun,ZOU Chunyan,JIA Guobin,ZHANG Ao,CAI Xiangzhou,CHEN Jingen
        Vol. 45, Issue 6, Article number: 060605(2022) DOI: 10.11889/j.0253-3219.2022.hjs.45.060605
        摘要：BackgroundHelium-xenon gas cooled nuclear reactor adopts helium-xenon gas as the coolant and is able to apply the integral Brayton cycle. It has advantages in miniaturization and lightweight design, which has attracted more and more attention worldwide. But rare severe accidents studies have been carried out for the small helium-xenon gas cooled reactor. Probabilistic safety assessment (PSA) is an important method to evaluate the safety of a reactor system. The results obtained by PSA can provide a valuable basis for improving the core design, identifying fault, guiding operation, etc. whilst the occurrence frequency of initial events is required for PSA analysis.PurposeThis paper aims to evaluate the accident occurrence frequency for the small helium-xenon gas cooled reactor to provide an input for PSA analysis.MethodsBased on the main technical characteristics of a small innovation helium-xenon cooled mobile nuclear power system (SIMONS), the occurrence frequency of typical accidents was analyzed by referring to the operational experiences and data of high temperature gas cooled reactor (HTGR) and light water reactor (LWR). Intensity analyses were performed on the frequency of accidents such as increase or decrease of core heat removal, abnormal reactivity and power distribution, pipe break and abnormal equipment leakage, anticipated transient without scram (ATWS), and loss of offsite power (LOOP).ResultsThe calculation results show that the accidents of heat removal increase and decrease, abnormal reactivity and power distribution, pipe break and abnormal equipment leakage, ATWS, and LOOP have an occurrence frequency of 3.90×10-2 RY-1, 2.36×10-1 RY-1, 2.69×10-2 RY-1, 6.50×10-2 RY-1, 2.69×10-2 RY-1 and 4.60×10-2 RY-1, respectively.ConclusionsThe calculated results can be taken as the inputs for the PSA study of the SIMONS, providing basic reference value for further PSA analysis of mobile nuclear power system.  
        关键词：Small helium-xenon cooled reactor;Probabilistic safety assessment;Fault tree   
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        发布时间：2024-10-25
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