最新刊期
      卷 41 ， 期 10 ， 2018

        NUCLEAR ENERGY SCIENCE AND ENGINEERING

      • Zhen HOU,Chuangxiong CAI,Yapeng ZHANG,Qun YANG,Zhaozhong HE,Kun CHEN
        Vol. 41, Issue 10, Article number: 100603(2018) DOI: 10.11889/j.0253-3219.2018.hjs.41.100603
        摘要：Background The application of passive safety systems can contribute to security and possibly reduce spending target of new nuclear power plant designs. Analysis methods and design must be employed to ensure that the systems perform their intended functions. Purpose This study aims to analyze the natural circulation of air inside the air cooling channel of molten salt-air heat exchanger in the nitrate natural circulation loop (NNCL). Methods Numerical simulation was employed to study the heat transfer performance by the FLUNT6.3 software. Both the air velocity field and distribution of temperature field were studied to analyze the characteristics of flow fields inside the air-cooled channel of molten salt-air heat exchanger. Results The distribution graph of velocity field and temperature field under various operating conditions was made into charts and graphics. The transient distribution variation rules of different sections are obtained. The results are approximately consistent with the record summarized by optical fiber measurement. Conclusions The results show that the molten salt-air heat exchanger of air cooling channel can form good natural circulation and take away the heat. It provides a theoretical basis for the operation and transformation of the air-cooled channel.  
        关键词：NNCL;Chimney;Natural circulation;Computational fluid dynamics   
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        发布时间：2021-05-19
      • Zhen CAO,Kemei CAO,Jiayun WANG
        Vol. 41, Issue 10, Article number: 100605(2018) DOI: 10.11889/j.0253-3219.2018.hjs.41.100605
        摘要：Background Uncertainty exists in melt pool parameters when postulated severe accident occurs in reactor, and heat flux distribution obtained by two-layer or three-layer melt pool configuration would vary from each other, hence it is necessary to analyze the uncertainty of in vessel retention (IVR) in different configurations. Purpose This study aims to investigate quantization uncertainty brought by three-layer configuration. Methods First of all, the self-developed code SPIRE was employed to verify with references and analyze the uncertainty of IVR in three-layer melt pool configuration based on core damage frequency (CDF). The input parameters were obtained according to the simulation results of accident scenarios. Then the three-layer melt pool configuration results were compared with that of two-layer melt pool configuration. Finally, uncertainty analysis was carried out based on Monte Carlo sampling and sensitive analysis. Result Compared with the two-layer melt pool configuration results, the safety margin at bottom of melt was decreased notably whilst safety margin at top of ceramic layer was increased. In 125 000 cases generated by sampling, conditional failure probability in two-layer condition is 0, while in three-layer condition is 7.11×10-5 (failure occurred in light metallic layer). Conclusion Sensitivity analysis showed that, within the scope of this study, the probability distribution for input parameters had little influence on the result; conditional failure probability was notably affected by the uranium oxidation fraction; melt fraction of core had certainty influence on safety margin at top of ceramic layer.  
        关键词：In vessel retention;Uncertainty analysis;Monte Carlo sampling   
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        发布时间：2021-05-19
      • Yongsong ZHAO,Haitao FANG,Xilin ZHANG,Xingbin ZHOU,Qin ZENG,Hongli CHEN
        Vol. 41, Issue 10, Article number: 100606(2018) DOI: 10.11889/j.0253-3219.2018.hjs.41.100606
        摘要：Background The Lead-cooled fast reactor (LFR) features high operation temperature, low-pressure and chemically inert liquid lead with good thermodynamic properties as coolant, hence it has an irreplaceable advantage in production of electricity and consuming actinides from spent pressurized water reactor (PWR) fuel. Purpose This study aims to explore preliminary design on core physics of the 1 000 MW (thermo) medium-size modular lead-cooled fast reactor (M2LFR-1000) proposed by University of Science and Technology of China (USTC). Methods After obtaining the atom density of the nuclides at different burn-up levels by using SRAC/COREBN code, the Monte Carlo code MCNP (Monte Carlo N Particle Transport Code) was employed to conduct the preliminary neutronic design of the core and burn-up analysis. Results The results of calculations cover the core power distribution, reactivity coefficient, neutron kinetic parameters, control rod worth and core lifetime. Especially, the capability of M2LFR-1000 core to transmute minor actinides was evaluated. Conclusions Results show that the M2LFR-1000 core scheme is reasonable, satisfies the design requirements and has excellent capability to transmute Minor Actinides.  
        关键词：Lead-cooled fast Reactor;Core physics;Transmute;Minor actinides   
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        发布时间：2021-05-19
      • Lailai QIN,Zhenghai XIA,Shaozhong GU,Yuhua MA,Ke DENG,Jiayu LIU,Zhaowei MA,Qin ZHANG,Guo YANG,Fei WEI,Shengwei WU,Guangliang BAO,Guimin LIU,Wei LIU
        Vol. 41, Issue 10, Article number: 100604(2018) DOI: 10.11889/j.0253-3219.2018.hjs.41.100604
        摘要：Background Tritium in the atmosphere exists mainly as tritiated water (HTO), tritiated hydrogen (HT) and tritiated methane (CH3T). Radiation hazard of tritium is related to its chemical form. Atmospheric tritium in these three chemical forms should be measured simultaneously in the vicinity of nuclear facilities. Purpose This study aims to evaluate the level of atmospheric tritium in these three chemical forms accurately. Methods Based on the principle of high temperature catalytic oxidation and low temperature cold trap collection, a novel atmospheric tritium sampling system and measurement method were developed. Catalytic efficiencies for hydrogen and methane at different temperatures were measured. Concentrations of hydrogen and methane that needed were evaluated. And the concentrations of atmospheric tritium in the vicinity of Qinshan nuclear power plant (QNPP) were preliminary measured. Results Catalytic efficiencies for hydrogen and methane by using self-developed atmospheric sampling system could up to be about 99%, and water vapor collecting efficiency could be more than 95%. The concentrations of atmospheric tritium in the vicinity of QNPP, displayed in a decreasing order, were HTO, CH3T and HT. Conclusion The novel atmospheric tritium sampling system had the ability to collect HTO, HT and CH3T simultaneously. Atmospheric tritium in forms of HTO, HT and CH3T were firstly measured in the vicinity of QNPP. The concentrations of HT and CH3T measured were comparable to the background levels, which indicated that the sampling system and measurement method in this paper had a very high sensitivity and could be applied to atmospheric tritium sampling within environmental levels in different forms.  
        关键词：Tritiated water (HTO);Tritiated hydrogen (HT);Tritiated methane (CH3T);Atmospheric tritium sampling system   
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        发布时间：2021-05-19
      • Hongkang MIAO,Yushuang CHEN,Liushuai LYU,Naxiu WANG
        Vol. 41, Issue 10, Article number: 100601(2018) DOI: 10.11889/j.0253-3219.2018.hjs.41.100601
        摘要：Background The molten-salt heat exchanger is an important part of thorium molten salt reactor with liquid fuel (TMSR-LF1) integrated simulation platform, and its thermohydraulic performace is critical to the safety in operation. Furthermore, there are many problems in traditional shell and tube heat exchangers. It is very important to develop new heat exchanger. Purpose This study aims to redesign heat exchange fins to improve the compactness and thermohydraulic performance of molten salt heat exchanger by numerical simulation. Methods Simulation software FLUENT was employed to design and improve different fin types, and the numerical results of each type were compared and analyzed from three aspects:pressure drop, heat transfer coefficient and comprehensive performance index. The numerical simulation under the condition of water is carried out, and the results are compared with those of molten salt. Results Compared with the traditional rectangular fins, the heat transfer coefficient of streamline fin in molten salt is increased from 3.6% to 6.7%, the comprehensive performance index is increased by 2% on average, the overall compactness is enhanced, and the heat transfer capacity is greatly improved at high velocity. The improved streamline fin has a minimum pressure drop of 6.2% and 12% lower than that of the rectangular fin and the streamline fin, respectively. The comprehensive performance index of each fin was greatly improved under the water condition, but the streamline fin was no longer superior to the traditional rectangular fin in the water phase. Conclusion It reflects the unique applicability of streamline fin type in molten salt medium.  
        关键词：Plate fin heat exchanger;Type design;Numerical simulation;Heat transfer performance evaluation   
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        发布时间：2021-05-19
      • Yunpeng HE,Yuanxia LAO,Sen SUN,Wenxiao NIU,Nan QIU,Yuan WANG
        Vol. 41, Issue 10, Article number: 100602(2018) DOI: 10.11889/j.0253-3219.2018.hjs.41.100602
        摘要：Background Currently, high entropy alloys (HEAs) have attracted increasing interest as structural materials for the development of fusion and Generation-fission reactors due to their high strength and ductility Ⅳ improved fracture toughness, retarded energy dissipation, and suppressed damage accumulation. The accumulation of helium may result in degradation of structural material properties, and affecting the service and safety of the reactor. Purpose This study aims to investigate the responses of CuAlTiWV high entropy alloy thin films to helium induced and annealing. Methods Helium atoms were introduced in CuAlTiWV high entropy alloy thin films by magnetron sputtering in He/Ar mixed atmosphere. The microstructure and phase composition of the films were characterized by field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD) respectively. The bond strength and failure mode of the films were confirmed by scratch adhesion test and FESEM. Results The microstructure of the CuAlTiWV high entropy alloys without helium infusion and annealing possesses body centered cubic phase and intermetallic compound phase with nano-sized particles diffusely distributed in the amorphous phase matrix. The phase structure of the CuAlTiWV high entropy allay remains stable with helium introduced and annealing whilst helium may change the microstructure and morphology of the films, hence reduce the adhesion properties and modify the failure pattern in scratch test. Conclusion This study provides a useful reference for further evaluation of the radiation resistance properties of HEAs and research of HEAs as structural materials for new generation fusion reactors.  
        关键词：High entropy alloys;Helium;Phase structure;Annealing;Failure pattern   
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        发布时间：2021-05-19

        NUCLEAR ELECTRONICS AND INSTRUMENTATION

      • Huaiqiang ZHANG,Weihuang LU,Bin TANG
        Vol. 41, Issue 10, Article number: 100401(2018) DOI: 10.11889/j.0253-3219.2018.hjs.41.100401
        摘要：Background The noise suppression, pile-up identification and amplitude extraction of the pulse signal are affected by the choice of digital shaping method and parameters in the digital nuclear spectrometer system, which directly affect the system's energy resolution and maximum pulse count rate. Purpose We developed a digital signal processing platform based on MATLAB to build multiple digital shaping algorithm verification platforms and implement nuclear pulse signal processing. Methods The simulation nuclear signals and the sampled signals can be achieved separately to Gaussian, trapezoidal and triangular shapes in different digital shaping methods and different shaping parameters, and then completed pile-up identification, baseline estimation and amplitude extraction. Results The γ-ray energy spectrum of 137Cs (NaI detector) and X-ray energy spectrum of Fe source (Si-PIN detector) are obtained respectively in different digital shaping methods and different shaping parameters. Conclusion The digital gaussian shaping shows better energy resolution characteristics, triangular shaping shows better maximum pulse count rate characteristics, and trapezoidal shaping shows better overall characteristics. Trapezoidal shaping is used to obtain the 137Cs energy spectrum and the Gaussian shaping is used to obtain the Fe energy spectrum, which shows that as the shaping parameters increase, the energy resolution is better and the maximum pulse count rate is lower.  
        关键词：Nuclear pulse signal;Digital shaping;MATLAB;Energy resolution   
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        发布时间：2021-05-19

        LOW ENERGY ACCELERATOR, RAY AND APPLICATIONS

      • Weichong NI,Wenjun CAI,Guolin GAO
        Vol. 41, Issue 10, Article number: 100202(2018) DOI: 10.11889/j.0253-3219.2018.hjs.41.100202
        摘要：Background The detection limit of manmade radionuclide in airborne monitoring is an important specification to measure detectable ability of airborne monitoring for nuclear and/or radiation. Purpose This study aims to find effect factors of detection limits of manmade radionuclide in airborne monitoring. Methods Based on the airborne monitoring data for the airborne monitoring system with NaI(Tl) detectors of the large volume (downward-looking for 50 341 cm3/upward-looking for 12 585 cm3), Y-12 and Y-5 model wing-fixed aircraft, different altitude, and areas with the different radiation background levels, research diversification of detection limit of manmade radionuclide 137Cs and 60Co. Results Detection limits of manmade radionuclides decrease with the reducing of airborne altitude and flight speed. On the same airborne altitude, detection limits are corresponding to largen with the raise of radiation background level. Detection limits of manmade radionuclides are of the minimum on the waters. Detection limits are opposite to largen with the reducing of gamma-ray energy of manmade radionuclides. Conclusion Research provides important basis on how to control factors effectively and reduce detection limits of manmade radionuclides.  
        关键词：Airborne monitoring for nuclear and/or radiation;NaI(Tl) detectors;Airborne gamma ray spectrometer;137Cs;60Co;Detection limit   
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        发布时间：2021-05-19
      • Zesong WANG,Rui ZHANG,Canxin TIAN,Zhenguo WANG,Dejun FU
        Vol. 41, Issue 10, Article number: 100201(2018) DOI: 10.11889/j.0253-3219.2018.hjs.41.100201
        摘要：Background Due to the influences from durable years, work environment and replacement parts of the dual megavolt tandem accelerator, the terminal voltage output is not accurate enough to ensure the stability of the incident ion energy depends on the terminal voltage acceleration. Purpose This study aims to calibrate terminal voltage output of megavolt accelerator for ion-beam materials characterization. Methods Taking the 2×1.7 MV accelerator as an example, the calibration method on the terminal voltage is making use of the non-Ruhterford backscattering spectrometry (Non-RBS) spectrum of 12C(p, p)12C, and the proton beam was irradiated vertically on the surface of high-purity graphite target, which was characterized by the scattering peak of the isolated resonance at around 1 750 keV. Results Combined with multichannel analyzer (MCA) and SIMNRA 6.05 code, the threshold energy of the resonance scattering reaction between incident proton and the surface of graphite target can be detected as (1 744±2) keV. The actual terminal voltage was extrapolated and the error after calibration also was analyzed. Conclusion This calibration method on the terminal voltage provides a reference for megavolt Van der Graff accelerator or tandem accelerator.  
        关键词：Accelerator;Terminal voltage;Non-RBS;Energy calibration   
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        发布时间：2021-05-19
      • Junhui WANG,Baoguo ZHANG,Wanxin WEN,Xuegang CHU,Cuiping YANG,Dongdong ZHOU
        Vol. 41, Issue 10, Article number: 100203(2018) DOI: 10.11889/j.0253-3219.2018.hjs.41.100203
        摘要：Background With the development of radiotherapy technology, new challenges have been posed for radiation dose planning techniques. Liquid scintillators have been studied a lot for dose measurement, its luminous intensity is proportional to the deposition energy, which can be used to measure the absorbed dose. Purpose This study aimed to develop water-equivalent liquid scintillator materials for the measurement of absorbed dose in tumor radiotherapy and radioprotection. Methods The liquid scintillator used in this experiment is composed of dodecylbenzene, dimethyl sulfoxide (DMSO), Triton X-100, 2, 5-diphenyloxazole (PPO) and 1, 4-bis-(5-phenyloxazol-2-yl)-benzene (POPOP). First, the best concentration ratio of the above materials with good water-equivalence was calculated according to the effective atomic number, electron density formula and Monte Carlo program GEANT4 (GEometry And Tracking 4). The liquid scintillator was prepared according to the optimal concentration ratio, and its water-equivalence as well as radioluminescent properties were verified using the biological X-ray irradiance and multi-channel spectrometer respectively. Results The results showed that the optimal component of 1 L liquid scintillator is 0.09 L of DMSO, 0.36 L of dodecylbenzene, 0.55 L of Triton-X, 4 g·L-1 of PPO and 0.2 g·L-1 of POPOP. The as-prepared liquid scintillator material has good water-equivalence (the ratio of absorbed dose to water is close to 1 with difference less than 0.1%) and retains radioluminescent property (its luminous efficiency is 1/3 of that of a typical commercial liquid scintillator). Conclusion This new liquid scintillator can be used as a phantom and dose detector in cancer radiotherapy and radioprotection.  
        关键词：Liquid scintillator;GEANT4;Dose verification;Water equivalency   
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        发布时间：2021-05-19

        SYNCHROTRON RADIATION TECHNOLOGY AND APPLICATIONS

      • Chao YAO,Jianhui CHEN,Dong WANG,Chunlei LI
        Vol. 41, Issue 10, Article number: 100101(2018) DOI: 10.11889/j.0253-3219.2018.hjs.41.100101
        摘要：Background Coherence is the most striking and fundamental property of the light waves produced by X-ray free-electron lasers (XFEL). The implementation of many experimental techniques exploiting coherent radiation from XFEL requires accurate characterization of spatial properties of the radiation at the sample positon. Purpose This paper aims to investigate the two-dimensional transverse coherence of the self-amplified spontaneous emission (SASE) of a free-electron laser radiation based on near-field heterodyne speckle. Methods The laser pulse is irradiated on the nanoparticle solution making Brownian movement to produce near-field heterodyne speckle. Use a splitter to split each single pulse into two equal-amplitude pulses and two statistically independent raw images are obtained simultaneously for accurate extraction of the heterodyne speckle intensity distribution. The square root of the two-dimensional power spatial frequency spectrum of the heterodyne speckle yields the modulus of the complex coherence factor. Results Theoretical and simulation results proved that the accurate extraction of heterodyne signal and availability of a full two-dimensional coherence map are possible. Conclusion The above-mentioned method has the capability to probe the real-time coherence property of XFEL photon pulses produced from SASE mode.  
        关键词：Heterodyne speckle;SXFEL;Spatial coherence;Twin measurement   
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        发布时间：2021-05-19
      • Ruoou YANG,Fanfei SUN,Ziang ZHAO,Jingtai ZHAO,Zheng JIANG
        Vol. 41, Issue 10, Article number: 100102(2018) DOI: 10.11889/j.0253-3219.2018.hjs.41.100102
        摘要：Background Cobalt carbide (Co2C) has recently been reported to catalyze the Fischer-Tropsch to olefin (FTO) conversion of syngas with high selectivity. However, electronic state and coordination structure of cobalt carbide is limited by its complex reaction. Purpose This study aims to clarify the effect of alkalis of CoMn catalysts for FTO and understanding the atomic structure of cobalt carbide nanoparticles in the CoMn catalyst. Methods X-ray absorption fine structure (XAFS) experimental on beamline (BL14W1) of XAFS spectroscopy at the Shanghai Synchrotron Radiation Facility (SSRF) is conducted to explore the electronic state and coordination structure of cobalt carbide with the effects of alkalis. Results X-ray absorption near-edge structures (XANES) spectra indicts that Na, K acted as electronic donors to cobalt than Li. EXAFS spectra clarified show that the atomic structure of cobalt carbide nanoparticles. Conclusion The Na, K promoter had benefited the formation of the cobalt carbide in the evolution of the FTO catalysts.  
        关键词：Fischer-Tropsch to olefin;Co2C;Alkalis;X-ray absorption fine structure   
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        发布时间：2021-05-19

        NUCLEAR PHYSICS, INTERDISCIPLINARY RESEARCH

      • Kun SUN,Chao XIONG,Liangquan GE,Qingxian ZHANG,Qingju HE,Meng WANG,Yi GU
        Vol. 41, Issue 10, Article number: 100501(2018) DOI: 10.11889/j.0253-3219.2018.hjs.41.100501
        摘要：Background Due to different measuring time, the measured data may fluctuate abnormally. Therefore, it is not easy to extract anomalous information caused by ores effectively in airborne gamma spectrometry. Purpose The aim was to reduce the impact caused by different measurement time, low background field, highlight anomalies, and help in guiding for metallogenic prognosis. Methods Since the wavelet transform is good at dealing with unsteady sampled data signals, this method used wavelet transform to perform multi-scale decomposition on the data of each measurement line unit. According to the coefficient of variation, the wavelet basis function was selected to transform the measured data, and the approximate signal was filtered by soft threshold to reconstruct the detail signal. Results After the approximate signals were filtered by soft thresholds, the non-geological background information containing data influenced by different measurement time can be effectively removed, and the detail information can be reconstructed to reduce the impact caused by different measurement time. Conclusion Through verifying the corrected measured data, combined with the ground anomaly inspection result of airborne gamma spectrum and the geological map of the mining area, the result shows that this method can significantly weaken the error caused by time domain batches, narrow the anomaly ranges, and improve the recognition accuracy of ore-causing anomaly points. Moreover, the shape of anomalies is consistent with the ground anomaly inspection result and the distribution of radionuclides can be restored in the survey area.  
        关键词：Airborne gamma-ray spectrometry;Anomaly information;Wavelet transform;Line unit correction   
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        发布时间：2021-05-19
      • Xianghong CHEN,Huawei YU,Yue ZHOU,Feng ZHANG,Zhigang WANG
        Vol. 41, Issue 10, Article number: 100502(2018) DOI: 10.11889/j.0253-3219.2018.hjs.41.100502
        摘要：Background Borehole diameter (bore diameter) and standoff are important parameters that affect the precision of the logging while drilling (LWD) tool. Purpose This study aims at the method of accurately calculating the instrument-to-hole standoff and borehole diameter by using the azimuthal density LWD. Methods A Monte Carlo simulation was used to establish the instrument calculation model, and the simulation results and experimental data were benchmarked. Then, the effect of 0~5 cm standoff on the response of the detector was studied by changing the standoff size, formation density and mud density. Finally, the standoff size can be calculated by measuring the detector's density, formation density, and mud density whilst the caliper can determined by using the geometric relationship. Results The density measured by the detector is affected by the standoff, mud density, and the density of the formation. When the difference between the formation density and the mud density (difference in the medium density) are constant, the difference between the formation density and the far density (measured density difference) are proportional to the value of standoff. The calculation accuracy of borehole diameter reaches 0.1 cm. Conclusion This study provides a theoretical foundation for calculating standoff and borehole diameter in practical projects in the future.  
        关键词：LWD density loggings;Standoff;Monte Carlo simulation;Borehole diameter   
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