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Study on inherent neutron sources in MSR

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Nuclear Science and Techniques 2018年第4期29卷 146-154页

作者： Rui-Min Ji Cheng-Gang Yu Ming-Hai Li Rui Yan yang zou Gui-Min Liu Shanghai Institute of Applied Physics Chinese Academy of Sciences Jiading Campus Shanghai 201800 China University of Chinese Academy of Sciences Beijing 100049China

The molten salt reactor(MSR) has received much recent attention. The presence of beryllium and the mixing of actinides with light nuclei in the fuel salt result in a relatively strong neutron source that can affect the surveillance at subcritical and transient characteristics during operation. In this study, we predict the inherent neutron sources based on a MSR model. The calculation shows that in the fresh core, the inherent neutron sources are mainly from alpha-induced neutrons. After power operation, the inherent neutron sources become remarkably stronger due to photoneutrons. Although being an insignificant part in the total neutron population during operation, the inherent neutron sources can be used as the installed neutron source after shutdown. If the MSR has continuously operated at full power(2 MWt) for 10 days,then there would be no need for the installed source within80 days after shutdown. After operating constantly for500 days, the installed neutron source can be eliminated within 2 years after shutdown.

关键词： MSR Fuel salt Inherent neutron source Photoneutron Alpha-induced neutron

Avoiding sealing failure of flanged connection for tubes made of dissimilar materials subjected to elevated temperature

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Nuclear Science and Techniques 2019年第1期30卷 107-112页

作者： Qi-Ming Li Chong Zhou Jian Tian Yao Fu yang zou Na-Xiu Wang Shanghai Institute of Applied Physics Chinese Academy of Sciences

Carbonic composite materials and ceramics appear to be excellent structural materials for parts subjected to very high temperatures in molten salt reactors(MSRs), in which the reactor core outlet temperature is normally above 700℃. Because of the high temperature,there are major challenges in the sealing of flanged connections for tubes made of alloys and nonmetallic materials. In this study, an improved method for sealing bolted flange connections for tubes made of dissimilar materials at high temperature is analyzed. The study focuses on the compensation mechanism for the difference in thermal expansion between the bolts and the flanges. An angle is introduced for the sealing surface in the flanged connection to provide effective sealing. The arctangent of the angle is the ratio of the thickness between the theoretical core of the sealing surface and the outside end face of the flange to the distances between the axis of the flanged joint and the theoretical core of the sealing surface of the flange; the sealing surface of the flange, which is made of the same material as the fastening assemblies, faces the fastening assemblies. To ensure effective sealing, the frictional coefficient between the two sealing surfaces should not exceed the tangent of the angle. This result does not agree well with the solution given by previous researchers. Further, in the modified flanged connection, the compression of each bolt in the clamped condition is increased to maintain the compaction force unchanged without increasing the number of bolts on the flanged joint.

关键词： Sealing Composite flanged connections Thermal expansion Mechanical analysis Molten salt reactors

Multi-technique characterizations of main elements in the vehicle exhaust particles collected in a tunnel in Shnaghai

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Nuclear Science and Techniques 2011年第4期22卷 205-211页

作者： JIN Chan FAN Xiaoyan LI Yan LIANG Feng LI Yulan zou yang yang Yongji XIE Yaning Department of Biophysics College of Basic Medical Sciences Second Military Medical University Shanghai 200433 China Shanghai Institute of Applied Physics Chinese Academy of Sciences Shanghai 201800 China Institute of High Energy Physics the Chinese Academy of Sciences Beijing 100039 China

In this study,vehicle exhaust particles were collected three locations (the middle,entrance and outside) of the Dapu Road tunnel in downtown Shanghai,and the particle samples were characterized using SEM,XAFS,ICP-MS and M?ssbauer spectrometry,and the oxidative damage was assessed by plasmid *** iron-containing particles are found from vehicle exhaust,and iron oxide is the major species in all *** concentration in the particles inside the tunnel is higher than that the outside *** iron particles inside the tunnel have higher proportion of water-soluble fraction in hydrous iron sulfate form or smaller ***2 is the main soluble fraction in zinc-containing particles,while higher percentage of insoluble fraction existed in the particles outside of *** species of lead-containing particles are PbSO4,Pb3(PO4)2 and *** addition,the soluble fraction of other transition metallic elements as Ti and V is higher in the particles inside the tunnel than that outside the *** plasmid DNA assay results indicate that the particles from vehicle exhaust have a stronger oxidative damage and inflammation than that from outside of the tunnel.

关键词：打浦路隧道颗粒浓度汽车尾气收集技术质粒DNA 水合硫酸铁刻划 XAFS方法

A new potential risk factor in patients with erectile dysfunction and premature ejaculation： folate deficiency

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Asian Journal of Andrology 2014年第6期16卷 902-906页

作者： Wen-Jie Yan Nan Yu Tai-Lang Yin Yu-]ie zou Jing yang Reproductive Medical Center Renmin Hospital of Wuhan University Wuhan China.

We investigated serum folic acid （FA） levels in patients with erectile dysfunction （ED） and/or premature ejaculation （PE）. Fasting serum samples were obtained from 42 patients with ED, 36 with PE, 25 ED patients with PE, and 30 healthy men; the mean intravaginal ejaculation latency time （IELT） was measured during a 4 weeks baseline period. Levels of sex hormones （follicle-stimulating hormone, luteinizing hormone, total testosterone）, homocysteine （Hcys）, and FA were measured using chemiluminescent immunoassays. The sexual functions of PE patients and normal control men were evaluated using the Chinese Index of Premature Ejaculation （CIPE）. The abridged Intemational Index of Erectile Function-5 （IIEF-5） questionnaire was used to gauge erectile quality for ED patients and for normal controls. Serum FA concentrations were lower in ED （7.61 ~ 3.97 ng ml-1）, PE （9.37 ＋ 3.40 ng ml-1）, and ED/PE （8.84 ＋ 4.28 ng m1-1） patients than in healthy men （12.23 ~ 5.76 ng ml-z, P〈 0.05）. No significant differences in sex hormone levels were found between patients with sexual dysfunction and healthy controls （P 〉 0.05）. There were positive correlations between serum FA concentrations and ClPE scores （r= 0.530, P〈 0.01）, IIEF-5 scores （r= 0.589, P〈 0.01）, and IELT （r= 0.445, P〈 0.01）; negative correlations with Hcys concentrations （r= -0.487, P〈 0.01） were found in all participants. These findings showed a strong relationship between serum FA levels and sexual dysfunction, possibly due to an effect of FA on the metabolism of nitric oxide, Hcys, and 5-hydroxytryptamine.

关键词： 5-hydroxytryptamine erectile dysfunction folic acid homocysteine nitric oxide premature ejaculation

Comparative Study of Lightweight Corundum with Different Microstructures and Its Effect on Slag Resistance of Al2O3-MgO Castables

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China's Refractories 2017年第4期26卷 17-23页

作者： zou yang GU Huazhi HUANG Ao ZHANG Meijie The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and TechnologyWuhan 430081China

Corundum -spinel castables containing lightweight aggregates have drawn many attentions due to their po- tential for energy-saving, especially when applied in the high-temperature region, such as the work lining of refi- ning ladle. One main aspect that restricts their applica- tion is the slag corrosion performance. In this study, one dense tabular corundum and three kinds of lightweight corundum were chosen as aggregates to prepare four dif- ferent corundum - spinel castables. The slag resistance was compared through the induction furnace corrosion test. SEM - EDS, XRD, and thermodynamic and kinet- ics analysis were adopted for the discussion of the corro- sion mechanism. Results show that the crystal grain size and shape of aggregates are important for the slag corro- sion resistance of lightweight corundum -spinel castables under dynamic condition （enforced convection） , yet the effects of pore characteristics are not dominated. Aggre- gates with large flake-like crystal grains show a thicker dissolution diffusion boundary layer and a lower dissolution rate, resulting in a favorable corrosion resist- ance of the castable. The poor microstructure of the ag- gregates, namely, larger pores and small and spherical grains, would cause deterioration of castables＇ slag resistance.

关键词： lightweight corundum spinel castables microstructure slag corrosion thermodynamics

Influences of ^7Li enrichment on Th-U fuel breeding for an Improved Molten Salt Fast Reactor(IMSFR)

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Nuclear Science and Techniques 2017年第7期28卷 105-113页

作者： Guang-Chao Li yang zou Cheng-Gang Yu Jian-Long Han Jin-Gen Chen Hong-Jie Xu Shanghai Institute of Applied Physics Chinese Academy of Sciences Shanghai 201800 China CAS Innovative Academies in TMSR Energy System Shanghai 201800 China University of Chinese Academy of Sciences Beijing 100049China

The molten salt fast reactor(MSFR) shows great promise with high breeding ratio(BR),large negative temperature coefficient of reactivity,high thermal-electric conversion efficiency,inherent safety,and online *** on an improved MSFR optimized by adding axial fertile salt and a graphite reflector,the influences of ~7Li enrichment on Th-U breeding are investigated,aiming to provide a feasible selection for the molten salt with high fissile breeding and a relatively low technology requirement for ~7Li *** the self-developed molten salt reactor reprocessing sequence based on SCALE6.1,the burn-up calculations with online reprocessing are carried *** are explored including BR,^(233)U production,double time(DT),spectrum,~6Li inventory,neutron absorption,and the tritium *** results show that the Li enrichment of 99.95% is appropriate in the fast fission *** this case,BR above 1.10 can be achieved for a long time,corresponding to the ^(233)U production of130 kg per year and DT of 36 *** 80 years' operation,the tritium production for 99.5% is only about 7kg,and there is no obvious increase compared to that for 99.9995%.

关键词：繁殖率熔盐富集铀燃料裂变反应堆快堆在线处理负温度系数

Neutronics analysis for MSR cell with different fuel salt channel geometries

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Nuclear Science and Techniques 2021年第1期32卷 75-84页

作者： Shi-He Yu Ya-Fen Liu Pu yang Rui-Min Ji Gui-Feng Zhu Bo Zhou Xu-Zhong Kang Rui Yan yang zou Ye Dai Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai 201800China University of Chinese Academy of Sciences Beijing 100049China

The neutronic properties of molten salt reactors(MSRs)differ from those of traditional solid fuel reactors owing to their nuclear fuel *** on the Monte-Carlo N particle transport code,the effects of the size and shape of the fuel salt channel on the neutron physics of an MSR cell are investigated systematically in this *** results show that the infinite multiplication factor(k?)first increases and then decreases with the change in the graphite cell size under certain fuel volume fraction(FVF)*** the same FVF and average chord length,when the average chord length is relatively small,the k?values for different fuel salt channel shapes agree *** the average chord length is relatively large,the k?values for different fuel salt channel shapes differ *** addition,some examples of practical applications of this study are presented,including cell selection for the core and thermal expansion displacement analysis of the cell.

关键词： Molten salt reactor Fuel salt channel Cell geometry Neutronics

Plutonium utilization in a small modular molten-salt reactor based on a batch fuel reprocessing scheme

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Nuclear Science and Techniques 2024年第4期35卷 15-28页

作者： Xue-Chao Zhao Rui Yan Gui-Feng Zhu Ya-Fen Liu Jian Guo Xiang-Zhou Cai yang zou Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai 201800China CAS Innovative Academies in TMSR Energy System Chinese Academy of SciencesShanghai 201800China University of Chinese Academy of Sciences Beijing 100049China

A molten salt reactor(MSR)has outstanding features considering the application of thorium fuel,inherent safety,sustainability,and resistance to ***,fissile material^(233)U is significantly rare at the current stage,thus it is difficult for MSR to achieve a pure thorium-uranium fuel ***,using plutonium or enriched uranium as the initial fuel for MSR is more *** this study,we aim to verify the feasibility of a small modular MSR that utilizes plutonium as the starting fuel(SM-MSR-Pu),and highlight its advantages and ***,the structural design and fuel management scheme of the SM-MSR-Pu were ***,the neutronic characteristics,such as the graphite-irradiation lifetime,burn-up performance,and coefficient of temperature reactivity were calculated to analyze the physical characteristics of the *** results indicate that plutonium is a feasible and advantageous starting fuel for a SM-MSR;however,there are certain shortcomings that need to be *** a 250 MWth SM-MSR-Pu,approximately 288.64 kg^(233)U of plutonium with a purity of greater than 90% is produced while 978.00 kg is burned every ten *** temperature reactivity coefficient decreases from -4.0 to -6.5 pcm K^(-1) over the 50-year operating time,which ensures a long-term safe ***,the amount of plutonium and accumulation of minor actinides(MAs)would increase as the burn-up time increases,and the annual production and purity of^(233)U will *** achieve an optimal burn-up performance,setting the entire operation time to 30 years is ***,more than 3600 kg of plutonium eventually accumulate in the *** research is required to effectively utilize this accumulated plutonium.

关键词： Molten salt fuel Plutonium utilization ^(233)U TRUs mole fraction Temperature feedback coefficient

Ice flux of alpine glaciers controls erosion and landscape in the Nianbaoyeze Shan,northeastern Tibetan Plateau

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Journal of Mountain Science 2023年第7期20卷 1884-1899页

作者： CHEN Xiao-jing WANG Jie zou Li-yang YAO Pan LEI Man-hong LIAO Jing-sheng Key laboratory of Western China’s Environmental Systems(Ministry of Education) College of Earth and Environmental SciencesLanzhou UniversityLanzhou 730000China Gansu Shiyang River Basin Scientific Observing Station Lanzhou 730000China 11th Geology Team of Zhejiang Province Wenzhou 325000China School of Geography and Tourism Jiaying UniversityMeizhou 514015China

The evolution of mountainous topography is the result of the interactions of climate,topography,and *** are one of the most active erosional forces sculpting mountainous ***,our ability to understand this erosional force is limited by the controversy regarding the major factors controlling glacial *** selected the Nianbaoyeze Shan,which is occupied by subcontinental glaciers(likely cold-based or polythermal glaciers)in the northeastern Tibetan Plateau,to study how erosion by alpine glaciers sculpts the *** first applied a power law model(y=axb)fit to the cross-profiles of glacial valleys and analyzed the controlling factor of glacial erosion;we then identified the morphometric characteristics of the cirques to analyze the influencing factors,and investigated the development patterns of glacial valleys and ***,we used hypsometry and the slopealtitude curves and reconstructed the palaeo-glacier surfaces and palaeo-Equilibrium Line Altitudes(ELAs)to determine if the glacial buzzsaw effect had impacted this glaciated region with subcontinental *** findings show that ice flux is the main factor controlling glacial *** this region,decreasing temperatures promote an increase in glacier mean size(i.e.,ice flux),which enhances the rate of glacial *** morphology is mainly influenced by aspect and the *** development patterns of glacial valleys and cirques were dominated by a widening *** ELAs of Marine Isotope Stage(MIS)-3 derived from the cirque floor altitudes or the Accumulation Area Ratio(AAR)and Area-Altitude Balance Ratio(AABR)coincide with the hypsometric maximum and the reduction in slopealtitude curves,which indicates that glacial buzzsaw has impacted this ***,the glacial buzzsaw effect has profoundly influenced the mountain heights and topographic evolution in this subcontinental glaciated region.

关键词： Nianbaoyeze Mountain Glacial erosion Ice flux Glacier reconstruction PalaeoELAs reconstruction Topographic evolution Widening process