Classical molecular dynamics simulations with global neural network machine learning potential are used to study early stage oxidation and dissolution behaviors of bcc Fe surfaces contacting with stagnant oxygen disso...Classical molecular dynamics simulations with global neural network machine learning potential are used to study early stage oxidation and dissolution behaviors of bcc Fe surfaces contacting with stagnant oxygen dissolved liquid leadbismuth eutectic(LBE-O).Both static and dynamic simulation results indicate that the early stage oxidation and dissolution behaviors of bcc Fe show strong orientation dependence under the liquid LBE environments,which may explain the experimental observations of uneven interface between iron-based materials and liquid LBE.Our investigations show that it is the delicate balance between the oxide growth and metal dissolution that leads to the observed corrosion anisotropy for bcc Fe contacting with liquid LBE-O.展开更多
The Fe_(949.7)Cr_(18)Mn_(1.9)Mo_(7.4)W_(1.6)B_(15.2)C_(3.8)Si_(2) amorphous coating was deposited on T91 steel substrate by using the high-velocity oxygen fuel(HVOF)spray technique to enhance the corrosion resistance ...The Fe_(949.7)Cr_(18)Mn_(1.9)Mo_(7.4)W_(1.6)B_(15.2)C_(3.8)Si_(2) amorphous coating was deposited on T91 steel substrate by using the high-velocity oxygen fuel(HVOF)spray technique to enhance the corrosion resistance of T91 stainless steel in liquid lead-bismuth eutectic(LBE).The corrosion behavior of the T91 steel and coating exposed to oxygen-saturated LBE at 400℃ for 500 h was investigated.Results showed that the T91 substrate was severely corroded and covered by a homogeneously distributed dual-layer oxide on the interface contacted to LBE,consisting of an outer magnetite layer and an inner Fe-Cr spinel layer.Meanwhile,the amorphous coating with a high glass transition temperature(Tg=550℃)and crystallization temperature(T_(x)=600℃)exhibited dramatically enhanced thermal stability and corrosion resistance.No visible LBE penetration was observed,although small amounts of Fe_(3)O_(4),Cr_(2)O_(3),and PbO were found on the coating surface.In addition,the amorphicity and interface bonding of the coating layer remained unchanged after the LBE corrosion.The Fe-based amorphous coating can act as a stable barrier layer in liquid LBE and have great application potential for long-term service in LBE-cooled fast reactors.展开更多
Studies of synergetic irradiation effects and liquid lead-bismuth eutectic(LBE) corrosion/embrittlement effects on ferritic/martensitic(F/M) steels are of great importance for developing high power spallation neutron ...Studies of synergetic irradiation effects and liquid lead-bismuth eutectic(LBE) corrosion/embrittlement effects on ferritic/martensitic(F/M) steels are of great importance for developing high power spallation neutron targets(>1 M W) such as the European Spallation Source(ESS) and Accelerator Driven System(ADS) facilities that can be used for transmuting long-lifetime radioactive wastes. Liquid LBE(45Pb-55Bi,in terms of mass fraction) has been selected as the candidate target material in high power spallation neutron targets due to its favourable thermal,physical & chemical properties,and to its high spallation neutron yield. 9Cr F/M steels such as T91(9Cr1M oVNb,in terms of mass fraction) have been chosen as the structural material for the targets due to their good mechanical properties and good resistance to irradiation induced swelling in fission neutron irradiation environments. For developing high power spallation neutron targets,behaviors of F/M steels in spallation neutron target irradiation environments and LBE corrosion/embrittlement effects have been extensively studied. However,many open questions have not been answered. The aim of this paper is to describe the present research situation on this topic. The obtained experimental data about LBE embrittlement effects on F/M steels is summarized and the influence of different parameters involved is analyzed to understand the influence effect on LBE embrittlement effect of F/M s.展开更多
Fast reactors used lead-bismuth eutectic (LBE) and lead as coolants possess very high level of inherent self-protection and passive safety against severe accident. So, population radiophobia can be overcome. That type...Fast reactors used lead-bismuth eutectic (LBE) and lead as coolants possess very high level of inherent self-protection and passive safety against severe accident. So, population radiophobia can be overcome. That type of reactors can be simultaneously more safely and more cheaply. As all other coolants, LBE and lead coolant (LC) possess the certain virtues and shortcomings. The presented report includes the comparative analysis of characteristic properties of those coolants, their impact on reactor safety, reliability and operating characteristics. The conclusion is made about promising usage of FRs with these coolants in future NP after the experience in operating of the prototypes of such reactors has been obtained.展开更多
Among different heavy liquid metals(HLMs), lead-bismuth eutectic(LBE) is considered at present as a potential candidate for the coolant of new generation fast reactors(critical and subcritical) and for liquid spallati...Among different heavy liquid metals(HLMs), lead-bismuth eutectic(LBE) is considered at present as a potential candidate for the coolant of new generation fast reactors(critical and subcritical) and for liquid spallation neutron sources and accelerator driven systems(ADS). A high temperature liquid LBE loop, KYLIN-II-M,has been built to study the characteristics of corrosion and fluidity of LBE at the Institute of Nuclear Energy Safety Technology. However, due to the sensors and execution components of the loop work at high temperatures and in severely corrosive environments, the reliability and security of the data acquisition and control system(DACS) of KYLIN-II-M face challenges during the loop operation. In order to meet the urgent needs for KYLIN-II-M's long-term stable operation, a virtualization and redundancy control system has been developed.The onsite operation result shows that the DACS is stable and reliable. In this paper, the experimental results are described in detail.展开更多
The tensile tests of T91 and T91Si steels at 200-450℃in air and at 350℃in oxygen-depleted liquid lead-bismuth eutectic(LBE)environment with strain rate of 1×10^(-5)-5×10^(-3)were performed.Results show tha...The tensile tests of T91 and T91Si steels at 200-450℃in air and at 350℃in oxygen-depleted liquid lead-bismuth eutectic(LBE)environment with strain rate of 1×10^(-5)-5×10^(-3)were performed.Results show that the activation energy of T91 steel is 103.45-246.76 kJ/mol and that of T91Si steel is 146.98-172.11 kJ/mol when Portevin-Le Chatelie(PLC)phenomenon occurs.The elongation reduction of T91 steel at 350℃is not specific to LBE environment,whereas the presence of LBE promotes crack initiation and propagation and affects the elongation of the material in the necking stage.With Si addition,the elongation,especially the uniform elongation at 350℃in LBE environment,improves,and the tendency toward crack propagation in T91 steel after slow tensile necking is reduced.The PLC phenomenon can be seen in both T91 and T91Si steels at high temperatures owing to the dynamic strain aging(DSA).The temperature ranges are different when DSA occurs,with 300-350℃and 250-350℃for T91 and T91Si steels,respectively.展开更多
Investigations on entropy generation and thermal irreversibility analysis are conducted for liquid lead-bismuth eutectic(LBE)in an annular pipe.To find better performance in convective heat transfer,the computational ...Investigations on entropy generation and thermal irreversibility analysis are conducted for liquid lead-bismuth eutectic(LBE)in an annular pipe.To find better performance in convective heat transfer,the computational fluid dynamics(CFD)code based on the finite volume method(FVM)is adopted to solve this problem.The elevated temperature LBE flows in the annular pipe,and four types of heat flux,including constant,linear increase and decrease,and parabolic distributions are imposed at the inside wall of the annular pipe.The investigations are conducted for the specific average heat input of 200 kW/m^(2),and the different Peclet number Pe is set from 1200 to 3200.The SST k-ωturbulent model and Cheng-Tak Prt model are adopted.The mesh independence validation and models verification are also conducted and the maximum Nu error is 5.43%compared with previous experimental correlations.The results from the local and system scales,respectively,including volumetric dimensionless entropy generation,Ns,Be,and Ep,are discussed.The results indicate that the viscous friction and heat transfer caused by entropy generation can be found in the viscous sub-layer and buffer layer respectively.Heat transfer is the primary factor that leads to irreversible losses.Besides,the results show that the best thermodynamic performance occurs under parabolic distributed heat flux in the research scope.展开更多
The compatibility of the austenitic AISI 304 steel with Pb-Bi-Sn alloy was analyzed. The AISI 304 steels were immersed in stagnant molten Pb-33.3Bi-33. 3Sn alloy at 400, 500 and 600℃ for different exposure times （10...The compatibility of the austenitic AISI 304 steel with Pb-Bi-Sn alloy was analyzed. The AISI 304 steels were immersed in stagnant molten Pb-33.3Bi-33. 3Sn alloy at 400, 500 and 600℃ for different exposure times （100-2 000 h） respectively. XRay diffraction spectrum （XRD） with a Y-4Q system （CuKα,λ= 0. 154 78 nm） was used to identify the phases on the surface of specimens after exposing to Pb-Bi-Sn liquid metal （LM）. The surface and cross section of the specimens were analyzed by means of scanning electron microscopy （SEM） and energy dispersive X-ray analysis （EDX）. The result showed that a FeSn alloy layer on the surface of all specimens was formed, and it prevented AISI 304 steel matrix from penetration attack and loss of alloy elements at 400 and 500 ℃.展开更多
The cavitation erosion of weld joint and base metal of China low activation martensitic（CLAM）steel in liquid lead-bismuth eutectic alloy（LBE）at 550°C was investigated to simulate the cavitation erosion of the...The cavitation erosion of weld joint and base metal of China low activation martensitic（CLAM）steel in liquid lead-bismuth eutectic alloy（LBE）at 550°C was investigated to simulate the cavitation erosion of the first wall and the nuclear main pump impeller in the accelerator driven sub-critical system（ADS）.A suit of ultrasonic cavitation facility was self-designed to study the cavitation erosion.By studying the surface micro topography,roughness and mean pit depth of the tested specimens,it was found that some crater clusters and large scale cracks appeared on the tested specimen surface after the formation of numerous single craters,and the base metal exhibited much better cavitation erosion resistance than the weld bead due to the difference in their mechanical properties and microstructures.In addition,by comparing the results of static corrosion and cavitation erosion,it could be concluded that the cavitation erosion and the dissolution and oxidation corrosion in liquid LBE would accelerate mutually.展开更多
Newly developed sintering aid Na5.6Cu1.2Sb10O29 (NCS) and lead-bismuth-free piezoceramics (Na0.5K0.44Li0.06) Nb0.95Sb0.05O3 (NKLNS) were prepared by the conventional solid state reaction. The effects of sintering aid ...Newly developed sintering aid Na5.6Cu1.2Sb10O29 (NCS) and lead-bismuth-free piezoceramics (Na0.5K0.44Li0.06) Nb0.95Sb0.05O3 (NKLNS) were prepared by the conventional solid state reaction. The effects of sintering aid NCS on the electrical properties of NKLNS were investigated. It was found that the addition of a proper amount of sintering aid NCS to NKLNS is effective not only on improving the density and the piezoelectric activity, but also on reducing the dielectric loss of NKLNS. The NKLNS doped with 0.4 mol% NCS has a piezoelectric constant d33 as high as 261pC/N and an electromechanical coupling factor k33 above 60%. These results show that NCS-doped NKLNS is a promising and practicable candidate for lead-bismuth-free piezoceramics.展开更多
基金the National Natural Science Foundation of China(Grant No.U1832206).
文摘Classical molecular dynamics simulations with global neural network machine learning potential are used to study early stage oxidation and dissolution behaviors of bcc Fe surfaces contacting with stagnant oxygen dissolved liquid leadbismuth eutectic(LBE-O).Both static and dynamic simulation results indicate that the early stage oxidation and dissolution behaviors of bcc Fe show strong orientation dependence under the liquid LBE environments,which may explain the experimental observations of uneven interface between iron-based materials and liquid LBE.Our investigations show that it is the delicate balance between the oxide growth and metal dissolution that leads to the observed corrosion anisotropy for bcc Fe contacting with liquid LBE-O.
基金financially supported by the National Natural Science Foundation of China (Nos. 52061135207, 51871016, 51921001, 5197011039, 5197011018, and U20b200318)the China Nuclear Power Technology Research Institute Co., Ltd
文摘The Fe_(949.7)Cr_(18)Mn_(1.9)Mo_(7.4)W_(1.6)B_(15.2)C_(3.8)Si_(2) amorphous coating was deposited on T91 steel substrate by using the high-velocity oxygen fuel(HVOF)spray technique to enhance the corrosion resistance of T91 stainless steel in liquid lead-bismuth eutectic(LBE).The corrosion behavior of the T91 steel and coating exposed to oxygen-saturated LBE at 400℃ for 500 h was investigated.Results showed that the T91 substrate was severely corroded and covered by a homogeneously distributed dual-layer oxide on the interface contacted to LBE,consisting of an outer magnetite layer and an inner Fe-Cr spinel layer.Meanwhile,the amorphous coating with a high glass transition temperature(Tg=550℃)and crystallization temperature(T_(x)=600℃)exhibited dramatically enhanced thermal stability and corrosion resistance.No visible LBE penetration was observed,although small amounts of Fe_(3)O_(4),Cr_(2)O_(3),and PbO were found on the coating surface.In addition,the amorphicity and interface bonding of the coating layer remained unchanged after the LBE corrosion.The Fe-based amorphous coating can act as a stable barrier layer in liquid LBE and have great application potential for long-term service in LBE-cooled fast reactors.
基金Funded by the National Natural Science Foundation of China(No.91226203)
文摘Studies of synergetic irradiation effects and liquid lead-bismuth eutectic(LBE) corrosion/embrittlement effects on ferritic/martensitic(F/M) steels are of great importance for developing high power spallation neutron targets(>1 M W) such as the European Spallation Source(ESS) and Accelerator Driven System(ADS) facilities that can be used for transmuting long-lifetime radioactive wastes. Liquid LBE(45Pb-55Bi,in terms of mass fraction) has been selected as the candidate target material in high power spallation neutron targets due to its favourable thermal,physical & chemical properties,and to its high spallation neutron yield. 9Cr F/M steels such as T91(9Cr1M oVNb,in terms of mass fraction) have been chosen as the structural material for the targets due to their good mechanical properties and good resistance to irradiation induced swelling in fission neutron irradiation environments. For developing high power spallation neutron targets,behaviors of F/M steels in spallation neutron target irradiation environments and LBE corrosion/embrittlement effects have been extensively studied. However,many open questions have not been answered. The aim of this paper is to describe the present research situation on this topic. The obtained experimental data about LBE embrittlement effects on F/M steels is summarized and the influence of different parameters involved is analyzed to understand the influence effect on LBE embrittlement effect of F/M s.
文摘Fast reactors used lead-bismuth eutectic (LBE) and lead as coolants possess very high level of inherent self-protection and passive safety against severe accident. So, population radiophobia can be overcome. That type of reactors can be simultaneously more safely and more cheaply. As all other coolants, LBE and lead coolant (LC) possess the certain virtues and shortcomings. The presented report includes the comparative analysis of characteristic properties of those coolants, their impact on reactor safety, reliability and operating characteristics. The conclusion is made about promising usage of FRs with these coolants in future NP after the experience in operating of the prototypes of such reactors has been obtained.
基金Supported by the Accelerator Driven Systems Project of the Chinese Academy of Sciences(No.XDA03040000)
文摘Among different heavy liquid metals(HLMs), lead-bismuth eutectic(LBE) is considered at present as a potential candidate for the coolant of new generation fast reactors(critical and subcritical) and for liquid spallation neutron sources and accelerator driven systems(ADS). A high temperature liquid LBE loop, KYLIN-II-M,has been built to study the characteristics of corrosion and fluidity of LBE at the Institute of Nuclear Energy Safety Technology. However, due to the sensors and execution components of the loop work at high temperatures and in severely corrosive environments, the reliability and security of the data acquisition and control system(DACS) of KYLIN-II-M face challenges during the loop operation. In order to meet the urgent needs for KYLIN-II-M's long-term stable operation, a virtualization and redundancy control system has been developed.The onsite operation result shows that the DACS is stable and reliable. In this paper, the experimental results are described in detail.
文摘The tensile tests of T91 and T91Si steels at 200-450℃in air and at 350℃in oxygen-depleted liquid lead-bismuth eutectic(LBE)environment with strain rate of 1×10^(-5)-5×10^(-3)were performed.Results show that the activation energy of T91 steel is 103.45-246.76 kJ/mol and that of T91Si steel is 146.98-172.11 kJ/mol when Portevin-Le Chatelie(PLC)phenomenon occurs.The elongation reduction of T91 steel at 350℃is not specific to LBE environment,whereas the presence of LBE promotes crack initiation and propagation and affects the elongation of the material in the necking stage.With Si addition,the elongation,especially the uniform elongation at 350℃in LBE environment,improves,and the tendency toward crack propagation in T91 steel after slow tensile necking is reduced.The PLC phenomenon can be seen in both T91 and T91Si steels at high temperatures owing to the dynamic strain aging(DSA).The temperature ranges are different when DSA occurs,with 300-350℃and 250-350℃for T91 and T91Si steels,respectively.
基金supported by the National Key R&D Program of China(2020YFB1901900)。
文摘Investigations on entropy generation and thermal irreversibility analysis are conducted for liquid lead-bismuth eutectic(LBE)in an annular pipe.To find better performance in convective heat transfer,the computational fluid dynamics(CFD)code based on the finite volume method(FVM)is adopted to solve this problem.The elevated temperature LBE flows in the annular pipe,and four types of heat flux,including constant,linear increase and decrease,and parabolic distributions are imposed at the inside wall of the annular pipe.The investigations are conducted for the specific average heat input of 200 kW/m^(2),and the different Peclet number Pe is set from 1200 to 3200.The SST k-ωturbulent model and Cheng-Tak Prt model are adopted.The mesh independence validation and models verification are also conducted and the maximum Nu error is 5.43%compared with previous experimental correlations.The results from the local and system scales,respectively,including volumetric dimensionless entropy generation,Ns,Be,and Ep,are discussed.The results indicate that the viscous friction and heat transfer caused by entropy generation can be found in the viscous sub-layer and buffer layer respectively.Heat transfer is the primary factor that leads to irreversible losses.Besides,the results show that the best thermodynamic performance occurs under parabolic distributed heat flux in the research scope.
基金Item Sponsored by Foundation of National Key Laboratory of Science and Technology on Nuclear Fuel and Materials of China(2009C7001)
文摘The compatibility of the austenitic AISI 304 steel with Pb-Bi-Sn alloy was analyzed. The AISI 304 steels were immersed in stagnant molten Pb-33.3Bi-33. 3Sn alloy at 400, 500 and 600℃ for different exposure times （100-2 000 h） respectively. XRay diffraction spectrum （XRD） with a Y-4Q system （CuKα,λ= 0. 154 78 nm） was used to identify the phases on the surface of specimens after exposing to Pb-Bi-Sn liquid metal （LM）. The surface and cross section of the specimens were analyzed by means of scanning electron microscopy （SEM） and energy dispersive X-ray analysis （EDX）. The result showed that a FeSn alloy layer on the surface of all specimens was formed, and it prevented AISI 304 steel matrix from penetration attack and loss of alloy elements at 400 and 500 ℃.
基金supported by the National Natural Science Foundation of China with Grant Nos.51375216 and 51505197the Open-Fund Research of State Key Lab of Advanced Welding and Joining with Grant No.AWJ-16-M07the Fusion Digital Simulation(FDS)Team for support the CLAM steel
文摘The cavitation erosion of weld joint and base metal of China low activation martensitic（CLAM）steel in liquid lead-bismuth eutectic alloy（LBE）at 550°C was investigated to simulate the cavitation erosion of the first wall and the nuclear main pump impeller in the accelerator driven sub-critical system（ADS）.A suit of ultrasonic cavitation facility was self-designed to study the cavitation erosion.By studying the surface micro topography,roughness and mean pit depth of the tested specimens,it was found that some crater clusters and large scale cracks appeared on the tested specimen surface after the formation of numerous single craters,and the base metal exhibited much better cavitation erosion resistance than the weld bead due to the difference in their mechanical properties and microstructures.In addition,by comparing the results of static corrosion and cavitation erosion,it could be concluded that the cavitation erosion and the dissolution and oxidation corrosion in liquid LBE would accelerate mutually.
基金Supported by the National Natural Science Foundation of China (Grant No. 50572056)the Natural Science Foundation of Shandong Province, China (No. Z2003F04)the Basic Science Talent Training Foundation of China
文摘Newly developed sintering aid Na5.6Cu1.2Sb10O29 (NCS) and lead-bismuth-free piezoceramics (Na0.5K0.44Li0.06) Nb0.95Sb0.05O3 (NKLNS) were prepared by the conventional solid state reaction. The effects of sintering aid NCS on the electrical properties of NKLNS were investigated. It was found that the addition of a proper amount of sintering aid NCS to NKLNS is effective not only on improving the density and the piezoelectric activity, but also on reducing the dielectric loss of NKLNS. The NKLNS doped with 0.4 mol% NCS has a piezoelectric constant d33 as high as 261pC/N and an electromechanical coupling factor k33 above 60%. These results show that NCS-doped NKLNS is a promising and practicable candidate for lead-bismuth-free piezoceramics.
