This study investigates the impact of silicon(Si)on the corrosion resistance and post-corrosion toughness of ferrite/martensitic(F/M)steels in a liquid lead-bismuth eutectic(LBE)environment.Corrosion tests were perfor...This study investigates the impact of silicon(Si)on the corrosion resistance and post-corrosion toughness of ferrite/martensitic(F/M)steels in a liquid lead-bismuth eutectic(LBE)environment.Corrosion tests were performed on HT-9 and EP-823(1.17 wt%Si)steels at 550℃for 1000 h under oxygen-controlled conditions.The resulting oxide layer consisted of an outer magnetite layer,a spinel layer and an inner oxide zone(IOZ).A Si-rich oxide layer was identified within the spinel and IOZ layers of EP-823,which slowed the growth rate of the oxide layer,enhanced antioxidant performance,and inhibited dissolution corrosion by the LBE.Post-corrosion mechanical properties were evaluated using a small punch test.Results showed a significant reduction in HT-9's toughness within 240 h of corrosion,while EP-823 exhibited increased brittleness after 500 h due to Si-promoted carbide and Laves phase precipitation,significantly reducing its toughness.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
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
To study the interaction between molten noneutectic alloys and subcooled water during severe nuclear accidents,an experimental investigation was carried out by injecting molten lead–bismuth non-eutectic alloy(LBNE,70...To study the interaction between molten noneutectic alloys and subcooled water during severe nuclear accidents,an experimental investigation was carried out by injecting molten lead–bismuth non-eutectic alloy(LBNE,70%Pb-30%Bi)into the water in a free-fall style using the visualized thermo-hydraulic characteristics in melt coolant interaction(VTMCI)facility.The effects of various experimental parameters,including water temperature,melt temperature,melt penetration velocity,and water depth,on the molten LBNE jet fragmentation characteristics were studied.The research shows that compared with lead–bismuth eutectic,larger fragments,less spherical fragments,and more porous debris beds are generated for LBNE.Higher water or melt temperatures facilitate molten LBNE fragmentation,resulting in higher debris bed sphericity and lower debris bed porosity.A higher melt temperature leads to smaller fragment sizes,except that a cake-like debris bed is formed for very high alloy superheat and very low water subcooling.More approximate spherical particles were generated in the film boiling zone than in the thermal interaction zone.Fragment size decreases with an increase in the melt penetration velocity,but the debris bed porosity and sphericity variation was not obvious.The effect of water depth on molten LBNE fragmentation behavior was not obvious under the current experimental conditions.Compared with other fragmentation theories,the Weber number theory better predicted the fragment volume mean diameter.In addition,a melt-jet behavior mode diagram that describes the competition between the hydrodynamic and thermal interactions and diagrams of debris bed porosity and sphericity that show the influence of thermal factors were analyzed in this study.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
随 Nb 含量的增加,HP 合金蠕变断裂强度的变化表现出极大值特征。在含碳0.4(wt%)的HP 合金中添加0.5(wt%)以下的 Nb,主要起固溶强化作用;当 Nb 量约1.5(wt%)时,可以获得最佳的蠕变断裂强度。其原因是在共晶组织中形成了形态复杂的共晶 N...随 Nb 含量的增加,HP 合金蠕变断裂强度的变化表现出极大值特征。在含碳0.4(wt%)的HP 合金中添加0.5(wt%)以下的 Nb,主要起固溶强化作用;当 Nb 量约1.5(wt%)时,可以获得最佳的蠕变断裂强度。其原因是在共晶组织中形成了形态复杂的共晶 NbC,在晶内析出了高度弥散的二次 NbC,以及由于 Nb 的加入提高了组织稳定性;当 Nb 量进一步提高时,由于共晶 NbC 形成了片层状共晶团以及晶内 M_(23)C_6大量减少使蠕变断裂强度下降。展开更多
基金supported by the National Natural Science Foundation of China(No.52301121).
文摘This study investigates the impact of silicon(Si)on the corrosion resistance and post-corrosion toughness of ferrite/martensitic(F/M)steels in a liquid lead-bismuth eutectic(LBE)environment.Corrosion tests were performed on HT-9 and EP-823(1.17 wt%Si)steels at 550℃for 1000 h under oxygen-controlled conditions.The resulting oxide layer consisted of an outer magnetite layer,a spinel layer and an inner oxide zone(IOZ).A Si-rich oxide layer was identified within the spinel and IOZ layers of EP-823,which slowed the growth rate of the oxide layer,enhanced antioxidant performance,and inhibited dissolution corrosion by the LBE.Post-corrosion mechanical properties were evaluated using a small punch test.Results showed a significant reduction in HT-9's toughness within 240 h of corrosion,while EP-823 exhibited increased brittleness after 500 h due to Si-promoted carbide and Laves phase precipitation,significantly reducing its toughness.
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.
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the Science and Technology Program of Guangdong Province(No.2021A0505030026)Basic and Applied Basic Research Foundation of Guangdong Province(No.2021A1515010343).
文摘To study the interaction between molten noneutectic alloys and subcooled water during severe nuclear accidents,an experimental investigation was carried out by injecting molten lead–bismuth non-eutectic alloy(LBNE,70%Pb-30%Bi)into the water in a free-fall style using the visualized thermo-hydraulic characteristics in melt coolant interaction(VTMCI)facility.The effects of various experimental parameters,including water temperature,melt temperature,melt penetration velocity,and water depth,on the molten LBNE jet fragmentation characteristics were studied.The research shows that compared with lead–bismuth eutectic,larger fragments,less spherical fragments,and more porous debris beds are generated for LBNE.Higher water or melt temperatures facilitate molten LBNE fragmentation,resulting in higher debris bed sphericity and lower debris bed porosity.A higher melt temperature leads to smaller fragment sizes,except that a cake-like debris bed is formed for very high alloy superheat and very low water subcooling.More approximate spherical particles were generated in the film boiling zone than in the thermal interaction zone.Fragment size decreases with an increase in the melt penetration velocity,but the debris bed porosity and sphericity variation was not obvious.The effect of water depth on molten LBNE fragmentation behavior was not obvious under the current experimental conditions.Compared with other fragmentation theories,the Weber number theory better predicted the fragment volume mean diameter.In addition,a melt-jet behavior mode diagram that describes the competition between the hydrodynamic and thermal interactions and diagrams of debris bed porosity and sphericity that show the influence of thermal factors were analyzed in this study.
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.
文摘随 Nb 含量的增加,HP 合金蠕变断裂强度的变化表现出极大值特征。在含碳0.4(wt%)的HP 合金中添加0.5(wt%)以下的 Nb,主要起固溶强化作用;当 Nb 量约1.5(wt%)时,可以获得最佳的蠕变断裂强度。其原因是在共晶组织中形成了形态复杂的共晶 NbC,在晶内析出了高度弥散的二次 NbC,以及由于 Nb 的加入提高了组织稳定性;当 Nb 量进一步提高时,由于共晶 NbC 形成了片层状共晶团以及晶内 M_(23)C_6大量减少使蠕变断裂强度下降。
