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
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.
