In the ever fusion experiments in SWIP, pellet forming process was carried out through adjusting relative devices by staff member in site, which will make every pellet-forming process slight distinction and will resul...In the ever fusion experiments in SWIP, pellet forming process was carried out through adjusting relative devices by staff member in site, which will make every pellet-forming process slight distinction and will result in pellet difference in shape, size and intensity. In the intervals of HL-2A discharges, staff member have to go site to accomplish the pellet-forming process, this wastes human power and increase the potential danger. So it is necessary to develop a remote control system to perform the pellet-forming process. The control system needs have the features of real-time, reliability and be easy to operate and maintain.展开更多
For an analysis of the oxidation behavior of UO2 nuclear fuel pellet under a loss of water coolant accident in a spent nuclear fuel pool of an LWR, thermodynamic assessments of UO2 oxidation were carried out under var...For an analysis of the oxidation behavior of UO2 nuclear fuel pellet under a loss of water coolant accident in a spent nuclear fuel pool of an LWR, thermodynamic assessments of UO2 oxidation were carried out under various atmospheric conditions. In a steam atmosphere, it was assessed that UO2 would not be fully oxidized into U3O8 due to the relatively lower oxygen partial pressure, while UO2 will be fully oxidized into U3O8 in an air atmosphere. In an air and steam mixture atmosphere, the UO2 oxidation was dominantly affected by the air volumetric fraction, because of the relatively higher oxygen partial pressure of air. In addition, the effect of H2 volumetric fraction on the oxygen partial pressure under a mixture atmosphere was calculated, and it was revealed that UO2 pellet oxidation could be reduced above the critical value of H2 volumetric fraction.展开更多
At present, the technology of biomass fuel composite molding technique is relatively lagging in China, which brings several negative influences, such as high energy consumption, short service life of the equipment. Th...At present, the technology of biomass fuel composite molding technique is relatively lagging in China, which brings several negative influences, such as high energy consumption, short service life of the equipment. The current situation of the biomass pellet fuel molding technology at home and abroad was introduced, and the development direction in China was put forward, which was of great significance for enhancing the level of pellet fuel molding technology in China.展开更多
Pellet injection is an attractive technology for core-fueling and magnetohydrodynamic study in magnetic-conflnement fusion devices like tokamaks and stellarators.It can inject solid hydrogen/deuterium pellets into the...Pellet injection is an attractive technology for core-fueling and magnetohydrodynamic study in magnetic-conflnement fusion devices like tokamaks and stellarators.It can inject solid hydrogen/deuterium pellets into the plasma with deeper density deposition compared with other fueling methods,such as gas pufflng.A three-barrel H_(2)pellet injection system was installed on the J-TEXT tokamak and experiments were carried out.The pellets are formed in three barrels cooled by a cryocooler and compressor system at around 9 K,and are 0.8 mm/1 mm diameter and 0.8 mm length.The pellet is launched by helium propellant gas and injected from the lowfleld side of the plasma.The normal range of pellet speed is 210–310 m s^(-1)for different propellant gas pressures.Due to the three-barrel structure,the number of injected pellets can be adjusted between one and three.Pellets can be launched sequentially with arbitrary time intervals,which enables flexible applications.The results of the experiments show that pellet fueling efflciency can reach 50%.The energy conflnement time increased by about 7.5–10 ms after pellet injection.展开更多
Based on the two-dimensional kinetic ablation theory of the hydrogen pellet ablation developed by Kuteev [B.V. Kuteev, Nuclear Fusion, 35 (1995) 431], an algorithm of erosion speed and ablation rate calculations for L...Based on the two-dimensional kinetic ablation theory of the hydrogen pellet ablation developed by Kuteev [B.V. Kuteev, Nuclear Fusion, 35 (1995) 431], an algorithm of erosion speed and ablation rate calculations for Li, Be, and B impurity pellets in reactor-relevant plasma has been derived. Results show compatibilities of lithium pellet injection used in α-particle diagnostics are positive in comparison with other solid impurity pellets (e.g. Be, B and C). Using the 2-D Kuteev lentil model, including kinetic effects, we find that currently existing pellet injection techniques will not meet core-fueling requirements for ITER-FEAT. A pressure as high as 254 MPa must be applied to a pellet accelerator with a 200 cm-long single-stage pneumatic gun, in order to accelerate a pellet with a radius rpo = 0.5 cm to a velocity of vpo, 24 × 105 cm/s penetrating 100 cm into the ITER plasma core. Comparisons of pellet velocity- and radius-dependent penetration depth between the Neutral Gas Shielding and the Kuteev's models are made. However, we find that the isotopic effects can lead to a 33% lower pellet speed for solid DT, compared to an identical H2 pellet penetrating the same length in ITER-FEAT plasma, and our calculations show that HFS injection will much improve core fueling efficiency.展开更多
文摘In the ever fusion experiments in SWIP, pellet forming process was carried out through adjusting relative devices by staff member in site, which will make every pellet-forming process slight distinction and will result in pellet difference in shape, size and intensity. In the intervals of HL-2A discharges, staff member have to go site to accomplish the pellet-forming process, this wastes human power and increase the potential danger. So it is necessary to develop a remote control system to perform the pellet-forming process. The control system needs have the features of real-time, reliability and be easy to operate and maintain.
文摘For an analysis of the oxidation behavior of UO2 nuclear fuel pellet under a loss of water coolant accident in a spent nuclear fuel pool of an LWR, thermodynamic assessments of UO2 oxidation were carried out under various atmospheric conditions. In a steam atmosphere, it was assessed that UO2 would not be fully oxidized into U3O8 due to the relatively lower oxygen partial pressure, while UO2 will be fully oxidized into U3O8 in an air atmosphere. In an air and steam mixture atmosphere, the UO2 oxidation was dominantly affected by the air volumetric fraction, because of the relatively higher oxygen partial pressure of air. In addition, the effect of H2 volumetric fraction on the oxygen partial pressure under a mixture atmosphere was calculated, and it was revealed that UO2 pellet oxidation could be reduced above the critical value of H2 volumetric fraction.
基金Supported by the Special Fund for Agro-Scientific Research in the Public Interest(201003063)the Key Technology R&D Program of Jiangsu Province(BE2013412)the Fund for Independent Innovation of Agricultural Sciences in Jiangsu Province(XC(13)3030)~~
文摘At present, the technology of biomass fuel composite molding technique is relatively lagging in China, which brings several negative influences, such as high energy consumption, short service life of the equipment. The current situation of the biomass pellet fuel molding technology at home and abroad was introduced, and the development direction in China was put forward, which was of great significance for enhancing the level of pellet fuel molding technology in China.
基金supported by the National MCF Energy R&D Program of China(No.2019YFE03010004)the National Key R&D Program of China(Nos.2018YFE0309100 and 2017YFE0302000)+1 种基金the National Magnetic Conflnement Fusion Science Program(Nos.2015GB111002 and 2015GB104000)National Natural Science Foundation of China(Nos.11775089,11905077,51821005 and 11575068)。
文摘Pellet injection is an attractive technology for core-fueling and magnetohydrodynamic study in magnetic-conflnement fusion devices like tokamaks and stellarators.It can inject solid hydrogen/deuterium pellets into the plasma with deeper density deposition compared with other fueling methods,such as gas pufflng.A three-barrel H_(2)pellet injection system was installed on the J-TEXT tokamak and experiments were carried out.The pellets are formed in three barrels cooled by a cryocooler and compressor system at around 9 K,and are 0.8 mm/1 mm diameter and 0.8 mm length.The pellet is launched by helium propellant gas and injected from the lowfleld side of the plasma.The normal range of pellet speed is 210–310 m s^(-1)for different propellant gas pressures.Due to the three-barrel structure,the number of injected pellets can be adjusted between one and three.Pellets can be launched sequentially with arbitrary time intervals,which enables flexible applications.The results of the experiments show that pellet fueling efflciency can reach 50%.The energy conflnement time increased by about 7.5–10 ms after pellet injection.
文摘Based on the two-dimensional kinetic ablation theory of the hydrogen pellet ablation developed by Kuteev [B.V. Kuteev, Nuclear Fusion, 35 (1995) 431], an algorithm of erosion speed and ablation rate calculations for Li, Be, and B impurity pellets in reactor-relevant plasma has been derived. Results show compatibilities of lithium pellet injection used in α-particle diagnostics are positive in comparison with other solid impurity pellets (e.g. Be, B and C). Using the 2-D Kuteev lentil model, including kinetic effects, we find that currently existing pellet injection techniques will not meet core-fueling requirements for ITER-FEAT. A pressure as high as 254 MPa must be applied to a pellet accelerator with a 200 cm-long single-stage pneumatic gun, in order to accelerate a pellet with a radius rpo = 0.5 cm to a velocity of vpo, 24 × 105 cm/s penetrating 100 cm into the ITER plasma core. Comparisons of pellet velocity- and radius-dependent penetration depth between the Neutral Gas Shielding and the Kuteev's models are made. However, we find that the isotopic effects can lead to a 33% lower pellet speed for solid DT, compared to an identical H2 pellet penetrating the same length in ITER-FEAT plasma, and our calculations show that HFS injection will much improve core fueling efficiency.
