The COREP （CORE Power） code has been developed by the Reactor Physics Department of the Jozef Stefan Institute for the nuclear design calculations of the PWR （Pressurized Water Reactor） cores. The code and applied...The COREP （CORE Power） code has been developed by the Reactor Physics Department of the Jozef Stefan Institute for the nuclear design calculations of the PWR （Pressurized Water Reactor） cores. The code and applied methods have been developed and tested only for the determination of the pin power in the reactor core. Recent development of the three dimensional visualization capabilities at the author＇s department enables fine mesh neutron flux and power distribution presentation in the whole reactor region. The COREP code has been supplemented with additional option to enable generation of fme mesh neutron flux data in the core and reflector domain. Accuracy of the generated fine mesh results has been determined for the 2-D IAEA and typical NPP Krsko case.展开更多
This research presents the results of system validation tests for an SOFC power system. In the study, the system was heated up without electric device, i.e., the fuel providing the required thermal energy through an i...This research presents the results of system validation tests for an SOFC power system. In the study, the system was heated up without electric device, i.e., the fuel providing the required thermal energy through an integrated BOP （balance of plant）. The ex-situ experiments, without an SOFC stack installed in the system, were fast conducted to investigate the operability of a BOP apparatus. It was found that the BOP possessed high conversion rates for both steam reforming and water gas shift reactions. The total fuel concentration of hydrogen and carbon monoxide from the reformer was around 91.2%. The system validation tests showed that, with the natural gas as fuel, the output power from the stack reached to 1,060 W, while the fuel utilization efficiency and electrical efficiency were 67.16% and 45.0%, respectively. A steady 600-hour system operation test was carried out at an average system temperature of 694℃. Of which, a 36-cell stack was employed for the test. Meanwhile, the current, voltage and output power were 26 A, 32.3 V and 840 W, respectively, and its electrical efficiency was around 33.4%.展开更多
Developing efficient platinum(Pt)-based electrocatalysts is enormously significant for fuel cells.Herein,we report an integrated electrocatalyst of ultralow-Pt alloy encapsulated into nitrogen-doped nanocarbon archite...Developing efficient platinum(Pt)-based electrocatalysts is enormously significant for fuel cells.Herein,we report an integrated electrocatalyst of ultralow-Pt alloy encapsulated into nitrogen-doped nanocarbon architecture for efficient oxygen reduction reaction.This hybrid Pt-based catalyst achieves a mass activity of 3.46 A mg^(-1)_(pt)the potential of 0.9 V vs.RHE with a negligible stability decay after 10,000 cycles.More importantly,this half-cell activity can be expressed at full cell level with a high Pt utilization of 10.22 W mg^(-1)_(Pt cathode)and remarkable durability after 30,000 cycles in single-cell.Experimental and theoretical investigations reveal that a highly strained Pt structure with an optimal Pt-0 binding energy is induced by the incorporation of Co/Ni into Pt lattice,which would account for the improved reaction kinetics.The synergistic catalysis due to nitrogen-doped nanocarbon architecture and active Pt component is responsible for the enhanced catalytic activity.Meanwhile,the strong metal-support interaction and optimized hydrophilic properties of nanocarbon matrix facilitate efficient mass transport and water management.This work may provide significant insights in designing the low-Pt integrated electrocatalysts for fuel cells and beyond.展开更多
Before rise-to-power tests, the actual measured value of heat released from the Reactor Pressure Vessel(RPV) or removed by the Vessel Cooling System(VCS) cannot be obtained. It is difficult for operators to evaluate t...Before rise-to-power tests, the actual measured value of heat released from the Reactor Pressure Vessel(RPV) or removed by the Vessel Cooling System(VCS) cannot be obtained. It is difficult for operators to evaluate the reactor outlet coolant temperature supplied from the High Temperature Engineering Test Reactor(HTTR) before rise-to-power tests. Therefore, when the actual measured value of heat released from the RPV or removed by the VCS are changed during rise-to-power tests, operators need to evaluate quickly, within a few minutes, the heat removed by the VCS and the reactor outlet coolant temperature of 30 MW, at 100% reactor power, before the temperature achieves 967℃ which is the maximum temperature limit generating the reactor scram. In this paper, a rapid evaluation method for use by operators is presented. The difference between the experimental and analytical results was within 30(k W) and it is appropriate that the presented evaluation method can be applied; therefore, operators can analyze the heat removed by the VCS quickly, within a few minutes, before and during Rise-to-Power Tests.展开更多
文摘The COREP （CORE Power） code has been developed by the Reactor Physics Department of the Jozef Stefan Institute for the nuclear design calculations of the PWR （Pressurized Water Reactor） cores. The code and applied methods have been developed and tested only for the determination of the pin power in the reactor core. Recent development of the three dimensional visualization capabilities at the author＇s department enables fine mesh neutron flux and power distribution presentation in the whole reactor region. The COREP code has been supplemented with additional option to enable generation of fme mesh neutron flux data in the core and reflector domain. Accuracy of the generated fine mesh results has been determined for the 2-D IAEA and typical NPP Krsko case.
文摘This research presents the results of system validation tests for an SOFC power system. In the study, the system was heated up without electric device, i.e., the fuel providing the required thermal energy through an integrated BOP （balance of plant）. The ex-situ experiments, without an SOFC stack installed in the system, were fast conducted to investigate the operability of a BOP apparatus. It was found that the BOP possessed high conversion rates for both steam reforming and water gas shift reactions. The total fuel concentration of hydrogen and carbon monoxide from the reformer was around 91.2%. The system validation tests showed that, with the natural gas as fuel, the output power from the stack reached to 1,060 W, while the fuel utilization efficiency and electrical efficiency were 67.16% and 45.0%, respectively. A steady 600-hour system operation test was carried out at an average system temperature of 694℃. Of which, a 36-cell stack was employed for the test. Meanwhile, the current, voltage and output power were 26 A, 32.3 V and 840 W, respectively, and its electrical efficiency was around 33.4%.
基金the National Natural Science Foundation of China(22075092 and 21805104)the Program for Huazhong University of Science and Technology(HUST)Academic Frontier Youth Team(2018QYTD15)The Innovation and Talent Recruitment Base of New Energy Chemistry and Device(B21003)。
文摘Developing efficient platinum(Pt)-based electrocatalysts is enormously significant for fuel cells.Herein,we report an integrated electrocatalyst of ultralow-Pt alloy encapsulated into nitrogen-doped nanocarbon architecture for efficient oxygen reduction reaction.This hybrid Pt-based catalyst achieves a mass activity of 3.46 A mg^(-1)_(pt)the potential of 0.9 V vs.RHE with a negligible stability decay after 10,000 cycles.More importantly,this half-cell activity can be expressed at full cell level with a high Pt utilization of 10.22 W mg^(-1)_(Pt cathode)and remarkable durability after 30,000 cycles in single-cell.Experimental and theoretical investigations reveal that a highly strained Pt structure with an optimal Pt-0 binding energy is induced by the incorporation of Co/Ni into Pt lattice,which would account for the improved reaction kinetics.The synergistic catalysis due to nitrogen-doped nanocarbon architecture and active Pt component is responsible for the enhanced catalytic activity.Meanwhile,the strong metal-support interaction and optimized hydrophilic properties of nanocarbon matrix facilitate efficient mass transport and water management.This work may provide significant insights in designing the low-Pt integrated electrocatalysts for fuel cells and beyond.
文摘Before rise-to-power tests, the actual measured value of heat released from the Reactor Pressure Vessel(RPV) or removed by the Vessel Cooling System(VCS) cannot be obtained. It is difficult for operators to evaluate the reactor outlet coolant temperature supplied from the High Temperature Engineering Test Reactor(HTTR) before rise-to-power tests. Therefore, when the actual measured value of heat released from the RPV or removed by the VCS are changed during rise-to-power tests, operators need to evaluate quickly, within a few minutes, the heat removed by the VCS and the reactor outlet coolant temperature of 30 MW, at 100% reactor power, before the temperature achieves 967℃ which is the maximum temperature limit generating the reactor scram. In this paper, a rapid evaluation method for use by operators is presented. The difference between the experimental and analytical results was within 30(k W) and it is appropriate that the presented evaluation method can be applied; therefore, operators can analyze the heat removed by the VCS quickly, within a few minutes, before and during Rise-to-Power Tests.
