With the advantages of high reliability, power density, and long life, nuclear power reactors have become a promising option for space power. In this study, the Reactor Excursion and Leak Analysis Program 5(RELAP5), w...With the advantages of high reliability, power density, and long life, nuclear power reactors have become a promising option for space power. In this study, the Reactor Excursion and Leak Analysis Program 5(RELAP5), with the implementation of sodium–potassium eutectic alloy(NaK-78) properties and heat transfer correlations, is adopted to analyze the thermal–hydraulic characteristics of the space nuclear reactor TOPAZ-Ⅱ.A RELAP5 model including thermionic fuel elements(TFEs), reactor core, radiator, coolant loop, and volume accumulator is established. The temperature reactivity feedback effects of the fuel, TFE emitter, TFE collector,moderator, and reactivity insertion effects of the control drums and safety drums are considered. To benchmark the integrated TOPAZ-Ⅱ system model, an electrical ground test of the fully integrated TOPAZ-Ⅱ system, the V-71 unit,is simulated and analyzed. The calculated coolant temperature and system pressure are in acceptable agreement with the experimental data for the maximum relative errors of 8 and 10%, respectively. The detailed thermal–hydraulic characteristics of TOPAZ-Ⅱ are then simulated and analyzed at the steady state. The calculation results agree well with the design values. The current work provides a solid foundation for space reactor design and transient analysis in the future.展开更多
Project New Orion entails a pulsed nuclear space propulsion system that utilizes photofission through the implementation of an ultra-intense laser. The historical origins derive from the endeavors of Project Orion, wh...Project New Orion entails a pulsed nuclear space propulsion system that utilizes photofission through the implementation of an ultra-intense laser. The historical origins derive from the endeavors of Project Orion, which utilized thermonuclear devices to impart a considerable velocity increment on the respective spacecraft. The shear magnitude of Project Orion significantly detracts from the likelihood of progressive research development testing and evaluation. Project New Orion incorporates a more feasible pathway for the progressive research development testing and evaluation of the pulsed nuclear space propulsion system. Photofission through the application of an ultra-intense laser enables a much more controllable and scalable nuclear yield. The energy source for the ultra-intense laser is derived from a first stage liquid hydrogen and liquid oxygen chemical propulsion system. A portion of the thermal/kinetic energy of the rocket propulsive fluid is converted to electrical energy through a magneto-hydrodynamic generator with cryogenic propellant densification for facilitating the integral superconducting magnets. Fundamental analysis of Project New Orion demonstrates the capacity to impart a meaningful velocity increment through ultra-intense laser derived photofission on a small spacecraft.展开更多
In this paper, we investigate local properties in the system of completely 1-summing mapping spaces. We introduce notions of injectivity, local reflexivity, exactness, nuclearity and finite-representability in the sys...In this paper, we investigate local properties in the system of completely 1-summing mapping spaces. We introduce notions of injectivity, local reflexivity, exactness, nuclearity and finite-representability in the system of completely 1-summing mapping spaces. First we obtain that if V has WEP, V is locally reflexive in the system (Ⅱ<sub>1</sub>(⋅,⋅), π<sub>1</sub>(⋅)) if and only if it is locally reflexive in the system (Ⅰ(⋅,⋅), t(⋅)). Furthermore we prove that an operator space V ⊆ B(H) is exact in the system (Ⅱ<sub>1</sub>(⋅,⋅), π<sub>1</sub>(⋅)) if and only if V is finitely representable in {M<sub>n</sub>}<sub>n∈N</sub> in the system (Ⅱ<sub>1</sub>(⋅,⋅), π<sub>1</sub>(⋅)). At last, we show that an operator space V is finitely representable in {M<sub>n</sub>}<sub>n∈N</sub> in the system (Ⅱ<sub>1</sub>(⋅,⋅), π<sub>1</sub>(⋅)) if and only if V = C.展开更多
基金supported by the China National Postdoctoral Program for Innovative Talents(No.BX201600124)China Postdoctoral Science Foundation(No.2016M600796)the National Natural Science Foundation of China(No.11605131)
文摘With the advantages of high reliability, power density, and long life, nuclear power reactors have become a promising option for space power. In this study, the Reactor Excursion and Leak Analysis Program 5(RELAP5), with the implementation of sodium–potassium eutectic alloy(NaK-78) properties and heat transfer correlations, is adopted to analyze the thermal–hydraulic characteristics of the space nuclear reactor TOPAZ-Ⅱ.A RELAP5 model including thermionic fuel elements(TFEs), reactor core, radiator, coolant loop, and volume accumulator is established. The temperature reactivity feedback effects of the fuel, TFE emitter, TFE collector,moderator, and reactivity insertion effects of the control drums and safety drums are considered. To benchmark the integrated TOPAZ-Ⅱ system model, an electrical ground test of the fully integrated TOPAZ-Ⅱ system, the V-71 unit,is simulated and analyzed. The calculated coolant temperature and system pressure are in acceptable agreement with the experimental data for the maximum relative errors of 8 and 10%, respectively. The detailed thermal–hydraulic characteristics of TOPAZ-Ⅱ are then simulated and analyzed at the steady state. The calculation results agree well with the design values. The current work provides a solid foundation for space reactor design and transient analysis in the future.
文摘Project New Orion entails a pulsed nuclear space propulsion system that utilizes photofission through the implementation of an ultra-intense laser. The historical origins derive from the endeavors of Project Orion, which utilized thermonuclear devices to impart a considerable velocity increment on the respective spacecraft. The shear magnitude of Project Orion significantly detracts from the likelihood of progressive research development testing and evaluation. Project New Orion incorporates a more feasible pathway for the progressive research development testing and evaluation of the pulsed nuclear space propulsion system. Photofission through the application of an ultra-intense laser enables a much more controllable and scalable nuclear yield. The energy source for the ultra-intense laser is derived from a first stage liquid hydrogen and liquid oxygen chemical propulsion system. A portion of the thermal/kinetic energy of the rocket propulsive fluid is converted to electrical energy through a magneto-hydrodynamic generator with cryogenic propellant densification for facilitating the integral superconducting magnets. Fundamental analysis of Project New Orion demonstrates the capacity to impart a meaningful velocity increment through ultra-intense laser derived photofission on a small spacecraft.
文摘In this paper, we investigate local properties in the system of completely 1-summing mapping spaces. We introduce notions of injectivity, local reflexivity, exactness, nuclearity and finite-representability in the system of completely 1-summing mapping spaces. First we obtain that if V has WEP, V is locally reflexive in the system (Ⅱ<sub>1</sub>(⋅,⋅), π<sub>1</sub>(⋅)) if and only if it is locally reflexive in the system (Ⅰ(⋅,⋅), t(⋅)). Furthermore we prove that an operator space V ⊆ B(H) is exact in the system (Ⅱ<sub>1</sub>(⋅,⋅), π<sub>1</sub>(⋅)) if and only if V is finitely representable in {M<sub>n</sub>}<sub>n∈N</sub> in the system (Ⅱ<sub>1</sub>(⋅,⋅), π<sub>1</sub>(⋅)). At last, we show that an operator space V is finitely representable in {M<sub>n</sub>}<sub>n∈N</sub> in the system (Ⅱ<sub>1</sub>(⋅,⋅), π<sub>1</sub>(⋅)) if and only if V = C.
