Electronuclear educational program
Dedicated to the project "Creating a transport and energy module based on megawatt class N-AETs". The theory of calculation of nuclear power plants and some reflections.
Any type of NPP includes three main elements: a source of primary energy (nuclear reactor or radioisotope generator), a converter of primary energy into electrical energy and a device for diverting a part of the primary energy not used in the conversion process into the surrounding space.
')
The solid lines in the figure show the supply and removal of thermal energy using coolant circuits or heat pipes.
In some cases (dashed lines), heat is directly transferred from the source to the converter and to the device for heat removal due to thermal conductivity of the corresponding connecting devices.
Heat converters are divided into machine and machineless or direct. Gas turbine and steam turbine installations are referred to as machine converters. It is also possible to use piston expansion machines and Stirling engines. The main types of direct heat transducers, which are of particular importance for space energy, are thermoelectric and thermionic emitters (see pictures).
Long-lasting heat removal in space without mass ejection is possible only by radiation. For this reason, devices for heat removal are cooler emitters. The most widespread are designs of refrigerating emitters in the form of finned tubes through which coolant flows, connected in cylindrical or conical panels. Recently, refrigeration emitters based on heat pipes have also been widely used. In some cases, the coolant may be absent, and thermal energy is radiated directly from the surface of the converter, which is finned for this purpose.
Refrigerated emitters of the tubular type are among the most significant in terms of mass and dimensions of the elements of the power plant. The proportion of their mass, depending on the type and power of the NPI, can be from 30 to 70%.
In addition to the considered basic elements, space devices have other devices and components. These include: protection from the radiation of a nuclear reactor, pipelines, pumps for pumping coolant, power frames, etc. The characteristics of these devices are determined mainly by their structural perfection and contribute to ensuring the optimal basic parameters of the workflow, without having a noticeable effect on the choice of type, schemes and the parameters of the main elements.
The rest can be found in the book "Power plants with nuclear sources of primary energy" and in Wikipedia in the article "Nuclear reactors on spacecraft . "
Reflections I spent in the framework of the thesis ( matkad ) 15 years ago. Intermediate orbit is needed because, according to the existing international agreements, it is impossible to turn on a nuclear power unit below 800 km.
What happened in a nutshell:
Angara with Plesetsk makes a low 24 tons. With an electrical power of 150kW, a payload of 3,500kg for 153 days reaches the GSO.
New installation claimed megawatt class. If this is thermal power (as I think), then with existing technologies, 50kW of electricity can be squeezed out of it. Then a simple flight to the GSO will take years and in general it is not clear how this will reduce the flight to Mars.
Megawatts of electricity somewhat alter the situation of flights, but it greatly complicates the discharge of excess heat.
Fellow developers, share information or take to yourself. You are welcome.
Theory
Any type of NPP includes three main elements: a source of primary energy (nuclear reactor or radioisotope generator), a converter of primary energy into electrical energy and a device for diverting a part of the primary energy not used in the conversion process into the surrounding space.
')
The solid lines in the figure show the supply and removal of thermal energy using coolant circuits or heat pipes.
In some cases (dashed lines), heat is directly transferred from the source to the converter and to the device for heat removal due to thermal conductivity of the corresponding connecting devices.
Heat converters are divided into machine and machineless or direct. Gas turbine and steam turbine installations are referred to as machine converters. It is also possible to use piston expansion machines and Stirling engines. The main types of direct heat transducers, which are of particular importance for space energy, are thermoelectric and thermionic emitters (see pictures).
Long-lasting heat removal in space without mass ejection is possible only by radiation. For this reason, devices for heat removal are cooler emitters. The most widespread are designs of refrigerating emitters in the form of finned tubes through which coolant flows, connected in cylindrical or conical panels. Recently, refrigeration emitters based on heat pipes have also been widely used. In some cases, the coolant may be absent, and thermal energy is radiated directly from the surface of the converter, which is finned for this purpose.
Refrigerated emitters of the tubular type are among the most significant in terms of mass and dimensions of the elements of the power plant. The proportion of their mass, depending on the type and power of the NPI, can be from 30 to 70%.
In addition to the considered basic elements, space devices have other devices and components. These include: protection from the radiation of a nuclear reactor, pipelines, pumps for pumping coolant, power frames, etc. The characteristics of these devices are determined mainly by their structural perfection and contribute to ensuring the optimal basic parameters of the workflow, without having a noticeable effect on the choice of type, schemes and the parameters of the main elements.
The rest can be found in the book "Power plants with nuclear sources of primary energy" and in Wikipedia in the article "Nuclear reactors on spacecraft . "
Reflections
Reflections I spent in the framework of the thesis ( matkad ) 15 years ago. Intermediate orbit is needed because, according to the existing international agreements, it is impossible to turn on a nuclear power unit below 800 km.
What happened in a nutshell:
Angara with Plesetsk makes a low 24 tons. With an electrical power of 150kW, a payload of 3,500kg for 153 days reaches the GSO.
New installation claimed megawatt class. If this is thermal power (as I think), then with existing technologies, 50kW of electricity can be squeezed out of it. Then a simple flight to the GSO will take years and in general it is not clear how this will reduce the flight to Mars.
Megawatts of electricity somewhat alter the situation of flights, but it greatly complicates the discharge of excess heat.
Fellow developers, share information or take to yourself. You are welcome.
Source: https://habr.com/ru/post/377331/
All Articles