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BES-5
BES-5, also known as Bouk or Buk (russian: бук, translation=beech), was a Soviet thermoelectric generator that was used to power 31 satellites in the US-A (RORSAT) project. The heat source was a uranium 235 fast fission nuclear reactor (FNR). Background Spacecraft nuclear reactors are typically fast reactors for the following reasons. First, normal moderator materials (carbon, water) add bulk and mass which is not desirable in a spacecraft. Second, for reasons of nucleonics the fuel must be highly enriched to have a lightweight critical mass (similar to small reactor designs on nuclear submarines). Note that some of the 238U (which is fertile and not fissile) will be converted to 239Pu during operation, and this is taken into consideration during the design and while estimating the power output and design life expectancy. Reactor design The design of the BES-5 FNR is such that a sub-critical assembly exists into which a rod of fissile material is inserted. Feedback and mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Nuclear Power Systems In Space
This list of nuclear power systems in space includes nuclear power systems that were flown to space, or at least launched in an attempt to reach space. Such used nuclear power systems include: * radioisotope heater units (RHU) (usually produce heat by spontaneous decay of ) * radioisotope thermoelectric generators (RTG) (usually produce heat by spontaneous decay of and convert it to electricity using a thermoelectric generator) * miniaturized fission reactors (usually produce heat by controlled fission of highly enriched and convert it to electricity using a thermionic converter) Systems never launched are not included here, see Nuclear power in space. Initial total power is provided as either electrical power (We) or thermal power (Wt), depending on the intended application. See also *Outer Space Treaty * List of high-altitude nuclear explosions *Nuclear power in space * List of artificial radiation belts * :Nuclear-powered robots References {{DEFAULTSORT:Nuclear p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
US-A
Upravlyaemy Sputnik Aktivnyy (russian: Управляемый Спутник Активный for Controlled Active Satellite), or US-A, also known in the west as Radar Ocean Reconnaissance Satellite or RORSAT (GRAU index 17F16K), was a series of 33 Soviet reconnaissance satellites. Launched between 1967 and 1988 to monitor NATO and merchant vessels using radar, the satellites were powered by nuclear reactors. Because a return signal from an ordinary target illuminated by a radar transmitter diminishes as the inverse of the fourth power of the distance, for the surveillance radar to work effectively, US-A satellites had to be placed in low Earth orbit. Had they used large solar panels for power, the orbit would have rapidly decayed due to drag through the upper atmosphere. Further, the satellite would have been useless in the shadow of Earth. Hence the majority of the satellites carried type BES-5 nuclear reactors fuelled by uranium-235. Normally the nuclear reactor cores were e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nuclear Power In Space
Nuclear power in space is the use of nuclear power in outer space, typically either small fission systems or radioactive decay for electricity or heat. Another use is for scientific observation, as in a Mössbauer spectrometer. The most common type is a radioisotope thermoelectric generator, which has been used on many space probes and on crewed lunar missions. Small fission reactors for Earth observation satellites, such as the TOPAZ nuclear reactor, have also been flown. A radioisotope heater unit is powered by radioactive decay and can keep components from becoming too cold to function, potentially over a span of decades. The United States tested the SNAP-10A nuclear reactor in space for 43 days in 1965, with the next test of a nuclear reactor power system intended for space use occurring on 13 September 2012 with the Demonstration Using Flattop Fission (DUFF) test of the Kilopower reactor. After a ground-based test of the experimental 1965 Romashka reactor, which used u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kosmos 1402
Kosmos 1402 (russian: Космос 1402) was a Soviet spy satellite that malfunctioned, resulting in the uncontrolled re-entry of its nuclear reactor and its radioactive uranium fuel. Kosmos 1402 was launched on August 30, 1982, and re-entered the atmosphere on 23 January 1983. The fission reactor entered a few days later; on 7 February 1983. Kosmos 1402 was a RORSAT surveillance satellite that used radar for monitoring NATO vessels. The power source for the satellite was a BES-5 nuclear fission reactor, which used about of enriched uranium as a fuel source. The satellite operated in low Earth orbit, and the reactor was designed to eject to a higher parking orbit at the end of the satellite's mission, or in the event of a mishap. This ejection mechanism was implemented in the RORSAT satellites after a nuclear accident caused by a previous malfunction of Kosmos 954, five years earlier over Canada's Northwest Territories. In response to the Kosmos 954 mishap, RORSAT satellites we ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Romashka Reactor
The Romashka reactor (russian: Ромашка, translation=chamomile) was a Soviet experimental nuclear reactor. It began operation in 1964, and was developed by the Kurchatov Institute of Atomic Energy. The reactor used direct thermoelectric conversion to create electricity, rather than heating water to drive a turbine. It is thus similar to a radioisotope thermoelectric generator, but higher power. The Romashka reactor was developed with the intention of using nuclear power in space satellites, but was superseded by the more powerful BES-5 reactor. The project was canceled after the death of Sergei Korolev, who was heavily involved in the project. Reactor design The fuel was of highly enriched uranium (90% ) in the form of UC2 (uranium carbide). A beryllium reflector was used on the ends of the reactor, and electricity was generated using silicon-germanium semiconductors. The Romashka reactor didn't use liquid coolant; it was designed to be simple, compact, and light. Tempe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fast-neutron Reactor
A fast-neutron reactor (FNR) or fast-spectrum reactor or simply a fast reactor is a category of nuclear reactor in which the fission chain reaction is sustained by fast neutrons (carrying energies above 1 MeV or greater, on average), as opposed to slow thermal neutrons used in thermal-neutron reactors. Such a fast reactor needs no neutron moderator, but requires fuel that is relatively rich in fissile material when compared to that required for a thermal-neutron reactor. Around 20 land based fast reactors have been built, accumulating over 400 reactor years of operation globally. The largest of this was the Superphénix Sodium cooled fast reactor in France that was designed to deliver 1,242 MWe. Fast reactors have been intensely studied since the 1950s, as they provide certain decisive advantages over the existing fleet of water cooled and water moderated reactors. These are: * More neutrons are produced when a fission occurs, resulting from the absorption of a fast neutron, t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beryllium
Beryllium is a chemical element with the symbol Be and atomic number 4. It is a steel-gray, strong, lightweight and brittle alkaline earth metal. It is a divalent element that occurs naturally only in combination with other elements to form minerals. Notable gemstones high in beryllium include beryl ( aquamarine, emerald) and chrysoberyl. It is a relatively rare element in the universe, usually occurring as a product of the spallation of larger atomic nuclei that have collided with cosmic rays. Within the cores of stars, beryllium is depleted as it is fused into heavier elements. Beryllium constitutes about 0.0004 percent by mass of Earth's crust. The world's annual beryllium production of 220 tons is usually manufactured by extraction from the mineral beryl, a difficult process because beryllium bonds strongly to oxygen. In structural applications, the combination of high flexural rigidity, thermal stability, thermal conductivity and low density (1.85 times that of water) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermoelectric Generator
A thermoelectric generator (TEG), also called a Seebeck generator, is a solid state device that converts heat flux (temperature differences) directly into electrical energy through a phenomenon called the ''Seebeck effect'' (a form of thermoelectric effect). Thermoelectric generators function like heat engines, but are less bulky and have no moving parts. However, TEGs are typically more expensive and less efficient. Thermoelectric generators could be used in power plants to convert waste heat into additional electrical power and in automobiles as automotive thermoelectric generators (ATGs) to increase fuel efficiency. Radioisotope thermoelectric generators use radioisotopes to generate the required temperature difference to power space probes. History In 1821, Thomas Johann Seebeck discovered that a thermal gradient formed between two different conducting material (has electromagnetic property) can produce electricity. At the heart of the thermoelectric effect is the fact tha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Uranium 235
Uranium-235 (235U or U-235) is an isotope of uranium making up about 0.72% of natural uranium. Unlike the predominant isotope uranium-238, it is fissile, i.e., it can sustain a nuclear chain reaction. It is the only fissile isotope that exists in nature as a primordial nuclide. Uranium-235 has a half-life of 703.8 million years. It was discovered in 1935 by Arthur Jeffrey Dempster. Its fission cross section for slow thermal neutrons is about 584.3±1 barns. For fast neutrons it is on the order of 1 barn. Most but not all neutron absorptions result in fission; a minority result in neutron capture forming uranium-236. Natural decay chain :\begin \ce \begin \ce \\ \ce \end \ce \\ \ce \begin \ce \\ \ce \end \ce \end Fission properties The fission of one atom of uranium-235 releases () inside the reactor. That corresponds to 19.54 TJ/ mol, or 83.14 TJ/kg. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prompt Criticality
In nuclear engineering, prompt criticality describes a nuclear fission event in which criticality (the threshold for an exponentially growing nuclear fission chain reaction) is achieved with prompt neutrons alone (neutrons that are released immediately in a fission reaction) and does not rely on delayed neutrons (neutrons released in the subsequent decay of fission fragments). As a result, prompt supercriticality causes a much more rapid growth in the rate of energy release than other forms of criticality. Nuclear weapons are based on prompt criticality, while nuclear reactors rely on delayed neutrons or external neutrons to achieve criticality. Criticality An assembly is critical if each fission event causes, on average, exactly one additional such event in a continual chain. Such a chain is a self-sustaining fission chain reaction. When a uranium-235 (U-235) atom undergoes nuclear fission, it typically releases between one and seven neutrons (with an average of 2.4). In thi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kosmos 954
Kosmos 954 (russian: Космос 954) was a reconnaissance satellite launched by the Soviet Union in 1977. A malfunction prevented safe separation of its onboard nuclear reactor; when the satellite reentered the Earth's atmosphere the following year, it scattered radioactive debris over northern Canada, some of the debris landing in the Great Slave Lake next to Fort Resolution, NWT. This prompted an extensive multiyear cleanup operation known as Operation Morning Light, which the Canadian government billed the Soviet Union for over Can$6 million, and for which the USSR eventually paid just Can$3 million in compensation. Launch and operation The satellite was part of the Soviet Union's RORSAT programme, a series of reconnaissance satellites which observed ocean traffic, including surface vessels and nuclear submarines, using active radar. It was assigned the Kosmos number 954 and was launched on 18 September 1977 at 13:55 UTC from the Baikonur Cosmodrome, on a Tsyklon-2 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SNAP-10A
SNAP-10A (Systems for Nuclear Auxiliary Power, aka Snapshot for Space Nuclear Auxiliary Power Shot, also known as OPS 4682) was a US experimental nuclear powered satellite launched into space in 1965 as part of the SNAPSHOT program.SNAPSHOT NASA Glenn Research Center, March 20, 2007. Retrieved 3 April 2019. Gunther's Space Page. Retrieved 3 April 2019. The test marked both the world's first operation of a nuclear reactor in orbit, [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
