Radioactive engine. How does a nuclear engine work?

© Oksana Viktorova/Collage/Ridus

Statement made by Vladimir Putin during his address Federal Assembly, about availability in Russia cruise missile, driven by a nuclear-powered engine, caused a storm of excitement in society and the media. At the same time, until recently, quite little was known to both the general public and specialists about what such an engine is and the possibilities of its use.

Reedus tried to figure out what kind of technical device the president could be talking about and what made it unique.

Considering that the presentation in the Manege was not made for an audience of technical specialists, but for the “general” public, its authors could have allowed a certain substitution of concepts, Georgiy Tikhomirov, deputy director of the Institute of Nuclear Physics and Technology of the National Research Nuclear University MEPhI, does not rule out.

“What the president said and showed, experts call compact power plants, experiments with which were carried out initially in aviation, and then in deep space exploration. These were attempts to solve the insoluble problem of a sufficient supply of fuel when flying over unlimited distances. In this sense, the presentation is completely correct: the presence of such an engine ensures an arbitrary power supply for the systems of a rocket or any other device for a long time" he told Reedus.

Work with such an engine in the USSR began exactly 60 years ago under the leadership of academicians M. Keldysh, I. Kurchatov and S. Korolev. In the same years, similar work was carried out in the USA, but was discontinued in 1965. In the USSR, work continued for about another decade before it was also considered irrelevant. Perhaps that’s why Washington didn’t react too much, saying that they were not surprised by the presentation of the Russian missile.

In Russia, the idea of ​​a nuclear engine has never died - in particular, since 2009, the practical development of such a plant has been underway. Judging by the timing, the tests announced by the president fit perfectly into this joint project of Roscosmos and Rosatom - since the developers planned to conduct field tests of the engine in 2018. Perhaps, due to political reasons, they pushed themselves a little and moved the deadlines “to the left”.

“Technologically, it is designed in such a way that the nuclear power unit heats the gas coolant. And this heated gas either rotates the turbine or creates jet thrust directly. A certain cunning in the presentation of the rocket that we heard is that its flight range is not infinite: it is limited by the volume of the working fluid - liquid gas, which can physically be pumped into the rocket tanks,” says the specialist.

At the same time, a space rocket and a cruise missile have fundamentally different schemes flight control, since they have different tasks. The first flies in airless space, it does not need to maneuver - it is enough to give it an initial impulse, and then it moves along the calculated ballistic trajectory.

A cruise missile, on the other hand, must continuously change its trajectory, for which it must have a sufficient supply of fuel to create impulses. Whether this fuel will be ignited by a nuclear power plant or a traditional one is not important in this case. The only thing that matters is the supply of this fuel, Tikhomirov emphasizes.

“The meaning of a nuclear installation when flying into deep space is the presence on board of an energy source to power the systems of the device for an unlimited time. In this case, there may be not only a nuclear reactor, but also radioisotope thermoelectric generators. But the meaning of such an installation on a rocket, the flight of which will not last more than a few tens of minutes, is not yet entirely clear to me,” the physicist admits.

The Manege report was only a couple of weeks late compared to NASA's February 15 announcement that the Americans were resuming research work on a nuclear rocket engine that they abandoned half a century ago.

By the way, in November 2017, the China Aerospace Science and Technology Corporation (CASC) announced that a nuclear-powered spacecraft would be created in China by 2045. Therefore, today we can safely say that the global nuclear propulsion race has begun.

Skeptics argue that the creation of a nuclear engine is not a significant progress in the field of science and technology, but only a “modernization of a steam boiler”, where instead of coal and firewood, uranium acts as fuel, and hydrogen acts as a working fluid. Is the NRE (nuclear jet engine) so hopeless? Let's try to figure it out.

First rockets

All the achievements of mankind in the exploration of near-Earth space can be safely attributed to chemical jet engines. The operation of such power units is based on the conversion of the energy of the chemical reaction of fuel combustion in an oxidizer into the kinetic energy of the jet stream, and, consequently, the rocket. The fuel used is kerosene, liquid hydrogen, heptane (for liquid propellant rocket engines (LPRE)) and a polymerized mixture of ammonium perchlorate, aluminum and iron oxide (for solid propellant rocket engines (SRRE)).

It is common knowledge that the first rockets used for fireworks appeared in China in the second century BC. They rose into the sky thanks to the energy of powder gases. The theoretical research of the German gunsmith Konrad Haas (1556), Polish general Kazimir Semenovich (1650), and Russian Lieutenant General Alexander Zasyadko made a significant contribution to the development of rocket technology.

The American scientist Robert Goddard received a patent for the invention of the first liquid-propellant rocket. His apparatus, weighing 5 kg and about 3 m long, running on gasoline and liquid oxygen, took 2.5 s in 1926. flew 56 meters.

Chasing speed

Serious experimental work on the creation of serial chemical jet engines started in the 30s of the last century. In the Soviet Union, V. P. Glushko and F. A. Tsander are rightfully considered the pioneers of rocket engine construction. With their participation, the RD-107 and RD-108 power units were developed, which ensured the USSR's primacy in space exploration and laid the foundation for Russia's future leadership in the field of manned space exploration.

During the modernization of the liquid-turbine engine, it became clear that the theoretical maximum speed of the jet stream could not exceed 5 km/s. This may be enough to study near-Earth space, but flights to other planets, and even more so to the stars, will remain a pipe dream for humanity. As a result, already in the middle of the last century, projects for alternative (non-chemical) rocket engines began to appear. The most popular and promising installations were those using the energy of nuclear reactions. The first experimental samples of nuclear space engines (NRE) in the Soviet Union and the USA passed test tests back in 1970. However, after the Chernobyl disaster, under public pressure, work in this area was suspended (in the USSR in 1988, in the USA - since 1994).

The operation of nuclear power plants is based on the same principles as thermochemical ones. The only difference is that the heating of the working fluid is carried out by the energy of decay or fusion of nuclear fuel. The energy efficiency of such engines significantly exceeds chemical ones. For example, the energy that can be released by 1 kg of the best fuel (a mixture of beryllium with oxygen) is 3 × 107 J, while for polonium isotopes Po210 this value is 5 × 1011 J.

The released energy in a nuclear engine can be used in various ways:

heating the working fluid emitted through the nozzles, as in a traditional liquid-propellant rocket engine, after conversion into electricity, ionizing and accelerating particles of the working fluid, creating an impulse directly by fission or synthesis products. Even ordinary water can act as a working fluid, but the use of alcohol will be much more effective, ammonia or liquid hydrogen. Depending on the state of aggregation of the fuel for the reactor, nuclear rocket engines are divided into solid-, liquid- and gas-phase. The most developed nuclear propulsion engine is with a solid-phase fission reactor, using fuel rods (fuel elements) used in nuclear power plants as fuel. The first such engine within American project Nerva underwent ground testing in 1966, operating for about two hours.

Design features

At the heart of any nuclear space engine is a reactor consisting of a core and a beryllium reflector housed in a power housing. The fission of atoms of a combustible substance, usually uranium U238, enriched in U235 isotopes, occurs in the core. To impart certain properties to the decay process of nuclei, moderators are also located here - refractory tungsten or molybdenum. If the moderator is included in the fuel rods, the reactor is called homogeneous, and if it is placed separately, it is called heterogeneous. The nuclear engine also includes a working fluid supply unit, controls, shadow radiation protection, and a nozzle. Structural elements and components of the reactor, which experience high thermal loads, are cooled by the working fluid, which is then pumped into the fuel assemblies by a turbopump unit. Here it is heated to almost 3,000˚C. Flowing through the nozzle, the working fluid creates jet thrust.

Typical reactor controls are control rods and turntables made of a neutron-absorbing substance (boron or cadmium). The rods are placed directly in the core or in special reflector niches, and the rotary drums are placed on the periphery of the reactor. By moving the rods or turning the drums, the number of fissile nuclei per unit time is changed, regulating the level of energy release of the reactor, and, consequently, its thermal power.

To reduce the intensity of neutron and gamma radiation, which is dangerous for all living things, primary reactor protection elements are placed in the power building.

Increased efficiency

A liquid-phase nuclear engine is similar in operating principle and design to solid-phase ones, but the liquid state of the fuel makes it possible to increase the temperature of the reaction, and, consequently, the thrust of the power unit. So, if for chemical units (liquid turbojet engines and solid propellant rocket engines) the maximum specific impulse (jet flow velocity) is 5,420 m/s, for solid-phase nuclear engines and 10,000 m/s is far from the limit, then the average value of this indicator for gas-phase nuclear propellant engines lies in the range 30,000 - 50,000 m/s.

There are two types of gas-phase nuclear engine projects:

An open cycle, in which a nuclear reaction occurs inside a plasma cloud from a working fluid held electromagnetic field and absorbing all the generated heat. Temperatures can reach several tens of thousands of degrees. In this case, the active region is surrounded by a heat-resistant substance (for example, quartz) - a nuclear lamp that freely transmits emitted energy. In installations of the second type, the temperature of the reaction will be limited by the melting point of the flask material. At the same time, the energy efficiency of a nuclear space engine is slightly reduced (specific impulse up to 15,000 m/s), but efficiency and radiation safety are increased.

Practical achievements

Formally, the American scientist and physicist Richard Feynman is considered to be the inventor of the nuclear power plant. The start of large-scale work on the development and creation of nuclear engines for spacecraft as part of the Rover program was given at the Los Alamos Research Center (USA) in 1955. American inventors preferred installations with a homogeneous nuclear reactor. The first experimental sample of "Kiwi-A" was assembled at a plant at the nuclear center in Albuquerque (New Mexico, USA) and tested in 1959. The reactor was placed vertically on the stand with the nozzle upward. During the tests, a heated stream of spent hydrogen was released directly into the atmosphere. And although the rector worked for low power only about 5 minutes, the success inspired the developers.

In the Soviet Union, a powerful impetus for such research was given by the meeting of the “three great Cs” that took place in 1959 at the Institute of Atomic Energy - the creator atomic bomb I.V. Kurchatov, the chief theorist of Russian cosmonautics M.V. Keldysh and the general designer of Soviet rockets S.P. Korolev. Unlike the American model, the Soviet RD-0410 engine, developed at the design bureau of the Khimavtomatika association (Voronezh), had a heterogeneous reactor. Fire tests took place at a training ground near Semipalatinsk in 1978.

It is worth noting that quite a lot of theoretical projects were created, but before practical implementation it never came to fruition. The reasons for this were the presence of a huge number of problems in materials science, the lack of human and financial resources.

For note: an important practical achievement was the flight testing of nuclear-powered aircraft. In the USSR, the most promising was the experimental strategic bomber Tu-95LAL, in the USA - the B-36.

Project "Orion" or pulsed nuclear rocket engines

For flights in space, a pulsed nuclear engine was first proposed to be used in 1945 by an American mathematician of Polish origin, Stanislaw Ulam. In the next decade, the idea was developed and refined by T. Taylor and F. Dyson. The bottom line is that the energy of small nuclear charges, detonated at some distance from the pushing platform on the bottom of the rocket, imparts great acceleration to it.

During the Orion project, launched in 1958, it was planned to equip a rocket with just such an engine capable of delivering people to the surface of Mars or the orbit of Jupiter. The crew, located in the bow compartment, would be protected from the destructive effects of gigantic accelerations by a damping device. The result of detailed engineering work was marching tests of a large-scale mock-up of the ship to study flight stability (ordinary explosives were used instead of nuclear charges). Due to the high cost, the project was closed in 1965.

Similar ideas for creating an “explosive aircraft” were expressed by Soviet academician A. Sakharov in July 1961. To launch the ship into orbit, the scientist proposed using conventional liquid-propellant rocket engines.

Alternative projects

A huge number of projects never went beyond theoretical research. Among them there were many original and very promising ones. The idea of ​​a nuclear power plant based on fissile fragments is confirmed. Design features and the design of this engine makes it possible to do without a working fluid at all. The jet stream, which provides the necessary thrust characteristics, is formed from spent nuclear material. The reactor is based on rotating disks with subcritical nuclear mass (atomic fission coefficient less than unity). When rotating in the sector of the disk located in the core, a chain reaction is started and decaying high-energy atoms are directed into the engine nozzle, forming a jet stream. The preserved intact atoms will take part in the reaction at the next revolutions of the fuel disk.

Projects of a nuclear engine for ships performing certain tasks in near-Earth space, based on RTGs (radioisotope thermoelectric generators), are quite workable, but such installations are of little promise for interplanetary, and even more so interstellar flights.

Engines powered by nuclear fusion have enormous potential. Already at the present stage of development of science and technology, a pulsed installation is quite feasible, in which, like the Orion project, thermonuclear charges will be detonated under the bottom of the rocket. However, many experts consider the implementation of controlled nuclear fusion to be a matter of the near future.

Advantages and disadvantages of nuclear powered engines

The indisputable advantages of using nuclear engines as power units for spacecraft include their high energy efficiency, providing high specific impulse and good thrust performance (up to a thousand tons in airless space), and impressive energy reserves during autonomous operation. The current level of scientific and technological development makes it possible to ensure the comparative compactness of such an installation.

The main drawback of nuclear propulsion engines, which caused the curtailment of design and research work, is the high radiation hazard. This is especially true when conducting ground-based fire tests, as a result of which radioactive gases, uranium compounds and its isotopes, and the destructive effects of penetrating radiation may enter the atmosphere along with the working fluid. For the same reasons, it is unacceptable to launch a spacecraft equipped with a nuclear engine directly from the surface of the Earth.

Present and future

According to the assurances of Academician of the Russian Academy of Sciences, General Director of the Keldysh Center Anatoly Koroteev, it is fundamentally new type nuclear engine in Russia will be created in the near future. The essence of the approach is that the energy of the space reactor will be directed not to directly heating the working fluid and forming a jet stream, but to produce electricity. The role of propulsion in the installation is assigned to a plasma engine, the specific thrust of which is 20 times higher than the thrust of chemical jet devices existing today. The head enterprise of the project is a division of the state corporation Rosatom, JSC NIKIET (Moscow).

Full-scale prototype tests were successfully completed back in 2015 on the basis of NPO Mashinostroeniya (Reutov). The date for the start of flight testing of the nuclear power plant is November of this year. Essential Elements and the systems will have to be tested, including on board the ISS.

The new Russian nuclear engine operates in a closed cycle, which completely eliminates the release of radioactive substances into the surrounding space. Mass and overall characteristics The main elements of the power plant ensure its use with existing domestic Proton and Angara launch vehicles.

Valery Lebedev (review)

• In history, there have already been developments of cruise missiles with a ramjet nuclear air engine: this is the SLAM rocket (aka Pluto) in the USA with the TORY-II reactor (1959), the Avro Z-59 concept in the UK, developments in the USSR.
• Let's touch on the principle of operation of a rocket with a nuclear reactor. We are talking only about a ramjet nuclear engine, which was precisely what was meant in Putin's speech in his story about a cruise missile with an unlimited flight range and complete invulnerability. The atmospheric air in this rocket is heated by the nuclear assembly to high temperatures and is ejected from the rear nozzle at high speed. Tested in Russia (in the 60s) and among the Americans (since 1959). It has two significant drawbacks: 1. It stinks like the same nuclear bomb, so during the flight everything on the trajectory will be clogged. 2. In the thermal range it stinks so much that even a North Korean satellite with radio tubes can see it from space. Accordingly, you can knock down such a flying kerosene stove with complete confidence.
  So the cartoons shown in the Manege led to bewilderment, which grew into concern about the (mental) health of the director of this garbage.
  IN Soviet time such pictures (posters and other pleasures for generals) were called “Cheburashkas”.

  In general, this is a conventional straight-through design, axisymmetric with a streamlined central body and shell. The shape of the central body is such that, due to shock waves at the inlet, the air is compressed (the operating cycle starts at a speed of 1 M and higher, to which it is accelerated by a starting accelerator using conventional solid fuel);
  - inside the central body there is a nuclear heat source with a monolithic core;
  - the central body is connected to the shell by 12-16 plate radiators, where heat is removed from the core by heat pipes. The radiators are located in the expansion zone in front of the nozzle;
  - material of radiators and central body, for example, VNDS-1, which maintains structural strength up to 3500 K in the limit;
  - to be sure, we heat it up to 3250 K. The air, flowing around the radiators, heats up and cools them. It then passes through the nozzle, creating thrust;
  - to cool the shell to acceptable temperatures, we build an ejector around it, which at the same time increases thrust by 30-50%.

  An encapsulated monolithic nuclear power plant unit can either be installed in the housing before launch, or kept in a subcritical state until launch, and the nuclear reaction can be started if necessary. I don’t know how exactly, this is an engineering problem (and therefore amenable to solution). So this is clearly a weapon of the first strike, don’t go to grandma.
  An encapsulated nuclear power plant unit can be made in such a way that it is guaranteed not to be destroyed upon impact in the event of an accident. Yes, it will turn out to be heavy - but it will turn out to be heavy in any case.

  To reach hypersound, you will need to allocate a completely indecent energy density per unit time to the working fluid. With a 9/10 probability, existing materials will not be able to handle this over long periods of time (hours/days/weeks), the rate of degradation will be insane.

  And in general, the environment there will be aggressive. Protection from radiation is heavy, otherwise all the sensors/electronics can be thrown into a landfill at once (those interested can remember Fukushima and the questions: “why weren’t robots given the job of cleaning?”).

  Etc.... Such a prodigy will “glow” significantly. It is not clear how to transmit control commands to it (if everything is completely screened there).

  Let's touch on authentically created missiles with a nuclear power plant - an American design - the SLAM missile with the TORY-II reactor (1959).

  Here is this engine with a reactor:

  The SLAM concept was a three-mach low-flying rocket of impressive dimensions and weight (27 tons, 20+ tons after the launch boosters were jettisoned). The terribly expensive low-flying supersonic made it possible to make maximum use of the presence of a practically unlimited source of energy on board; in addition, an important feature of a nuclear air jet engine is the improvement of operating efficiency (thermodynamic cycle) with increasing speed, i.e. the same idea, but at speeds of 1000 km/h it would have a much heavier and larger engine. Finally, 3M at an altitude of a hundred meters in 1965 meant invulnerability to air defense.

  

  Engine TORY-IIC. The fuel elements in the active zone are hexagonal hollow tubes made of UO2, covered with a protective ceramic shell, assembled in incalo fuel assemblies.

  It turns out that previously the concept of a Cruise Missile with a nuclear power plant was “tied up” at high speed, where the advantages of the concept were strong, and competitors with hydrocarbon fuel were weakening.

• Video about the old American SLAM rocket

• The missile shown at Putin’s presentation is transonic or weakly supersonic (if, of course, you believe that it is the one in the video). But at the same time, the size of the reactor decreased significantly compared to TORY-II from the SLAM rocket, where it was as much as 2 meters including the radial neutron reflector made of graphite.
  Diagram of the SLAM rocket. All drives are pneumatic, the control equipment is located in a radiation-attenuating capsule.

  Is it even possible to install a reactor with a diameter of 0.4-0.6 meters? Let's start with a fundamentally minimal reactor - a Pu239 pig. Good example The implementation of such a concept is the Kilopower space reactor, which, however, uses U235. The diameter of the reactor core is only 11 centimeters! If we switch to plutonium 239, the size of the core will drop by another 1.5-2 times.
  Now from minimum size we will begin to step towards a real nuclear air jet engine, remembering the difficulties. The very first thing to add to the size of the reactor is the size of the reflector - in particular, in Kilopower BeO triples the size. Secondly, we cannot use U or Pu blanks - they will simply burn out in the air flow in just a minute. A shell is needed, for example from incaloy, which resists instant oxidation up to 1000 C, or other nickel alloys with a possible ceramic coating. Application large quantities the shell material in the core immediately increases the required amount of nuclear fuel several times - after all, the “unproductive” absorption of neutrons in the core has now increased sharply!
  Moreover, the metal form of U or Pu is no longer suitable - these materials themselves are not refractory (plutonium generally melts at 634 C), and they also interact with the material of the metal shells. We convert the fuel into the classical form of UO2 or PuO2 - we get another dilution of the material in the core, this time with oxygen.

  Finally, let's remember the purpose of the reactor. We need to pump a lot of air through it, to which we will give off heat. approximately 2/3 of the space will be occupied by “air tubes”. As a result, the minimum diameter of the core grows to 40-50 cm (for uranium), and the diameter of the reactor with a 10-centimeter beryllium reflector to 60-70 cm.

  An airborne nuclear jet engine can be shoved into a rocket with a diameter of about a meter, which, however, is still not radically larger than the stated 0.6-0.74 m, but is still alarming.

  One way or another, the nuclear power plant will have a power of ~several megawatts, powered by ~10^16 decays per second. This means that the reactor itself will create a radiation field of several tens of thousands of roentgens at the surface, and up to a thousand roentgens along the entire rocket. Even installing several hundred kg of sector protection will not significantly reduce these levels, because Neutron and gamma rays will be reflected from the air and “bypass the protection.” In a few hours, such a reactor will produce ~10^21-10^22 atoms of fission products with an activity of several (several tens) petabecquerels, which even after shutdown will create a background of several thousand roentgens near the reactor. The rocket design will be activated to about 10^14 Bq, although the isotopes will be primarily beta emitters and are only dangerous by bremsstrahlung X-rays. The background from the structure itself can reach tens of roentgens at a distance of 10 meters from the rocket body.

  All these difficulties give the idea that the development and testing of such a missile is a task on the verge of the possible. Need to create whole set radiation-resistant navigation and control equipment, test it all in a fairly comprehensive way (radiation, temperature, vibration - and all this for statistics). Flight tests with a working reactor can at any moment turn into a radiation disaster with a release of hundreds of terrabecquerels to several petabecquerels. Even without catastrophic situations, depressurization of individual fuel elements and the release of radionuclides are very likely.
  Because of all these difficulties, the Americans abandoned the SLAM nuclear-powered rocket in 1964.

  Of course, in Russia there is still the Novaya Zemlya test site where such tests can be carried out, but this will contradict the spirit of the treaty banning nuclear weapons tests in three environments (the ban was introduced to prevent systematic pollution of the atmosphere and ocean with radionuclides).

  Finally, I wonder who in the Russian Federation could develop such a reactor. Traditionally, the Kurchatov Institute (general design and calculations), Obninsk IPPE (experimental testing and fuel), and the Luch Research Institute in Podolsk (fuel and materials technology) were initially involved in high-temperature reactors. Later, the NIKIET team became involved in the design of such machines (for example, the IGR and IVG reactors are prototypes of the core of the RD-0410 nuclear rocket engine). Today NIKIET has a team of designers who carry out work on the design of reactors (high-temperature gas-cooled RUGK, fast reactors MBIR), and IPPE and Luch continue to engage in related calculations and technologies, respectively. In recent decades, the Kurchatov Institute has moved more toward the theory of nuclear reactors.

  To summarize, we can say that the creation of a cruise missile with air-jet engines with a nuclear power plant is generally a feasible task, but at the same time extremely expensive and complex, requiring a significant mobilization of human and financial resources, as it seems to me in to a greater extent than all other announced projects ("Sarmat", "Dagger", "Status-6", "Vanguard"). It is very strange that this mobilization did not leave the slightest trace. And most importantly, it is completely unclear what the benefits of obtaining such types of weapons (against the background of existing carriers) are, and how they can outweigh the numerous disadvantages - issues of radiation safety, high cost, incompatibility with strategic arms reduction treaties.

  The small-sized reactor has been developed since 2010, Kiriyenko reported about this in the State Duma. It was assumed that it would be installed on a spacecraft with an electric propulsion system for flights to the Moon and Mars and tested in orbit this year.
  Obviously, a similar device is used for cruise missiles and submarines.

  Yes, it is possible to install a nuclear engine, and successful 5-minute tests of a 500 megawatt engine, made in the states many years ago for a cruise missile with a ram jet for a speed of Mach 3, in general, confirmed this (Project Pluto). Bench tests, of course (the engine was “blown” with prepared air of the required pressure/temperature). But why? Existing (and projected) ballistic missiles are sufficient for nuclear parity. Why create a weapon that is potentially more dangerous (for “our own people”) to use (and test)? Even in the Pluto project it was implied that such a missile flies over its territory at a considerable altitude, descending to sub-radar altitudes only close to enemy territory. It's not very good to be next to an unprotected 500 megawatt air-cooled uranium reactor with materials temperatures over 1300 Celsius. True, the mentioned rockets (if they are really being developed) will be less powerful than Pluto (Slam).
  Animation video from 2007, issued in Putin’s presentation for showing the latest cruise missile with a nuclear power plant.
  
  Perhaps all this is preparation for the North Korean version of blackmail. We will stop developing our dangerous weapon- and you lift the sanctions from us.
  What a week - the Chinese boss is pushing for lifelong rule, the Russian one is threatening the whole world.

Already at the end of this decade, a nuclear-powered spacecraft for interplanetary travel may be created in Russia. And this will dramatically change the situation both in near-Earth space and on the Earth itself.

The nuclear power plant (NPP) will be ready for flight in 2018. This was announced by the director of the Keldysh Center, academician Anatoly Koroteev. “We must prepare the first sample (of a megawatt-class nuclear power plant. – Expert Online’s note) for flight tests in 2018. Whether she will fly or not is another matter, there may be a queue, but she must be ready to fly,” RIA Novosti reported his words. The above means that one of the most ambitious Soviet-Russian projects in the field of space exploration is entering the phase of immediate practical implementation.

The essence of this project, the roots of which go back to the middle of the last century, is this. Now flights into near-Earth space are carried out on rockets that move due to the combustion of liquid or solid fuel in their engines. Essentially, this is the same engine as in a car. Only in a car does gasoline, when burned, push the pistons in the cylinders, transferring its energy through them to the wheels. And in a rocket engine, burning kerosene or heptyl directly pushes the rocket forward.

Over the past half century, this rocket technology has been perfected all over the world to the smallest detail. But the rocket scientists themselves admit that . Improvement - yes, it is necessary. Trying to increase the payload of rockets from the current 23 tons to 100 and even 150 tons based on “improved” combustion engines - yes, you need to try. But this is a dead end from an evolutionary point of view. " No matter how much rocket engine specialists around the world work, the maximum effect we get will be calculated in fractions of a percent. Roughly speaking, everything has been squeezed out of existing rocket engines, be they liquid or solid fuel, and attempts to increase thrust and specific impulse are simply futile. Nuclear power propulsion systems provide a multifold increase. Using the example of a flight to Mars, now it takes one and a half to two years to fly there and back, but it will be possible to fly in two to four months “- the former head of the Russian Federal Space Agency assessed the situation at one time Anatoly Perminov.

Therefore, back in 2010, the then President of Russia, and now Prime Minister Dmitry Medvedev By the end of this decade, an order was given to create in our country a space transport and energy module based on a megawatt-class nuclear power plant. It is planned to allocate 17 billion rubles from the federal budget, Roscosmos and Rosatom for the development of this project until 2018. 7.2 billion of this amount was allocated to the Rosatom state corporation for the creation of a reactor plant (this is being done by the Dollezhal Research and Design Institute of Energy Engineering), 4 billion - to the Keldysh Center for the creation of a nuclear power propulsion plant. 5.8 billion rubles are allocated by RSC Energia to create a transport and energy module, that is, in other words, a rocket ship.

Naturally, all this work is not done in a vacuum. From 1970 to 1988, the USSR alone launched more than three dozen spy satellites into space, equipped with low-power nuclear power plants such as Buk and Topaz. They were used to create an all-weather system for monitoring surface targets throughout the World Ocean and issuing target designation with transmission to weapon carriers or command posts - the Legend naval space reconnaissance and target designation system (1978).

NASA and American companies that produce spacecraft and their delivery vehicles have not been able to create a nuclear reactor that would operate stably in space during this time, although they tried three times. Therefore, in 1988, a ban was passed through the UN on the use of spacecraft with nuclear power propulsion systems, and the production of satellites of the US-A type with nuclear propulsion on board in the Soviet Union was discontinued.

In parallel, in the 60-70s of the last century, the Keldysh Center carried out active work on the creation of an ion engine (electroplasma engine), which is most suitable for creating a high-power propulsion system operating on nuclear fuel. The reactor produces heat, which is converted into electricity by a generator. With the help of electricity, the inert gas xenon in such an engine is first ionized, and then positively charged particles (positive xenon ions) are accelerated in an electrostatic field to a given speed and create thrust when leaving the engine. This is the operating principle of the ion engine, a prototype of which has already been created at the Keldysh Center.

« In the 90s of the 20th century, we at the Keldysh Center resumed work on ion engines. Now a new cooperation must be created for such a powerful project. There is already a prototype of an ion engine on which basic technological and design solutions can be tested. But standard products still need to be created. We have a set deadline - by 2018 the product should be ready for flight tests, and by 2015 the main engine testing should be completed. Next - life tests and tests of the entire unit as a whole.“, noted last year the head of the electrophysics department of the Research Center named after M.V. Keldysh, Professor, Faculty of Aerophysics and Space Research, MIPT Oleg Gorshkov.

What is the practical benefit for Russia from these developments? This benefit far exceeds the 17 billion rubles that the state intends to spend by 2018 on creating a launch vehicle with a nuclear power plant on board with a capacity of 1 MW. Firstly, this is a dramatic expansion of the capabilities of our country and humanity in general. A nuclear-powered spacecraft provides real opportunities for people to accomplish things on other planets. Now many countries have such ships. They also resumed in the United States in 2003, after the Americans received two samples of Russian satellites with nuclear power plants.

However, despite this, a member of the NASA special commission on manned flights Edward Crowley for example, he believes that a ship for an international flight to Mars should have Russian nuclear engines. " Russian experience in the development of nuclear engines is in demand. I think Russia has a lot of experience both in the development of rocket engines and in nuclear technology. She also has extensive experience in human adaptation to space conditions, since Russian cosmonauts made very long flights “,” Crowley told reporters last spring after a lecture at Moscow State University on American plans for manned space exploration.

Secondly, such ships make it possible to sharply intensify activity in near-Earth space and provide a real opportunity to begin the colonization of the Moon (there are already projects for the construction of nuclear power plants on the Earth’s satellite). " The use of nuclear propulsion systems is being considered for large manned systems, rather than for small spacecraft, which can fly on other types of installations using ion engines or solar wind energy. Nuclear propulsion systems with ion engines can be used on an interorbital reusable tug. For example, transport cargo between low and high orbits, and fly to asteroids. You can create a reusable lunar tug or send an expedition to Mars“, says Professor Oleg Gorshkov. Ships like these are dramatically changing the economics of space exploration. According to calculations by RSC Energia specialists, a nuclear-powered launch vehicle reduces the cost of launching a payload into lunar orbit by more than half compared to liquid rocket engines.

Third, these are new materials and technologies that will be created during the implementation of this project and then introduced into other industries - metallurgy, mechanical engineering, etc. That is, this is one of those breakthrough projects that can really push both the Russian and global economies forward.

Every few years some
the new lieutenant colonel discovers Pluto.
After that, he calls the laboratory,
to find out future fate nuclear ramjet.

This is a fashionable topic these days, but it seems to me that a nuclear ramjet engine is much more interesting, because it does not need to carry a working fluid with it.
I assume that the President’s message was about him, but for some reason everyone started posting about the YARD today???
Let me collect everything here in one place. I'll tell you, interesting thoughts appear when you read into a topic. And very uncomfortable questions.

A ramjet engine (ramjet engine; the English term is ramjet, from ram - ram) is a jet engine that is the simplest in the class of air-breathing jet engines (ramjet engines) in design. It belongs to the type of direct reaction jet engines, in which thrust is created solely by the jet stream flowing from the nozzle. The increase in pressure necessary for engine operation is achieved by braking the oncoming air flow. A ramjet engine is inoperative at low flight speeds, especially at zero speed; one or another accelerator is needed to bring it to operating power.

In the second half of the 1950s, during the era cold war, projects of ramjet engines with a nuclear reactor were developed in the USA and USSR.


Photo by: Leicht modifiziert aus http://en.wikipedia.org/wiki/Image:Pluto1955.jpg

The energy source of these ramjet engines (unlike other ramjet engines) is not chemical reaction combustion of fuel, but the heat generated by a nuclear reactor in the heating chamber of the working fluid. The air from the input device in such a ramjet passes through the reactor core, cooling it, heats itself up to the operating temperature (about 3000 K), and then flows out of the nozzle at a speed comparable to the exhaust speeds for the most advanced chemical rocket engines. Possible purposes of an aircraft with such an engine:
- intercontinental cruise launch vehicle of a nuclear charge;
- single-stage aerospace aircraft.

Both countries created compact, low-resource nuclear reactors that fit into the dimensions of a large rocket. In the USA, under the Pluto and Tory nuclear ramjet research programs, bench fire tests of the Tory-IIC nuclear ramjet engine were carried out in 1964 (mode full power 513 MW for five minutes with a thrust of 156 kN). No flight tests were conducted and the program was closed in July 1964. One of the reasons for closing the program is to improve the design ballistic missiles with chemical rocket engines, which fully ensured the solution of combat missions without the use of schemes with relatively expensive nuclear ramjet engines.
It’s not customary to talk about the second one in Russian sources now...

The Pluto project was supposed to use low-altitude flight tactics. This tactic ensured secrecy from the radars of the USSR air defense system.
To achieve the speed at which a ramjet engine would operate, Pluto had to be launched from the ground using a package of conventional rocket boosters. The launch of the nuclear reactor began only after Pluto reached cruising altitude and was sufficiently removed from populated areas. The nuclear engine, which gave an almost unlimited range of action, allowed the rocket to fly in circles over the ocean while awaiting the order to switch to supersonic speed towards a target in the USSR.

SLAM concept design

It was decided to conduct a static test of a full-scale reactor, which was intended for a ramjet engine.
Since the Pluto reactor became extremely radioactive after launch, it was delivered to the test site via a specially built, fully automated railway line. Along this line, the reactor moved over a distance of approximately two miles, which separated the static test stand and the massive “dismantling” building. In the building, the “hot” reactor was dismantled for inspection using remotely controlled equipment. Livermore scientists monitored the testing process using a television system located in a tin hangar far from test bench. Just in case, the hangar was equipped anti-radiation shelter with a two-week supply of food and water.
Only to ensure the supply of concrete necessary for the construction of walls dismantling building(the thickness was from six to eight feet), the United States government purchased the entire mine.
Millions of pounds of compressed air were stored in 25 miles of oil production pipes. The compressed air was intended to be used to simulate the conditions in which a ramjet engine finds itself during flight at cruising speed.
To ensure high air pressure in the system, the laboratory borrowed giant compressors from the submarine base in Groton, Connecticut.
The test, during which the unit ran at full power for five minutes, required forcing a ton of air through steel tanks that were filled with more than 14 million 4cm diameter steel balls. These tanks were heated to 730 degrees using heating elements, in which oil was burned.

Installed on a railway platform, Tori-2S is ready for successful testing. May 1964

On May 14, 1961, engineers and scientists in the hangar from which the experiment was controlled held their breath as the world's first nuclear ramjet engine, mounted on a bright red railway platform, announced its birth with a loud roar. Tori-2A was launched for only a few seconds, during which it did not develop its rated power. However, the test was considered successful. The most important thing was that the reactor did not ignite, which some representatives of the Atomic Energy Committee were extremely afraid of. Almost immediately after the tests, Merkle began work on creating a second Tori reactor, which was supposed to have more power with less weight.
Work on Tori-2B has not progressed beyond the drawing board. Instead, the Livermores immediately built the Tory-2C, which broke the silence of the desert three years after testing the first reactor. A week later, the reactor was restarted and operated at full power (513 megawatts) for five minutes. It turned out that the radioactivity of the exhaust was significantly less than expected. These tests were also attended by Air Force generals and officials from the Atomic Energy Committee.

At this time, the customers from the Pentagon who financed the Pluto project began to be overcome by doubts. Since the missile was launched from US territory and flew over the territory of American allies at low altitude to avoid detection by Soviet air defense systems, some military strategists wondered whether the missile would pose a threat to the allies. Even before the Pluto missile drops bombs on the enemy, it will first stun, crush and even irradiate allies. (Pluto flying overhead was expected to produce about 150 decibels of noise on the ground. By comparison, the noise level of the rocket that sent the Americans to the Moon (Saturn V) was 200 decibels at full thrust.) Of course, ruptured eardrums would be least problem, if you were exposed to a naked reactor flying overhead, frying you like a chicken with gamma and neutron radiation.

Tori-2C

Although the rocket's creators argued that Pluto was also inherently elusive, military analysts expressed bafflement at how something so noisy, hot, large and radioactive could remain undetected for as long as it took to complete its mission. At the same time, the US Air Force had already begun to deploy Atlas and Titan ballistic missiles, which were capable of reaching targets several hours before a flying reactor, and the USSR anti-missile system, the fear of which became the main impetus for the creation of Pluto. , never became an obstacle for ballistic missiles, despite successful test interceptions. Critics of the project came up with their own decoding of the acronym SLAM - slow, low, and messy - slowly, low and dirty. After the successful testing of the Polaris missile, the Navy, which had initially expressed interest in using the missiles for launch from submarines or ships, also began to abandon the project. And finally, the cost of each rocket was 50 million dollars. Suddenly Pluto became a technology with no applications, a weapon with no viable targets.

However, the final nail in Pluto's coffin was just one question. It is so deceptively simple that the Livermoreians can be excused for deliberately not paying attention to it. “Where to conduct reactor flight tests? How do you convince people that during the flight the rocket will not lose control and fly over Los Angeles or Las Vegas at low altitude?” asked Livermore Laboratory physicist Jim Hadley, who worked on the Pluto project until the very end. He is currently working on detecting nuclear tests being carried out in other countries for Unit Z. By Hadley's own admission, there were no guarantees that the missile would not get out of control and turn into a flying Chernobyl.
Several solutions to this problem have been proposed. One would be a Pluto launch near Wake Island, where the rocket would fly figure-eights over the United States' part of the ocean. “Hot” missiles were supposed to be sunk at a depth of 7 kilometers in the ocean. However, even when the Atomic Energy Commission persuaded people to think of radiation as a limitless source of energy, the proposal to dump many radiation-contaminated rockets into the ocean was enough to stop work.
On July 1, 1964, seven years and six months after the start of work, the Pluto project was closed by the Atomic Energy Commission and the Air Force.

Every few years, a new Air Force lieutenant colonel discovers Pluto, Hadley said. After this, he calls the laboratory to find out the further fate of the nuclear ramjet. The lieutenant colonels' enthusiasm disappears immediately after Hadley talks about problems with radiation and flight tests. No one called Hadley more than once.
If anyone wants to bring Pluto back to life, he might be able to find some recruits in Livermore. However, there won't be many of them. The idea of ​​what could become one hell of a crazy weapon is best left in the past.

Technical characteristics of the SLAM rocket:
Diameter - 1500 mm.
Length - 20000 mm.
Weight - 20 tons.
The range is unlimited (theoretically).
Speed ​​at sea level is Mach 3.
Weapons - 16 thermonuclear bombs(each power is 1 megaton).
The engine is a nuclear reactor (power 600 megawatts).
Guidance system - inertial + TERCOM.
The maximum skin temperature is 540 degrees Celsius.
Airframe material - high temperature, stainless steel Rene 41.
Sheathing thickness - 4 - 10 mm.

Nevertheless, the nuclear ramjet engine is promising as a propulsion system for single-stage aerospace aircraft and high-speed intercontinental heavy transport aircraft. This is facilitated by the possibility of creating a nuclear ramjet capable of operating at subsonic and zero flight speeds in rocket engine mode, using on-board propellant reserves. That is, for example, an aerospace aircraft with a nuclear ramjet starts (including takes off), supplying working fluid to the engines from the onboard (or outboard) tanks and, having already reached speeds from M = 1, switches to using atmospheric air.

As Russian President V.V. Putin said, at the beginning of 2018, “a successful launch of a cruise missile with a nuclear power plant took place.” Moreover, according to him, the range of such a cruise missile is “unlimited.”

I wonder in what region the tests were carried out and why the relevant nuclear test monitoring services slammed them. Or is the autumn release of ruthenium-106 in the atmosphere somehow connected with these tests? Those. Chelyabinsk residents were not only sprinkled with ruthenium, but also fried?
Can you find out where this rocket fell? Simply put, where was the nuclear reactor broken up? At what training ground? On Novaya Zemlya?

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Now let's read a little about nuclear rocket engines, although that's a completely different story

A nuclear rocket engine (NRE) is a type of rocket engine that uses the energy of fission or fusion of nuclei to create jet thrust. They can be liquid (heating a liquid working fluid in a heating chamber from a nuclear reactor and releasing gas through a nozzle) and pulse-explosive (low-power nuclear explosions at an equal period of time).
A traditional nuclear propulsion engine as a whole is a structure consisting of a heating chamber with a nuclear reactor as a heat source, a working fluid supply system and a nozzle. The working fluid (usually hydrogen) is supplied from the tank to the reactor core, where, passing through channels heated by the nuclear decay reaction, it is heated to high temperatures and then thrown out through the nozzle, creating jet thrust. There are various designs of nuclear propulsion engines: solid-phase, liquid-phase and gas-phase - corresponding to the state of aggregation of nuclear fuel in the reactor core - solid, melt or high-temperature gas (or even plasma).


East. https://commons.wikimedia.org/w/index.php?curid=1822546

RD-0410 (GRAU Index - 11B91, also known as "Irgit" and "IR-100") - the first and only Soviet nuclear rocket engine 1947-78. It was developed at the Khimavtomatika design bureau, Voronezh.
The RD-0410 used a heterogeneous thermal neutron reactor. The design included 37 fuel assemblies, covered with thermal insulation that separated them from the moderator. ProjectIt was envisaged that the hydrogen flow first passed through the reflector and moderator, maintaining their temperature at room temperature, and then entered the core, where it was heated to 3100 K. At the stand, the reflector and moderator were cooled by a separate hydrogen flow. The reactor went through a significant series of tests, but was never tested for its full operating duration. The out-of-reactor components were completely exhausted.

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And this is an American nuclear rocket engine. His diagram was in the title picture


Author: NASA - Great Images in NASA Description, Public Domain, https://commons.wikimedia.org/w/index.php?curid=6462378

NERVA (Nuclear Engine for Rocket Vehicle Application) is a joint program of the US Atomic Energy Commission and NASA to create a nuclear rocket engine (NRE), which lasted until 1972.
NERVA demonstrated that the nuclear propulsion system was viable and suitable for space exploration, and in late 1968 the SNPO confirmed that the newest modification of NERVA, the NRX/XE, met the requirements for a manned mission to Mars. Although the NERVA engines were built and tested to the maximum extent possible and were considered ready for installation on a spacecraft, most of the American space program was canceled by the Nixon administration.

NERVA has been rated by the AEC, SNPO, and NASA as a highly successful program that has met or exceeded its goals. the main objective program was to “create technical base for nuclear rocket propulsion systems to be used in the design and development of propulsion systems for space missions.” Almost all space projects using nuclear propulsion engines are based on NERVA NRX or Pewee designs.

Mars missions were responsible for NERVA's demise. Members of Congress from both political parties decided that a manned mission to Mars would be a tacit commitment for the United States to support the costly space race for decades. Each year the RIFT program was delayed and NERVA's goals became more complex. After all, although the NERVA engine had many successful tests and strong support from Congress, it never left Earth.

In November 2017, the China Aerospace Science and Technology Corporation (CASC) published a roadmap for the development of China's space program for the period 2017-2045. It provides, in particular, for the creation of a reusable ship powered by a nuclear rocket engine.