Proposals and projects
Already in the fifties, several years before the launch of the first satellite and the manned spacecraft, the prospects for the development of chemical-fueled rocket engines were determined. The latter made it possible to obtain very high characteristics, but the growth of parameters could not be infinite. In the future, the engines had to "rest against the ceiling" of their capabilities. In this regard, for the further development of space-rocket systems, fundamentally new solutions were required.
Built but not tested RD0410 type YARD
In 1955, academician M.V. Keldysh took the initiative to create a rocket engine of a special design, in which a nuclear reactor would act as a source of energy. The development of this idea was entrusted to NII-1 of the Ministry aviation industry; V.M. Ievlev. In the shortest possible time, specialists worked out the main issues and proposed two options for a promising NRE with the best characteristics.
The first engine variant, designated as “Scheme A”, proposed the use of a solid-phase reactor and solid heat exchange surfaces. The second option, Scheme B, provided for the use of a reactor with a gas-phase active zone — the fissile material had to be in the plasma state, and the thermal energy was transferred to the working body through radiation. Experts compared the two schemes and found the variant "A" more successful. In the future, it was he who worked most actively and even reached the full-fledged trials.
In parallel with the search for optimal designs of NRE, there was a study of the creation of a scientific, industrial and testing base. So, in 1957 year V.M. Ievlev proposed a new concept of testing and refinement. All basic structural elements had to be tested at different stands, and only after that they could be assembled into a single structure. In the case of Scheme A, such an approach implied the creation of full-scale reactors for testing.
In 1958, a detailed resolution of the Council of Ministers appeared, determining the course of further work. MV were appointed to be responsible for the development of the NRE. Keldysh, I.V. Kurchatov and S.P. Korolev. In NII-1 a special department was formed headed by V.M. Ievlev, who had to deal with a new direction. Also dozens of research and design organizations were involved in the work. Participation of the Ministry of Defense was planned. Determined the schedule of work and other nuances of an extensive program.
Subsequently, all project participants actively interacted in one way or another. In addition, in the sixties, conferences were held twice devoted exclusively to the subject of NRE and related issues.
As part of the NRE development program, it was proposed to apply a new approach to testing and testing the necessary units. In this case, experts are faced with a serious problem. Testing of some products was to be carried out in a nuclear reactor, but such measures were extremely difficult or even impossible. The tests could have been hampered by difficulties of an economic, organizational or environmental nature.
In this regard, new methods of testing products without the use of nuclear reactors were developed. Similar checks were divided into three stages. The first involved the study of processes in the reactor on models. Then the nodes of the reactor or engine had to undergo mechanical and hydraulic "cold" tests. Only after that the nodes should be checked in high-temperature conditions. Having separately worked out all the components of the NREs on the stands, it was possible to proceed to the assembly of a full-fledged experimental reactor or engine.
For carrying out three-stage testing of nodes by forces of several enterprises, they have developed and built various stands. Of particular interest is the technique for high temperature testing. During its development, new gas heating technologies had to be created. From 1959 to 1972, the research institute 1 developed a whole range of high-power plasma torches that heated gases to 3000 ° K and allowed high-temperature tests to be carried out.
Especially for testing "Scheme B" had to develop even more complex devices. Such tasks required a plasma torch with an output pressure of hundreds of atmospheres and a temperature of 10-15 thousand degrees K. By the end of the sixties, a technology of heating the gas based on its interaction with electron beams appeared, which allowed to obtain the required characteristics.
Resolution of the Council of Ministers provided for the construction of a new facility at the Semipalatinsk proving ground. There should have been built a test bench and an experimental reactor for further testing of fuel assemblies and other components of the NRE. All the main facilities were built by 1961 year, and at the same time the first start-up of the reactor took place. Then polygon equipment was refined and improved several times. For the placement of the reactor and personnel were intended several underground bunkers with the necessary protection.
In fact, the project of a promising YARD was one of the most daring undertakings of its time, and therefore led to the development and construction of a mass of unique devices and devices for testing purposes. All these booths made it possible to conduct a lot of experiments and collect a large amount of data of various kinds suitable for the development of various projects.
In the late fifties, the most successful and promising option was considered to be a type “A” engine. This concept proposed the construction of a nuclear reactor based on a reactor with heat exchangers responsible for heating the gaseous working fluid. The release of the latter through the nozzle should have created the desired thrust. With all the simplicity of the concept, the implementation of such ideas was associated with a number of difficulties.
First of all, the problem of choosing materials for the construction of the core was manifested. The design of the reactor had to withstand high thermal loads and maintain the required strength. In addition, it was supposed to pass thermal neutrons, but it did not lose its characteristics due to ionizing radiation. Uneven heat release in the core was also expected, which made new demands on its design.
To search for solutions and to refine the structure, a special workshop was organized at SRI-1, which was to do model fuel assemblies and other components of the core. At this stage, various metals and alloys, as well as other materials, were tested. Tungsten, molybdenum, graphite, high-temperature carbides, etc. could be used to fabricate fuel assemblies. The search for protective coatings preventing the destruction of the structure was also carried out.
In the course of the experiments, optimal materials were found for the manufacture of individual components of the NRE. In addition, it was possible to confirm the fundamental possibility of obtaining a specific impulse of the order of 850-900. This gave the advanced engine the highest performance and a significant advantage over chemical fuel systems.
The reactor core was a cylinder with a length of about 1 m and a diameter of 50 mm. In this case, the creation of 26 variants of fuel assemblies with various features was envisaged. Following the results of the subsequent tests, they chose the most successful and effective ones. The fuel assembly design found included the use of two fuel compositions. The first was a mixture of uranium-235 (90%) with niobium or zirconium carbide. This mixture was molded in the form of a four-beam twisted rod with a length of 100 mm and a diameter of 2,2 mm. The second composition consisted of uranium and graphite; it was made in the form of hexagonal prisms 100-200 mm in length with an 1-mm internal channel having a lining. The rods and prisms were placed in a sealed heat-resistant metal housing.
The tests of assemblies and elements at the Semipalatinsk test site began in the year 1962. In two years of work, the 41 reactor was launched. First of all, we managed to find the most effective version of the core content. All major solutions and specifications were also confirmed. In particular, all the nodes of the reactor coped with heat and radiation loads. Thus, it was found that the developed reactor is able to solve its main task - to heat gaseous hydrogen to 3000-3100 ° K at a given flow rate. All this allowed to start the development of a full-fledged nuclear rocket engine.
11B91 on "Baikal"
In the early sixties, work began on the creation of a full-fledged NRE based on existing products and developments. First of all, NII-1 studied the possibility of creating a whole family of rocket engines with different parameters suitable for use in various projects of rocket technology. From this family, it was first decided to design and build a low-thrust engine - 36 kN. Such a product could later be used in a promising upper stage suitable for sending spacecraft to other celestial bodies.
In 1966, SRI-1 and the Chemical Automation Design Bureau began collaborative work on shaping and designing the future NRE. Soon the engine received indices 11B91 and RD0410. Its main element was a reactor called IR-100. Later, the reactor was named IRGIT ("Research reactor for group studies of TVEL"). It was originally planned to create two different YARDs. The first was an experimental product for testing at the test site, and the second was a flight model. However, in 1970, two projects were combined with a view to conducting field testing. After that, KBXA became the leading developer of the new system.
Using the groundwork for preliminary research in the field of NRE, as well as using the existing test base, we were able to quickly determine the future look of the 11B91 and begin a full technical design.
At the same time, the “Baikal” stand complex was created for future tests at the test site. The new engine was proposed to be tested in an underground structure with a complete set of protection. Provision was made for the collection and settling of gaseous working fluid. In order to avoid emissions of radiation, the gas had to be kept in gas holders, and only after that it could be released into the atmosphere. Due to the particular complexity of the work, the Baikal complex was built for about 15 years. His last objects were completed after the first tests began.
In 1977, at the Baikal complex, a second workplace for pilot plants was commissioned, equipped with means for supplying the working fluid in the form of hydrogen. 17 September completed the physical launch of the product 11B91. 27 March 1978-th energy launch. 3 July and 11 August conducted two fire tests with the full operation of the product as a YARD. In these tests, the reactor was gradually brought to power 24, 33 and 42 MW. Hydrogen was heated to 2630 ° K. In the early eighties, two other prototypes were tested. They showed power up to 62-63 MW and heated the gas to 2500 ° K.
At the turn of the seventies and eighties, it was about creating a full-fledged NRE, fully suitable for installation on missiles or upper stages. The final appearance of such a product was formed, and tests at the Semipalatinsk test site confirmed all the main design characteristics.
The finished engine RD0410 was noticeably different from existing products. It was distinguished by the composition of the units, the layout and even the appearance, due to other principles of work. In fact, the RD0410 was divided into several main blocks: the reactor, the means for feeding the working fluid, and the heat exchanger and the nozzle. The compact reactor occupied a central position, and other devices were placed next to it. The YARD also needed a separate tank for liquid hydrogen.
The total height of the RD0410 / 11B91 products reached 3,5 m, the maximum diameter was 1,6 m. The mass, taking into account radiation protection, was 2 t. The calculated engine thrust in the vacuum reached 35,2 kN or 3,59 tf. The specific impulse in the void is 910 kgf • s / kg or 8927 m / s. The engine could be turned on 10 times. Resource - 1 h. By some modifications in the future it was possible to improve the characteristics to the desired level.
It is known that the heated working fluid of such a YARD had limited radioactivity. However, after the tests he was defended, and the area where the stand was located had to be closed for a day. The use of such an engine in the atmosphere of the Earth was considered unsafe. At the same time, it could be used as part of accelerating units starting work outside the atmosphere. After use, such blocks should be sent to the burial orbit.
Back in the sixties, the idea of creating a power plant based on YARDs appeared. The heated working fluid could be fed to a turbine connected to a generator. Such power plants were of interest for the further development of astronautics, since they made it possible to get rid of the existing problems and limitations in the field of electricity generation for onboard equipment.
In the eighties, the idea of a power plant reached the design stage. Worked out a project of such a product based on the engine РД0410. One of the experimental reactors IR-100 / IRGIT was used in experiments on this topic, during which it ensured the operation of the generator with a power of 200 kW.
The main theoretical and practical work on the subject of the Soviet YARD with a solid-phase active zone was completed by the mid-eighties. The industry could begin the development of an accelerating unit or another rocket and space technology for an existing RD0410 engine. However, such work has not been able to start on time, and soon their start was impossible.
At this time, the space industry already did not have enough resources for the timely implementation of all plans and ideas. In addition, the notorious Perestroika soon began, putting an end to the mass of proposals and developments. The reputation of nuclear technology was seriously affected by the Chernobyl accident. Finally, at that time it was not without problems of a political nature. In 1988, all work on the YARD 11B91 / РД0410 was stopped.
According to various sources, at least until the beginning of 2000, some facilities of the Baikal complex still remained at the Semipalatinsk test site. Moreover, in one of the so-called. workplaces still housed an experimental reactor. KBXA managed to make a full-fledged RD0410 engine, suitable for installation on the future upper stage. However, the technique for its use remained in the plans.
Developments on the YARD found application in the new project. In 1992, a number of Russian enterprises jointly developed a dual-mode engine with a solid-phase core and working fluid in the form of hydrogen. In the rocket engine mode, such a product must develop 70 kN thrust with a specific impulse 920 s, and the energy mode provides 25 kW of electrical power. Such a NRE was proposed for use in interplanetary spacecraft projects.
Unfortunately, at that time the situation did not favor the creation of a new and bold rocket and space technology, and therefore the second version of the nuclear rocket engine remained on paper. As far as we know, domestic enterprises still show a certain interest in the NRE-related topics, but the implementation of such projects is not yet possible or feasible. Nevertheless, it should be noted that in the framework of previous projects, Soviet and Russian scientists and engineers were able to accumulate a significant amount of information and get the most important experience. This means that when a need arises and a corresponding order in our country, a new NRE can be created of the type tested in the past.
Akimov V.N., Koroteev A.S., Gafarov A.A. and others. Research Center named after M. Keldysh. 1933-2003: 70 years at the forefront of rocket and space technology. - M: "Mechanical Engineering", 2003.