IPPE imeni A.I.Leypunsky - Space Reactors

JSC SSC RF - IPPE
Joint Stock Company State Scientific Center of the Russian Federation - 
Institute for Physics and Power Engineering named after AI Leypunsky

In the 1990s, Americans were amazed when it became clear that the world's only nuclear power plants launched into space were not created at the Kurchatov Institute (where their designs were not brought to flight tests), but in Obninsk, at the Physics and Power Engineering Institute . In the United States, they worked on solving the same problems and knew that these were installations of the highest complexity, since they combine the two most technically sophisticated industries: space and reactor.

Work on the creation of nuclear reactors for aircraft was begun at Laboratory B in the early 1950s. The first such installations were nuclear rocket engines (NRE) with high traction, using hydrogen as a working fluid.

The initiators of work on rocket engines were young and talented scientists I.I. Bondarenko and V.Ya. Pupko . We emphasize that these two, yesterday’s graduates of Moscow State University, who appeared at Laboratory B just a couple of years ago, began to develop their ideas on their own initiative, at first - in their free time, i.e. in the evenings and at night, despite the extreme workload of the main work. And so the foundation was laid for work "in space" at the institute. They also fulfilled the first evaluative characteristics of NRE for ballistic nuclear missiles. The calculations were performed for a hydrogen coolant and other, heavier working fluids (ammonia, alcohol, etc.). These estimates were further systematized in the report "Ballistic Atomic Missile", released in 1954.

The management of the IPPE (at the beginning of the work on NRE was headed by D.I. Blokhintsev , and after his departure, A.I. Leipunsky ) picked up the idea and organized a discussion of the draft NRE at the highest level; A.P. participated in it Zavenyagin, S.P. Korolev, V.P. Glushko, M.V. Keldysh.

The proposed nuclear rocket engine could create a thrust on Earth of about 200 tons, while the reactor used a dual-zone, homogeneous. The outlet temperature of the working fluid - hydrogen - in front of the nozzle should have been about 3000 K. The main objection of the rockets was caused by the use of hydrogen, which in the liquid state has an abnormally low density and therefore requires the use of large tanks. In addition, the hydrogen in the tanks must be maintained in a cryogenic state, which is not easy. At the IPPE, fairly convincing estimates were made of the weight and size of tanks and the entire rocket as a whole, and the great promise of hydrogen as a working medium for rockets was shown. The IPPE insisted on choosing this particular working fluid for NRE, where it is especially promising, since the hydrogen atoms do not mix with the heavier oxygen atoms in the combustion chamber, as required for conventional missiles. Nevertheless, at the insistent demand of the rocket launchers, joint studies of nuclear-powered rockets and ballistic missiles with traditional working fluids (ammonia, hydrazine, alcohol, etc.) were organized. As a result, these studies only confirmed the correctness of the choice of hydrogen as the working medium of the NRE.

In 1956-1965 together with OKB-456 (V.P. Glushko) and NII-1 (M.V. Keldysh), the Institute of Physics and Technology examined options for propulsion and test reactors with various moderators and developed optimal methods and solutions for the development of nuclear propulsion systems. Later, in an effort to use a small thrust rocket of the smallest scale, scientists at the IPPE began developing small heterogeneous reactors with zirconium hydride as a moderator and a beryllium reflector, in which the channels with fuel elements were separated from the moderator by powerful fibrous thermal insulation from graphite. It was of this type that 3.6 tons thrust reactors (IR-100, or later called IRGIT) passed fire tests at the Baikal stand base near Semipalatinsk in the late 1970s and early 1980s. These tests have shown very encouraging results.

Another direction of the development of nuclear engines for aircraft in the IPPE was the research begun in 1954 on the feasibility of creating aviation nuclear power plants (AES) with a liquid metal coolant (sodium, lithium) in the reactor circuit. That is, it was already about installing reactors on airplanes. The first calculations of such an installation were presented in 1954 and sent to the developers of aircraft. Subsequently, various studies of aircraft installations for the TU-119 experimental aircraft (based on the TU-95 strategic bomber), the AN-22 anti-submarine aircraft and others were carried out, and a number of pre-draft projects were created. However, when in the OKB A.N. Tupolev, the design of the TU-95 aircraft was studied with such an installation, the costs of its creation were estimated at 1 billion rubles,

An even more important area of work was the creation of spaceborne nuclear power plants. Research on this problem at the IPPE began in 1956, when it became known that the OKB-1 (S.P. Korolev) was developing a R-7 carrier rocket capable of placing a relatively large load into orbit of an artificial Earth satellite. The staff of the IPPE led by I.I. Bondarenko came up with the idea of the possibility of launching into space a satellite with a nuclear power plant on board. The idea was supported by A.I. Leipunsky. S.P. Korolev also supported this proposal and included a clause on the development of a space nuclear power plant in the Decree of the Central Committee of the CPSU and the Council of Ministers of the USSR on the creation of a powerful launch vehicle designed, in particular, for flying to the moon. IPPE was appointed as the supervisor of work After developing nuclear power plants with machine-based energy conversion (mercury and potassium vapor, gas turbine circuit) and other options, preference was given to a direct conversion circuit with semiconductor elements.

The space thermoelectric installation was named YaUU BUK. A small-sized fast neutron nuclear reactor with a semiconductor thermoelectric generator located outside the reactor was developed for it. The reactor core is enclosed in a thin hexagonal housing, in which 37 fuel rods are installed in tight packaging. Each contained blocks of uranium-molybdenum alloy and end beryllium reflectors. Behind the housing was a beryllium reflector, in which beryllium rods - regulatory bodies moved in parallel. The reflector was made in the form of individual parts pulled together by three steel tapes; upon emergency entry into the atmosphere from space, these tapes burn out and the reflector falls apart. Reactor physics was worked out at the IPPE at a specially created critical bench.

The first flight tests took place on October 3, 1970 on the Cosmos-367 spacecraft. In total, 33 launches were launched into space into near-Earth orbits as part of the spacecraft of the naval space reconnaissance combat system. Each installation worked a different time in orbits at an altitude of 280-240 kilometers (apogee-perigee) and developed a useful electric power of 2.3-2.5 kW. The maximum accumulated life of one installation was 135 days. The last spacecraft with the BUK nuclear power plant (Cosmos-1933) was launched into the orbit of an artificial satellite on March 15, 1988, after which the launches were stopped.

In parallel, the institute conducted extensive research on the creation of a converter reactor with the more promising - thermionic - principle of direct energy conversion. Compared to thermoelectric conversion, thermionic conversion allows increasing efficiency, increasing resource and improving the overall dimensions of the power plant and the spacecraft. As a result, the first in the world TOPAZ intermediate-energy thermionic converter-converter with intermediate neutrons was created at the IPPE.

The development of thermionic nuclear installations began in 1958, when it became known about reactor experiments being prepared at the Los Alamos National Laboratory of the USA with single-element samples of power generating elements. The sources of the development of the problem of thermionic emission in the USSR also stood II. Bondarenko and V.Ya. Pupko , who managed to interest a group of enthusiasts in the IPPE and beyond (Krasnaya Zvezda, Energia, etc.) with this task. A.I.Leipunsky made a big contribution to the formation of this direction, to the creation of the TOPAZ thermionic nuclear power plant, the research and testing base for it.

For life tests of power generating channels in 1962, a “direct conversion loop” was created and began to operate in the reactor of the First NPP. To conduct ground-based energy tests of thermionic nuclear power plants, a unique test bench was built at the IPPE, equipped with all systems for testing full-size installations (vacuum chamber, remote cutting department, building slides of the reactor assembly and general building stacks of the nuclear power plant as a whole, etc.).

The first flight model of the TOPAZ nuclear power plant was launched into space as an onboard power source on the Cosmos-1818 satellite on February 2, 1987. The nuclear power plant worked in space for about six months, until the cesium stock on board was exhausted. The second TOPAZ sample (on Cosmos-1876) was launched on July 10, 1987, into a safe orbit of 813/797 km. He worked in this orbit for about a year, also until the cesium reserve was exhausted. These flight tests, which became the first (and only) in the world tests of a thermionic emission nuclear power plant, were highly appreciated by the world community.

Computational, theoretical and experimental studies of the physics of reactor converters and the protection of space nuclear power plants were carried out in the department of V.Ya. Pupko . Design, technological and material science developments of thermionic electric generating channels and their manufacture were carried out in the V.A. department Malykh , and work on thermal physics and liquid metal coolant - in the department of V.I. Subbotin . A.A. made a great contribution to the creation of space nuclear power plants. Abagyan, P.M. Bologov, A.A. Vizgalov, I.M. Gusakov, A.I. Yeltsov, I.P. Zasorin, A.V. Zrodnikov, V.I. Ionkin, I.V. Istomin, V.A. Linnik, F.P. Raskach, E.A. Stumbur, A.P. Trifonov, Yu.S. Yuriev and many others.

At the Semipalatinsk test site from 1960 to 1989, work was carried out to create a nuclear rocket engine.

• IGR reactor complex;
• Baikal-1 bench complex with the IVG-1 reactor and two workstations for working out 11B91 products;
• RA (IRGIT)reactor

The IGR reactor is a thermal neutron pulsed reactor with a homogeneous core, which is a masonry of graphite blocks containing uranium assembled in the form of columns. The reactor reflector is formed from similar blocks containing no uranium. The reactor does not have a forced core cooling. The heat released during the operation of the reactor is accumulated by the masonry, and then transferred to the water of the cooling circuit through the walls of the reactor vessel.

From 1962 to 1966 in the IGR reactor, the first tests of model nuclear fuel rods were carried out. The test results confirmed the possibility of creating fuel rods with solid heat transfer surfaces operating at temperatures above 3000K, specific heat fluxes up to 10 MW / m2 under conditions of high-power neutron and gamma radiation (41 launches were conducted, 26 model fuel assemblies of various modifications were tested).

In 1971-1973 the IGR reactor dynamic tests of high-temperature NRE fuel for thermal strength were carried out, during which the following parameters were realized:

• specific energy release in the fuel - 30 kW / cm3;
• specific heat flux from the surface of the fuel rods - 10 MW / m2;
• coolant temperature - 3000K
• the rate of change of the temperature of the coolant with increasing and decreasing power is 1000 K / s; the
• duration of the nominal mode is 5 from

From 1974 to 1989 the IGR reactor tested FAs of various types of nuclear reactors, nuclear reactors and gas-dynamic plants with hydrogen, nitrogen, helium and air coolants. From 1971 to 1993 investigations were made of the exit from fuel into a gaseous coolant (hydrogen, nitrogen, helium, air) in the temperature range 400 ... 2600 K and deposition of fission products in the gas circuits, the sources of which were experimental fuel assemblies located in the IGR and RA reactors.