Now it seems strange, but just a decade after the bombing of Hiroshima, which showed all the "charms" of radiation, the world literally fell in love with atomic energy. The designers of the USSR and the United States enthusiastically came up with what other transport to put the nuclear reactor on. In addition to nuclear submarines and icebreakers, which exist to this day, nuclear planes, cars and even airships were designed. And the engineers of the middle of the twentieth century seriously dreamed of giant trains that would be pulled into the distance by a diesel locomotive with an atomic heart for thousands and thousands of kilometers.
To the tundra on a wide track
If we talk about reality, then unlike the program for creating nuclear bombers - and the USSR even tested a specially designed reactor in the air - the history of designing nuclear mega-trains did not go so far. Neither experimental models of locomotives, nor tracks corresponding to the plan were built. Everything stopped at the level of draft designs. At the same time, unlike the deeply classified work on the creation of the same atomic-powered aircraft, the idea of diesel locomotives powered by reactors was promoted in newspapers, books and popular science magazines. The newspaper Gudok, the publication of the USSR Ministry of Railways, wrote in 1956: “In the conditions of the North, the Far East and the deserts of Central Asia, it is not always advisable to electrify newly built railway lines. In these conditions, it is better to use nuclear locomotives,which could work autonomously, without the supply of large quantities of fuel or other materials … Of course, a nuclear locomotive will be much heavier than a steam locomotive or diesel locomotive of the same power. But if such a locomotive is sent to a remote highway, for example, to the Arctic, then it will operate there intermittently throughout the entire winter season without additional supply. It is very easy to turn it into a mobile power plant. In addition, it will be able to supply energy to baths, laundries, greenhouses for growing vegetables. "then he will work there intermittently throughout the winter season without additional supplies. It is very easy to turn it into a mobile power plant. In addition, it will be able to supply energy to baths, laundries, greenhouses for growing vegetables. "then he will work there intermittently throughout the winter season without additional supplies. It is very easy to turn it into a mobile power plant. In addition, it will be able to supply energy to baths, laundries, greenhouses for growing vegetables."
But cucumber beds in the Arctic Circle, of course, were not the ultimate dream for those who believed in the bright future of the railway atom. The idea of mega-trains looked much more ambitious and pretentious. They were supposed to consist of a mighty nuclear locomotive and giant carriages, set on an ultra-wide track, which would be 2.5-3 times wider than the standard adopted in our country - 1520 mm. At the same time, the cargo capacity of freight cars of this class could be comparable to that of a river cargo ship, and double-deck passenger cars would offer travelers unprecedented space and comfort. The picture presented on the first spread of our article is a collective visual image of such a project made by a contemporary artist.
NPP on wheels
Promotional video:
Sometimes we hear about projects of "atomic steam locomotives", but of course no one was going to rotate the wheels of a locomotive with steam power. It was planned to use electric motors as a drive for the wheels, which in turn would be powered from a nuclear power plant located inside the locomotive, built according to the classical scheme. As a result of a nuclear reaction, heat is generated, which is transferred to the coolant, and it gives off heat to the water in the steam generator. The resulting steam flows through pipes to the turbine, and the turbine, in turn, drives the shaft of the electric generator in rotation.
The figure below shows a diagram of a single-section locomotive, in which both the reactor, the generator, and the electric motors are inside a single body, only the reactor with a heat exchanger is covered with a bioprotection partition. There is information that a three-section option was also considered, in which a special section, isolated by bioprotection, connected to two other couplers was allocated for the reactor.
Noteworthy is the number of locomotive axles: the designers foresaw that its huge weight would force the load to be more evenly distributed on the track. The idea of a train with a nuclear reactor is simple, and there are no fundamental obstacles to its implementation. But why, then, do we still not ride in palace cars and conquer the Arctic expanses on nuclear locomotives?
Obviously, the question of the feasibility of building giant atomic-powered trains splits into two: the possibility of using nuclear energy in passenger transport and the technical and economic justification of a significant expansion of the railway track.
Concrete and lead
Actually, nothing prevents the use of the decay energy of an atomic nucleus in the transport industry, and moreover, it is actively used. Approximately 75% of electricity in France is generated by nuclear power plants, so the famous high-speed TGV trains, powered by electricity from the overhead contact network, can in some sense be considered "atomic trains." But is it possible or necessary to carry the entire power plant with you? The only reason for this is the possibility of long-term operation of the vehicle without refueling where there is no fuel and suitable infrastructure. For icebreakers on long voyages in Arctic waters, or submarines on alert in another hemisphere, long-term energy autonomy is extremely important. It would not interfere with strategic bombers or anti-submarine aircraft,which could circle over the ocean for days, far from the home airfield. However, nuclear aircraft had to be abandoned, and for approximately the same reasons that prevented the implementation of projects of locomotives with nuclear reactors. And the main reason is biological protection.
The nuclear reactor of the locomotive would have to be insulated with a thick layer of lead or concrete, and from all sides. It is impossible to confine oneself to the wall between the reactor and the driver's cab - after all, in this case, lethal radiation will hit everything that is on the sides of the track, under bridges and on overpasses passing over the tracks. The total weight of such biological shielding would be hundreds of tons, moreover, it would take up a significant volume. If we take into account that nuclear reactors created in the 1950s were themselves large in size, then the size and weight of a nuclear locomotive would be simply titanic. Perhaps for this reason, the designers immediately began to think about the fact that the standard track would have to be replaced by an ultra-wide track. But is it enough to just push the rails apart to solve this problem?
Why unscrew the rails
As Viktor Mikhailovich Bogdanov, advisor to the director of the Scientific Research Institute of Railway Transport, told us, in the past, a very exotic project for the construction of ultra-wide railway lines in the USSR was really discussed. The authors of the idea proposed to remove two internal rails on double-track railways. The remaining outer rails would form a track about six meters wide!
“Initially, in our country, railways were designed with the greatest overall dimensions. If in Western Europe the maximum permissible load per meter of track is 6 tons, in the USA on most of the highways - 8.5-9 tons, then in Russia this value can reach 12 tons, explains Viktor Mikhailovich. - Track structures (bridges, tunnels, overhead catenary infrastructure) have also been designed for wagons with increased dimensions. There is even a certain margin for oversized cargo. But all this, of course, is not designed for giant wagons and locomotives, which could travel on a six-meter track. It is enough to estimate the possible volume and weight of such a car, and it becomes clear that at full load (even with eight axles) the load per meter of track will be tens of tons. And this despite the fact that the properties of the path, embankments, bridges will remain the same."
Obviously, a nuclear mega-train would not only have to lay a wider track, but re-calculate and create the entire infrastructure. As a result, for technical and economic reasons, the idea of creating one wide track from two standard ones was rejected. Much farther in the development of ultra-wide-gauge (3000 mm) roads went in Nazi Germany (our magazine talked about this in detail in the March issue), but even there it did not go beyond the design documentation, and after the collapse of the Hitler regime, this idea was no longer returned, considering its manifestation of economically unjustified gigantomania.
Chernobyl.
News from the south
If Hiroshima did not interfere with the love that flared up half a century ago for everything nuclear (except for bombs, of course), then the Chernobyl disaster, on the contrary, caused a wave of radiophobia and rejection of the "peaceful atom" in the world. Many are frightened by the very idea that somewhere near human dwellings an atomic reactor will be rushing along the rails. What if a disaster strikes and the locomotive collapses? What if this catastrophe will be "helped" by terrorists who will certainly not miss the opportunity to make out the path in front of the speeding train?
But no matter how great the fear of radiation, humankind is more and more worried about the prospects for a global energy crisis associated with a shortage of fossil fuels, as well as environmental problems that are exacerbated by atmospheric pollution from the burning of hydrocarbons. Therefore, it cannot be ruled out that progress in the field of nuclear technologies (primarily in ensuring their greater safety) will in the near future become the reason for the revival of interest in nuclear transport.
Recently, in different countries of the world, new types of nuclear reactors are being developed - compact and safer than the existing ones. Back in the 90s, the South African state-owned company Escom announced its intention to build a so-called ball-bed modular reactor (PBMR), and recently (January 30, 2020) it was announced that the company hopes to resume work on the project. The PBMR modular reactor will not have the usual fuel rods. As fuel cells, it is proposed to use balls consisting of graphite, including microscopic inclusions of uranium oxide in silicon carbide capsules. An inert gas (helium is best suited) is blown through the balls, which removes the heat generated during the reaction. PMBR belongs to the type of high temperature reactors,and the heated gas has sufficient energy to directly drive the low pressure turbine or transfer heat to another heat transfer medium through the heat exchanger. This greatly improves the efficiency of the entire system.
But the main thing in such a reactor is high passive safety. In principle, there can be no overheating with an explosion according to the scenario of the Chernobyl accident in it, since a natural feedback system is built into the design. Even if the flow of cooling gas stops and the temperature starts to rise, when a certain value is reached, the reaction will stop by itself.
Another project of a compact, safe and not too expensive nuclear reactor was proposed by scientists from the Federal University of Rio Grande do Sul (Brazil). Based on the technology of a boiling nuclear reactor, the device also uses fuel in the form of balls interspersed with uranium oxide - however, water acts as a coolant.
If both of these and many other similar projects are brought to the declared parameters, it will be possible to think about using smaller and safer nuclear devices in transport. Who knows, perhaps it is in South Africa or Brazil - a country with long distances and a long-standing interest in alternative energy sources - that the idea of atomic trains will nevertheless find a second wind.
Author: Oleg Makarov