Back in the 1950s the Soviet generals wanted to create a nuclear airplane – a long range strategic bomber that would allow them to carry out airstrikes far away. The idea was welcomed and work began on creating a nuclear aircraft.
Why the need for a nuclear plane? As per their calculations, the supersonic planes of big size for the transportation of bombs required over 10,000 tonnes of fuel for only one flight and the storage of such huge amounts of fuel in one place was quite a problem. You can check out the very first proposed design for the plane with atomic nuclear reactor onboard below.
In June 1952, the leading Soviet nuclear engineer Alexandrov claimed that engines powered using atomic force shall be ready in a few years, however, during that time the heavy bombers appeared as well. The nuclear plane, still under development, was given the name of ‘M-50’. Initially, the nuclear engine was supposed to be incorporated at the front, however, later designs had it moved backwards.
Three separate group of engineers were working on M-50 and it was known by three different names; M-52, M-56K and M-60. Many of these planes featured nuclear engines that employed the use of molten metals, molten lithium or sodium, for transferring heat from the nuclear reactor to the engine. The engines were also capable of working with the regular aircraft fuel.
These planes also featured a smaller plane that was incorporated within so that the mothership won’t have to fly low for taking out targets. Instead, the smaller jet would carry out precise bombing while the mothership remained at supersonic altitudes. This model of the plane was never finished and the lead engineer was assigned to another crucial task; building ballistic missiles.
Another group managed to build this aircraft; it made use of propellers for its movement but was still a nuclear-powered strategic bomber. Its development was carried out in TU agency. You can see the scheme of the nuclear turbo engine of TU lab below.
This is another kind of the engine developed by the same. The nuclear elements were installed in round fashion around the engine. The plane was given the name TU-95LAL. The pilot’s cabin featured a thick layer of radiation protection, however, the sides were left unattended and the radiation could leak from the sides. This plane was able to go into the skies and within one year it had completed 34 flights. The project was abandoned due to the risk of contaminating areas with the radioactive waste that was being leaked from the sides. 
Afterwards, the soviets worked on another heavy plane, the AN-22 01-07. Following the first two projects and their failure, the knowledge gained was put to good use and in 1970s, this amazing plane was built. According to the engineer, “The only waste it produced was the heated air stream. It was more ecologically sound than even the regular gas powered planes – no waste at all.” The engine was known as ‘combined turbojet nuclear engine’.
