Russia's decision to use a liquid metal coolant reactor on its fifth-generation nuclear submarine Husky has raised concerns among naval experts as to why such an advanced reactor is a mixed blessingIt turns out that about this kind of reactor, the two superpowers of the United States and the Soviet Union have already tried it before, and there have been tragic lessons. Among the nuclear submarines, there is a kind of nuclear submarine that is specially born to hunt other nuclear submarines, this kind of underwater killer with a sailing speed that exceeds the general nuclear submarine and has excellent silent performance, that is, the liquid metal reactor nuclear submarine, in this field, the two superpowers of the United States and the Soviet Union have had a fierce competition.
As early as the early days of the development of nuclear submarines, the United States and the Soviet Union respectively demonstrated three different types of nuclear reactor structures, namely pressurized water reactors, liquid metal cooling reactors, and helium cooling reactors. To put it simply, this kind of reactor uses liquid metal sodium or sodium-potassium alloy as the coolant, replacing the traditional water cooling method as the main heat energy transfer material of the submarine nuclear reactor, so that the nuclear reactor can operate with higher output power and provide more powerful kinetic energy for the submarine.
In addition, the liquid metal cooling reactor also has a natural advantage, that is, it has the ability of natural circulation, and the water pump and other devices are canceled on the reactor, which greatly reduces the noise of the submarine reactor operation, making the submarine high-speed and efficient. Both the United States and the Soviet Union have developed liquid metal reactor nuclear submarines, and these nuclear submarines are all aimed at hunting other nuclear submarines, which shows their huge technical advantages over pressurized water reactor nuclear submarines.
As early as early 1952, General Dynamics of the United States built a liquid metal cooling reactor land simulation reactor in West Milton, codenamed SIR-A, and General Dynamics had a very obvious intention to install it in a simulated nuclear submarine module for research and testing. The General Dynamics approach was found by the US Navy to have strong application prospects, and in 1953 appropriation 2$2.5 billion to General Dynamics, which hopes it will continue to develop such a nuclear reactor.
In 1953, the U.S. Navy had already built its first nuclear submarine, the Nautilus, and ordered its first liquid metal cooled reactor nuclear submarine with great foresight, naming it "Seawolf", codenamed SSN-575. The meaning of the United States is very clear, that is, it wants to hunt other nuclear submarines in the sea like sheep. The Americans were ambitious, so the construction was fast, and only two years later the nuclear submarine was launched, and in 1956 it began to operate, using a reactor codenamed S2G and a coolant of liquid metal sodium.
The Seawolf has an underwater speed of 30 knots, compared to the Nautilus nuclear submarine and other conventionally powered submarines that only had a speed of just over 20 knots at that time, the Seawolf's sensitivity is simply unparalleled, and it is equipped with a sonar with stronger search capabilities, which gives hope to the Americans. However, at this time, the haze of a nuclear submarine with a liquid metal reactor also began to appear, that is, a serious failure, and the tragedy began.
Compared to pressurized water reactors, liquid metal cooled reactors can provide efficient heat transfer, but their coolant, liquid metal sodium, produces severe nuclear radiation when it flows through the reactor. In contrast, PWRs use water as a coolant and can also act as a moderating agent for radiation isolation. In the actual operation of the liquid metal cooling reactor, it is found that once water accidentally flows into the reactor, it will react violently with sodium, but because the reactor uses water as the steam generation material, the leakage at any point in the entire reactor will lead to direct contact between water and sodium, and the nuclear reactor will become a time bomb that may be used at any time.
In addition, American researchers also found that once the Seawolf's reactor is started, it cannot be stopped, because once the liquid metal reactor is out of use, the entire reactor will solidify and can never be restarted, so the entire reactor must always be kept at a high temperature to ensure that the liquid metal sodium is always in a melting state, and the reactor must be started even when it is berthed on the coast, which has caused difficulties in the maintenance and maintenance of the reactor in peacetimeIt's hellish as hell to be struck.
Before the first trial voyage of the Seawolf, there was a leakage of liquid metal sodium coolant, and the radioactive nuclear radiation spread uncontrollably in multiple compartments on the nuclear submarine, and in this way, the Seawolf's S2G reactor operated until December 1958, during which he never participated in any combat operations and combat readiness duty due to frequent accidents. In this way, the Americans' attempt at a liquid metal reactor ended in failure.
As early as the development of the SSN-575 "Seawolf" nuclear submarine in the United States, in October 1955, the Soviet Union had already carried out the development of its own liquid metal cooling reactor. In the process of research and development, the Soviets learned the lesson of the United States and no longer used sodium metal as a coolant, but switched to lead-bismuth alloy as a coolant.
The Soviet Union's liquid metal reactor nuclear submarine project code 645, from 1956 began to design the whole boat, in 1958 began to start construction at the Severodvinsk 402 shipyard, launched in 1962, when the United States Seawolf has been abandoned, the Soviets are full of confidence, thinking that they will be the first country in the world to fully master the relevant technology, the Soviet Union gave this nuclear submarine the number K-27, but the Soviets had a good idea, but the result was more tragic than the United States.
Of course, the 645 nuclear submarine still has a huge advantage over the traditional nuclear submarine, and it is equipped with two specially developed VT-1 liquid lead-bismuth alloy cooled nuclear reactors, with a total output of more than 35,000 horsepower, which is enough to drive the aircraft carrier forward, and the output power of the VM-A pressurized water reactor on the 627 627A N-class nuclear submarine developed earlier by the Soviet Union has increased by 43%, and like the S2G reactor in the United States, it has achieved a natural cycle, the underwater speed of the submarine is as high as 32 knots, and the silent performance is also very good, but the Soviets also found the problem encountered by the Americans, that is, the internal temperature of the reactor must be kept above 125 for a long time, otherwise the reactor will also solidify, which is very unfavorable for use and maintenance.
In 1964, the K27 nuclear submarine entered the southern waters of the Atlantic Ocean to carry out a secret mission, but the VT1 reactor on the nuclear submarine suddenly failed, and the internal temperature of the reactor was not running smoothly, and a serious liquid metal coolant solidification accident occurred. If the reactor is solidified and no longer runs, it is not afraid, but after the coolant of the reactor solidifies, the reactor operation fault is suddenly automatically eliminated and the operation is resumed.
And that's just the beginning. In 1965, after rest and repairs, the Soviet Navy decided to resume the operation of the K27, so that it re-entered the combat sequence, this time the Soviets decided to use the K-27 nuclear submarine to track the American aircraft carrier, but on August 26 of that year, the K27 nuclear submarine suddenly broke out after completing the tracking mission, and the superheated water vapor in the reactor leaked into the nuclear submarine, which again caused a certain **. This is not yet the climax of the catastrophe. The Soviets then suspended the use of the K-27 for a period of time, but they were not reconciled, so in May 1968, the Soviet Navy again sent the K-27 nuclear submarine to the Barents Sea for navigation training, but the disaster happened again, on May 24, the reactor of the K-27 nuclear submarine suddenly lost control, the accident caused the nuclear radiation dose in the nuclear submarine cabin exceeded the human capacity, and 9 crew members risked their lives to enter the reactor compartment for repairs, and soon died due to severe radioactive contamination。
The Soviets were so disappointed that they decided to abandon the nuclear submarine, but the VT1 reactor on the K27 could not be terminated because of the core reaction, so the Soviets could only secretly tow it to the waters near Novaya Zemlya, sink it to a depth of 33 meters, and abandon it, and then until the 90s of the last century, the radiation dose in this area greatly exceeded the normal value, and the reactor operated until the end of the 80s. This is the development process of the liquid metal coolant reactor nuclear submarine, even if he is so terrible, but the United States and Russia are still working hard to develop it, Russia's latest planning of the fifth generation of nuclear submarine Husky is basically determined to use the liquid metal coolant nuclear reactor, it can be seen that the future around this is no longer new, but powerful, terrible nuclear reactor competition, still will not stop. This is the horror of military technology, and the charm of military technology is also here.