History of the formation of nuclear submarines

Nuclear submarines are the types of ships operated by the energy of nuclear reactions. It has advantages in performance compared to other types of ships that are very significant. Thanks to huge energy from nuclear, nuclear ships can operate at high speed for a long time. Typically, the current generation of nuclear submarines can operate for 25 consecutive years without refueling.

To date, more than 140 nuclear vessels operate by more than 180 small-capacity nuclear reactors and more than 12,000 years of maritime operation of accumulated reactors. Most of them are nuclear submarines but are now widely used from icebreakers to modern nuclear carriers.

In the future when fossil fuel sources become exhausted and transport restrictions are limited, nuclear propulsion will be more widely used in maritime operations. Besides, with the exaggerated concerns about safety, they have more or less caused political restrictions on access to this technology.

Development history of nuclear submarines

Waterway nuclear propulsion began to develop in the 1940s and the first experimental reactor began operating in the US in 1953. At the historic moment on January 21, 1954, at the factory closed Groton, Connecticut, with the appearance of President Dwight Eisenhower, the first US-built nuclear submarine in the world, launched with the name Nautilus *, marking the revolutionary development. in the history of the world submarine industry. Nautilus can move at a speed of 23 knots (42.5 km / h), the speed above water reaches 20 knots / h (37 km / h) achieving a record speed at that time.

Photo: Nautilus nuclear submarine launch in 1954, source of subguru.

The success of the nuclear submarine Nautilus prompted the parallel development of the Skate-class submarine operated by a single pressure water reactor (single PWR - single pressurised water reactors), and a USS Enterprise aircraft carrier. by 8 Westinghouse reactors in 1960. And it is impossible not to mention the birth of the USS Long Beach nuclear cruiser in 1961. (These ships still serve the US military until the end of 2012). . By 1962 the US Navy had 26 active nuclear submarines and 30 other submarines built. It can be said that nuclear energy has revolutionized the Navy. However, this technology is only shared with the UK, while other countries such as France, Russia and China have developed separately.

Following the success of the US Skate-class submarine class, the development of the reactor was adopted by a series of standard designs built by both Westinghouse and GE, a single reactor. Power supply capacity for each individual vessel. And Rolls Royce also built similar units for the Royal Navy submarines and later developed designs to the PWR-2 generation. Russia alone developed both PWR models and designed a lead-bismuth-cooled reactor, though not permanently.

The largest nuclear submarines at that time weighed 26,500 tons (34,000 tons when underground) belonging to the Typhoon class of Russia, operated by two PWR 190 megawatt thermal power (MWt) reactors, which were later replaced by the ships. underground 24,000 t Oscar-II.

Photo: Russian Typhoon nuclear submarine.

US Navy nuclear safety reports are outstanding, thanks in part to high levels of standardization in naval nuclear power plants and strict maintenance. In addition, the high quality of the US Navy's training program has also contributed to this achievement. In contrast, the initial Soviet efforts led to serious accidents - five damaged reactors were completely irreparable, and worse, resulted in radiation leaks. There are more than 20 deaths reported by radiation. So to the third generation Russian PWR reactor (late 1970), safety and reliability became a top priority. (In addition to reactor incidents, fires and other accidents also resulted in the loss of two US submarines and about four Soviet submarines, four of which were fire resulting in casualties.)

Structure of nuclear submarines

Basic construction of nuclear submarines.

There are many types of nuclear submarines, but in general they have the basic components as shown in the description:

The body of the submarine shell is firmly designed in a cylindrical shape with two ends and ends connected seamlessly to the cone and the end is a convex hemisphere in the hydrodynamic shape, inside the vessel is mounted with ballast water, Hemisphere chamber with sound sonar antenna and propeller shaft. The inside of the hull body has a solid structure covered with a layer of insulating material, light sound insulation, covering and separating all the compartments in the hull as a chamber for missile launchers and equipment compartments. with a stern motive, along with a hydro sound antenna radar system, followed the stern at the rear. With a small area of ​​the inside of the hull, the submarine could be considered a ship with a smooth main compartment. Such hull design method, according to experts, minimized the ability to produce negative hydrodynamic noise, achieving the highest underground mobile speed with the lowest noise level compared to submarines. There are two main compartments. The hard and resistant bulkheads will divide the ship into secondary compartments, each of which will divide the ship compartment into several working floors. The bow section, the missile section and the stern compartment are open and closed to provide goods, facilities, missile bullets and torpedoes.

Ballast water tank : Located in the front and back position of the submarine. Help control the depth of the vessel by sucking and draining water. Thereby it can help the ship to rise or dive easily

Center of attack control : Coordinating operation of navigation system, communication, weapons. A place to direct all sailors' activities.

1. Antennas Sonar: Placed at the position of the bow, helping submarines to detect strange objects with SONAR waves (reflected waves).
2. Missile launch system: The modern generation of ships is equipped to destroy terrestrial targets
3. Torpedo chamber: Torpedoes are ready to attack targets in naval battles
4. Sail: The hull of the hull, including radar columns, communication antennas, telescopes
5. Steering wheel: Mounted along the hull to direct navigation.

Filtration system : Seawater will be removed with salt for domestic use and motor supply. Air pressure is also provided by removing CO2 and impurities.

Sailor room : The regular area of ​​crew members includes: Private rooms of officers; Living room rest; Buffet; Kitchen on board; Dining room of the crew .

Control center : control operation of turbines, generators, reactors

1. Engine chamber: Contains the main turbine to control the propeller, hydraulic system, air compressor and generator.
2. Propeller: Equipped with steam turbine and generator. Steam is generated by a nuclear reactor.

Nuclear reactor : Covered by a thick metal layer weighing nearly 100 tons. Inside is also reinforced by radioactive alloy layer. A reactor consists of: control bar, fuel bar, furnace shell, coolant, retarder, thermal load system.

1. Control bar: usually need a cylinder shape, made of materials capable of absorbing high neutrons such as boron, cadmium or stainless steel. Control bar used to control chain reaction, changing the use of heat.
2. Fuel bar: in which the heat released from the fission reaction. -The furnace shell: usually designed with safe materials, to avoid damaging radiation.
3. Coolant: flowing through the furnace core can transfer heat to a steam generator so that steam can be used in a turbine generator to produce electricity.
4. Thermal load system: It is duty to load the heat output to start the active zone. One can use heat loaders as ordinary water, heavy water, liquid sodium or liquid lead .

Photo: Top of nuclear submarine reactor.

Active construction of PWR pressure water reactor

Summary: Heat is generated in a nuclear reactor to boil water, create steam and then turbine to generate electricity. In a nuclear reactor, heat is generated by nuclear fission. The uranium and plutonium nuclei in the fuel are bombarded by neutrons, split into two pieces, and released energy as new neutrons and heat. These new neutrons cause subsequent fission and thus produce a chain reaction.

Reactor construction.

Water in cycle 1 (primary) is pumped through the reactor to convey to the boiler the amount of heat generated in the furnace. Since water in cycle 1 has a temperature of up to 320 ° C, it must be kept at a high pressure of 16Mpa - about 157 times atmospheric pressure to keep water in a liquid state (preventing water from boiling).

Pressure is maintained stable by steam in the pressure regulator (see diagram). This high-pressure hot water is then conveyed to the steam generator (boiler), where the water of cycle 2 is turned into high-temperature and high-pressure steam that rotates the rotor turbine generator units. electricity. So create an electric current to operate the engine. The vapor is then stopped to form a closed-loop water and returned to the steam generator (circulating water 2). The use of the system has two cycles to increase safety and isolate the radioactive zone (within cycle 1).

In the normal operating mode, the thermal energy from the reactor is transmitted to the steam, pneumatic vapor assemblies that are pushed into the turbine blades, making the rotors and rotating the spindle, shaft dynamics. The main adopts reducer box transmission to the screwshaft and rotary propeller. In the low noise operation mode, the diagram is more complicated - steam from the steam pneumatic assembly is transmitted to the steam turbine generator station, supplying electricity to the screwshaft rotary motor.