Boiling Water Reactor is literally a type of reactor that uses boiling water to cool nuclear fuel. Its working principle is: cooling water flows from the bottom of the reactor into the core to cool the fuel rods and take away the heat generated by fission. , The cooling water temperature rises and gradually vaporizes, and finally a mixture of steam and water is formed. After passing through the steam-water separator and steam dryer, the separated steam is used to drive the steam turbine to generate electricity. The Fukushima Nuclear Power Plant was built in the 1970s as a boiling water reactor.
The boiling water reactor is composed of pressure vessels, fuel elements, control rods, and steam-water separators. The steam-water separator is located in the upper part of the core. Its function is to separate steam and water droplets and prevent water droplets from entering the steam turbine and causing damage to the steam turbine blades.
The difference between a boiling water reactor and a pressurized water reactor is that the coolant water passes through the core to become steam at about 285°C and is directly introduced into the steam turbine. Therefore, the boiling water reactor has only one loop, eliminating the need for the steam generator.
Compared with other types of reactors such as heavy water reactors, light water reactor nuclear power plants have the advantages of relatively simple structure and operation, small size, low cost, economical fuel, and good safety, reliability and economy. The disadvantage is that low-enriched uranium must be used. At present, countries that use light water reactors mostly rely on the United States and the CIS for nuclear fuel supply. In addition, the utilization rate of natural uranium in light water reactors is low. If a series of light water reactors are developed, they will use more than 50% more natural uranium than a series of heavy water reactors.