Pressurized Water Reactor Internals

The pressurized water reactor is the mainstream reactor type in the current global commercial nuclear power plants. Its core function is to convert nuclear energy into thermal energy through a controlled nuclear fission chain reaction and drive the generator set to efficiently output electrical energy. As the "heart" of a nuclear power plant, the pressurized water reactor adopts a dual-circuit heat exchange system: in the first circuit, high-pressure water (pressure of about 15.5 MPa) absorbs the heat generated by the fission of nuclear fuel (uranium-235) in the core, and the water temperature can reach 330°C but remains liquid; the high-temperature and high-pressure water then enters the steam generator, transfers the heat to the ordinary water in the second circuit, and generates steam to drive the steam turbine to generate electricity. This design greatly reduces the risk of radioactive material leakage by physically isolating the nuclear reaction area from the power generation system. The key structures of the pressurized water reactor include the pressure vessel (which contains the core and nuclear fuel), the control rod drive mechanism (which regulates the reaction rate) and the containment (the ultimate barrier). It has high technical maturity and strong operational stability, accounting for more than 60% of the world's operating nuclear power units. Taking the "Hualong One" independently developed by my country as an example, it adopts a core layout of 177 fuel assemblies, with a digital instrumentation and control system, which can withstand a magnitude 9 earthquake and a large aircraft collision, and has a power generation efficiency of more than 35%. In addition, the modular design of the pressurized water reactor (such as the overall hoisting of the steel containment of the AP1000) and the breakthrough in localization (the self-reliance rate of key equipment exceeds 90%) support the export of my country's nuclear power technology and become the core carrier of the "national business card" level strategic industry.