Nuclear Reactor Core

The nuclear reactor is the energy conversion center of a nuclear power plant. Its core function is to convert the nuclear energy of nuclear fuel (such as uranium-235) into thermal energy through a controlled nuclear fission chain reaction, and drive the power generation system to produce electricity. As the "heart" of a nuclear power plant, the reactor consists of key components such as the core, control rods, pressure vessels, and coolant loops: the nuclear fuel rods in the core are arranged in a specific array, and neutron impact triggers fission and releases a large amount of heat; the control rods (containing boron carbide or silver indium cadmium materials) can accurately adjust the neutron flux to maintain a stable reaction rate; the coolant (such as water, liquid metal or helium) circulates in the pressure vessel, transporting the heat of the core to the steam generator, driving the steam turbine to generate electricity. Taking a pressurized water reactor (PWR) as an example, the high-pressure water in the first loop (pressure of about 15.5 MPa) transfers the high temperature of 330°C to the second loop to generate steam, realizing the cascade conversion of nuclear energy and electrical energy, while ensuring that radioactive substances do not leak through physical isolation. Modern reactor technology (such as the third-generation "Hualong One" and the fourth-generation high-temperature gas-cooled reactor) integrates multiple safety barriers: prestressed concrete containment can withstand magnitude 9 earthquakes and aircraft collisions, and passive cooling systems (such as the core water tank of AP1000) can still automatically remove residual heat when the power is off, greatly reducing the risk of core meltdown. The technological iteration of nuclear reactors (such as the increase in fuel enrichment to 5% and the extension of the core refueling cycle to 18 months) has significantly improved power generation efficiency (thermal efficiency of more than 35%), and its modular design (such as small reactor SMR) and localization breakthroughs (the self-reliance rate of key equipment exceeds 90%) have further supported nuclear power to become a strategic pillar of low-carbon energy transformation. There are more than 400 units in operation worldwide, and the annual power generation accounts for more than 10% of the world's total electricity.