This blog post explores why electricity is essential and how power plants reliably produce and supply it.
Electricity has become an indispensable part of modern life. From the household appliances we use daily to the large machinery operating in factories, electricity plays a vital role in countless ways. Moreover, as digital devices like smartphones and computers have become deeply embedded in our lives, the importance of electricity has only grown more prominent. To ensure a stable supply of this essential electricity, countless power plants operate day and night, functioning according to highly complex engineering principles.
To produce the electricity needed around the clock, somewhere, hot and powerful steam is constantly driving machinery called turbines without pause. These turbines play a central role in the electricity generation process, and producing the high-temperature steam needed to drive them is one of the power plant’s primary tasks. This steam is produced in different ways at various types of power plants, each method having its own advantages and disadvantages.
Thermal power plants and nuclear power plants utilize their respective fuels to continuously generate the high-temperature steam required for electricity production. For example, thermal power plants burn fossil fuels like coal or natural gas to generate heat, while nuclear power plants utilize the heat produced when radioactive materials like uranium undergo nuclear fission. These fuels trigger reactions that generate immense heat, which is then transferred to adjacent cooling water. The cooling water absorbs this heat and is converted into high-temperature steam, which is then used to drive turbines. Thus, all thermal and nuclear power plants, regardless of their form or structure, fundamentally generate steam continuously from this flow of heat.
Power plants are equipped with complex and sophisticated engineering structures to implement this principle. A distinctive feature of nuclear power plants is the existence of two distinct cooling system approaches. Each approach has its own advantages and disadvantages, and experts continue to debate which is superior. This article excludes that debate and will only briefly cover the structural characteristics of each type of plant.
The first type to examine is the boiling water reactor (BWR). As its name suggests, a boiling water reactor is so called because the cooling water in contact with the fuel undergoes ‘boiling’ and converts into steam. Inside this reactor, the fuel is submerged in cooling water maintained at an appropriate level. This cooling water absorbs heat from the fuel and begins to boil. The reactor has inlets and outlets for the coolant, and the steam escapes the reactor through these outlets. The steam leaving the reactor moves to the turbine, providing the power to generate electricity. After passing through the turbine and completing its task, the steam returns to its liquid form and flows back into the reactor. Thus, the boiling water reactor operates with fuel, water, and steam interacting within a single space.
The second type we will examine is the pressurized water reactor. Unlike the boiling water reactor, the pressurized water reactor maintains the coolant inside the reactor at high temperature and pressure to suppress steam generation. This reactor also contains fuel and coolant, with the coolant filling the reactor vessel and inlet/outlet pipes. However, the coolant is isolated from the outside environment and confined under high temperature and pressure, preventing it from boiling inside the reactor while still receiving heat transfer. The coolant that generates steam is located externally. This external coolant contacts the reactor’s hot surfaces, absorbs heat, and converts into steam. Unlike in boiling water reactors where heat from the fuel is transferred directly to steam, in pressurized water reactors, heat transfer occurs in stages through the fuel, coolant, and tubes.
Ultimately, the key difference is that in boiling water reactors, steam is generated directly around the fuel, while in pressurized water reactors, steam is generated outside the tubes containing the fuel and coolant. This difference arises from the design and operating principles of the two reactor types, and each approach can be advantageous in specific situations. Boiling water reactors may have lower initial construction costs due to their relatively simple structure, while pressurized water reactors offer the advantage of more stable thermal management.
Thus, the two main types of nuclear power plant reactors—boiling water and pressurized water—significantly impact a plant’s efficiency and safety based on their respective characteristics. With advances in modern technology, these reactor designs are becoming increasingly sophisticated, and power plants worldwide continue to refine these technologies.
