On December 6, my country's major national science and technology project with completely independent intellectual property rights and the world's first fourth-generation nuclear power station was officially put into commercial operation in Rongcheng, Shandong Province, marking that my country has reached the world's leading level in the research and development and application of fourth-generation nuclear power technology. High-temperature gas-cooled reactor technology is the latest generation of nuclear power technology.
What is a high-temperature gas-cooled reactor?
High-temperature gas-cooled reactor includes the two keywords "high temperature" and "gas-cooled". "High temperature" means that the reactor core uses high-temperature-resistant materials such as graphite, which allows the reactor core outlet temperature to reach a height that is difficult to reach for other reactor types. It can not only generate electricity efficiently, but also use high temperatures to achieve comprehensive utilization of nuclear energy and achieve multiple goals with one stone. "Gas cooling" means that the reactor uses inert gas helium for core cooling and heat transfer, rather than the "water cooling" method of traditional pressurized water reactor nuclear power plants. Helium does not easily react with other materials in the reactor at high temperatures, so it is called a "high-temperature gas-cooled reactor."
High-temperature gas-cooled reactor: "inherently" safe nuclear reactor
Safety is the lifeline of nuclear energy development. As an advanced reactor type of the fourth generation of nuclear energy technology, high-temperature gas-cooled reactors have "natural" inherent safety. Where does such safety come from?
The high-temperature gas-cooled reactor is called a "meltdown-proof reactor" and its safety is inherent safety realized from the design principle stage.
Inherent safety = no leakage, no loss of control, no meltdown
Zhang Zuoyi, Dean of the Institute of Nuclear and New Energy Technology at Tsinghua University: By definition, an intrinsically safe reactor does not rely on human intervention or external power under any accident or natural disaster conditions. The reactor can naturally cool according to natural laws and the core will not melt.
Inherent safety magic weapon one: four layers of high-temperature-resistant “armor”
The fist-sized black ball in front of you is the fuel ball of the high-temperature gas-cooled reactor.
Wang Rui, debugger of Huaneng Shidaowan High Temperature Gas-cooled Reactor Demonstration Project: The outermost layer is graphite, and there are about 12,000 fuel particles inside. Each fuel particle contains the nuclear fuel used to undergo nuclear fission reactions and release energy. Unlike other fuels, the nuclear fuel here is wrapped in four layers of high-temperature-resistant ceramic "armor", which can effectively prevent the leakage of radioactive materials.
Inherent Safety Magic Weapon Two: Nuclear Power Plant Made of “Building Blocks”
The high-temperature gas-cooled reactor demonstration project adopts a modular design and is composed of two modular reactors. Each module is a small reactor that can operate independently and can continuously load and unload nuclear fuel at any time.
Entering the "no man's land" of high-temperature gas-cooled reactor debugging
A large amount of research and design work has been carried out internationally on high-temperature gas-cooled reactor technology, but commercial power plants have never been successfully built. The high-temperature gas-cooled reactor demonstration project entered the debugging stage in July 2020 and was officially put into production today. It has passed many hurdles in the debugging and operation of the unit and entered the "no man's land" of the world's nuclear power technology.
The debugging work of a nuclear power plant is equivalent to "clearing mines" for the unit. For a high-temperature gas-cooled reactor demonstration project with more than 2,200 first sets of equipment, there is no experience to follow and it is extremely difficult. The Shidaowan Nuclear Power Plant has the world's largest and heaviest nuclear power pressure vessel. It is a large metal tank used to wrap the reactor core and helium. Helium molecules are small and easy to leak, so the first task of debugging is to verify the sealing of the pressure vessel.
Wang Rui, debugger of Huaneng Shidaowan High Temperature Gas-cooled Reactor Demonstration Project: This can be said to be a rare large-volume, high-pressure test with high potential risks. We need to monitor more than 100 risk points on the pressure vessel that may leak, and at the same time control its temperature to avoid equipment damage.
After nearly 30 months of debugging work, engineering personnel have completed more than 700 debugging tests, developed six key core technologies for debugging and operation unique to high-temperature gas-cooled reactors, successfully verified the inherent safety and continuous operation capabilities of high-temperature gas-cooled reactors, and achieved safe and stable operation of the unit.