>LAST YEAR engineers at China’s Shidaowan nuclear power plant turned off the pumps pushing coolant around the reactor core. Then they waited. At a typical power plant, this would have been dangerous. Nuclear reactions create lots of heat, which is normally transferred by a coolant and then converted into electricity. With the pumps off, the nuclear fuel might have continued to heat up until it liquefied and damaged the reactor. Such “meltdowns” can release radiation. That is what happened in 2011 at the Fukushima Dai-ichi nuclear plant in Japan after a tsunami damaged its cooling systems.
>But no such disaster occurred at Shidaowan. At first the reactor did heat up. Then it cooled down before any damage was done, says a paper by the plant’s engineers published in July. This was thanks to the plant’s clever design. Conventional reactors are powered by long fuel rods containing uranium. At Shidaowan, though, the fuel is in the form of tiny particles of uranium coated with carbon and other chemicals, and embedded in tennis-ball-sized spheres. These are known as “pebbles”. They can cope with extremely high temperatures without melting.
>Shidaowan is an example of a “fourth generation” reactor. Scientists hope these models will be able to generate power more safely and efficiently than older ones. Many countries are trying to develop them. But only China has one operating at a commercial scale (Shidaowan was plugged into the grid in December). And with this test, its engineers have shown that a theoretical advantage of fourth-generation reactors works in practice. It is a demonstration that China is “exceptionally capable in nuclear”, says Jacopo Buongiorno of the Massachusetts Institute of Technology.
>China connected its first civilian reactor to the grid in 1991, some three decades after America had done the same. Now, though, China is ten to 15 years ahead of America in deploying fourth-generation nuclear technology, according to the Information Technology & Innovation Foundation, a think-tank in Washington. China is also building conventional reactors far more quickly. Of the 60 or so plants under construction globally, 45% are in China.
>When it comes to fourth-generation reactors, there are half a dozen possible designs. Chinese engineers are trying to build plants based on all of them, but they did not invent any of them. Shidaowan, for example, is based on an experimental German model. China is adept at bringing such designs to life. Its “special sauce” is the ability “to prototype and test and modify until they’ve squeezed out every drop of efficiency”, says David Fishman of Lantau Group, a consultancy. Generous state financing and good supply chains help, too.
>China has several uses for these plants. It hopes to reduce its dependence on imported oil and gas by relying more on nuclear power. Such energy is also cleaner than that from fossil fuels. China is building lots of wind turbines and solar panels, but these depend on the co-operation of nature. Nuclear power is a more reliable way to meet baseload demand (the minimum level of power required to keep things running). So it is seen as a good replacement for some of the thousands of coal-fired power stations in the country. China aims to increase the proportion of its electricity produced by nuclear plants from around 5% today to 18% by 2060.
>Fourth-generation reactors have other uses, too. Some models run at even higher temperatures than conventional nuclear power plants. The heat this creates can be used in sectors, such as chemical manufacturing, which require high temperatures for industrial processes (at the moment this heat is usually generated by burning fossil fuels). In August the government approved the construction of another fourth-generation model, which will provide heat for a chemical plant in the south-eastern province of Jiangsu.
>China’s nuclear power stations, like those elsewhere, use nuclear fission, which splits the nucleus of a heavy element. But Chinese scientists are chasing the dream of nuclear fusion, which aims to mimic the process that powers the sun. Fusion plants might produce a near limitless supply of energy, while creating much less radioactive waste than fission plants. And, unlike fission plants, they would not require uranium, which China has to import. But maintaining a fusion reaction that produces more energy than is put into it is tricky.
>China spends about twice as much as America on fusion research, reckon officials in Washington. Chinese scientists are filing more fusion-related patents than those of any other country. Last year the government set up China Fusion Energy, a company that aims to commercialise the technology and link up nuclear firms and universities. Still, a dose of realism is in order: scientists have spent decades trying to make fusion work. For now, fourth-generation reactors will have to do. ■
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>LAST YEAR engineers at China’s Shidaowan nuclear power plant turned off the pumps pushing coolant around the reactor core. Then they waited. At a typical power plant, this would have been dangerous. Nuclear reactions create lots of heat, which is normally transferred by a coolant and then converted into electricity. With the pumps off, the nuclear fuel might have continued to heat up until it liquefied and damaged the reactor. Such “meltdowns” can release radiation. That is what happened in 2011 at the Fukushima Dai-ichi nuclear plant in Japan after a tsunami damaged its cooling systems.
>But no such disaster occurred at Shidaowan. At first the reactor did heat up. Then it cooled down before any damage was done, says a paper by the plant’s engineers published in July. This was thanks to the plant’s clever design. Conventional reactors are powered by long fuel rods containing uranium. At Shidaowan, though, the fuel is in the form of tiny particles of uranium coated with carbon and other chemicals, and embedded in tennis-ball-sized spheres. These are known as “pebbles”. They can cope with extremely high temperatures without melting.
>Shidaowan is an example of a “fourth generation” reactor. Scientists hope these models will be able to generate power more safely and efficiently than older ones. Many countries are trying to develop them. But only China has one operating at a commercial scale (Shidaowan was plugged into the grid in December). And with this test, its engineers have shown that a theoretical advantage of fourth-generation reactors works in practice. It is a demonstration that China is “exceptionally capable in nuclear”, says Jacopo Buongiorno of the Massachusetts Institute of Technology.
>China connected its first civilian reactor to the grid in 1991, some three decades after America had done the same. Now, though, China is ten to 15 years ahead of America in deploying fourth-generation nuclear technology, according to the Information Technology & Innovation Foundation, a think-tank in Washington. China is also building conventional reactors far more quickly. Of the 60 or so plants under construction globally, 45% are in China.
>When it comes to fourth-generation reactors, there are half a dozen possible designs. Chinese engineers are trying to build plants based on all of them, but they did not invent any of them. Shidaowan, for example, is based on an experimental German model. China is adept at bringing such designs to life. Its “special sauce” is the ability “to prototype and test and modify until they’ve squeezed out every drop of efficiency”, says David Fishman of Lantau Group, a consultancy. Generous state financing and good supply chains help, too.
>China has several uses for these plants. It hopes to reduce its dependence on imported oil and gas by relying more on nuclear power. Such energy is also cleaner than that from fossil fuels. China is building lots of wind turbines and solar panels, but these depend on the co-operation of nature. Nuclear power is a more reliable way to meet baseload demand (the minimum level of power required to keep things running). So it is seen as a good replacement for some of the thousands of coal-fired power stations in the country. China aims to increase the proportion of its electricity produced by nuclear plants from around 5% today to 18% by 2060.
>Fourth-generation reactors have other uses, too. Some models run at even higher temperatures than conventional nuclear power plants. The heat this creates can be used in sectors, such as chemical manufacturing, which require high temperatures for industrial processes (at the moment this heat is usually generated by burning fossil fuels). In August the government approved the construction of another fourth-generation model, which will provide heat for a chemical plant in the south-eastern province of Jiangsu.
>China’s nuclear power stations, like those elsewhere, use nuclear fission, which splits the nucleus of a heavy element. But Chinese scientists are chasing the dream of nuclear fusion, which aims to mimic the process that powers the sun. Fusion plants might produce a near limitless supply of energy, while creating much less radioactive waste than fission plants. And, unlike fission plants, they would not require uranium, which China has to import. But maintaining a fusion reaction that produces more energy than is put into it is tricky.
>China spends about twice as much as America on fusion research, reckon officials in Washington. Chinese scientists are filing more fusion-related patents than those of any other country. Last year the government set up China Fusion Energy, a company that aims to commercialise the technology and link up nuclear firms and universities. Still, a dose of realism is in order: scientists have spent decades trying to make fusion work. For now, fourth-generation reactors will have to do. ■
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