Efforts to expand nuclear energy have long been hampered by fears of a major nuclear meltdown. The new Chinese reactor design is the first full-scale demonstration of a fully meltdown-proof reactor.
Despite the rapid growth of renewable energy, many argue that nuclear power still has a role to play in the race to decarbonize our electricity supply. But events like Chernobyl and Fukushima have made people understandably wary.
Modern reactor designs are much safer than previous generations, but there is still a risk of a nuclear meltdown. This occurs when the cooling system of the plant fails, often causing a power outage that can lead to a runaway overheating of the core. This can cause an explosion that destroys the containment and disperses radioactive materials.
But now researchers in China have conducted tests to prove that a new type of reactor design is essentially impervious to meltdown. lineThey described tests that cut power to an operating nuclear power plant, which was able to cool itself passively.
“The nuclear behavior and temperatures within the various reactor structures demonstrate that the reactor can cool naturally without active intervention,” the authors wrote. “The test results demonstrate, for the first time, that inherent safety exists at commercial scale.”
Tsinghua researchers conducted the tests on the 200-megawatt high-temperature gas-cooled reactor pebble-bed module (HTR-PM) in Shandong province, which entered commercial operation in December last year. The new design of the plant replaces the fuel rods found in conventional reactor designs with a large number of “pebbles,” each a few inches across and made of graphite, containing a small amount of uranium fuel inside.
This approach greatly reduces the energy density of the reactor fuel, making it easier for the heat to dissipate naturally if the cooling system fails. Small-scale prototype reactors have been built in China and Germany, but a full-scale demonstration of the safety of this technology has not yet been achieved.
To test the new reactor, researchers intentionally cut power to the plant’s two reactor modules and observed the results. Both modules cooled naturally in about 35 hours without any intervention. The researchers claim this is proof that the design is “inherently safe” and should significantly reduce safety system requirements for future reactors.
Researchers admit that the design makes power generation about 20 percent more expensive than conventional reactors, but they believe that costs will come down as the technology becomes mass-produced.
China is not the only country building such reactors. The U.S. company X-Energy has designed an 80-megawatt pebble-bed reactor called the Xe-100, which is currently awaiting a decision from the Nuclear Regulatory Commission on an operating license.
however, New Scientist Note that this technology cannot be used to retrofit existing power plants, so there is still a risk of collapse of older plants. And it generally takes a huge amount of time and money to build a nuclear power plant, so it is unlikely that this technology will make up a significant portion of the world’s nuclear fleet any time soon.
But by demonstrating that it is possible to build a reactor that can withstand a meltdown, the researchers have neutralized one of the main objections to using nuclear energy to solve the climate crisis.
Image source: Tsinghua University
