TRISO (TRi-structural ISOtropic) nuclear fuel cells are a type of advanced nuclear fuel designed to enhance the safety and efficiency of nuclear reactors. Each TRISO particle is a tiny, spherical fuel pellet encased in multiple layers of protective materials that act as a barrier. This barrier contains the radioactive fission products, preventing them from escaping even under extreme conditions. TRISO fuel is highly resistant to high temperatures and radiation, making it particularly suited for next-generation reactors.
Shidaowan’s twin 100-MW units encase the uranium capsules in graphite shells about the size of billiard balls. In this design, the nuclear fission reaction occurs slower than in conventional reactors, but the fuel can withstand higher temperatures for longer. Furthermore, the heat from the fission is dispersed, creating a passive cooling process. There’s another safety mechanism: while most reactors use large volumes of water to cool down, this system uses a small amount of helium, which can also withstand higher temperatures.
If the nuclear reactor suffers a crisis, it can’t overheat and meltdown because of the passive cooling system — at least, this was the theory. Researchers at Tsinghua University in China have now put the theory to the test, performing two safety tests by shutting off the active power supply to see if the decay heat could be removed passively.
The reactors passed with flying colors, cooling down just as expected.
“The results of the tests manifest the existence of commercial-scale inherent safety for the first time,” the researchers write in an article published in the journal Joule.
https://www.zmescience.com/ecology/renewable-energy-ecology/nuclear-plant-meltdown-triso/
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