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https://www.popularmechanics.com/sci...r-power-balls/

A new technology scientists are calling “power balls” could revolutionize nuclear power plants by allowing for much higher temperatures without a meltdown incident. The secret? Tiny seeds of uranium that are layered with protective coating, ensuring they stay cool at temperatures up to and exceeding 3,000 degrees Fahrenheit.

Triso (tristructural isotope) particles are like tiny Everlasting Gobstoppers of nuclear fuel. A core of uranium and oxygen is coated with layers of protective ceramic and graphite. The ceramic (silicon carbide) has been used for a century to make things like sandpaper and ceramic automobile brakes. It’s extremely heat-tolerant and is also used in construction of furnaces and as a heat-resistant shielding in LEDs.

The grains are made with processes that sound like the food science people pull out on Top Chef. First, uranium is mixed with a chemical that allows it to break into gummy beads just a millimeter across—like the microplastic beads you might find in a face wash. In a special oven, the beads are contact-coated with graphite that’s made to collapse from its gas form into solid layers. Then, thousands of these chocolate-coated uranium Dippin’ Dots are packed into individual pellets.

A company called BWXT is the major pusher for these micro uranium gobstoppers, which it’s also testing with a government-sponsored 3D-printed nuclear reactor. The other company is X-energy, whose TRISO-X FUEL can be seen in the images in this article.

Within a nuclear power plant context, the grains of protected uranium simply can’t melt down, proponents say. In a traditional fission reactor like the ones used today, fuel allowed to heat out of control will eventually cook itself into a meltdown. If that meltdown escalates, the heat can destroy the protective measures in place around the reactor. Instead, the tiny power granules have their own deescalation process built in.

Existing plants have redundant and extreme safety systems, but there’s a human and programming element in these plants that can go wrong in a way that maxes out all the containment and redundancy. The scientists pushing “power balls” say their inherently safe nature means these next-generation plants don’t need costly containment in the same way, which could save time and money.

For decades, nuclear authorities around the world have built larger and larger power plants. The impulse makes sense, because especially in China, huge plants are a way to provide a ton of power for 160 cities that have at least one million people. Nuclear is environmentally cleaner, at least today, and replaces or supplements coal-firing plants that are increasingly out of step on the global stage. But the larger the traditional fission plant, the more elaborate the safety procedures and structures must be.

In decades of nuclear power, there have been very few partial or full meltdown events, but the extreme damage and enduring poisoning these events cause has cast a shadow over any nuclear power. The 2011 meltdown at Fukushima in Japan was induced by an earthquake, which could happen almost anywhere in some form. In China, there are dozens of individual reactors that are multiple times larger in output than the reactors at Fukushima, and many of these are positioned in clusters at major power plants.

The next generation of nuclear power reactors is modular and much smaller than traditional plants, with no need to design a brand new, sprawling facility from the ground up on a huge tract of rural land. But much remains to be proven before these plants can be built.