The research team at MIT are using oxide materials, like those found in rechargeable batteries, to create actuators that bend and perform in high heat. This actuator shouldn’t cave in under pressure (Photo via MIT)


It’s not exactly easy to carry out maintenance tasks inside a nuclear plant. Equipment doesn’t always hold up and breaks under pressure. The Tokyo Electric Power Co. learned this the hard way when they sent in a robot inside Fukushima’s nuclear reactor, which died on the job. It’s a problem, but MIT researchers may have found a new way to make actuators that can be used in boiling hot environments.


These new actuators depend on a system that uses oxide materials like those found in rechargeable batteries. Here, the ion moves in and out of the material when charging making them expand and contract. Too much expanding and contracting can damage the lifetime of a battery cell, but actually proves to be desirable for high-temperature actuators.


Because these materials can function at temperatures higher than 500 degrees Celsius they can easily be bent. This bending motion can be used for maintenance robots that have to work inside nuclear reactors. When the oxide material is combined with other material with constant dimensions, there’s a chance it can make actuators that bend when the oxide expands or contacts.

While there are more conventional materials, like piezoelectric devices, that can create motion with electricity, they don’t work well at high temperatures. This new system has the possibility of creating sensors and actuators that can handle extremely high temperatures. These devices can be used to open and close valves in hot environments.


Researchers have been working on this new system for years. They achieved such great results due to a high resolution, probe-based mechanical measurement system they developed for high-temperature conditions. This system gives them “precision measurements of material motion that here relate directly to oxygen levels.” In other words, it let them measure the cycling in and out of oxygen in metal oxide. The researchers got these measurements by placing a thin layer of metal oxide on a substrate. They then used the detection system, which can read small displacements on a scale of nanometers, or billionths of a meter.


Though they relied on one type of oxide compound for the process, researchers believe these findings can be applied to a wide variety of oxide materials and other kinds of ions along with oxygen. These new actuators would give equipment and future robots that have to work in nuclear reactors a fighting to chance to get the job done and come out of it relatively unscathed. The team’s studies were published in the journal Nature Materials.


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