Researchers at the Oak Ridge National Laboratory (ORNL) recently successfully developed a transistor fashioned out of Gallium Nitride (GaN) that can withstand the heat and radiation near the core of a nuclear reactor. Scientists found that the GaN transistor can survive temperatures up to 125 degrees Celcius (257F), the limits of the reactor's safety threshold, and they predict it can last for five years in the extreme conditions.
Traditional silicon-based transistors could not withstand the intense nuclear environments, thus requiring them to be placed behind shielding. This means that these processors must be connected to the analog sensors inside the reactor via cables.
"Our work makes measuring the conditions inside an operating nuclear reactor more robust and accurate," said Kyle Reed, the team leader behind the ORNL research. 'When you have lengthy cables, you end up with a lot of noise, which can interfere with the accuracy of the sensor information. By placing electronics closer to a sensor, you increase its accuracy and precision."
Silicon chips are susceptible to radiation, with stray particles from trace radioactive material (and even the background radiation of the universe) enough to change the information within them, as explained by Veritasium. Much stronger radiation sources, like the ones inside a nuclear reactor, could even damage them. That's why traditional processors would not survive in such a hostile environment.
GaN has been used for the better part of a decade, usually in compact, high-power devices like these USB-C laptop chargers. However, it doesn't see much application beyond that, as Gallium Nitride tends to be more expensive and difficult to work with than silicon. Nevertheless, its hardy nature makes it the ideal candidate for niche applications such as these.
In fact, GaN chips have been used for space flight, where they can withstand the ionizing radiation that happens when the rocket leaves the earth's atmosphere. According to ORNL's testing, the GaN processor could survive for at least three days at up to 125 degrees Celsius close to the core of the Ohio State University Research Reactor. The team eventually concluded that the GaN device they tested could last for more than five years near the core of the reactor—the usual required maintenance cycle for nuclear plants.
What's more interesting is that GaN chips are more susceptible to thermal damage than radiation. "Since the ultimate goal is to design circuits with these materials, once we understand the temperature and radiation effects, we can compensate for them in the circuit design," Reed said.
Aside from better sensor accuracy and recording, GaN chips are also crucial in developing smaller, modular reactors. Aside from the usual government and military applications, developing these portable nuclear plants could also fuel our AI future as GPUs become more power hungry each year. In fact, Microsoft is looking to build some of them for its data centers, and the U.S. government is already in talks with tech companies about their future power demands.
GaN chips are mostly found in USB-C chargers today. But if this nuclear research moves forward, we might soon find them in the nuclear power plants of the future, too.
