Sensor Survives Reactor-Level Heat and Radiation, Paving the Way for Real-Time Monitoring

• Firing up the heat
• Small chip, big implications

Generating nuclear power takes a lot of energy—extreme heat, pressure, and radiation—that every part of a reactor must withstand each time. Naturally, engineering the perfect apparatus is a difficult task, but researchers continue to discover astonishing ways to advance nuclear technology, the latest of which involves a tiny chip with not-so-tiny performance.

In a recent release, University of Maine researchers announced new microelectronic sensors that tolerate both the radiation levels and extreme temperatures of a nuclear reactor’s core. At the same time, the sensor captures real-time operational data, giving engineers and operators invaluable insight into the reactor’s activity.

“Since many advanced reactors currently under development operate at these temperatures, there is a high demand on the sensors to monitor them,” Mauricio Pereira da Cunha, the project’s principal investigator, said in the release. “The successful development of these sensors will address and alleviate technology barriers that currently hinder the rollout of advanced nuclear reactors.”

Firing up the heat

The sensor is intended to live inside the furnace of reactors for nuclear fission, which generates large loads of energy by splitting two heavy molecules. Specifically, the researchers hope to install the sensors in advanced high-temperature reactors, which run on helium gas and contain ceramic materials to more efficiently and safely generate nuclear energy.

However, these reactors reach higher temperatures than what existing sensors can withstand, as their advantages come with the “higher thermal efficiencies that are attained at higher temperatures,” the researchers explained.

The team, on the other hand, had two decades of expertise in refining similar sensors. This motivated them to spend the last two years developing and testing a sensor strong enough for the next-generation reactors—and, while they were at it, make the sensor tiny to widen its range of applications.

Small chip, big implications

For the project, the team created seven sensors, all tested at the Nuclear Reactor Laboratory at the Ohio State University, according to a report by the Department of Energy’s Office of Nuclear Energy. Each sensor was 100 nanometers thick—roughly 1,000 times thinner than a strand of hair—and carried platinum-based alloy electrodes packed with alumina caps.

Impressively, all seven sensors “remained functional” and “showed no signs of degradation” despite five days of the reactor blasting them at its maximum power, at about 1,500 degrees Fahrenheit (800 degrees Celsius), the report explained. Early analyses also implied that the sensors were resilient against radiation, too.

“In addition to extreme temperatures, we’re now also exposing these sensors to intense, in-core levels of nuclear radiation at the same time,” Luke Doucette, the project’s senior research scientist, said in the release. “This adds an entirely new dimension of difficulty in terms of what types of sensor materials can survive in these conditions and remain functional.”

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