New aerogel detects radioactive gas in nuclear plants with 96% accuracy

Researchers have created an innovative aerogel that provides real-time measurements with high sensitivity to specific radioactive gases.

The aerogel produced by a group led by a French National Centre for Scientific Research (CNRS) team could become crucial for monitoring the operation of nuclear power reactors.

Researchers developed a transparent aerogel made of scintillating nanoporous material that can detect gases in real-time. Krypton-85 can be detected with 96 percent efficiency and tritium with 18 percent.

The method is highly sensitive, measuring less than 100 mBq per cm³ in 100 seconds, and can detect both gases simultaneously, an improvement over previous methods.

According to the team, the approach offers a quicker and more cost-effective substitute for the existing ones, which are often intricate and expensive.

Radioactive monitoring

Among the most frequent radioactive gases released by the nuclear industry during the production of power or recycling of radioactive waste are tritium (3H), krypton-85 (85Kr), and carbon-14 (14C).

While these radionuclides do not pose a significant risk, precise measurement is essential for monitoring the correct operation of nuclear power plants and averting mishaps.

On the other hand, radionuclides are pure beta emitters whose radioactive disintegration does not produce gamma-ray emissions; as such, special techniques are needed for their identification and measurement.

According to researchers, the current methods are still expensive and complicated. They are based on the concepts of either gas-liquid mixing or gas-gas mixing. They also produce waste, are inefficient for some radioactive gasses being studied, and are unable to discriminate between radionuclides quickly.

Aiming to address the shortcoming, scientists have developed a dependable and economical real-time detection technology based on gas-solid mixing.

Efficient gas detection

The team’s effort is based on the synthesis of an aerogel with a diameter of a few centimeters and a thickness of one centimeter, employing nanoparticles of materials that are scintillating and around five nanometers in size. With only 15 percent solids, this composite is translucent and has a very porous structure akin to a sponge.

Thanks to this unusual construction, the gas diffuses quite easily. The aerogel transforms the energy created by the emission of electrons during radioactive decay into visible light when the gas enters the scintillation vial and comes into contact with it. An extremely sensitive sensor device that can quantify each photon nearly instantly detects this flash of light.

Detailed examination of these light emissions led to the creation of a novel technique for identifying and quantifying online pure beta emissions of various energies, including tritium and krypton-85, in the same gas sample.

According to the team, a cutting-edge experiment on radioactive gases allowed for the theoretical and experimental development and confirmation of these results.

“This new approach to detecting radioactive gas has paved the way for the widespread use of sensors for monitoring civilian nuclear activities,” said researchers in a statement .

The technology could be adapted to detect other beta-emitting radionuclides, such as carbon-14 (14C), xenon-133 (133Xe), and argon-37 (37Ar), expanding its use to civilian, medical, and military applications.

The details of the team’s research were published in the journal Nature .