Soil Microbes as Nuclear Probes
The chief scientist of DNN TECH—the University of Tennessee’s federally funded consortium to enhance nuclear nonproliferation techniques—is not a nuclear engineer.
But he is certainly someone nuclear engineers can rely on.
“I’ve been studying the microbiomes (communities of microorganisms) of Department of Energy (DOE) sites for 50 years,” said Terry Hazen, the Governor’s Chair for Environmental Biotechnology and a professor in the Department of Civil and Environmental Engineering (CEE). “Because I have a lot of experience, (other consortium members) rely on me for advice on different sites that might have samples they can obtain (related to) certain types of radiation events.”
New types of nuclear reactors are constantly being developed and deployed to meet the world’s growing demand for carbon-free energy. Unfortunately, that also creates new opportunities for bad actors to try to steal radioactive materials.
The DOE National Nuclear Security Administration’s (NNSA) Office of Defense Nuclear Nonproliferation (DNN) ensures that nuclear and radioactive materials are carefully controlled and only used for energy production. In 2025, the University of Tennessee established TECH, the Enabling Capabilities in Technology Consortium, to develop new nuclear nonproliferation capabilities.
One of TECH’s key focus areas is understanding how nuclear and radioactive materials change the environment as they move through the energy pipeline, making it easier to prevent and detect illicit displacement. That’s where Hazen’s experience in microbiology comes in.
In 2026, Hazen and his students shared an important discovery about the types of microbes that live in and around different DOE sites, establishing a method of tracing very small levels of radionuclides that has garnered attention from national laboratories across the country.
“Dr. Hazen’s microbiome research at nuclear sites is an important part of DNN TECH’s fundamental research in the first TECH area of earth, environmental, atmospheric, and space science,” said TECH Director Jason Hayward, a professor in the Department of Nuclear Engineering. “Given the interesting results to date, it’s quite possible that gaining a deeper understanding of how microbiome populations correlate with the activities of nuclear sites could become useful in nuclear nonproliferation.”
Precise Microbial Response
As reactors and other facilities in the nuclear fuel lifecycle operate, they are careful to keep any release of radiological materials below levels that could affect human or animal health. However, tiny trickles of uranium, thorium, and other radionuclides (radioactive elements) are enough to significantly shift the balance of microbial communities living near a facility.
“A lot of people think the radioactive (material) is damaging the microorganisms, and in fact, that’s usually not true,” Hazen said. “(Instead) it may depend upon a particular isotope or a particular type of material the (microbes) need for their nutrition.”
The radionuclides coming from a reactor or other facility contain a lot of energy, so the species capable of harnessing that energy flourish around them, becoming much more abundant than usual.
Oak Ridge National Laboratory’s High Flux Isotope Reactor (HFIR) has been operational since 1975, producing heavy elements like plutonium and curium and transuranic isotopes like californium-252. Hazen and his former student Isis Fukai (PhD/EECS, ’26) recognized it as the perfect site to investigate how specific these microbiome effects could be.
“It was peculiar that when we actually saw exactly where the samples came from around the HFIR reactor, they corresponded to particular contaminants,” Hazen said. “We can look at (a sample) and say, ‘Because we’re seeing these particular groups of microorganisms, it suggests that there should be a thorium reactor nearby.’”
Microbiomes—Big Advantages
Using microbial species to infer what kind of radionuclides might be nearby has a lot of advantages. If standardized, the method could be used to identify unsanctioned transfers of nuclear material that are too small to be detected through conventional means. Microbiome analysis tools are very widespread and comparatively inexpensive, so DNN researchers could significantly broaden their investigations at low relative cost.
One of the biggest benefits is researcher safety. Soil samples from DOE sites sometimes include high enough concentrations of radionuclides that studying them requires full-body radiation protection and shipping them to other labs further analysis is impossible.
By contrast, small samples of microorganisms from contaminated sites can provide the same information and opening analysis to partner institutions across the country without putting researchers at risk.
Hazen and Fukai presented their work during DNN TECH’s annual review last year, garnering excitement from all consortium members—including all three of the nation’s NNSA national laboratories.
“They were very interested in what we were doing because they may be able to use it at their sites too,” Hazen said. “And we were willing to cooperate with them and do some analyses for the other DNN TECH consortium labs. (This approach) would help them out quite a bit.”
Contact
Izzie Gall ([email protected])