Microbial janitors are helping their human counterparts with nuclear clean-up. Researchers plan to coax naturally occurring microbes to clean radioactively contaminated walls and ceilings at a shut down reactor in the United Kingdom.
Researchers from the Department of Energy's Idaho National Engineering and Environmental Laboratory (INEEL) in partnership with British Nuclear Fuels, plc (BNFL) are launching a yearlong test of a microbial decontamination technology at a nuclear reactor at the Sellafield reprocessing plant in the UK. The technology will be used to remove surface contamination on a concrete wall at the reactor in a proof-of-concept test run.
The microbes' job is to eat and be merry -- it's the corrosive microbial by-product that does the researchers' work. As the microbes metabolize an elemental sulfur nutrient source, they create sulfuric acid. The sulfuric acid etches the concrete surface and loosens the contaminated layers. When enough concrete has been loosened, researchers put the kibosh on the microbial feeding frenzy by dropping the humidity, causing the microbes to die off (the microbes cannot survive in ambient humidity). Then they vacuum the degraded concrete bits off the walls, ceiling or floor, and dispose of it.
Currently, a common treatment for radioactively contaminated concrete involves chipping it away until workers reach 'clean' concrete. This means the workers, hot and sweaty in full anti-contamination suits and respirators, are being exposed to radiation as they work. And they still have a substantial pile of radioactively contaminated concrete rubble and dust to dispose of when they're done.
In some cases, radiation fields may be too high for human exposure, even for a
few minutes, or the configuration of the space may not allow safe human access
at all. Then, the only alternative for facility operators may be to fill the
room with cement, do nothing, or demolish the entire building and treat all th
Contact: Deborah Hill
DOE/Idaho National Laboratory