A system was developed that can remove radioactive cesium contamination from porous structures such as brick and concrete that are hard to clean, as well as contamination from metal surfaces. The Supergel system focuses on rapid response, capturing as much of the contamination as possible, as quickly as possible, and filling a technology gap immediately.
The system consists of engineered nanoparticles and a super-absorbent polymer gel that work together to clean structures exposed to radioactive materials. The polymer Supergel that absorbs the radioactivity is similar to the absorbent material found in disposable diapers. When exposed to a wetting agent, the polymers form a kind of structural “scaffold” that allows the gel to absorb great amounts of liquid. The amount of contamination removed depends on the characteristics of the contaminated structure — its age, type of material, and whether painted or unpainted — and the radioactive isotope involved. Removal rates have ranged from roughly 80 to nearly 100 percent.
Operating much like an automatic car wash, the Supergel system follows a three-step process:
Remote spray washers apply a wetting agent and a super-absorbent gel onto the contaminated surface.
The wetting agent causes the bound radioactivity to re-suspend in the pores. The super-absorbent polymer gel suctions the radioactivity out of the pores, and it becomes fixed in the engineered nanoparticles that sit in the gel.
The gel is vacuumed and dehydrated, with only a small amount of radioactive waste remaining for disposal.
A key benefit of the Supergel technology is that it leaves structures intact. Until now, no effective technique existed to remove radioactive contamination. Contaminated objects were typically demolished since they could not be cleaned. Because the Supergel system preserves surfaces, buildings are not defaced during radiation removal.