As published in 2009 November U.S. Department of Energy, Office of Environmental Management Update Newsletter:
A gel that can be painted or sprayed on a wide range of surfaces and then peeled off after it dries—pulling radioactive and chemical contaminants with it—could be a huge help in completing many of the cleanup jobs on the Office of Environmental Management (EM)'s agenda.
That's why EM's Office of Deactivation and Decommissioning and Facility Engineering is now testing and evaluating a product called DeconGel™ made by Cellular Bioengineering Inc. (CBI) (www.cellularbioengineering.com) of Honolulu.
Conventional methods of decontaminating the interior walls, floors and other surfaces of contaminated buildings often rely on liquid "detergents" or physical methods to remove the contamination. But these approaches may require scrubbing or wiping that can spread contamination over a larger area.
DeconGel™ can be cheaper to use than other decontamination methods because it can be applied faster and typically generates smaller volumes of waste.
It also offers certain technical advantages. It can be applied to rough and smooth, painted and unpainted concrete surfaces as well as aluminum and steel. It fixes surface contaminants immediately and then penetrates into the pores and cracks and locks the embedded contamination into a polymer matrix as it dries.
When dry, the film resembles and has the consistency of a "thick Saran Wrap" says Andrew Szilagyi, EM's Project Management for the development of new D&D technologies. "You peel it off and crumble it up like aluminum foil or Saran Wrap then put it in a bag or a drum and there you go."
Depending on the contaminants involved, Szilagyi says it might be possible to dispose of the dried DeconGel™ through less stringent and less expensive disposal options than other cleanup methods would require. That could mean using an industrial landfill instead of a radiological disposal facility.
With more than 3,500 contaminated facilities, including nearly 1,000 buildings with radioactive contamination, EM has plenty of places to put DeconGel™ to work.
EM field tested DeconGel™ in January and February of this year at Oak Ridge National Laboratory in Tennessee, where paintable and sprayable versions were applied to the floor and walls in a hot cell area of Building 2026. The main contaminants of concern were americium and plutonium. Removal efficiencies ranged from a high of 90 percent to lower levels in areas previously treated with sealants or fixatives.
Paula Kirk of EM, who managed the field test at Oak Ridge, says the product has two distinct advantages over conventional methods of cleanup. "When DeconGel™ is applied, it strongly holds the airborned contaminants which become fixed under the gel. This is important when dealing with plutonium and other contaminants, as the radioactive particles can easily become airborned and can be spread by people walking across a floor."
She also noted that “If a floor needs to be ‘scrabbled’ [by mechanically removing surface layers of concrete to eliminate contamination] one could be looking at a signifi cantly larger secondary waste stream as opposed to the dried DeconGel™.”
DeconGel™ took a winding road to the gritty world of decontaminating concrete floors, says Michael Coy, CBI’s vice president for operations.
Hank Wuh, a former orthopedic surgeon with what Coy describes as “an innate interest in problem solving,” founded the company in 2003 and then set about finding a new way to treat corneal dystrophy, a set of conditions in which cloudy material builds up in the cornea and clouds vision.
The conventional medical approach had been to use corneal transplants to treat the condition. But Wuh wanted to find a different approach for the many parts of the world resist transplants because of religious and cultural taboos against taking tissue from another person.
So he set out down two roads—one was to find a way to grow new corneal cells from a small sample of cells taken from the patient’s own eye and the other was to create an artificial cornea from a polymeric hydrogel.
While testing polymers, one of the scientists on Wuh’s team discovered that the material they were working with might be able to remove radioactive isotopes from human skin.
After the company successfully tested the polymer’s radioactive removal properties on mice, it got a request from the Air Force, Coy recalls, to see if the polymer could be used to remove transuranic elements from the aluminum skin of an aircraft that had been contaminated.
It was while doing that testing, Coy says, that some of the polymer spilled on a laboratory floor. “We let it dry and we peeled it,” he says, “and there was this fairly white looking area in contrast to the surrounding floor. We said ‘what if we did this deliberately?’ and from that point on we started refining it.”
CBI, which has adopted the corporate motto of “Invent, Disrupt, Inspire” is still developing an artificial cornea. But DeconGel™, the product based on the accidental spill, is speeding ahead.
CBI began selling a commercial version of DeconGel™ last year to nuclear power utilities, hospitals and research laboratories that generate or use radioactive materials.
Coy says CBI now has “40 plus customers” and is “at an advanced stage of startup” in its commercial business.
EM has provided CBI with grants of $1.47 million in Fiscal Year 2009 and $1.59 in Fiscal Year 2010 to support testing of DeconGel™ at contaminated facilities and help the company develop and improved version of the product.
By the end of FY 2010, EM’s goal is to have a strong technical package—including case studies— in place to provide guidance on whether DeconGel™ is the right product for a particular cleanup need.
In addition to DeconGel’s™ use during deactivation and decommissioning of structures, Szilagyi hopes further testing may show the product can also be used by DOE’s research laboratories to clean up spills and treat contaminated tools and equipment. And, he says, it’s possible that use of this peelable gel might allow some contaminated buildings to be saved from demolition altogether and used for other purposes.
Read article from original source.
No comments:
Post a Comment