Contaminated metals prove costly to handlers
Whether radioactive metals fall under the responsibility of the Department of Energy (DOE) or the Nuclear Regulatory Commission (NRC), it is essential that contaminated metal not end up in the smelters of recyclers and steel and other metal producers.
“It’s a very expensive proposition to clean up a furnace that has inadvertently melted a radioactive material,” says Roy Sheely, project manager for Frankie Friend & Associates, a technical support sub-contractor to the DOE at the Oak Ridge facility in Tennessee. “In that case, all of the molten metal that has gone through is also contaminated. That is lost production and additional waste material requiring disposal in a regulated facility.
“Secondly, the company would have to shut the smelter down and clean up the system itself, often replacing components and so forth,” he adds. “Finally, the company would have to validate the clean-up using radiation survey instruments to make sure that all of the contamination was out of the system.
The foremost risk of radioactive steel entering the conventional recycling and production processes is not from contaminated steel, which typically has little if any radiation, but from what is called a “sealed source,” a type of radioactive material that is regulated by the NRC. Sealed sources are used in many industries as a means of gauging thickness and integrity of walls, or moisture in soil. Sheely notes that he is unaware of any cases where material from a DOE site has contaminated a smelter.
To prevent contamination, recyclers and steel mills employ sensors at their facilities to detect radioactive materials that are received, especially from “sealed sources.”
The DOE is responsible for regulation and for oversight of the disposal and recycling of radioactive materials, especially from “sealed sources,” in scrap materials that are received for processing.
The NRC is responsible for the regulation of radioactive materials used in the private sector, hospitals, universities, laboratories, and other sectors.
The NRC and its Agreement States license commercial companies to dispose of low-level radioactive waste from NRC regulated and DOE activities. One example would be Energy Solutions, Inc., which is primarily focused on processing NRC derived materials, although it does handle some DOE generated material. In addition to the DOE, other Energy Solutions customers include commercial nuclear power companies such as Duke Power and Florida Power and Light.
Not all steel in a facility that handles radioactive materials is contaminated. A good example of potential radioactive material would be the steel framework of the building that houses the radioactive material, nuclear process or nuclear reactor, as opposed to the actual process piping.
“The pipes from the process system would not be recycled, but the steel structure would be a candidate,” says Sheely, “and because of the way DOE administers its controls over the radioactive process, the steel structure itself could be termed as steel coming from a radiological area, even though it would not have been directly exposed to radioactivity in the past.”
DOE’s administrative controls are the result of policies implemented by former DOE Secretary Bill Richardson in January and July 2000.
At the time, Richardson created a team that looked at the feasibility of establishing a mini-mill recycling operation to consume the DOE’s steel and to provide products back for use within the department – steel rods and other feedstock material.
“The team surveyed each of the DOE facilities to identify where the generator sites were and would be,” says Sheely.
The DOE mini-mill study estimated that about one million tons of scrap metal would be generated in DOE facilities over a 20 to 25 year period. The majority of that material will come from the demolition of three DOE-owned, contractor-operated facilities in Oak Ridge, Tennessee; Paducah, Kentucky; and Portsmouth, Ohio. While owned by the federal government, the management of these facilities is contracted to the private sector. “There are several companies,” says Sheely. “Each of these facilities is operated by independent companies.”
Material deemed non-recyclable will likely be shipped for burial, either in a local regulated site or at a regulated site in middle of the country.
“Under current DOE policy,” says Sheely, “the remainder of the steel would not be recycled and recycle vendors are looking at opportunities that could use that steel, either in a local regulated site or as blocks to shield the radioactive process in high energy physics facilities such as the Spallation Neutron Source, Thomas Jefferson Laboratory, or some other high energy physics accelerator.
“Recycle vendors are also looking at using this type of steel as security barriers,” he adds. “You see lots of concrete barriers at government facilities. Make those same barriers out of steel and they would be five or six times more dense and thus absorb more energy on impact and provide more intrusion protection. This material would never get into a commercial recycling facility. A small number of those barriers have been fabricated on a proto-type basis, to understand what the process would be like should a decision be made to go into a production model.”
NRC-regulated materials could be treated similarly, but might not be re-used with DOE.
“The NRC has guidelines that allow commercial nuclear operators to recycle steel coming out of a radiological area that has no, or very low levels of, detectable radioactivity associated with it,” says Sheely, who stresses that whether it is the NRC or DOE, basic safety and environmental protection standards must be followed during the recycling process.
The demolition of nuclear powered naval vessels falls under the Nuclear Navy Program, which issues contracts to ship yards. The disposal of radioactive materials from these activities is handled by commercial companies like Energy Solutions.