It's not through luck that a domestic steel mill hasn't melted a radioactive source of scrap in more than two years. Steelmakers and scrapyards have taken steps to make sure that something "hot" doesn't become part of the hot metal.
And they continue to forge ahead with new monitoring and training programs aimed at making sure that what the U.S. Nuclear Regulatory Commission and state regulators euphemistically call "events" do not reoccur.
Virtually every steel mill in the United States has installed what are called radiation detection portals at the gates that each truck must pass through, or at the mills' railroad siding where scrap is unloaded from gondola cars. Most of the largest scrapyards also are equipped with similar portals and other detection systems.
Brian Winters, OmniSource Corp.'s corporate environmental manager, said the big Fort Wayne, Ind.-based scrap processor, now part of Steel Dynamics Inc., employs the best radiation detection technology that the company could find after an exhaustive year-long search. The goal was to be sure that any trucks coming into its yards or leaving them were clean, he said.
The Midwest scrap processor also has done a lot of upgrading in recent years at numerous smaller scrap companies it acquired that didn't use technology good enough for OmniSource, which uses a radiation portal system similar to the equipment used at many U.S. border crossings. All the portals are hooked into a computer system so that when a truck crosses the scale the operator gets a visual readout of any radioactivity. The system scans the load on a foot-per-foot basis as a truck passes through. If something is in there, Winters said, the system will tell the scale operators where to start looking. "It helps us figure out early on where to start looking for it. At that point we use hand-held devices."
The recurring problem of orphan sources hasn't gone away, but the steel and scrap industries have made strides in making sure they are captured, according to Ray Turner, manager of quality and radiation safety at David J. Joseph Co.'s River Metals LLC unit in Louisville, Ky. Joseph is now a part of Nucor Corp., Charlotte, N.C.
The two industries have learned how to deal with radioactive material a lot better. Scrapyards are just as much a victim of abandoned radioactive sources as steelmakers, he said. Like the mills, they don't want these materials contaminating their facilities.
The technology of radiation detection systems has improved over the years, according to Turner, an engineer regarded as the scrap industry's guru of radiation monitoring. The technology has improved, but the biggest strides have been the redundancy that steel mills and scrap processors have added to their facilities, he said. "People are putting them on shredder conveyors and shear conveyors, as well as entrance and exits of the plant sites. Some places are putting them inside the grapple on the crane," he said.
Scrapyards and steel mills are taking existing technology and adapting that to new applications. At steel mills, for example, monitoring equipment has been installed on charging buckets that convey scrap to the furnace.
These days, someone visiting a scrapyard or a mill will see more than a single gauge hanging over the entrance gate. "It used to be you would see a little PVC (polyvinyl chloride) pipe that held the gauge and was about 15 feet above a scale. Now you see large portal monitors and other detection equipment throughout a facility," Turner said.
Still, every day a steel mill somewhere in the country is finding a radioactive source in its melt material and many scrapyards are finding not one, but several, sources each day. "The problem has not gone away, (but) we have learned how to deal with it a lot better," Turner said.
The Institute of Scrap Recycling Industries (ISRI) said that one of the largest steps is the new training manual the Washington-based scrap industry organization is preparing. It is shaping up to be a comprehensive document that not only tells operators what to look for but also what to do if radioactive material shows up in the scrap stream, said John Gilstrap, ISRI's director of safety.
Awareness of the orphan source problem has increased among scrap processors, especially after a Midwest steel mill melted one in its furnace.
Shielded sources in the middle of a truckload of scrap might not be easily detected, so the yard's operators want to make certain the source isn't processed by their equipment to avoid exposing workers to radioactivity as well as damaging equipment. As a consequence, ISRI encourages scrapyards to monitor both inbound and outbound scrap shipments. MICHAEL MARLEY