By Christopher GardnerJune 4, 2019
The U.S. Army Corps of Engineers recently completed the safe removal of more than 1.5 million pounds of radioactive material from STURGIS - a WWII Liberty Ship turned into the first floating nuclear power plant in the 1960s.
The Corps' Baltimore District was tasked with the unique mission to decommission and dismantle the STURGIS, and its nuclear reactor, known as MH-1A, which was used to generate electricity for military and civilian use in the Panama Canal for several years before being shut down in 1976.
Beginning in 2015, all remaining radioactive material was removed while the vessel was in Galveston, Texas. The radioactive waste was transported to a licensed disposal facility in Andrews County, Texas. After the radiological decommissioning was complete, the project team had to figure out how to handle the hundreds of thousands of remaining pounds of traditional debris that was not radiologically contaminated. The STURGIS was dismantled at a shipyard in Brownsville, Texas, earlier this year.
"The STURGIS was a large vessel. Only a portion of the vessel was impacted by radiological contamination, so we had a lot of ship left to properly dispose of after the decommissioning was complete," said Baltimore District Project Manager Brenda Barber. "We looked at different alternatives for disposing of the more traditional waste and made a commitment to try to recycle as much of the vessel as possible."
With sustainability on their minds, the team implemented a process to recycle a tremendous amounts of debris - approximately 600,000 pounds of lead and more than 5,000 tons of steel and other assorted recyclables.
This recycling effort reduced the project's overall environmental impact while the team simultaneously addressed the vessel's remaining low-level radioactive waste in an environmentally conscious and safe way.
"Not only was our team able to safely package and ship all of the radioactive components of the STURGIS barge, we were also able to safely separate out hundreds of thousands of pounds of non-radioactive recyclables so the STURGIS could live on in other ways," Barber said.
Most of the recycling ended up being lead shielding and the steel that made up the ship itself.
Both lead and steel are highly recyclable due to their recovery rates. According to the International Lead Association, recycled lead is used more than mined lead. Common uses include lead-based batteries often found in vehicles and lead sheeting that can be used in construction for roofing as well as radiation shielding in the healthcare industry. Recycled steel can be reused in anything from automobiles to cans to building materials.
Recycling metal like steel and lead has significant environmental benefits, including less impact on landfills, minimization of emissions, and a reduction in the requirement for mining or producing virgin material.
The 5,364 tons of steel and other scrap metals recycled eliminated an estimated 6.36 million kilograms of carbon dioxide that would have been generated by the production of virgin steel according to Mike Berner's-Lee's 2011 work "How Bad are Bananas: The Carbon Footprint of Everything." This would be equivalent to taking more than 1,000 cars off the road for an entire year. It also saved approximately 13.41 million pounds of iron ore, 7.5 million pounds of coal, and 643,680 pounds of limestone.
Though difficult to quantify, recycling lead reduces the need for lead mining and in doing so reduces the associated human health and environmental impacts. Efficiently collecting and recycling lead also reduces the amount of hazardous lead released into the environment.
"In addition to being the right thing to do for the environment, our focus on recycling also provided the project with cost savings - less disposal costs, which made the entire effort a win-win," Barber said.