Scientific mission to track radwaste barrels on Atlantic seabed

With assistance from the French Research Institute for Exploitation of the Sea (Ifremer) and the Nuclear Safety and Radiation Protection Authority (ASNR) among other organizations, the Nuclear Ocean Dump Site Survey Monitoring (NODSSUM) project aims to map and assess the condition of more than 200,000 barrels of radioactive waste submerged at depths between 3,000 and 5,000 meters (about 2 to 3 miles) on the Atlantic’s Abyssal Plains, about 400 miles off the French coast.

The barrels are considered to contain low- and intermediate-level materials such as process sludge, contaminated metal parts, ion exchange resins, and laboratory equipment, among other wastes. To resist the pressures of the ocean depth, the waste was encased in bitumen or cement.

The United Kingdom, Belgium, and France all dumped radioactive waste in the Atlantic during the four decades before the practice was banned.

Two cruises: This is the first of two month-long cruises that CNRS has planned to investigate the condition of the barrels, which have a 25-year shelf life, and to understand how radionuclides behave in the deep ocean and their potential effects on marine ecosystems.

According to CRNS, during this first mission, scientists will crisscross the dumping sites using high-resolution sonar on board the new autonomous submersible UlyX, which will complete its first scientific dives. UlyX will initially navigate around 300 feet above the seafloor to map and identify the barrels, then photograph them from 30 feet. This will help identify the sites for initial water, sediment, and faunal samples without disrupting the barrels, CRNS said.

The second mission, expected next year, will measure the presence of radionuclides in the water and sediments, as well as in organisms collected from nearby. Background radiation levels will also be analyzed to distinguish between results caused by the submerged barrels and those originating from nuclear accidents, testing, and authorized effluents from nuclear power plants.

NODSSUM also intends to study radionuclide interactions in the ecosystem (bioavailability and potential ecological effects) and to characterize the processes of transporting radionuclides in the deep ocean (erosion, sedimentation, currents, bioturbation, etc.).