Scientific Mission to Map Barrels of Radioactive Waste Dumped in the Ocean

A team of scientists is preparing to take to the sea to carry out a critical mission of mapping and studying a nuclear waste disposal site that is littered with thousands of drums that were dumped by European countries in the North Atlantic Ocean.

Starting mid-June, the team intends to sail to the Abyssal Plains in the Northeast Atlantic Ocean where they plan to map out over 200,000 barrels containing radioactive waste which were dumped over a four-decade period spanning from 1946 to 1990. The drums are believed to be at depths of between 3,000 and 5,000 meters (1.8 to over 3 miles) and were sealed in bitumen or cement before being dumped into the ocean.

The Nuclear Ocean Dump Site Survey Monitoring (NODSSUM) project aims to map the main immersion area, understand the behavior of radionuclides in the deep ocean, and interactions with the ecosystem. The drums are said to contain mainly radioactive waste from the development of nuclear power produced by several European countries between 1949 and 1982.

According to declarations to the International Atomic Energy Agency made by the dumping states, the barrels contain low or intermediate-level radioactive residues like process sludge, contaminated metal parts, ion exchange resins, and laboratory and office equipment among others. Though the radioactive activity of the waste is believed to have decreased significantly since its immersion due to the natural decay of the isotopes, there are concerns that some long-lived elements may remain.

From June 15, scientists will be in the North Atlantic waters for a month-long mission to locate and detect possible leaks. The team is led by the French National Center for Scientific Research (CNRS) and includes scientists from the French Research Institute for Exploitation of the Sea (Ifremer), and the Nuclear Safety and Radiation Protection Authority (ASNR) among other organizations.

During the period, the team intends to crisscross the dumping sites by deploying the French Oceanographic Fleet underwater vehicle UlyX. Using its high-resolution sonar, the Ifremer-operated robot will navigate at approximately 70 meters above the seafloor to map and identify the barrels and will approach a distance of 10 meters to photograph them and identify areas for water, sediment, and fauna sampling.

Ultimately, the scientists will be able to analyze the presence of radionuclides in the water and their impact on the marine environment. The research ship they are using is equipped with radioactivity measurement instruments.

Based on the results of the first mission, a second expedition that is still in the planning stages will involve the deployment of a remotely operated robot or a manned submarine to carry out studies and samples in the direct vicinity of the barrels. The team is putting a strong emphasis on safety and has no intention of bringing the drums to the surface.

“Beyond the minimization of risks, the logistics would be too complex and without scientific interest. The objective of the project is to assess their state in situ, using underwater vehicles, and to study the environmental conditions around them,” states NODSSUM on its website.

The NODSSUM expedition is part of the Prime Radiocean project that is involved in missions that seek to better understand radioactive waste risks in marine environments, thus contributing to the development of safer and more sustainable nuclear waste management policies.