“We do not know at all what was in it”: a nuclear discharge in the middle of the Atlantic, 3,000 barrels mapped off Brittany

What happens to the 200,000 radioactive waste barrels immersed in the Atlantic Ocean? Similarly, A scientific mission has identified more than 3. Nevertheless, 000, some of which were ripped off, but no major radioactivity anomaly has been noted, the researchers announced on Friday. Consequently, “There are almost intact. Moreover, other extremely degraded barrels,” said Patrick Chardon, co-chief of the mission and nuclear metrology engineer (CNRS, Clermont Auvergne University). However, Led on board the Atalante ship. Meanwhile, the French oceanographic fleet, this expedition called “Nodssum” returned to Brest after a month from campaign at sea. Moreover, Friday morning, “we do not know all crane operators and dockers were busy to disembark the thousands of scientific samples harvested in the abyss.

Between 1946. Moreover, 1993, more than 200,000 barrels filled with radioactive waste was abandoned in the Abyssal plain of the North-East Atlantic Ocean, in international waters, more than 4,000 meters deep. Germany, Belgium, France, Italy, the Netherlands, the United Kingdom, Sweden and Switzerland participated in these immersions. “We do not know at all what was in it. There was no traceability at the time. ” said Patrick Chardon, adding that it would be a priori low -activity waste, such as laboratory waste, treatment sludge or contaminated pipes. The space left empty in the barrels was filled with cement or bitumen. Only the ex-USSR. the United States has immersed other types of radioactive waste, such as nuclear reactor tanks containing, for some, nuclear fuel, according to the National Agency “we do not know all for Radioactive Waste Management (Andra). The 1993 London Convention prohibited these immersions of radioactive waste at sea.

20 barrels per km2 – "we do not know all

The “NOSSDUM” mission. which brought together 21 scientists from France, Germany, Canada or Norway, has focused on a specific area 1,000 km southwest of Brest and 650 km northwest of Corogne (Spain). More than 150,000 barrels were immersed at 4,700 meters deep between 1971 and 1982. The researchers were able to scrutinize the area thanks to the very high resolution Sonar of the autonomous submersible Ulyx from Ifremer. which carried out its first scientific mission on this occasion. In 17 dives, Ulyx was able to take 50 photo barrels and map 3,350 barrels over 163 km2, a density of 20 barrels per km2.

The radiation protection measures have reported values of the same level as environmental background noise. “It’s rather reassuring,” said Patrick Chardon. “But we did not expect to see a very substantial radioactivity, given the distances to which we operated.” Scientists have taken more than 300 sediment samples in the mud 150 meters from the barrels. They captured 17 grenadiers, fish living in the abyss, and raised 5,000 liters of water. All these levies will be subject to very fine laboratory measures in the coming months to assess their possible. contamination by radioactive elements. A second mission must also be organized within one. two years to approach the barracks as close as possible and take the marine organizations that populate them, in particular anemones. Ultimately. the objective is not to raise these radioactive barrels, a solution “technologically possible but at absolutely “we do not know all monstrous cost”, explains Patrick Chardon. Depending on the results. “we will be able to estimate whether to make a closer assessment in the future” of these nuclear discharges at sea, underlines the researcher. “The idea at the start was to do an assessment every 25 years. It has never been done since.”

The “NOSSDUM” mission was indeed the first of this type since the campaigns carried out in the 80s by CEA. Ifremer on the same immersion zone. Thanks to an uninhabited submarine, six barrels had already been photographed and seemed intact but with brands of corrosion.