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Title: Whatever Happened to the 150,000 Tons of Radioactive Waste Stored
Under the Atlantic Ocean?

Link: https://hardware.slashdot.org/story/26/09/22/...

More than 200,000 barrels of low-level radioactive waste were stored on the
floor of the Atlantic Ocean between 1949 and 1982, reports ScienceAlert.
Whatever happened to those barrels? Scientists have descended to the wreckage
in a crewed submersible to investigate - and found many of the barrels
corroded and degraded, their contents spilling across the seafloor.
Surprisingly, this isn't necessarily a subversion of the original plan... The
International Atomic Energy Agency recommends that low-level waste be
disposed of in robust containment in isolation for at least a few hundred
years - but back in the mid-20th century, the recommendations were a little
different. The contemporaneous guidelines recommended that containers needed
to reach the seafloor intact and remain sealed only long enough for the short-
lived radionuclides to decay. After that, the remaining waste was expected to
slowly escape and disperse through the surrounding ocean. Not everything in
the barrels would conveniently decay away, however. They contained a
radioactive hodgepodge, including cesium-137, plutonium isotopes, and
tritium, some of which can persist for thousands of years... [A] few years
ago, nuclear engineer Patrick Chardon and marine geologist Javier Escart�n of
the French National Center for Scientific Research started to wonder what had
become of the dumped waste. That question eventually became NODSSUM - Nuclear
Ocean Dump Site Survey Monitoring - an interdisciplinary project bringing
together nuclear physics, geology, oceanography, biology, and marine
chemistry to find the barrels and investigate what, if anything, they were
doing to the surrounding environment.... [T]he barrels also appeared to
function as tiny oases on the otherwise sparsely populated sandy seafloor.
Anemones had attached themselves to the barrels. Sponges, sea cucumbers,
fish, and crustaceans lived around them, with crabs apparently particularly
fond of the artificial shelters... Instruments aboard the ship detected
significant signals of cobalt-60 and niobium-94, which the researchers could
specifically link to the dumped waste... [Samples are now being analyzed]
There is precedent, however, to suggest that even striking levels of
radioactivity around a source don't necessarily spread very far. A recent
study of the sunken Soviet submarine Komsomolets found radionuclide levels
hundreds of thousands of times above background immediately around the
leaking reactor - but those levels dropped sharply within just a few meters
as the material dispersed through the seawater. The NODSSUM team similarly
found that, despite the significant radioactive signals around the barrels,
activity levels weren't high enough to pose major radiation-protection
problems for the scientists handling the samples. [Their three-person
submersible] Nautile and the instruments it carried showed no signs of
contamination. The real achievement was mapping the exact location of the
barrels. "None of this means the waste is harmless," the article concludes -
but it also doesn't mean we're about to be overrun by radioactive crabs."

Read more of this story at Slashdot.

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