nuclear-news

Scientists commonly use the radioactive isotopes chlorine-36 and beryllium-10 to determine the ages of ice in ice cores, which are barrels of ice obtained by drilling into ice sheets. Chlorine-36 is a naturally occurring radioactive isotope, meaning it has a different atomic mass than regular chlorine. Some chlorine-36 forms naturally when argon gas reacts with cosmic rays in Earth’s atmosphere, but it can also be produced during nuclear explosions when neutrons react with chlorine in seawater.

Nuclear weapons tests in the United States carried out in the Pacific Ocean during the 1950s and the 1960s caused reactions that generated high concentrations of isotopes like chlorine-36. The radioactive isotope reached the stratosphere, where it traveled around the globe. Some of the gas made it to Antarctica, where it was deposited on Antarctica’s ice and has remained ever since.

Other isotopes produced by marine nuclear bomb testing have mostly returned to pre-bomb levels in recent years. Scientists expected chlorine-36 from the nuclear bomb tests to have also rebounded. But new research in AGU’s Journal of Geophysical Research: Atmospheres finds the Vostok region of Antarctica is continuing to release radioactive chlorine into the atmosphere. Since naturally produced chlorine-36 is stored permanently in layers of Antarctica’s snow, the results indicate the site surprisingly still has manmade chlorine produced by bomb tests in the 1950s and in the 1960s……… https://phys.org/news/2019-10-radioactive-chlorine-nuclear-antarctica.html