Environmental radioactivity part of the Chernobyl release was the caesium-137, this isotope is responsible for much of the long term (at least one year after the fire) external exposure which has occurred at the site. The caesium isotopes in the fallout have had an effect on farming. A large amount of caesium was released during the Goiânia accident where a radioactive source (made for medical use) was stolen and then smashed open during an attempt to convert it into scrap metal. The accident could have been stopped at several stages; first, the last legal owners of the source failed to make arrangements
Nuclear decommissioning effective in reducing NPP decommissioning costs. In France, decommissioning of Brennilis Nuclear Power Plant, a fairly small 70 MW power plant, already cost €480 million (20x the estimate costs) and is still pending after 20 years. Despite the huge investments in securing the dismantlement, radioactive elements such as plutonium, caesium-137 and cobalt-60 leaked out into the surrounding lake. In the UK, decommissioning of the Windscale Advanced gas cooled reactor (WAGR), a 32 MW prototype power plant, cost €117 million. A 2013 estimate by the United Kingdom's Nuclear Decommissioning Authority predicted costs of at least £100 billion to decommission the 19