Chernobyl disaster to residual radioactivity from Chernobyl in the plants they graze on in the wild during the summer. 1,914 sheep needed to be given uncontaminated feed for a period of time before slaughter during 2012, and these sheep were located in just 18 of Norway's municipalities, a decrease of 17 from the 35 municipalities affected animals were located in during 2011 (117 municipalities were affected during 1986). The after-effects of Chernobyl were expected to be seen for a further 100 years, although the severity of the effects would decline over that period. Scientists report this is due to radioactive caesium-137 isotopes
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