Radionuclides in the environment Nuclear energy is the one energy source that could meet the worlds growing energy needs and provide a smooth transition from fossil fuels to renewable energy in the coming decades and centuries. It is becoming abundantly clear that an increase in nuclear energy capacity will and probably must take place. However nuclear energy and the use of radionuclides for civilian and military purposes lead to extremely long lived waste that is costly and highly problematic to deal with. Therefore it is critically important ot understand the environmental implications of radionuclides for ecosystems