The electrical power production sector accounts for about 28 percent of global anthropogenic carbon dioxide emissions and constitutes by far the largest source of greenhouse gas emissions. That is why supposedly carbon dioxide-free nuclear power plants have frequently been praised as a panacea for addressing climate change. However, in 2013 nuclear electricity contributed just 10.6 percent of global electricity generation, and because electricity represents only 18 percent of total global final energy consumption, the nuclear share is just 1.7 percent of global final energy consumption. Even if generation in nuclear power plants could be increased significantly, nuclear power will remain a marginal energy source. Therefore, the turnaround in energy systems has to prioritize energy efficiency and the use of renewable energy technologies and cogeneration plants, which do not cause any more carbon dioxide emissions than nuclear power plants. Nuclear power plants may also contribute to climate change by emitting radioactive isotopes such as tritium or carbon 14 and the radioactive noble gas krypton 85.
Bulletin of Atomic Scientists 18th Feb 2016 read more »