This is a calculator provided by the Nuclear Energy Institute, so be aware of the "spin".

Nuclear energy use currently avoids the emission of over 2 billion tonnes of CO2, the main greenhouse gas, each year. Total primary energy (TPES) supply in 1995 was about 8.6 Gtoe (Gtoe = thousand million tonnes of oil equivalent) and this figure is expected to double by 2050. By 2010, the timeframe of the current climate change negotiations, TPES is expected to reach at least 10.5 Gtoe. Use this calculator to look at the effects of different energy mixes on this situation and see if you can increase supply while decreasing emissions.

What are the negatives of using nuclear power to produce energy?

Enter your estimate of energy demand and your mix for coal, nuclear, gas and oil and click on "calculate". The calculator will assume any shortfall in the numbers is to be made up by renewables.