1 Scenarios with an Intensive Contribution of Nuclear Energy to the World Energy Supply

Temperature stabilization requires that CO2 emissions be limited to less than 3 Gt Carbon equivalent, from the present level of more than 6 Gt. Despite an increase of primary energy demand by 250% in 2050 we find that a nuclear intensive scenario assuming the development of a 3000 GWe pool of PWR reactors by 2030 and of an additional 6000 GWe pool of U-Pu or Th-U reactors by 2050 would lead to temperature stabilization at a level 2 degrees above the pre-industrial level. 1-INTRODUCTION The signs of an already present global warming have been summarized and stressed by a recent IPCC 1 report. As can be seen on Figure1, climatic models show that the atmospheric concentration of Carbon Dioxide, and, thus, the temperature, could be stabilized only if annual anthropic emissions were reduced from the present level of 6 Gt 2 to 3 Gt Carbon equivalent. The later this reduced emission rate is reached, the higher the level of CO2 concentration and, thus, the average world temperature will be. Figure 1 Examples of anthropogenic CO2 emission patterns(left (b)). The curves are labeled by the asymptotic CO2 concentrations. Full and dashed lines correspond to different patterns leading to the same concentrations. The same concentration is obtained if the area below the curves are the same. Crosses refer to emissions by our scenario, circles to the IIASA A2 scenario. The evolutions of the CO2 concentration are shown on the right(a). From ref.2 By 2050 the world population should lie between 9 and 11 billion, as compared to the present 6 billion. Therefore, in order to stabilize the Carbon Dioxide concentration, a reduction of the average per capita emission by at least a factor of 3 has to be achieved. Thus, the present average CO2 per capita emission of 1 ton equivalent Carbon should be reduced to 0.3 tons. The actual reduction factor will depend on the emission level of individual countries. For example the US emit about 6 tons per capita, 20 times more than the target average! That we are not moving in the right direction is demonstrated by the projections of the IIASA-WEC report: emissions in 2050 range between 5 Gt in the most " ecological " scenario and 15 Gt in the most " industrial " one. Strong steps should be taken as soon as possible to decrease greenhouse gas emissions. Due to the legitimate needs of developing countries, …