The environmental performance of nuclear power generation should be based on objective evidence that can also be compared to other electricity generation technologies. For this purpose, Life Cycle Assessment (LCA) is appropriate because it allows for such an evaluation on a balanced and comprehensive basis. State-of-the-art LCA needs to be provided from both current, but also future perspective, considering the long time-horizon of potential operation of reactors in Switzerland. The overall environmental performance is suitably evaluated using Life Cycle Assessment methodology addressing the complete nuclear chain from uranium mining to nuclear waste disposal. The main objective of this project is the update and extension of LCI data of nuclear power generation in Switzerland.