There are in fact concerns about the amount of nuclear fuel available. See for example: https://arxiv.org/abs/0909.1421 https://arxiv.org/abs/0909.1421 and i

There are in fact concerns about the amount of nuclear fuel available. See for example: https://arxiv.org/abs/0909.1421 https://arxiv.org/abs/0909.1421 and in more length: http://theoildrum.com/files/O_118_Michael_Dittmar.pdf http://theoildrum.com/files/O_118_Michael_Dittmar.pdf The author also notes that, as of today, nuclear energy contributes only a very small part of the delivered energy mix.