Solar don't have the power density needed by US. Do a simple calculation of current energy levels plus 1% YOY, turns out that you would need to cover the world with panels in just a few decades. There are proved new technology on nuclear (like molten salt and front advancing reactors) that is orders of magnitude safer. The light water reactor design from the 50-60th used in this aging plants was funded by Navy and was appropriate for its use but is not the best solution for grid power generation. Applying this already tested and safe solutions (search for ORNL molten salt) will buy the time until fusion is here, new high temperature superconductors (REBCO in special) have completely changed the game here, and a small high field tokamaks should generate net gain in less than 20 years.