From what I've read, the reason for #2 is historical. You cannot make bombs with thorium reactors, and when bombs were being made is when most of the advances i

From what I've read, the reason for #2 is historical. You cannot make bombs with thorium reactors, and when bombs were being made is when most of the advances in nuclear power were made. Since then a number of accidents at nuclear power plants have rendered any advancements in nuclear power taboo in the US so there is no development, especially not in anything new nuclear-wise.