We currently have 104 commercial nuclear reactors in the US, and they are all based on the same "Light Water" design, originally developed for Navy submarines. Our use of this design on land creates many issues such as:
1) Generating highly radioactive nuclear waste
2) Possible reactor core meltdown
3) Possible explosion from pressure containment failure
An alternative "Molten Salt" design was built and operated in the 1960's at ORNL, but though it had none of these safety issues, funding was discontinued because Light Water designs were already completed.
Modern variations of Molten Salt fueled reactors are so efficient they can be fueled by the nuclear waste from current Light Water reactors, reducing and converting it to low radioactive levels. We should build at least one of these.