The United States should realize that the sort of disaster that happened in Japan is not something that is very likely to occur. The US must balance the likelihood of that sort of disaster against the benefits of nuclear power.
It is true that nuclear power has very serious risks, as shown in Japan and before that at Chernobyl and to a much lesser extent at Three Mile Island. However, these sorts of catastrophes are not very likely to occur.
The US needs to balance this risk against the risks and benefits of continuing on with our current methods of creating electricity. It needs to understand that fossil fuels have serious environmental costs that could be as catastrophic as nuclear meltdowns and are more likely to occur. It needs to balance the possibility of serious nuclear disasters against the likelihood of climate change caused by the use of fossil fuels.