"The biggest takeaway is the preparation for the tsunami was inadequate," said Robert Corradini, a distinguished professor at the University of Wisconsin College of Engineering and a member of the Nuclear Regulatory Commission's advisory committee on reactor safeguards.
"You're going to see refortification of plants for the tsunami. I expect that the NRC is going to slow down the process and do a re-analysis to make sure that nothing has been unturned in terms of lessons learned."
Corradini says the "Generation III-plus" plants proposed by Westinghouse, General Electric, Mitsubishi and the French firm Areva incorporate new designs that take in the lessons of past nuclear accidents at Three Mile Island and Chernobyl.
The AP1000 reactor, designed by Westinghouse, can be shut down for three days without power. Instead of pumps, valves and human operators, the plant uses airflow, pressure changes and gravity to gradually cool the reactor.
"Going forward you will see more reliance on passive safety systems that will automatically shut down the plant instead of generators and pumps," said Scott Shaw, a Westinghouse spokesman in Pittsburgh.