The Nuclear Regulatory Commission today approved Westinghouse Electric Co.'s design for the AP1000 reactor, a step that could clear the way for power companies to build the first nuclear plants in the United States since the 1970s.

All five commissioners voted at a meeting this morning to approve the 1,100-megawatt electric pressurized-water reactor, wrapping up a review process that lasted four years from when Westinghouse submitted an application to amend its design.

To get the certification, Westinghouse needed to demonstrate that its design would be able to withstand an aircraft crashing into the shield building, a 3-foot-thick structure of steel and concrete that protects the reactor. The company also needed to show the ability to shut down the reactor without an operator present and without normal access to power.

NRC Chairman Gregory Jaczko said in a statement today that the new design passed both of those tests.

The commission's unanimous decision drew praise from Westinghouse and from power companies that are hoping to build a new generation of nuclear plants for the first time since the Three Mile Island accident cast a pall over the industry.

"The road to receiving design certification has been long and sometimes arduous," Westinghouse CEO Aris Candris said in a statement. "But we've reached our final destination."

The company's design is being used at four plants under construction in China, and it could now be used for about a dozen reactors in the United States, pending approval from regulators.

First among them are two planned reactors for Southern Co.'s Vogtle power plant in Georgia, which has landed more than $8 billion in loan guarantees for the $14 billion project. Also hoping to move forward is South Carolina Electric & Gas Co., which wants to build two reactors at the V.C. Summer station near Columbia, S.C.

Having approved the general design, NRC could decide within the next few months whether to let Southern and SCE&G use it.

The decision was also met warmly by nuclear power supporters on Capitol Hill, such as Sen. Lamar Alexander (R-Tenn.).

"Nuclear power produces 70 percent of our country's pollution-free electricity and has the best safety record of any form of energy production," Alexander said in a statement. "This new design will make it easier to produce the huge amount of clean energy our economy needs to create good private-sector jobs."