The US approved a new nuclear plant design Thursday, paving the way for the country's first new nuclear power facilities since 1996 to be built.

The Nuclear Regulatory Commission gave the green light to Westinghouse's 1,100 megawatt AP1000 pressurized water reactor design, which is slated for use in two nuclear power plants in Georgia and South Carolina.

Both plants are already under construction.

The NRC said the design incorporates passive safety features "that would cool down the reactor after an accident without the need for human intervention."

In the wake of the 9/11 attacks of 2001, Westinghouse was required to design it to withstand being hit by an aircraft.

It also has to be able to shut down by itself even if the power is cut off -- as happened to Japan's Fukushima reactors in the March 11, 2011 earthquake-tsunami disaster that saw some of the units melt down.

"The design provides enhanced safety margins through use of simplified, inherent, passive, or other innovative safety and security functions, and also has been assessed to ensure it could withstand damage from an aircraft impact without significant release of radioactive materials," said NRC chairman Gregory Jaczko.

The approval will allow power utilities Southern Company and South Carolina Electric & Gas to move ahead on two new plants, each with two reactors, in Georgia and South Carolina, respectively.

Work is already well underway on the plants and they could come on line beginning in 2016, 20 years after the last nuclear reactor for power generation was commissioned in the country.

"The AP1000 is the reactor design that will set the foundation for the next generation of nuclear plants in the US" said Marilyn Kray, president of NuStart Energy Development, a consortium of utilities and reactor vendors that backed the process to gain approval for the Westinghouse design.