CHARLOTTE--The Nuclear Regulatory Commission has issued a preliminary finding in favor of allowing Duke Power to test a new fuel at its Catawba Nuclear Station on South Carolina's Lake Wylie.

Duke wants to test mixed-oxide, or MOX, fuel as early as next year. The fuel is made by mixing uranium oxide and plutonium oxide from older nuclear weapons and placing the material in fuel rods.

The tests won't make an accident at the plant much more likely or worsen the results if an accident happens, NRC determined.

"It is, in our minds, a significant hurdle to have to overcome," said Duke spokeswoman Rose Cummings. "NRC is essentially confirming our analyses."

The Blue Ridge Environmental Defense League hasn't decided how to respond to the finding, said Diane Curran, a Washington attorney representing the group. The league opposes the tests and says MOX fuel is dangerous.

The commission analyzed two possible accidents that MOX might influence.

The first looked at defects in the metal cladding that encases fuel rods. Under high pressure and high temperatures inside the reactor, failed cladding could release radioactive material into cooling water. The second examined the likelihood of an accident in handling MOX assemblies.

In neither case would MOX increase the odds of those accidents occurring nor would it make the consequences significantly worse, the commission said.

The NRC must wait until a comment period ends Aug. 12 before making the finding official. After that, the commission could issue the license to start tests.