The 35 percent who wanted to increase nuclear power usage exceeded the 28 percent who wanted to reduce its use, it said.

Concerns about how to safely store nuclear waste were one of the main factors influencing those who remain reluctant to expand nuclear operations, said Stephen Ansolabehere, the MIT political scientist who conducted the March survey of 1,200 people across the country.

"That uptick is favorable, but it's not a huge transformation. It's not like we've gone from a solid majority against to a solid majority in favor," Ansolabehere said.

"The level of discomfort with the technology has a lot to do with what is the big unsolved problem both at the elite level and at the public level -- which is how do you handle the waste?"

The survey found only 28 percent of US residents believed nuclear waste could be stored safely.

The finding comes at a time when officials in Washington and the power industry are calling for a "nuclear renaissance." The 100 US nuclear reactors are approaching the end of their lifespans, and power industry officials have said a wave of construction will be needed to keep nuclear's current share of 20 percent of the nation's electricity supply.

Merchant power company NRG Energy Inc. is planning to build a plant in Texas that would be the nation's first new nuclear power facility in about three decades.