The groups are protesting efforts to reward nuclear utilities, and even reactor vendors and uranium mining companies, for the failures at such new reactor construction sites as Vogtle 3 & 4 in GA, and Summer 2 & 3 in SC.
These proposed new reactors are each billions of dollars over budget, and many years behind schedule. And yet, this legislation would extend production tax credits for new nuclear generation, because the half-built reactors are going to miss their deadline for taking advantage of the subsidy. The subsidy was first enacted in 2005 under the Energy Policy Act signed by George W. Bush. Many of these same environmental coalition groups opposed the production tax credits 12 years ago, and opposed numerous other nuclear power subsidies to boot!
Extending the production tax credit could cost U.S. taxpayers many billions of dollars, if the new reactors are ever actually completed, and generate electricity.