After the Fukushima power plant disaster in Japan last year, the rising costs of nuclear energy could deliver a knockout punch to its future use in the United States, according to a researcher at the Vermont Law School Institute for Energy and the Environment.

"From my point of view, the fundamental nature of [nuclear] technology suggests that the future will be as clouded as the past," says Mark Cooper, the author of the report. New safety regulations enacted or being considered by the U.S. Nuclear Regulatory Commission would push the cost of nuclear energy too high to be economically competitive.

The disaster insurance for nuclear power plants in the United States is currently underwritten by the federal government, Cooper says. Without that safeguard, "nuclear power is neither affordable nor worth the risk. If the owners and operators of nuclear reactors had to face the full liability of a Fukushima-style nuclear accident or go head-to-head with alternatives in a truly competitive marketplace, unfettered by subsidies, no one would have built a nuclear reactor in the past, no one would build one today, and anyone who owns a reactor would exit the nuclear business as quickly as possible."

That government backing of nuclear energy is starting to change after the Fukushima meltdown. Even the staunchest nuclear advocates say that with new technologies, nuclear power can always be made safer, but nothing can offer a guarantee against a plant meltdown.

"In the wake of a severe nuclear accident like Fukushima, the attention of policymakers, regulators, and the public is riveted on the issue of nuclear safety," the report says. "The scrutiny is so intense that it seems like the only thing that matters about nuclear reactors is their safety."

Although several reports by nonpartisan groups have reinforced the perception that America's nuclear reactors aren't in danger of a meltdown, the public is wary. Earlier this month, an analysis of Fukushima by the American Nuclear Society blamed Japan's regulatory oversight and reaction to the meltdown for magnitude of the disaster. According to Michael Corradini, a co-author of that report, "things are acceptable going forward in the States."

"I don't think anything coming out of Fukushima would imply we aren't prepared," Corradini says.

Steven Kerekes, a spokesperson for the Nuclear Energy Institute, says that new safety measures are being placed in a new reactor set to go online in Georgia in 2017.

"There's some safety enhancements they're undertaking, despite the fact they're already safe," Kerkes says. "These enhancements will increase the margin of safety by another order of magnitude."

But according to a report by the Union of Concerned Scientists, 80 percent of America's nuclear reactors are vulnerable to at least one of the factors involved in the Fukushima disaster, including vulnerability to earthquakes, fire hazard and elevated spent fuel.

Retrofitting existing reactors with the latest safety equipment is extremely expensive, Cooper says.

"Regardless of what Congress does, the NRC has put on the table very serious and important changes in how we look at safety after Fukushima," Cooper says. "There was one permit [for a new reactor] issued recently, and there's a second one expected in the near future. Frankly, that's about it. I don't see any other reactors moving forward. The economics are so unfriendly that I don't think the rest of the [proposals] are very active."

That could be problematic for consumers, considering that the Environmental Protection Agency wants to limit carbon emissions from coal-fired power plants. People in the nuclear power industry point to the fact that coal pollution kills many more people than nuclear disasters, with some putting the ratio as high as 4,000 to 1.

Cooper says the very different natures of nuclear disaster versus coal pollution rightly makes people worried.