"The shale industry in the U.S. and what's happening in terms of production and development…has taken the world by surprise," said Margaret Hill, co-chair of the environmental practice at law firm Blank Rome. "I don't think anybody foresaw what was going to happen."
(Read more: Prince warns US shale could hurt Saudi economy)
Hill said the long-term prospects of the nuclear industry are uncertain at best, especially in a sector operating in the shadow of Japan's 2011 nuclear disaster. "The economics and the environment are driving development and the use of shale oll and gas to provide power," she said.
Furthermore, "the economics of nuclear plants are very difficult to maintain, and very costly to do so," she said. Hill pointed to issues that have for years dogged Yucca Mountain's nuclear facility in Las Vegas, Nevada, the site of vociferous environmental opposition.
For certain, some companies are pressing ahead with building a new plant: according to the Nuclear Energy Institute (NEI), companies have broken ground on five new plants since 2007, and 14 more are in the exploratory phases.
Exelon, the country's largest nuclear power operator, said this week that it isn't planning to shutter any of its nuclear plants, even as the company acknowledged the competitive threat posed by natural gas. The fuel source has slowly eroded the dominance of nuclear power and coal as inputs for generating electricity.
One industry source who asked not to be identified said that as more companies move to use natgas, its price will shoot up. That could create an opening for nuclear plants to reassert their value, he said.
"Every time you're in a feast period, you think the fest is going to last forever," he said, warning that prices won't remain low forever, especially if the U.S. moves to export natural gas. "As consumption increases, prices will go up."
Meanwhile, there are still about 100 active nuclear plants in the U.S. that employ more than 100,000 workers, according to NEI data. Those plants generate "substantial domestic economic value in electricity sales and revenue—$40 billion to $50 billion each year," NEI said.
Yet the landscape remains dotted with failing projects, with four reactors having been retired this year alone.
Just a few years ago, there were prospects for a nuclear revival, said Blank Rome's Hill. However, the resurgence of oil and gas production is changing all that.
"Some of it is definitely safety-related, such as [Japan's] Fukushima, but the primary driver has been the advent of shale gas in the last few years," Hill said. "I think we're just seeing the beginning of what's happening with shale development."
—By CNBC's Javier E. David