The U.S. is set to become the first nation to decide whether it's safe to operate nuclear power plants for 80 years, twice as long as initially allowed.

The majority of the nation's 99 reactors have already received 20-year extensions to their original 40-year operating licenses. Now, operators led by Dominion Resources Inc. want to expand the time frame further, potentially creating a precedent for an aging global fleet at a time when the economics of the industry are undergoing dramatic change.

Dominion said earlier this month it will request an extension from the U.S. Nuclear Regulatory Commission, which oversees the industry. The plan has already raised the ire of anti-nuclear campaigners who cite decades of wear and tear on the nation's reactors, as well as the 2011 Fukushima disaster. The NRC will release a draft report next month outlining safety measures needed to extend the time line.