Nuclear powerplant projects that had been put on hold may begin to go forward, following the Nuclear Regulatory Commission's approval of a final rule dealing with the environmental effects of continued storage of spent nuclear fuel.

The rule, which NRC commissioners approved on Aug. 26, concludes that spent fuel can be safely managed in dry casks indefinitely.

The regulation, proposed in September 2013, applies to the continued storage of used nuclear fuel between the end of a reactor's license period and the fuel's ultimate removal for disposal.

In 2012, the U.S. Court of Appeals for the D.C. Circuit had ordered the NRC to consider the possibility that a permanent repository for spent nuclear fuel, such as the site proposed beneath Nevada's Yucca Mountain, might never be built. The court also told the commission to do more analysis on spent-fuel-pool leaks and fires.

That ruling stemmed from environmental groups' 2011 lawsuit challenging the newly approved regulation's predecessor, the so-called waste confidence rule, which the appellate court also struck down.

After the court's 2012 action, NRC suspended 21 final licensing decisions on new reactors and renewals for reactor licenses and spent-fuel storage facilities.

In a separate Aug. 26 order, NRC lifted the suspensions on decisions put on hold pending approval of a final spent-fuel rule. The new regulation takes effect when it is published in the Federal Register. That is expected in September.

The Nuclear Energy Institute, an industry group, praised NRC for approving the rule within the 24-month period the appeals court set. Ellen Ginsberg, NEI vice president, secretary and general counsel, said in a statement, "This rule will maximize efficiency in the licensing and relicensing processes while ensuring the agency complies with the requirement of the National Environmental Policy Act to disclose the environmental impacts of used fuel storage."

But the Natural Resources Defense Council, one of the groups involved in the 2011 lawsuit, says the NRC vote could make it more difficult for individuals and groups to file waste-related licensing challenges.