Progress Energy's proposed Levy County nuclear plant cleared a major hurdle Friday with a report from federal regulators concluding that the proposed site would not harm the environment.

The conclusion of the Nuclear Regulatory Commission and the U.S. Army Corps of Engineers was largely expected. But the three-volume Final Environmental Impact Statement is a critical step toward approval of the federal operating license for the Levy plant.

"The Final Environmental Impact Statement is an important milestone to ensure new nuclear generation remains a viable energy option for meeting Florida's future baseload energy needs," Suzanne Grant, a Progress spokeswoman, said in a statement on the report.

Also on Friday, the NRC's Atomic Safety and Licensing Board denied a motion by opponents of the Levy project to extend the time for their challenge of the findings about the plant's impact on the environment. Opponents, led by the Ecology Party of Florida and the National Information Resource Service, a Maryland-based environmental group, have 45 days to file their initial responses.

Mary Olson, of the National Information Resource Service, said the findings in the environmental report do not seriously consider the impact of the project on water in Levy County nor do they include "lessons learned from the Fukushima disaster in Japan."

"It is fiction," Olson said of the NRC report.

Progress has yet to decide whether it will build the $22.4 billion, two-reactor Levy nuclear plant. The utility has said that it will make a final decision about the project after the NRC approves the operating license for the plant.

That process is expected to run through the end of 2013 as the NRC completes other reviews, including its final safety evaluation report.

Progress' most recent goal was to bring the first of the two reactors online by 2021 and the second about 18 months later. But because of delays in the construction timetable and soaring costs of the project, it is unclear when the plant will come online — if ever.

The Levy project is next on the NRC's list of projects under review for new nuclear plant operating licenses. The commission recently approved licenses for the first two projects on its list, Georgia Power's Vogtle nuclear plant and SCANA's V.C. Summer plant in South Carolina, which already are under construction.

Ivan Penn can be reached at ipenn@tampabay.com or (727) 892-2332.