Director Robert Stone made his reputation with documentaries such as "Radio Bikini," which in 1988 exposed the hazards of nuclear testing, and "Earth Days" in 2009, which celebrated the rise of environmentalism. So it's startling to witness the pro-nuclear power message of his film opening this week, "Pandora's Promise."

Stone begins with the story of his own conversion from anti-nuclear to the conclusion that "the rapid deployment of nuclear power is now the greatest hope we have for saving us." Along with his transformation, Stone gathers on camera five prominent activists who've traveled the same path from "anti" to "pro," including anti-Shoreham activist Gwyneth Cravens.

"Pandora's Promise" is intended to follow on the 2006 success of "An Inconvenient Truth," which woke many to the threats of global warming. At the same time, that film divided environmentalists who can't agree on the greater evil: nuclear power or climate change.

Stone's effort to repair the rift gives the film its name. Once the horrors had flown from Pandora's mythical box, in the bottom was hope. Nuclear power offers the hope of near-zero carbon emissions.

This compelling documentary pushed me further along my own conversion path. Among the thousands of faces the camera pans from the 1979 "No Nukes" concert in Battery Park City, I'm there with my college pals. "No nukes" is how I felt then, but now I am open to the possibilities.

In another New York moment, "Pandora's Promise" tells of the epic fight over the closed Shoreham nuclear power plant. "People were so afraid of it that they shut it down," says Richard Rhodes, a Pulitzer Prize-winning author and one of the film's converts to support for nuclear power.

That's too dismissive of Shoreham's history, of course. No valid evacuation plan, in case of an accident, was ever approved for Long Island.

This film is a full dose of strong opinion - and also supplies some much-needed facts. For example, "Pandora's Promise" reports that all the nuclear waste generated in U.S. history could fit in 10-foot-high barrels covering a single football field. New-generation reactors may actually use recycled nuclear waste. And nuclear warheads from Russia, reprocessed, are supplying 10 percent of America's electricity.

According to the World Health Organization and the United Nations, only 56 deaths can be tied to the 1986 disaster at Chernobyl, which is a design of reactor that's no longer built. Greenpeace and other activists claim that 1 million died. And the deaths and radiation poisoning widely feared after the Fukushima explosions in 2011 haven't happened.

"If you are exposed to the fallout from Fukushima ... the increased risk of getting cancer is estimated to be so infinitesimally small that you would never be able to identify its impact," says Mark Lynas, a British author and blogger on climate change.

Using a handheld digital device, Lynas finds more radioactivity coming from a sidewalk weed than on a Fukushima beach. Yet the interviews with Japanese parents who keep their children indoors because of fears of radioactivity are heart-rending.

"You can't reassure people," Lynas says. "People are so terrified ... because they don't have that background context of what radiation means, they can't actually decide for themselves what's safe."

New Yorkers will unfortunately have limited access to this film - at least in the first round. It's scheduled to screened at the Sunshine Cinema on the Lower East Side this week, in Rhinebeck beginning July 12, and in Albany starting July 19.

"Pandora's Promise" deserves wider distribution. It's essential viewing for anyone who cares about today's energy decisions.

This essay was first published in Newsday.