It's the year 1945. Germany and Japan have been defeated, a terrible war has drawn to a close and the world seems to be at peace again. People are looking for something - anything - that will give them hope. On the morning of August 6, 1945, a stunning announcement is broadcast over the radio by President Harry Truman. At exactly 6 PM the next day, famed physicist Albert Einstein will press a lever in a factory in California which will start a machine called a "nuclear reactor", a revolutionary new device that produces electricity in unprecedented quantity. This nuclear reactor draws its power from the splitting of atoms, a mechanism which has been part of the basic workings of the universe since the beginning of time. The fuel used in the reactor is the element uranium. A single pound of uranium provides the equivalent of 2 millions pounds of coal. President Truman's speech is considered a landmark in history, the moment when the most revolutionary energy source mankind has known was introduced to the public and a golden age of energy sufficiency and prosperity was inaugurated....

The above piece is fiction, of course. This is not how nuclear energy was introduced to the world. Instead it was delivered kicking and screaming on August 6, 1945 into the imagination of men and women by a blinding flash, a cloud of radioactive fallout and a blast wave that turned people into shrapnel-laden lumps of flesh and bone. It is one of the great might-have-beens to contemplate the impact of nuclear energy on our thinking had it been gradually brought into this world through peaceful means. As it happened, it was not Shippingport but Hiroshima that got seared into the public consciousness. Since then nuclear energy has been irrevocably associated with nuclear weapons. The psychologist Paul Slovic, one of the world's leading experts in the psychology of risk perception, has written how, when asked to imagine the consequences of a serious accident in a nuclear reactor, many people conjure up horrific and chimeric images much more akin to a nuclear weapons attack.

Yet there have always been those who have nurtured and promoted a realistic vision of nuclear energy in which nuclear weapons are no more than a semi-colon in the book of history. And in "Pandora's Promise", a clear-eyed and balanced film about the benefits of nuclear power, director Robert Stone introduces a cast of unlikely defenders of this awesome source of energy: environmentalists. Since the 1980s, the nuclear freeze movement aligned with other environmental concerns has turned environmentalists into nuclear's staunchest critics. A particularly startling crack in this otherwise unified front surfaced a few years ago when James Lovelock, a hardened environmentalist who would routinely leave climate change critics frothing at their mouths, came out with a full-throated exhortation in favor of nuclear energy. Pandora's Promises showcases five other well-known men and women who have long been known for their environmentalist activism and humanism. These include Stewart Brand (the publisher of the Whole-Earth Catalog), famed historian Richard Rhodes and Gweneth Cravens, a former nuclear critic who participated in rallies and who has carefully charted her conversion from naysayer to admirer in her book "Power to Save the World".

So why would environmentalists of all people support nuclear power? What changed these people's minds? Two things, primarily.

One was the gap between perception and reality that they uncovered on speaking to the experts and doing their own research. Foremost among their revelations was an accurate appraisal of the nebulous bogeyman named "radiation". The basic facts are well-known to informed audiences but they bear repeating: we are bathed in a sea of background radiation whose level often exceeds those from even the worst nuclear accidents like Chernobyl. When it comes to radiation it's all about context; mode of entry, type of radiation, dosage, instantaneous vs prolonged exposure. It is simply wrong to generalize and declare any kind of radiation leak to be catastrophic. There is no evidence that extremely low levels of radiation cause cancer, and the total number of deaths caused by even the worst nuclear accidents are a fraction of those from other causes like coal pollution and cigarette smoking.

Areas supposedly contaminated with high doses of radiation, such as the exclusion zone around Chernobyl, are home to thriving animal and human populations. The crew of Pandora's Promise criss-crosses the world holding Geiger counters, displaying radiation levels at various places; inside a flight, in high-altitude cities, in Chernobyl and Fukushima, in basements where radon is ubiquitous. They clearly point out how radiation at high-altitudes and during flying is higher than any radiation you might get from around nuclear reactors. They interview cheerful residents living in the Chernobyl exclusion zone for twenty-five years who demonstrate no excess cases of cancers. They point out how risks from radiation pale in comparison to many of the risks of ordinary life which we bear with a sunny disposition. Radiation might be the biggest example of what skeptic Michael Shermer calls patternicity, the tendency to fear something just because we cannot directly sense it.

If the chasm between the fear of radiation and its true role in our environment primed these skeptics' sense of proportion, the spectra of climate change put it into high gear. Nuclear power is the only high-density, low-carbon energy source that is ready to be deployed on a vast scale. When it comes to climate change, time is running out, and solutions have to be not just comprehensive but quick; as Lovelock says, "we have no time to experiment with visionary solutions". The film's proponents see nuclear power as the only energy source satisfying these twin criteria. And as they say, "every time you vote against nuclear power, you are voting in favor of fossil fuels". That opinion would be consistent with a recent study by James Hansen which calculated the millions of lives saved when nuclear power plants replace fossil fuels. Whatever the risks of radiation, they have to be balanced against the benefits accrued from the expansion of nuclear energy. Solar energy and other renewables may play a valuable and limited role in serving our energy needs, but their timely replacement of most of our energy demands on a global scale is not even on the horizon; with the sheer amount of energy required by the world and especially by rapidly developing nations like India and China, no other source promises to combine nuclear's ability for being low-carbon and high-energy. For the foreseeable future the only real choices are nuclear power and fossil fuels, and it shouldn't be hard to decide which one we want to choose.

So what does the future look like? The film makers talk about the mistakes that have dogged the nuclear industry, including the locking-in of certain inefficient reactor designs which produce waste and a failure to reprocess spent fuel, leading to hot waste that is both highly radioactive and expensive. Each of these problems has a technical solution whose main opponents have been political and emotional inertia. In case of waste, the actual amounts are tiny compared to waste from fossil fuel plants, and reprocessing and burning the waste in new reactors can ensure that we get rid of the most valuable and most proliferation-part of it, reducing its volume even further. One factor which they don't address and which they should have is cost: nuclear reactors have traditionally been very expensive to construct, although their fuel and operating costs are low. The problem with costs arose because reactor designers pursued false economies of scale; economies of scale work only when construction times are not too long and insurer bills start accruing only after actual deployment. It's also worth noting that the long construction times stemmed from sometimes unrealistic demands on safety; an equivalent coal plant that had to completely contain its own waste would have been prohibitively expensive.

The solution to the cost problem is to make reactors leaner and meaner, and that is what the film does talk about. Fortunately many prominent thinkers who also happen to be wealthy are supporting inspired research into new smaller, safer and more efficient reactors. Bill Gates for instance has lent his support to the traveling wave reactor, a contraption that could run for decades without refueling and waste removal. Bright young people like MIT graduate Leslie Dewan are starting companies for building reactors that can convert nuclear waste into electricity. Other reactor designs like small modular reactors, high-temperature reactors and pebble-bed reactors all promise a radical improvement over existing designs. They can burn more fuel and produce smaller amounts of waste, they are proliferation resistant, they are portable and quickly assembled at their target location and they have entirely passive safety mechanisms which can shut down the reactor even if all active backup systems fail. These Generation IV designs have been on the drawing board for a while, but what has changed is public awareness and the backing of prominent public figures.

Ultimately all the environmentalists in Pandora's Promise recognize a fundamental truth. The question is not just one of nuclear energy but of our responsibility toward our fellow human beings and future generations. What would our grandchildren say if they knew that we had such an awesome source of life-giving energy at our disposal and failed to make sensible use of it? What would they say if they found out that we let an opportunity to feed and clothe the world pass because of political bickering, knee-jerk emotional reactions and an inability to understand tradeoffs? The liberation of entire populations from the shackles of poverty and ignorance has been one of the triumphs of the human experiment, and it has largely been possible because of the twin pillars of harmonious systems of governance and technological breakthroughs, of which energy use must rank at the very top. If we deprive similar populations of the biggest chance they have to relive this transformation, we would have failed in our basic obligations to each other. Even with all our inequities and faults it's not a fate we deserve.

Note: Midway through this post I realized that Scientific American writer David Biello has also written an excellent post about the film which goes into more details. Well worth your time.