Tuesday, December 20, 2016

Nuclear Power Saves Lives

Would you believe it if I told you that nuclear power saves thousands of lives every year? You will—there's math to back it up.

When you think about life-saving technologies, nuclear energy isn’t typically the first thing that jumps to mind. Sure, there’s nuclear medicine, where we use radiation to attack cancer or create rare isotopes that allow doctors to image the body, but that’s not what most people think of when they think “nuclear”.

Pictured: The general public's perception of nuclear power.
Image Credit: 20th Century Fox & Gizmodo

On the one hand, harnessing the power of the atom gave us the ultimate tool of destruction, but it can be an equally powerful force for good in the world—if we let it. By reducing our reliance on fossil fuels, nuclear energy cuts smog and harmful emissions, like benzopyrene—a well known cancer-causing agent that’s found in both cigarette smoke and coal fly-ash.

Way back in the 1970s, the United States National Research Council’s Committee on Biologic Effects of Atmospheric Pollutants released their findings in a report, Particulate Polycyclic Organic Matter. The title alone is a mouthful, but the report itself contains over 300 pages of statistics and analysis on the dangers of carbon-based pollutants introduced into the environment by things like automobiles and power plants.

The big statistic from this report that I'd like you to see is found on page 224 of the document, where a linear regression analysis reveals a correlation between the rate of male lung cancer deaths and the amount of "solid fuel"—i.e. coal—that we burn every year. While statistical methods like this aren't perfect, they're important for helping us get a look at the big picture, and there are ways to account for those imperfections—for example, this model also takes cigarette smoking, the primary cause of lung cancer, into account.

What the regression analysis found was that, for every metric ton of coal burned per person per year—i.e. for every ~315 million tons of coal burned per year in the US—there's roughly a 20% increase in lung cancer deaths among men. "But what about women?" you might ask—but the data's less clear there. Women seem to be less susceptible to some types of lung cancer than men, although that seems to be changing and we're not sure why.

But back to the numbers. In the US, coal is used primarily for the generation of electrical power, providing 38% of the juice that keeps the lights on, the refrigerator running, and your phone charged. The remaining 62% comes from a variety of sources: most from "natural gas", some renewable energy like solar or wind, but third most significant source of electrical power in the US is nuclear energy, coming in at 19% of our total power supply in 2014.

But let's say the well-intentioned but dangerously misguided "No Nukes" movement gets their way and we legislate the US nuclear power industry out of existence. So now there's a gap of 19% between the grid's demand for energy and the amount that's being produced. Assuming the other sources grow proportionally to fill that gap, coal suddenly has to provide 47% of the nation's electricity needs, since 81% of the US's current electrical power is non-nuclear, and coal makes up 47% of that 81.

Now it's time to talk kilowatts. In 2014, we used 4.147 trillion kilowatt-hours (kWh) of electrical energy as a nation. 38% of that came from coal, but if we'd had to do without nuclear? An additional 9% of that juice—373 billion kilowatt-hours—would likely have come from coal. According to this resource, it takes 1.04 lb of coal to generate one kWh of power, which works out to 2120 kWh of energy generated for every metric ton of coal burnt (if you're following along to check our math at home, the linked resource uses "ton" to mean "short ton", which is 2000 lbs, rather than "metric ton", a.k.a. "tonne", which is 1000 kg. It's terrible, I know). So to get that extra 373 billion kWh, we'd have to burn an extra 176 million metric tons of coal every year.

Let's take another look at the units on that statistic from the National Academy of Sciences—a 20% increase in male lung cancer deaths for every ton of coal burnt per person per year. With a population of 319 million, that 176 million ton offset thanks to nuclear energy works out to 0.55 tons of coal per person per year. That corresponds to an 11% increase in male lung cancer deaths.

So how many lives is that? 158,000 people are expected to die of lung cancer in the US this year, and men make up about 60% of all lung cancer deaths in the US. 60% of 158,000 is 94,800, 11% of which is about 10,400—and there's our final answer. Keep in mind that this is something of a conservative estimate, assuming that only men are influenced by the environmental by-products of fossil fuel use.

How does that stack up next to the dangers of nuclear energy? Obviously it's no good to say "coal kills people, let's use nuclear instead" if nuclear is going to kill just as many people—but the simple fact is that it doesn't. During ordinary operating conditions, nuclear energy releases nothing but steam into the environment. Even in catastrophic scenarios, the death tolls associated with nuclear energy are paltry compared to the number of deaths prevented by curtailing emissions of toxic chemicals. While there's an enormous amount of misinformation* out there, the World Health Organization has estimated the cumulative casualty total for Chernobyl—the deadliest nuclear accident in history—at around 4,000. That means, at current levels of energy production, we could afford two Chernobyl-scale accidents every year in the US alone and we'd still be coming out ahead in terms of lives claimed by the nation's energy infrastructure.

Now obviously it'd be ideal to get our power from renewable sources like solar, which has a zero percent chance of killing you (unless you're a bird or a particularly foolhardy hang glider) but in terms of energy sources that don't depend on the weather, nuclear is clearly the safest.

Stephen Skolnick

*"Fake News" has been in the spotlight lately, but it's been around for a long time. Wild exaggerations of the damage done by Japan's Fukushima meltdown abound, and the same goes for Chernobyl.

3 comments:

  1. According to this article (http://m.spiegel.de/international/world/a-780810.html) life expectancy of the evacuees dropped from 65 to 58 years -- not because of cancer, but because of depression, alcoholism and suicide. There were more than 100,000 evacuees. How do you handle those numbers? Dr. Peter Nagel (peter.nagel@lexprimo.de)

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  2. @Dr. Peter - Simple. They shouldn't have been evacuated in the first place.
    http://www.japantimes.co.jp/news/2016/03/14/national/fukushima-evacuations-were-not-worth-the-money-study-says/#.WGdWBssRVnE

    Loss of life expectancy if they were not evacuated is estimated to be 8 months based on the LNH. Your article says evacuation caused a LLE of 7 years. Basically, the "misinformation" as mentioned in the article is killing 10 times more people than the disaster.

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    Replies
    1. I think he's talking about Chernobyl's evacuees.

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