Nuclear Energy Mythbusting
So Dr. Zoomie – We hear so much about nuclear energy from the anti-nuke crowd; some of what they say sounds plausible and some really doesn’t. I know you’ve got some experience with nuclear power and was wondering if you can tell me what you think are some of the worst myths about nuclear energy. Thanks!
Before starting an answer, let’s take a moment to put it in context – specifically the need to wean ourselves off of fossil fuels. Regardless of one’s thoughts regarding global warming, the fact is that the Earth holds only a finite amount of fossil fuels and that they will one day run out and, as that day approaches, they will become increasingly expensive to extract. To that I’d note that, as carbon dioxide dissolves into water it forms carbonic acid, which has adverse effects on the health of the ecosystem. These reasons alone are sufficient to justify reducing our use of fossil fuels – the prospect of climate change only amplifies to do so.
Luckily, we have a number of alternative energy sources; unfortunately, some are contingent on weather (e.g. solar and wind), some an be used only in limited areas (e.g. geothermal, hydrothermal, tidal power), and for too many the distance between the energy source and energy consumers is so great that too high a fraction of energy produced is lost by the time it reaches the customers. At the moment, nuclear energy stands virtually alone as a reliable, constant source of energy that can be located virtually anywhere. For this reason, it’s important to help people understand it better and, especially, to learn how to separate valid objections from the mythology. So here we go!
Myth: Nuclear reactors can explode like nuclear bombs
Fact: Let’s talk lighter fluid! I’m guessing you’ve seen how quickly a fire flares up when you, say, drop a match into a small pool of the stuff, and you probably know that, after it’s soaked into a piece of charcoal it takes longer to start burning and the flames build more gradually. Now picture mixing lighter fluid in with several ounces of dirt – will it light? Well…maybe, but it’s going to take a little patience. And there will come a point at which it just won’t light at all – just a few drops of lighter fluid mixed in with a pound of dirt won’t ever catch fire.
Now replace “lighter fluid” with “U-235,” change “pool of lighter fluid bursting into flame” to “highly enriched uranium exploding,” and “a few drops of lighter fluid mixed into several ounces of dirt” with “low-enriched uranium.” The reason for these substitutions? There are two main isotopes of uranium, U-235 (which fissions quite nicely) and U-238 (which does not). To make uranium fission rapidly enough to explode you need a lot of U-235, and the more you dilute the U-235 with the much less-fissile U-238 the less rapidly the reaction will proceed. In a nuclear weapon over 90% of the uranium atoms will fission while, in a nuclear reactor only 5-6% will do so. The concentration of U-235 in a commercial nuclear reactor is too sparse to cause a nuclear explosion just as a few drops of lighter fluid in several ounces of soil is too little to burst into flame.
Myth: Nuclear reactors are inherently dangerous
Fact: I was in the Navy’s Nuclear Power Program for eight years, most of which was spent operating nuclear reactor and propulsion plants; for half of my time in the Navy I lived within a few hundred feet of the reactor on my submarine and, even when we were in port, I was less than a quarter mile from the reactors on the other boats tied up in port – up to another dozen at any time. After leaving the Navy one of my homes was about two miles from a research reactor and another was less then five miles from a commercial nuclear power plant. And in spite of all of this happening after the accidents at Three Mile Island and Chernobyl I didn’t worry at all.
Don’t get me wrong – I know that people have died in nuclear reactor accidents and I understand that radiation can cause cancer. But here’s the thing – the fatality rate from nuclear energy (including the handful of reactor accidents) is a fraction the rate of deaths from other sources of energy. That’s not just my opinion – that’s the conclusion of a number of studies conducted by a variety of government agencies, scholars, and expert organizations around the world (see, for example, https://ourworldindata.org/grapher/death-rates-from-energy-production-per-twh). These both include the health effects of the Chernobyl accident the effects of Fukushima. You might also be interested to know that far fewer people die from nuclear reactor accidents per GW of electricity production than they do from coal mine disasters, refinery explosions, drill rig accidents, natural gas distribution, or hydroelectric dam failures.
Another factor to consider is that fossil fuels contain natural radioactivity – the geochemistry of uranium is such that it concentrates in the sorts of conditions that go on to form coal, oil, and natural gas deposits. Burning natural gas can release radon into your home, burning coal releases radioactivity from the coal into the environment and creates slightly radioactive fly ash, and extracting both natural gas and petroleum produces slightly radioactive waste. The bottom line is that whether you’re looking at short-term risk from accidents or long-term risk from cancer, nuclear energy stacks up quite favorably against any other form of energy (https://ourworldindata.org/safest-sources-of-energy).
Myth: There’s no safe level of radiation exposure
Fact: This one gets a little tricky – not because of the concept, but because scientists tend to talk about risk while non-scientists tend to talk about safety, and even though the two words are often used interchangeably, the way they tend to be used they don’t actually mean the same thing.
When a scientist talks about “risk” they are usually referring to a number – the risk that a person might get sick or die from a particular activity or from exposure to a particular substance. Thus, a scientist might say that exposing ten thousand people to a single chest x-ray (with a radiation exposure of about 0.01 rem for each x-ray) might lead to five people developing a fatal cancer over their lifetimes – a risk of five deaths per 10,000 x-rays, or a risk of 5×10-4 per x-ray. When I talk about risks from nuclear energy, from x-rays…or, for that matter, from driving, hang-gliding, or anything else – that’s what I’m talking about. Risk, as used by scientists, has nothing to do with making value judgements about the source of the risk or whether or not the source of the risk should (or should not) be permitted. Risk is used objectively – it’s just about the number.
“Safe,” on the other hand is entirely subjective – “safe” comes down to “do I feel comfortable performing this activity or being exposed to this?” I’ve talked with people who find a one-in-a-million risk of getting cancer from exposure to radiation to be utterly unacceptable, but they drive to work every day in spite of the much higher risk of being injured or killed in an accident. “Safe” is about how a risk is perceived by a person, and what’s safe to me might be wildly unsafe to you – and vice versa. I lived and worked on a nuclear submarine for four years – to me, the reactor was safe, the radiation was safe, and submarining in general was safe (although our electrical plant concerned me, and I was always on guard around our high-pressure air and hydraulics). What I didn’t like was driving San Diego’s highways – too many drivers, too many of whom were bad at it, and most of whom drove the roads multiple times daily with nary a concern.
To me, nuclear energy is safe because I know that, even with the accidents at Three Mile Island, Chernobyl, and Fukushima the number of fatalities around the world is substantially lower than from virtually any other form of energy; I also know that even if the nuclear reactor nearest to me suffers an accident it’s unlikely to harm me or anyone I know. I look at the 30,000-40,000 annual deaths from driving and it seems to me to be much less safe than nuclear energy, which has killed fewer people than that over the last 70 years. Don’t get me wrong – I still get in a car and drive when I have to, but I’m well aware of the risks, and I certainly don’t consider it to be a safe activity.
Myth: Another nuclear reactor accident is inevitable and will kill tens or hundreds of thousands of people
Fact: Hmmm…. Three Mile Island caused no fatalities (https://www.nrc.gov/reading-rm/doc-collections/fact-sheets/3mile-isle.html). Chernobyl has caused fewer than 100 fatalities to date and maybe as many as 400 or so over the lifetimes of all who were exposed world-wide (https://ourworldindata.org/safest-sources-of-energy). Fukushima resulted in slightly more than 2000 deaths, but not due to radiation as all of them were due to the evacuation (https://ourworldindata.org/what-was-the-death-toll-from-chernobyl-and-fukushima). I was in the Fukushima area just a month after the accident and can confirm that, while radiation dose rates were clearly elevated, they were only a fraction of what I measured myself in Ramsar, Iran, which has high levels of natural radiation (and where the average lifespan seems to be the same as in any other part of Iran.
Three data points are too few to make sweeping statements, but the fact is that four reactors melted down in Japan and Pennsylvania and one exploded (non-nuclear!) in Ukraine without causing the massive levels of death that so many have suggested. Not only that, but there are over 400 commercial nuclear power reactors operating around the world in addition to a few hundred military reactors; in all of these thousands of reactor-years of operation there have been so few major reactor accidents that we can count them on one hand. Compared to the number of accidents and deaths in coal mining and in petroleum and natural gas extraction and processing, nuclear energy stacks up fairly well.
Myth: There’s no place to put all that radioactive waste to keep it safe for the hundreds of thousands of years it’ll take to become safe
Fact: I really don’t know how much radioactive waste I’ve disposed of over the years. At the two universities I worked at we disposed of between 4000 and 5000 cubic feet of radioactive waste at each (all low-level radioactive waste), plus minor amounts while I was in the Navy and at other places I’ve worked. Two remediation projects I managed produced another several tens of thousands of cubic feet of waste – all fairly low-activity in spite of the large volume. So let’s assume I’ve generated (or overseen the generation of) 100,000 cubic feet of radioactive waste over my 40 years in radiation safety – that’ll cover an area the size of a football field to a depth of about two feet; not even knee-high. The remediation waste was tons of soil with low levels of radium and thorium in it while the waste at the university was primarily paper towels, latex gloves, and laboratory glassware; none of it was dangerous. In fact, over 95% of the world’s radioactive waste falls into the category of low-level radioactive waste and only about 1% consists of spent reactor fuel and other dangerously radioactive materials.
According to the International Atomic Energy Agency (IAEA), as of 2016 the global inventory of very low level and low level radioactive waste was about 35 million cubic meters or about 1 ¼ billion cubic feet. This sounds like a lot of waste – it’s enough to cover a square mile to a depth of just under 50 feet. But that represents all of the radioactive waste generated globally over a 60-year period, and it would fill only a 10% of the volume of the Puente Hills landfill near Los Angeles. There is plenty of room for the world’s radioactive waste.
The other thing to remember is that, while some of the individual radionuclides that we use have extraordinarily long half-lives, a long half-life means that the material is not highly radioactive. Uranium-238, for example, has a half-life of nearly 4.5 billion years while cobalt-60’s half-life is only a little more than 5 ¼ years. The uranium will be on Earth until long after our planet is swallowed by the Sun and dies. But how dangerous is it? Not very, actually – the uranium is so weakly radioactive that, to have the same amount of radioactivity as one milligram of Co-60 would require about one ton of U-238. Radioactive materials can either be dangerously radioactive or they can have a long half-life, but not both, and the longer it’s in storage the less dangerous it becomes.
And a few closing thoughts, if I may.
Nuclear energy is not perfect – no energy source is perfect – and it would be a mistake to make it our only source of energy. But it has – and should continue to have – a prominent place in our energy picture.