Some nuclear facts, conclusions
April 19, 2011 · 2:29 PM
When Publisher Brennan Purtzer asked me to write an article on nuclear energy, I was skeptical. I’m a scientist/engineer, not a writer. Would it be worth doing?
And then, that very evening, I heard a local news anchor report, “Iodine 131 has an eight-day half life. That means in a little over a week, half of it will be gone, and in another eight days the rest will be gone.” I was appalled. I can understand how an individual can be uninformed, but how can an entire news organization produce such an inaccurate statement? After all, the anchor merely reads what’s in front of him.
I can do better than that and so, here goes. First some facts and then some conclusions. Facts are facts, by the way.
Half life: It’s the amount of time it takes for half of the radiation in a given amount of material to decay. So, if you have, say 1,000 units of Iodine 131 at time zero, you’ll have 500 in eight days, and then half of that, or 250 units in another eight days, 125 in another 8 days, etc. Theoretically you never get to zero, but in the case of iodine you soon get so low that it’s negligible when compared to normal background radiation.
Background radiation: Mankind, and every other living thing, has evolved in a nonstop radioactive cloud. We’re exposed to cosmic radiation and radiation from naturally occurring elements in the earth and the air. A form of potassium is radioactive and so anything containing potassium is radioactive. But, thanks to the earth’s magnetic field and atmosphere, we’re sufficiently shielded from cosmic radiation that, well, here we are, and we are what we are. And most of the other naturally-occurring radiation is too low to matter, not that we could do much about it.
Trace: This term refers to negligible amounts of radiation, detectable only with highly sensitive, sophisticated devices. Bananas contain trace amounts of naturally radioactive potassium. The human body contains trace amounts of radiation from various elements. (No need to stop eating bananas or enjoying the proximity of a loved one.)
“Atomic” bombs: It’s very difficult to make a nuclear explosive device. Those few nations that have succeeded essentially copied our technology with and without permission. Nuclear reactors cannot explode like a bomb. That’s physically impossible.
Electricity: If you want electricity, you have to generate it. Around 55 percent of U.S. electricity is generated by burning coal. Twenty-two percent is nuclear. Most of the rest is hydroelectric (dams) or produced by burning other hydrocarbons such as oil and gas. Solar, wind, biomass, etc., contribute relatively small amounts of electricity to the grid.
Fuel cycle: When you talk about cost and risk, you must consider the entire fuel cycle of a power generator. What is involved in each step to build, operate and ultimately decommission a power plant? What is involved in each step of preparing and consuming fuel and disposing of the residue? Do you need to provide backup generation in the case the wind doesn’t blow, for example? Does it take more total energy to produce biofuel than you recover when you burn it?
Nuclear waste: When people use this term they generally mean spent fuel – nuclear fuel that has been exhausted after around three years of running a nuclear power plant. It’s highly radioactive and will be for a very long time. We’ve known what to do with it for more than 50 years: turn it into glass and bury it in a dry place. There’s also the nuclear waste from the weapons production programs (think Hanford storage tanks), which is different, and considerably more challenging, and more urgent, to manage.
Meltdown: Generally this is the term that is used when the reactor core loses coolant (usually water) such that the nuclear fuel structural integrity is lost due to melting. Melting can be limited or severe. But even a limited meltdown destroys the fuel and can create a major cleanup operation, plus possible loss of the power plant.
Nuclear accidents: There have been, notably, three now: Three Mile Island Unit 2 (TMI), Chernobyl and Fukushima. No one was killed or injured at TMI, but the reactor was destroyed. The TMI containment system contained the radioactivity in spite of a partial core meltdown. In fact, the TMI sister unit, next door, continues to operate.
Fukushima will require a major cleanup operation, possibly lasting for years. Some of the workers who went in early probably will suffer higher rates of cancer. But I can’t envision a transport mechanism whereby the Fukushima radiation arrives here in greater than trace amounts. Radiation coming directly from Fukushima does not appear to be a danger to us.
Now to some conclusions: Although I’ve been “out” of the nuclear business for over 30 years, I’m still comfortable with nuclear power. Had we built 1,000 nuclear power plants by the year 2000” as was proposed in the 1970s, we’d have a different world. Maybe better, maybe worse. No one knows what might have been.
All forms of power generation have pros and cons. Consider the environmental destruction, air pollution and direct and indirect loss of life from burning coal. Consider the geopolitical costs of being dependent on others for our petroleum.
What are the pros for nuclear power? National security, minimum climate impact, long term economics (ask any utility that owns one).
What are the cons? High capital cost. Very small risk of a very bad accident. Public uncertainty. No utility exec ever got fired for not building a nuclear power plant.
What would I do? Encourage as much deployment of solar power as possible.
I’d exploit our “vast” reserves of natural gas, if they’re really there and really economical to exploit.
In light of the Fukushima disaster, a review of our nuclear power plants is in order. While the NRC does a good job of regulation, the US has more nuclear power plants than any other country. And the average age is older, since most were built in the 1970s based on 1960’s technology. While they have served well, it may be prudent to begin retiring some of them. I’d replace them with newer nuclear power plants and I’d meet some our growing needs with nuclear power, at least until there is a better alternative. All forms of power generation involve costs, risks and benefits. I believe that nuclear power can continue to serve us well.
George Coulbourn, author of the above article, resides in Black Diamond.