Another Three Mile Island

Fukushima will probably be mostly harmless, misunderstood by the media, and a rallying point for anti-nuclear activists.

Matthew Shaffer
Tuesday, March 22, 2011

‘Nobody at Three Mile Island was actually hurt or killed, or anything of that nature,” remembers John McGaha, formerly a senior executive of Entergy, a Mississippi company that runs and operates nuclear utilities. “Versus if you look at some of the oil and chemical explosions we’ve had over the years . . . ”

McGaha and other experts tell National Review Online that Americans are unduly afraid of nuclear energy — in part because of the media’s disproportionate, distorted reporting on rare nuclear accidents like Three Mile Island and the recent problems in Japan. McGaha says the most deadly consequence of Three Mile Island might have been how it delayed the advancement of nuclear technology in the U.S.

Yes, officially, one or two incidents of cancer have been attributed to Three Mile Island. But even with those, there’s no way to know for sure. All of us have “a 16 percent lifetime chance of contracting cancer,” says Robert Henkin, professor emeritus of radiology at Loyola University in Chicago. So, he asks, “If that goes to 16.1 percent, how do you ever pick that out?” We can’t be certain there was any harm at all.

And yet the panic at the time outdid the current panic over the Fukushima reactors. “Governor Thornburg was debating whether he would evacuate 20 miles out,” Prof. Michael Corradini, chairman of engineering physics at the University of Wisconsin, remembers. And the newspaper headlines during the Three Mile Island crisis suggested much worse. “Strangely enough,” Professor Henkin says, Three Mile Island “was actually one of the great successes of the industry.”

It’s not remembered that way, of course. One reason seems to be that the terminology related to nuclear power has taken on sinister connotations. Consider radiation. Think of the panic that the headline “Radiation levels increase by 100 percent” could induce. But in reality, such radiation would be medically beneficial; it would promote “radiation hormesis” — the exercise of the immune system. “We get one unit of radiation per day. When we double that — they’ve done tests with animals — they show better health. It’s like doing pushups,” says Gilbert Brown, a professor of nuclear engineering at the University of Massachusetts–Lowell. That doesn’t prove we shouldn’t worry about much higher levels of radiation — but it indicates how our emotional response does not correspond to reality.

And how high are radiation levels in Japan right now? The International Atomic Energy Agency on Sunday said that radiation levels of 5.7 microsivierts per hour were detected at a 35-mile radius from Fukushima. This, Steve Kerekes of the Nuclear Energy Institue says, is “under what a nuclear-plant worker could be exposed to every day for his job” under the Nuclear Regulatory Commission’s guidelines. And even that measure may overrate the risk. “They intentionally set the limits very, very low — at much smaller levels than are actually dangerous, to encourage people to be very safe with radiation,” Professor Henkin says. Comparing Japan’s current levels with the data derived from the decades-long Atomic Bomb Project, which followed people exposed at various distances to the Hiroshima and Nagasaki explosions, Henkin concludes the following: “The dosage that people had to attain to achieve above-average incidence of cancer in a population is orders of magnitude above anything basically anybody [outside of the plants] in Japan is experiencing right now.”

Here’s another example: meltdown. The nuclear experts like to call it “the M-word.” “We use the term ‘meltdown,’ and it conjures up this disaster,” Brown says. But a meltdown is not always a catastrophe. “When you say ‘car accident,’ people know it could be a fender-bender, or it could be fatal. Nobody just assumes it was fatal. It should be the same with a meltdown. There are many scenarios in which a meltdown happens and nobody gets hurt,” Brown says.

Here’s what a typical meltdown really is, and how it may have happened in Fukushima. At the first sign of danger (to which nuclear reactors are very sensitive — the Fukushima reactors knew about and responded to the earthquake before people felt it), a nuclear reactor automatically shuts down the uranium-fission process by which it produces the vast majority of its heat. But that doesn’t stop all energy production. Uranium fission results in several radioactive byproducts, which produce roughly 6 percent of the heat of the normal, functioning reactor — and continue to do so after the fission itself stops. So at this point, nuclear engineers can avoid a meltdown by bleeding away 6 percent of the heat that a normal reactor gives off.

So why didn’t this work at Fukushima? It’s simple: Diesel generators — the power source for the reactors’ cooling systems — got wet. Amazingly enough, the reactors survived the Richter scale 9 earthquake when almost everything in the surrounding area was destroyed. But the tsunami, which came afterward, knocked out the generators. If the diesel generators had been properly equipped to deal with the wave, the Fukushima reactors would be fine. For now, keeping the reactors cool will be a pain, but a devastating meltdown doesn’t seem likely.

If the reactor is not sufficiently cooled, two things could go wrong. First, the metal in the containment vessel of the reactor might get so hot that it oxidizes any water that comes near it, producing a hydrogen bubble that could explode, as happened in two Fukushima reactors. The other hazard is that the reactor gets so hot that it partially melts (that is, a meltdown occurs, as it has in Fukushima), and if the melting is substantial, that might allow radioactive gases to escape and get mixed in with steam that’s on its way out of the plant. Even then, there are more lines of defense: charcoal filters that capture the radioactive particles while allowing the steam and noble gases through, and a double containment system that puts another wall (outside of the reactor) between the fuel and the public. If those don’t work, the radioactivity in the surrounding area will rise in proportion to the amount of radioactive byproducts released.

Professor Miller tells NRO that “the public has the notion that we’ll see this molten blob of material escaping into the environment. And that doesn’t happen.”

Here’s a final example: nuclear contamination. It’s a scary phrase, but what does it mean? Formally, Professor Henkin tells NRO, when a person is contaminated, “that means that person really ought to take a shower.” And this, Henkin says, is the highest level of exposure civilians have received from Fukushima.

Even so, many things went wrong in Japan last week. But they’re very unlikely to happen in the United States. As Prof. Dennis Beller, a nuclear-engineering researcher at UNLV, tells NRO, “U.S. nuclear plants are generally designed to a higher safety level than those in Japan.” To start with, we have more redundant and safer energy sources for our coolers. Also, we now have the technological capability to build reactors with automatic-convection cooling systems. That means no external power source will be required, so meltdowns would be prevented even when all power is shut off.

That’s the science. But the more important question going forward is one of policy. All the nuclear-energy experts emphasize that good policy means thinking about tradeoffs — choosing among feasible alternatives, rather than striving for perfection. So consider our options, and the consequences of several alternatives:

First, shutting down the production of new nuclear facilities would mean more reliance on old nuclear facilities, which are less safe. Second, shutting down or phasing out all nuclear facilities would necessitate greater reliance on other energy technologies that have their own dangers. As Professor Brown says, in a refrain common to all the nuclear experts, “Think of the BP explosion. Or Exxon Valdez. Those were pretty hellacious. And every month there’s a coal-mine disaster, and you read about pipelines exploding.” He recommends acknowledging that we are in “a pragmatic space. That doesn’t mean you don’t think every life is valuable. But you’re balancing risks, and acknowledging their reality in the real world we live in.”

The total death toll from Three Mile Island may have been zero, and Chernobyl claimed, by the estimates of the International Atomic Energy Agency, just 50 lives, despite what nuclear experts describe as the Soviet Union’s extreme incompetence. Each lost life is a tragedy. But in the 20th century, hydroelectric dams’ bursting, coal-mining disasters, and oil explosions have killed tens of thousands. And that includes just direct deaths from accidents, not indirect deaths from displacement, health problems caused by particulate matter, etc. Statistically speaking, nuclear experts claim, uranium fission is the safest major energy source in the world.

It’s possible that media overreaction and misunderstanding of the Fukushima incident will hold back the advance of nuclear energy. Chancellor Angela Merkel has ordered a complete shutdown of Germany’s seven oldest nuclear plants. Even if those plants did need to be updated, “You can make additions and updates without shutting down the plants,” Professor Beller says. Merkel’s restriction of the energy supply, he points out, will exacerbate an energy crisis and hurt “low-income people in particular in Germany.”

John McGaha fears the worst for the United States. “Every time there’s an event of any kind, even if, when it’s all said and done, nobody was hurt — anything that can be symbolic of the risk of nuclear energy provides fodder for the anti-nuclear groups to get on their horse and campaign against the industry.” And that will have international repercussions: “We’re still seen as the go-to country for any other country that wants to build its own program. The United States’ policies and designs set the standard for the rest of the world.”

There’s some reason for optimism, however. As Bill Miller, professor of nuclear science and engineering at the University of Missouri, says, “I noticed that the president and Secretary Chu have already stated that it’s tragic and we need to learn from it, but that doesn’t change the U.S. position on the need for nuclear power.”