I'm pleased, because I finally get to stop talking about nuclear-related points or events that are an issue and people may or may not know that they are, to a subject that many people think is an issue but most assuredly isn't.
There have been three nuclear power accidents major enough that the average person on the street might be able to name them: most recently is Fukushima, and turning back time a little farther gets you to Chernobyl and Three Mile Island (TMI). All three accidents were the result of failures in safety systems previously thought impossible, compounded by some pretty major human error. Two of them, Fukushima and Chernobyl, deserve the titles of major accidents and both vie for a top position in "world's most expensive accidents". Chernobyl left a fifth of a country irradiated to an largely uninhabitable degree, and the full effects of Fukushima have yet to be determined, even years later.
I will likely go into detail on at least one of these in a later post, but for today we're talking about TMI.
The Accident
I'll keep this brief, as accident analysis isn't the point of the post. In 1979 A stuck valve in the non-nuclear secondary system (the part that actually makes steam and turn turbines) lead to the inability to remove heat from the reactor, even after a full shutdown via SCRAM. Secondary pumps were unable to be started due to human operator confusion over valve status and improper maintenance performed the night before. Eventually heat built up enough to cause a partial core meltdown. In order to prevent further issues the operators were forced to vent nuclear products into the air, exposing the public living near the reactor to the material.
The Aftermath
A voluntary evacuation was suggested to pregnant women in the area. Within hours of the accident, several organizations, ranging from the EPA, the national lab, college research groups, and privately funded research, began a series of extensive tests to determine the full effects of the radioactive release.
Now, if you ask your parents, or maybe your grandparents, you might here some ridiculous stories about babies with multiple extra limbs, or fish in the local river with three eyes, or the more believable anecdote of increased miscarriage or other pre-natal issues in the area. However, the honest truth is that there was no determinable effect. Based on soil and air samples it is estimated that the two million people living in the vicinity of the plant received an average dose above background of 1.4 millirem. By comparison, a chest x-ray is 3.2 millirem, and people receive those all the time without issue. Now, there is a big difference between the voluntary 3.2 mrem from the x-ray, and the involuntary exposure to the 1.4 mrem from the power plant. But after long, extensive study by the EPA and the other groups, it was determined that not even one additional cancer death occurred as a result of the venting at TMI. [1]
What's more, we learned a lot of important lessons from TMI. Lessons in redundancy, and how to further remove the potential for human error in an accident scenario. Thanks to those lessons, America has never had another significant reactor event, and certainly no major exposure to the public. Unfortunately, we determined all of this far too late to prevent a panic in the public and in the government, which led to a moratorium on new reactors in America that lasted until just a couple years ago. It, along with Chernobyl, instilled a fear of nuclear in the general public that had just started to die off when Fukushima occurred.
The final takeaway is this: with only a handful of exceptions, the nuclear power plant down the road from you, or in the next town over, or wherever, is not exposing you to atmospheric radiation. Even in America's most significant reactor accident, no adverse health affects occurred.
[1] http://aje.oxfordjournals.org/content/132/3/397.full.pdf+html
I think that the nuclear community needs to emphasize what you said in this post: that the dose received by each person was less than a chest x-ray, and many important lessons were learned that have protected us from another significant event. If we all continue to state these facts, eventually our efforts will reverse the negative and sensationalist rhetoric that was fed to the public.
ReplyDeleteIt's true that more education on what you're exposed to and how it compares is important, and I do want to fight ignorance about the nuclear industry. Unfortunately it is still complicated by the fact that you choose to be exposed to a x-ray, but no one around TMI signed their consent to breath in the vented fumes! Still, it's important for people to know that even that forced exposure had zero health effects on anyone.
DeleteThis was a very good read. I do believe that the nuclear industry needs to invest more time and money into a good PR campaign to educate the public. Outreach programs would help immensely with the public ignorance.
ReplyDeleteThe chest x-ray example is really top notch, gonna keep that one in the ol' noggin for debating my pals. Thanks for the info!
ReplyDeleteGlad to provide! As I mentioned, there's a huge difference between the x-ray you volunteer for and the equivalent to half an x-ray that you might not have even known you received. So it's still unacceptable and I'm glad regulations were changed after TMI, but at least the practical effect is no one was hurt.
DeleteIs it a safe assumption that the 1.4 mrem above background could be considered a whole body effective dose? And if so, could that have any more negative effect to more sensitive organs than would be seen in a traditional voluntary chest X-ray?
ReplyDeleteIt is interesting to see the numerical results of how much radiation dose can be achieved from major accidents versus relatively common medical procedures. It will sure help reduce the fear on radiation.
ReplyDeleteDo you think that the stringent NRC regulations that were instated after TMI are necessary to prevent future accidents, or do you think that the licensing process has become too complicated and that ultimately it hinders the growth of reliable nuclear energy in the US?
ReplyDeleteTMI led to big changes in identifying common cause failure and trying to minimize risk. Yes, NRC regulation can be a hassle but if anything, not identifying the need for change before TMI crippled the nuclear industry. TMI contributed to the halting of nuclear development in the US because people became afraid.
DeleteIf I remember correctly from Power Plant Systems, there was a report on the possibility of an accident very similar to what occurred at TMI that was basically brushed off by the nuclear industry as being "too unlikely to be concerned with" put out just a few years before TMI. So as Nancy said, the NRC might be annoying but I'd much rather have an organization overly worried about dangers to the public than one that just assumes everything will be ok.
DeleteI like that you talked about Three Mile Island. Most posts and articles about nuclear accidents these days are more about Fukushima and Chernobyl and you don't really hear too much about TMI even though that's the only one that occurred in the US. A big problem with explaining radiation doses to the public is that they don't understand the units and what those numbers actually mean. That is why it is important to compare it to something they know, like a chest x-ray that they may have had in the last year.
ReplyDeleteThanks! Yeah, this one was close to home because it seems like every time I talk to a family member about nuclear power TMI comes up (many of my extended family live(d) in the area) and the amount of ignorance I hear spoken by otherwise intelligent people is very surprising. A lot of it comes from the media not helping, it'd rather ride the sensation than try to educate people.
DeleteWhat people forget about TMI is i t was the first big nuclear accident and because no one knew what the effect would be, a large radius around the plant was evacuated. Additionally, a part of the concern was panic incited by the media. A movie called the China Syndrome (which showed a nuclear accident burning a hole through the earth to China) had come out the week before and there wasn't 24 hour news so people had to wait for the nightly news just to find out what was going on.
ReplyDeleteI'd forgotten about The China Syndrome! That's such a terrible film. But you're entirely correct, the media was no help at all in this case. I understand that sensationalism gets higher ratings than education, but it still leaves such a bad taste in my mouth.
DeleteThe Defense in Depth mantra is quite possible one of the greatest industry qualities I've ever come across. Because of redundancy, quite possibly thousands of nuclear accidents have been avoided. Reactor SCRAM is much less stressful of a plant condition when personnel are aware of backups to backups.
ReplyDeleteI liked your bit about 'world's most expensive reactor.' It makes me wonder about the a Nuclear Reactor Owner's Club. Think of how exclusive...
Yeah, talking about DID in risk assessment and other classes is always kind of mind blowing, especially in just how low the limit for probability of failure or injury is.
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