Wednesday, March 23, 2011

Thursday, March 17, 2011

All Radiation is Not Created Equal

I have seen many alarming headlines and news-stories lately, saying things like "radiation clouds heading for the US from Japan" along with calls to protect your family now from this looming danger. Yesterday, I addressed the issue of using potassium iodide pills to block the radiation. Please read it if you haven't yet, but the short version is: those pills will not help much and they certainly won't block all the radiation as many people believe.

Radiation comes in many different forms. We are surrounded by and exposed to radiation all the time, since sunlight is radiation, as are radio waves, TV waves and microwaves. This type of radiation is called "non-ionizing" because when it is absorbed by matter (like your body) it does not produce charged particles known as ions.

Ionizing radiation, on the other hand, will strip electrons from the atoms in your body (or any other type of matter) when it is absorbed. This can wreak havoc in your tissues, since the result can be free radicals or other highly-reactive species that cause a cascade of worrisome events. 

We are exposed to ionizing radiation all the time, and our bodies have developed means to defend against a certain level of radiation in the environment. Free radical scavengers exist in our bodies and clean up the byproducts of ionizing radiation--as long as there's not too much of it.

Examples of ionizing radiation include X-rays, gamma rays, alpha rays and beta rays. The latter three are all produced in nuclear reactors and emitted by the substances which may be released when a nuclear reactor is damaged or explodes. An excellent, and very detailed, article about radiation can be found here.

A lot of attention has been focused in media reports on whether or not the explosions seen at the troubled reactors in Japan were "nuclear explosions" or not. (Apparently, they were not.) To me, this is irrelevant. An explosion that spreads radioactive material into the environment is a problem whether or not the source of the explosion was a thermonuclear event or a build-up of combustible gas. Nuclear explosions are much more powerful, of course, but the main reason they are so feared is because of the radioactive materials left behind afterward.

Last night, the special defense forces in Japan began an operation to flood the number 3 nuclear reactor at the Fukushima Daiishi power plant with water, and many wondered why they chose that particular reactor for their initial assault, when three others (numbers 1, 2 and 4) appear, visually, to be in much worse shape. I certainly don't know what led them to this decision, but perhaps the nature of the fuel rods inside reactor 3 had something to do with it.

Apparently (and I only know this from media reports, but I assume it is correct) the number 3 reactor uses a type of fuel rod known as MOX fuel, which stands for "mixed oxide." This name does not sound too alarming, until you read further to find that the MOX fuel rods are composed of a mixture of Uranium-238 (the usual fuel in a nuclear plant) and Plutonium-239, or Pu-230.

Pu-239 is not naturally occurring. It is produced in so-called breeder reactors by bombarding Uranium-238 with neutrons. It is used in nuclear weapons, which is why it's use in nuclear power plants has been controversial.

Pu-239 is chemically toxic, but it is also radioactive with a half life of 24,000 years. This means that half of a sample of Pu-239 will still be radioactive after 24,000 years have passed; the other half will have decayed by emitting what's known as alpha radiation.

Alpha radiation is actually a beam of helium atoms that have been stripped of their electrons, giving them a positive electrical charge. They are heavy and the energy they carry is, thus, low. Alpha rays can penetrate only 2-3 inches of air and can be stopped by a single sheet of paper or a thin layer of human skin.

The problem with alpha rays occurs when substances that emit them are breathed into the body or ingested through food and drink. Pu-239 is an alpha emitter and if it is present in particulates in the smoke coming out of a damaged reactor, anybody nearby needs to be shielded immediately. It is not clear to me how far Plutonium will travel in a "cloud" since that seems to depend on the size and nature of the particles in the smoke.

Another type of ionizing radiation produced in radioactive decay is beta radiation. These rays are actually electrons that travel with high speed. They can penetrate about an inch of water and about the same thickness of human flesh, but can be blocked by an eighth of an inch of aluminum, so special protective clothing is needed to block beta rays.

Gamma radiation is, by far, the most dangerous of all radiation produced by radioactive substances. Gamma radiation is pure energy (no particles are associated with it) and is very similar to X-rays. To block gamma radiation, 3 - 4 feet of concrete is required or, better yet, a few inches of lead. It is likely that the high radiation levels being measured near the Fukushima reactors is gamma radiation. Shielding workers from this type of radiation will be very difficult, if not impossible. 

It is important to realize that gamma radiation will not travel indefinitely through air as it will be absorbed by molecules of oxygen, nitrogen and water as it moves along, so there is no danger to anybody who stays far enough away. The bigger danger comes from the radioactive nuclei that may be escaping from the reactors. 

I would like to see more detailed information from the Japanese government and its electric utility TEPCO about the precise nature of the radiation they are measuring. A few bits of information are coming through about monitoring of Cesium and Iodine, but a fuller picture would help experts around the world do a better assessment of any dangers we all may be facing.

Wednesday, March 16, 2011

What You Need to Know About Potassium Iodide

As I have watched the situation in Japan go from bad to worse to completely unbelievable, I have wondered what I could do to help. I am so far away, and it doesn't seem I or my family can provide much help in any direct way. I can watch and pray and send money to relief organizations such as the American Red Cross or directly to the Japanese Red Cross Society, so I do, but am still left feeling like I want to help in a more direct way.

The unfolding nuclear power plant disaster has raised fears around the world, which I addressed in my post yesterday. These fears are not completely unfounded, but I have become concerned about some of the responses, particularly in countries outside of Japan. When I heard yesterday that people on the west coast of the US were so panicked by the situation that they had bought up all the supplies of potassium iodide, I suddenly knew how I could help more: by sharing what I know about nuclear chemistry and radiation.

And I know a considerable amount. As I explained in yesterday's post, I taught a course for over two decades that included a major section on nuclear power, the fate of nuclear waste, radiation in the environment and related topics. It is an issue near and dear to my heart and I feel it receives scant attention in our education system. We are paying the price for that educational lack now, since people need good, reliable information about all things nuclear and they aren't always getting it.

The first thing people need to know is that potassium iodide tablets will not protect you from the effects of all nuclear radiation or nuclear fission products. I'll explain why below, but the second point is that if you have purchased these tablets, do not take them until instructed by an official. Potassium iodide can have harmful side effects and should only be used if there is an immediate threat of poisoning by radioactive iodine in the environment.

There is plenty of information out there on the web about this issue, but I will repeat it to be sure everybody understands. Potassium iodide tablets only protect the thyroid, not the whole body, and all they do is help block your body's uptake of radioactive iodine, which is but one of the products that are produced by a nuclear fission reactor.

We, of course, might want to protect the thyroid from absorbing radioactive iodine since it could cause cancer, but this is only one of multiple issues to be concerned about. These tablets do not protect the body against gamma radiation or any of the other dangerous radioactive nuclides that might be present after a nuclear accident, including Cesium-137 and Strontium-90.

When the term "radiation" is used, it is usually not specified exactly what type of radiation we are talking about or measuring. There are different types of radiation: alpha, beta, gamma and neutron radiation, all with different health effects, but it is also important to know what the source of the radiation is. 

Radiation is given off when radioactive atoms that are produced in the process of nuclear fission "decay," which means they eject small charged particles or beams of energy at periodic intervals. Some of these radioactive elements decay rapidly. Half of a sample of radioactive Iodine-151, for example, will decay, and become non-radioactive, in only 8 days. Iodine-151 is, thus, said to have a "half life" of 8 days. On the other hand, the half-life of Cesium-137 is thirty years, so when radioactive Cesium is detected, people tend to be much more concerned. 

All of these radioactive species are dangerous, but the truly ominous products of nuclear fission processes are those with extremely long half-lives, such as Iodine-129, which has a half life of nearly 16 million years, or Uranium-235, one of the components of active fuel rods. Its half-life is a whopping 700 million years. Here is a helpful primer on radioactivity in the natural environment with lots of links to other useful information.

It is unlikely that any of these long-lived radionuclides, if they were accidentally released from one of the damaged reactors in Japan, would ever reach the shores of the US. And we encounter radiation in our daily lives all the time, since the earth is constantly bombarded with cosmic rays and there are many, many naturally-occurring radioactive elements in the environment--and in our own tissues, for that matter. 

So, in one sense, we in the US need to calm down a bit and try to keep things in perspective. The people in the area closely surrounding the nuclear plants in Fukushima have good reason for immediate concern, but that doesn't mean the entire world is going to suffer the same effects.

And, yet, I believe we should be cautious and wary and pay close attention to what is going on. The US is the world's largest producer of nuclear energy, and our 104 nuclear reactors provide nearly 20% of the country's energy needs. Whether we go forward with building more is one question, but we already have plenty of reactors on hand to take care of and understand. All of us need to educate ourselves so that we fully grasp what any authorities may tell us. Your health, quite literally, depends on it.

Tuesday, March 15, 2011

A Radioactive Topic

Burial Site for the SL-1 Reactor in Idaho
The crisis in Japan expanded this weekend from an enormous earthquake, a catastrophically destructive tsunami, and hundreds of aftershocks to now include an ongoing and rapidly evolving crisis with several nuclear power plants in the Fukushima region

The threat posed by the damaged nuclear reactors has raised concern around the world. Some have downplayed these concerns, suggesting that people over-react to anything with the words "nuclear" or "radiation" in it, but I disagree. We should be worried. Very worried.

Many stories have appeared in the US press asking: could something like the situation in Japan happen in our country? In fact, something very similar did happen here, fifty years ago. And although it occurred just a few miles from where I was living at the time, I only learned of this in the last few days.

As I was looking up links to include in this post, I came across a series of articles about an accident that occurred at the Atomic Energy Commission (AEC) site in the Arco Desert outside my hometown on January 3, 1961. The circumstances are eerily similar to what we're hearing about at the Fukushima nuclear power plant. At around 9pm on that January day in 1961, a steam explosion occurred at reactor SL-1, an experimental nuclear reactor at the site. A control rod had been pulled out of the core, causing the reactor to go critical. The explosion was caused by a sudden upsurge in heat that explosively converted liquid water into steam.

Three workers were killed by the physical effects of the explosion but their bodies were so radioactive that they were buried in lead-lined caskets. The radiation exposure was due to the contents of the reactor being sprayed around by the explosion. The entire building and what was left of the reactor are still buried in the desert just outside my hometown. The accompanying image shows the marker sitting next to a pile of rock that looks just like dozens of other piles of rock I have passed by many times on my way to visit my grandparents.

I was five years old at the time so, of course, I remember nothing about this. I've found a newspaper article and a story in Time magazine, both published in 1961, that show the public was aware of what happened. Perhaps this explains my mother's insistence that we never eat the snow; she warned us repeatedly about "nuclear fallout" and how it could be in the snow. I always thought her fear was somewhat irrational, due to Cold War tensions, but now that I've learned about this little-known nuclear accident, I wonder if she had more immediate reasons to be fearful.

Some people are afraid of things they don't understand, and the mere mention of the words "nuclear" or "radiation" can generate irrational fear, or fear based not on facts but wild speculations and misunderstandings. This does not mean that all fear is irrational, however, and sometimes it is an appropriate emotion. I have not yet reached the point where the situation in Japan is making me feel actual fear, but I am concerned--and this concern is based on quite a bit of knowledge about nuclear topics.

I taught introductory college Chemistry for over twenty years and always included an in-depth unit on radioactive decay processes as the basis of nuclear power generation. I was one of only a few professors who covered this topic, but I felt compelled to teach it, and teach it thoroughly. It's possible that experiences in my early childhood had made me especially attuned to the importance of this topic, but I also knew that essentially no attention was paid to it in most science classrooms, and I wanted to do what little I could to remedy this lack.

At the end of each term, I always had a few students who had learned what I was trying to get across: that this topic is very important and whether we are in favor of nuclear power or not, we need people who understand it, since the materials and power plants exist and must be handled properly. These students would want advice about graduate programs, places they could go to pursue further study, but there were very few options available to them.

I have continued to be dismayed by the lack of opportunity to study and learn about nuclear energy in the US--it is as if the very topic is radioactive and people in our country shun it, wanting it to go away because it frightens them. The topic isn't going to go away, though, and sometimes the best defense is education.

It's possible that my passion about this topic was set at an early age. I grew up in Idaho Falls, about forty miles from the AEC site where the SL-1 accident occurred. The site is now known as the Idaho National Lab, and is a Department of Energy (DOE) facility. Many of my friends parents worked at the site, but I didn't understand for a very long time what they were doing out there.

Part of the reason was that I was young and had other concerns, but there was also a great deal of secrecy involved. The facts about the SL-1 accident apparently became more widely known only in the 1980s and later when the Freedom of Information Act was invoked to get at information about it. 

Also, the Cold War was raging at the time of the accident, and much of the activity going on at the site in the Arco Desert involved not just the development of nuclear power generators, but also weapons development and other military operations. We now know, for example, that tons of radioactive waste from the development of atomic weapons at the Rocky Flats Plant in Colorado were buried throughout the 1950s and 60s in that desert just above the aquifer for the Snake River Plain.

This situation became a huge news story in southeastern Idaho in the 1990s when there were suggestions that the aquifer might be contaminated with radioactive decay components. For more than two decades, DOE has been cleaning up the aquifer, and trying to prevent any additional seepage of buried waste into the groundwaters. There has been a great deal of controversy about cover-ups, mismanagement by government contractors, and on and on. It is all an unfortunately familiar-sounding story.

So, perhaps my readers and followers on Twitter will forgive me if I become a little obsessed with the unfolding events in Japan. There is a lot to keep track of, and a lot to understand. Stay tuned for more.

Saturday, March 12, 2011

Scientific Disasters

Tsunami inundates city of Natori in Japan (Kyodo News/AP)
The catastrophic events occurring in Japan in the last two days show just how important good science reporting is to the public welfare. These events have (so far) included a magnitude 8.9 earthquake in Japan, dozens of aftershocks, an enormously destructive tsunami and, now, an ongoing emergency with several nuclear reactors damaged in the quake. 

All aspects of this event involve scientific topics and the public needs to understand both what has happened, what is likely to happen in the near future and long term, and what lessons (if any) we can draw from these tragic events in planning for the future.

I am not a journalist, and although I write about science I do so as a scientist, not a science journalist, so perhaps I have no place criticizing people who work in those fields. As a scientist, I have been so thoroughly trained in the values of the scientific enterprise that those values have become part of my ethical framework. When I see deviations from these ingrained values, I feel that a wrong has been committed.

To a scientist, truth is the highest ideal and all scientists strive to find out what the truth is, whether it be the exact mechanism that led to a particular earthquake or the precise sequence of events that have led to several overheated nuclear reactors in the earthquake zone. I realize that other people may not have these values, and may prefer to hear comforting statements if the truth is too hard to bear. I personally feel, though, that I would rather have the truth no matter how bad it is, and I will seek comfort in my own way.

Journalists say they seek the truth, too, but I wonder if some may have other sets of values, for example, seeking out (or even generating) controversy and drama. Despite the fact that I'm not a journalist, I have found myself with plenty of friends who are, and most freely admit that journalism, as a field, is driven by the idea that "controversy sells." Perhaps this explains the post yesterday by a young science writer entitled "Today's Tsunami: This is What Climate Change Looks Like."

After reading this piece, which claimed to show a link between climate change and earthquake-generated tsunamis, I immediately contacted a former colleague of mine at the National Science Foundation to ask his professional opinion, as a climate scientist, about whether climate change could be linked to more severe earthquakes or tsunamis. His response: "Absolute rubbish." 

He went on to explain that the more important issue linking tsunamis and climate change is the increasing numbers of people living along coastlines and the accompanying decrease in barrier marshes that are known to mitigate the impact of a tsunami. This important issue is not mentioned at all in the piece linked to above. It seems I wasn't the only one outraged by this article, and other journalists took the author to task, such as in this piece by Tom Yulsman.

A corrected article was posted this morning, so it seems as if the author might have gotten the message, but a careful reading shows he is apologizing only for the title, not the content of the article. And the "update" added today confuses the issue even further by seemingly equating tsunamis with storm surges that, as we know (or should know), accompany hurricanes. A hurricane is not an earthquake, and despite the fact that a storm surge might look like a tsunami, it doesn't take a scientist to know that these two phenomena are completely unrelated.

I have already seen the unfortunate effects of this type of uninformed writing, in comments on blogs, Facebook and Twitter from members of the public who seem to think that yesterday's horrific earthquake and tsunami could, somehow, be traced back to our lack of attention to global warming. Where did they get this idea? As a former science professor, I fully understand the confusion that members of the public have about scientific issues, but it is our duty as scientists--and science journalists--to help people keep all this complicated information straight.

I am no global warming skeptic and I fully agree that we need to pay attention, now, to the impact of our own activities on the planet, but publishing a provocatively-titled piece that seems designed more to draw attention than increase people's understanding, will set us back in those efforts. A few more people may read your article, but what will be the long-term consequences for the planet of spreading misinformation?

The catastrophe in Japan continues, and the need for good science reporting remains as we move to the next phase of this tragedy. Already there is a great deal of conflicting information out there about what is happening with several damaged nuclear reactors. The situation itself has drama aplenty, and there are ongoing controversies about nuclear energy that are guaranteed to muddy the waters of any facts that are released by the authorities. 

The public, both in Japan and around the world, is, understandably, on the verge of panic about this development, so solid reporting of well-researched facts is of utmost importance. I hope my colleagues in the science journalism community will rise to this challenge, so that we don't amplify the effects of an actual disaster by committing a scientific disaster.

Monday, March 7, 2011

Writing for the Red Cross

Today I am participating in a fund-raiser for the American Red Cross organized by my friend, Holly Tucker, aka @history_geek on Twitter.

Holly is the author of the recently published book Blood Work, a riveting tale of fire and plague, empire building and international distrust that accompanied the development of the "new" (in the 1600s) medical procedure of transfusing blood from one person, or animal, to another.

Holly also publishes the blog, Wonders and Marvels, in which she digs up and chronicles the most amazing (and sometimes disgusting!) stories from the history of medicine and all sorts of other strange places.

My post, "What the Red Cross Means to Me" is up this morning on the Write for Red website. In it I tell the story of how I failed miserably in my first attempt to "give" to the Red Cross.

The fundraiser involves a series of auctions of books and writing-related stuff and a new round of bidding just opened. There is some really good stuff among the donated items--check it out and put in your bid now!

Wednesday, March 2, 2011