Friday, February 12, 2016

Review: Radiation: What It Is, What You Need to Know

Radiation: What It Is, What You Need to Know Radiation: What It Is, What You Need to Know by Robert Peter Gale
My rating: 3 of 5 stars

This book is reasonable at addressing commonplace radiophobia and addresses radiation from all sources, natural and man made, especially medical. A lesser amount of attention was given to accidental radiation releases from nuclear power, and given it was for primarily this reason I chose to read the book, I was slightly disappointed. In all though, I found it worthwhile.

I am one of those people who are of the opinion that if we wish to maintain and enhance our standard of living for the future, especially if we ultimately decide that fossil-fuel carbon dioxide inputs need to be eliminated as much as possible, then only nuclear power will be able to maintain us in the energy-available standard to which we've become accustomed. More energy makes life more productive and more enjoyable and more long-lasting for all. We should be efficient about our use, certainly, but energy abundance give us comfort and choice. We would not have this under a purely renewable-source energy economy. So, does it make sense to exclude nuclear power on safety grounds, from the outset? That's a question I was hoping the book would help me answer.

In the book, nuclear power disasters were discussed, just not in the clearest way, and the information given was fragmented across the chapters. I hoped for an answer to the question of whether it's actually necessary to cordon off large territorial exclusion zones in response to such catastrophes, in the interests of protecting human health. I was left to gather the fragments presented in the book, and make a judgement about this myself, which ended up like this:

In such disasters there three isotopes which convey just about all the radioactivity exposure risk to people in the general vicinity of the release: I-131, Cs-137, and Sr-90.

I-131 is risky, but mostly to children, and only for a short time (about three months overall), and only if foodstuffs produced within the affected area aren't temporarily replaced with outside supplies during the danger period. In Japan, food was handled expertly and most Japanese have iodine rich diets which tend to make them far less at-risk to start with.

Cs-137 is pretty ubiquitous, and has a very long half-life, making it especially concerning to the public. But this long half-life also means that the activity of the element is very low, reducing risk. Its biological half-life is also quite short, happily, further greatly reducing risks to human health. Any amount of it you do manage to ingest is likely to be excreted again before hardly any of it at all will have a chance to deposit radioactive energy in your tissue. So the great concern over this, perhaps second most prevalent element released in an accident, is probably misplaced.

Sr-90 has a half-life similar to Cs-137, but has a complex biological half-life. To our bodies, it resembles calcium, and so some proportion may end up migrating into bones and teeth, where it will probably stay long enough to release a good portion of its radioactive energy.

This is pretty much all the book has to say on those matters: two-to-one in favor of the idea that our reaction to the risks from a catastrophic nuclear accident is hysterical. The Sr-90 question deserves more attention. How much of this is present around an accident zone? What's the risk?

Since this is supposed to be a book review, I won't detail them here, but I've encountered various materials that offer me some pretty great hope for Cs-137 in particular, that this is just not enough of a risk to human health to warrant massive exclusion zones with their life-altering permanent evacuations and costly and elaborate washing and soil-stripping operations. According to this work, people could return to their homes and lives in the zone like that around Fukushima right now, if they wanted to, and not be at significant added risk for future radiogenic health problems.

For Sr-90, while a significant product of fission, it's non-volatile nature makes it much less likely than the others to escape to the environment in significant amounts during a disaster. This may be the best reason to allay concerns with it. Sr-90 was more of a risk during the era of atmospheric atomic weapons testing, and for the Japanese atomic bomb survivors, from the fallout nuclear weapons produce. This main source of Sr-90 exposure has long been now, happily, over.

I-131 seems to be the single biggest risk in a reactor disaster, and with its short half-life, within a few months of a point immediately following a meltdown with containment loss, it is simply no longer a factor, it has all decayed away. In the early phase, people should do their best to avoid exposure if they can, but for most it will be enough simply to eat clean food from outside the affected area, and follow limited evacuation for those most at risk (e.g. families with young children).

For people like the Japanese, who have ready access to clean replacement foodstuffs, and a diet rich in natural iodine, little special action is needed. Most are best served by eating outside food and waiting things out.

For others, like those near Chernobyl in 1986, short-term evacuation with supplemental iodine administration, particularly to the young, would've produced similarly low levels of risk. The impoverished condition of most of the population, and lack of a robust food system were main drivers increasing their risks.

However, in both cases once the I-131 has decayed off there's no longer much risk. People could move back into the zone and resume life as before. To allay fear, those who want them could obtain dosimeters to understand and place into perspective the actual radioactivity they are receiving. Most people would probably see amounts very close to the original background radiation anyway. A few may see more, and this can be either rationalized in terms of measuring it against statistics (an education requirement attaches to do this effectively). Or, anyone who feels uncomfortable by the amount they see, no matter how small, can be allowed to take charge of their lives as before and choose to move away. In this way, people are empowered to freely identify and manage their risks as they choose, just as in other parts of their lives.

The important takeaways here are (1) people are overly fearful of radiation, despite living lives continuously within its effects, and in some cases depending on it /for/ health, (2) understanding the real risks from radiation may allow us to overcome these fears and make more intelligent choices regarding how we obtain the energy we need to enjoy the lives we desire.

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