: for those who prefer pictures, xkcd has a very nice illustration
What with all the sirens going off around the Japanese reactors (who merely got jostled a tad by a 9.0 earthquake AND a tsunami), the meeja has been reaching new depths of science ignorance and frantically passing it on to anyone who will listen. I thought it might be time for them to review a few basic concepts. Yes, this will be on the test. The test called LIFE.
1) There is No Such Thing as Completely Safe
. I know, you want your binky and your teddy bear and a non-gender-specific parent to soothe you with promises that nothing bad can hurt you. The Universe can hurt you when it puts its mind to it, real bad, and there's not much you can do about it. The good news is these extreme events rarely happen. When they do, certain thumbsuckers ignore facts such as a) nobody has been killed by the reactor accident (yet), even though b) it is a very serious accident and c) the earthquake plus tsunami FAR exceeded the design parameters. Of a 40 year old reactor design. Under the circumstances, I'd say they did pretty well.
A) What Kind of Radiation?
This is all radiation.
Radiation is electromagnetic energy in the form of waves. (We're staying non-relativistic here.) I don't want to alarm the meeja (oh hell, yes I do!) but all humans who are alive emit radiation. Infrared, or heat. What the frothers probably mean when they wail about "radiation" is ionizing radiation (some UV, x-rays, and gamma rays) which is energetic enough to ionize (remove an electron), hence the name. The other kind of "radiation" is radioactive
material which emits particles
. Depending on what type, you can shield yourself with a piece of paper, lead foil, or massive amounts of concrete. Sorry, there is no known method to shield against cosmic rays (actually particles and highly energetic ones at that) (see #1 above). Radioactive material danger
is complex to assess and depends on things like particle type, energy of said particle, dose, time over which a dose is spread, exposed organs, and even some natural variation of the organism
. In short, I don't believe any meeja talking head is capable of correctly assessing the danger of a leak from a nuclear power plant. They have a hard time understanding what they are told by experts, or even transmitting it correctly. I would not believe any risk assessments that did not come directly from an individual trained in radioactive material safety. And I certainly would not credit radioactive risks hyped by someone who smokes
III) Nuclear Thingamajigs:
This was my favorite sign at Berkeley. "Nuclear-free zone". It made me giggle. I didn't have the heart to tell them that their organic free-range dolphin-safe grapes contained nuclei. So did the bottled water, the hemp socks, the air, and, well, everything. Every atom has a nucleus. The vast majority of the time, it just sits there and doesn't bother anyone. There are two ways for a nucleus to abandon its mild-mannered ways -- fusion, and fission. Fusion is the process which gets us that glowing ball in the sky known as the Sun. If you smoosh two atoms together to the point where their nuclei fuse, lots and lots of energy is released. I believe most hippies consider sunlight natural and good even though it involves nuclei. Go figure. And yes, even a fusion plant, should we build one, will generate radioactive waste (just not as much, and with a much shorter half-life). Yes, that means the Sun is radioactive. Don't tell the Gaia-worshipers.
Fission is the process where a nuclei is split, and lots and lots of energy is released. Most hippies are violently anti-fission, even though it involves nuclei. All reactor plants so far are fission (we're working on fusion Really Hard Now, and have been since I was a baby physicist). There are some very good explanations
of how fission reactors (and the particular design used in the Japanese plants) work. The big point the talking heads are missing is that fission
can be completely stopped, and yet natural radioactive decay
of the fuel can generate a metric shitload (official term) of heat. Heat that can start fires, build up explosive levels of radioactive steam, etc. Not good, and I would not recommend licking any of the fuel rods either, but nowhere near a mushroom cloud or the "glowing ball of molten plutonium heading for the center of the Earth" hysteria.