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Fukishima Springs Water Leak
sl4shd0rk writes "The Japanese Fukishima crisis took a turn for the worse this week as it was found a barrier built to contain contaminated water has been breached; a leak defined by 20 trillion to 40 trillion becquerels of radioactive tritium. This is yet another problem on top of a spate of errors plaguing the 2011 nuclear disaster site. Nuclear regulatory official Shinji Kinjo has cited Tokyo Electric Power Company as having a 'weak sense of crisis' as well as hinted at previous bunglings by TEPCO as the reason one cannot 'just leave it up to Tepco alone.' If Nuclear energy is ever to move forward, these types of disasters need to be eliminated."
...actually means nothing to most readers not in the field. So, some comparisons:
Radioactivity from potassium in an average human body: 4000 Bq.
Radioactivity from potassium in entire human population of Earth: ~30 trillion Bq.
Radioactivity from one kilogram of radium: 37 trillion Bq.
Radioactivity released during Three Mile Island event: 481 thousand trillion Bq.
Radioactivity released during Chernobyl event: 5.2 million trillion Bq.
I'm thinking not to panic just yet.
Actually, this is a relatively small amount of radiation, a Curie is 3.7 * 10^10 becquerels, or roughly 40 billion becquerels, roughly 1/1000 of this leak. If this were a point source, and you were 1 meter away, your dose would be 1000 rem per hour, which would reach a 50% probability of being lethal (300 rem) in roughly 20 minutes. Since it is a disseminated source, and there's no one anywhere close to that near it, I'd say this is pretty much overblown hype. I used to work in the radiation measurement industry, and the preceding is pretty much quick and dirty shortcuts (ignoring quality factors and the conversion to rads, for instance,) but it's close enough for government work.
One becquerel is defined as the decay of one atom of a radioisotope per second. So it's a rate. 40 trillion becquerel would be 40 trillion (4*10^13) tritium atoms decaying per second. Tritiated water (T2O) has a molar mass of 22.0315 grams per mole. A mole is 6.022*10^23 molecules. So 6.022*10^23 molecules of T2O has a mass of 22.0315 grams, therefore 40 trillion molecules has a mass of (4*10^13)*22.0315/(6.022*10^23) or 1.46*10^-9 grams. Assuming a density of 1 gram/ml and 1/20th of a ml per drop, we're talking super-heavy water gushing out of this leak at the incredible rate of just under a drop per year.
When our name is on the back of your car, we're behind you all the way!
Everything can be made 100% safe in theory
Theories are nice, but reality is a bit more problematic.
While nuclear risks can be mitigated somewhat as can risks from other sources of power, the problem is what happens when they do fail. Every single other source of power is able to be cleaned up while walking the site in a matter of days. Nuclear makes quite a large area uninhabitable for decades.
People in cars cause accidents....accidents in cars cause people
But we have figured out what to do with it. Bury it in Yucatan. However, once again, government and society have gotten in the way.
When our name is on the back of your car, we're behind you all the way!
Plus, even in the explanation page, it seems that the becquerel is usually expressed with per-volume or per-weight measure.
For radiation release events like this, it's simply the overall amount released for the whole event. You don't need per volume or weight.
The per volume amount will eventually depend on how much the contamination gets diluted, but that's location dependent and probably unknown right now.
It sounds to me someone used this unit with the express intent of making it sound big and scary, and that's disingenuous even if accurate.
More likely, they used it because it's a standard SI unit, unlike the curie. Using curies would be more like quoting distances in furlongs because you think that meters sound "too scary" due to the bigger numbers.
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The anti nukes seem to love bigging up the true technical measures by splitting them into smaller units (i.e. turning 1Sv into 1000 mSv). Exaggeration without actually exaggerating anything. It's rather clever actually.
You're reaching a little here; you have a point with the trillion Bq thing but doses are usually quoted in mSv, because it's a convenient size. 1mSv is the recommend maximum annual dose for members of the public, for example. I don't see quoting doses in mSv as any more unusual than an engineer giving a length as 1200mm.