EDIT: by who knows, I just mean I'm not aware of the scale, I could imagine it getting pretty bad. It's just that with all the sensationalism and non comprehension of basic statistics in some articles, I feel pretty misinformed on the subject.
The article says that 400 metric tons of contaminated water are being added every day. Let's say that leakage rate goes on for 5 years. That's about a million metric tons of contaminated water.
The volume of the Pacific Ocean is about 660 million cubic kilometers. One cubic kilometer of water weighs about a billion metric tons; so the a million metric tons of radioactive water is one 660 billionth of the volume of the Pacific Ocean.
Now let's talk about the fuel rods. An accident involving those could potentially have effects similar to Chernobyl in terms of spreading radiation; but since there are four reactors at risk at Fukushima, we would expect the global effects to be about four times the global effect of Chernobyl. While the global effects of Chernobyl were certainly measurable, they hardly amounted to "an apocalyptic disaster", or even one fourth of one.
Ton for ton, I can see your point of how it's only a drop in the ocean, but if that drop is highly radioactive and spreads in the currents, wouldn't that be enough to cause serious damage?
I'm not sure what you mean here. Radioactive water is just water with some radioactive atoms dissolved in it. The total number of radioactive atoms in the million tons of radioactive water is fixed; they don't multiply. (In fact the number gradually decreases as the radioactive atoms decay.)
if that drop is highly radioactive and spreads in the currents, wouldn't that be enough to cause serious damage?
It will get diluted as it spreads; that was my point. The waters off the coast where Fukushima is are certainly not safe to fish in right now; but that's because the radioactivity is concentrated in a much smaller volume of water.
By if you use that definition you yourself would be considered "radioactive" as you are always walking around carrying quite a few radioactive isotopes, including Carbon-14 (as made famous by "carbon dating" from geology) and Potassium-40.
As pdonis notes, radioactive contaminants dilute just as well as any other contaminant in water. Assuming it more-or-less evenly mixes within the Pacific Ocean, you could essentially dump all of Fukushima into that ocean and not see large changes in overall ocean radioactivity.
Fukushima stores a lot more fuel than Chernobyl did. It's not just four times Chernobyl.
http://www.zerohedge.com/article/amount-radioactive-fuel-fuk...
Also the Soviets reacted pretty fast in comparison to TEPCO and made sure, that a lot of the material did not escape, while TEPCO doesn't seem to be very competent in this regard...
It looks like the total right now is about 10 times Chernobyl, but if TEPCO keeps transferring more spent fuel to the storage pools, it could go up to 24 times Chernobyl (the total spent fuel inventory).
I would still argue that 24 times Chernobyl is nowhere near "apocalyptic" on a global scale. But you're right, it's good to work with the correct numbers.
the Soviets reacted pretty fast in comparison to TEPCO and made sure, that a lot of the material did not escape
Once they had a chance to react, yes. But a lot of the radioactive material inside the Chernobyl reactor was released with the combined hydrogen and graphite explosion which happened very early in the sequence of events, before anything could be contained. After that explosion, as I understand it, there wasn't a lot left to contain. The only way that release could have been prevented would have been if the Soviets had had the sense to build a secondary containment structure around the reactor, which they didn't.