The most easily understandable and comprehensive information source I have seen on risks associated with different levels of radioactivity comes from a comic strip. Using different colors to represent different orders of scale, xkcd's creator, Randall Munroe, was able to represent information in a clearer manner than I have yet to see from a reputable scientific organization.
When I type "Fukushima radiation" into Google, I get a mish-mash of confusing, unhelpful, outdated or sensationalist articles from a random mix of sources, none looking very trustworthy or comforting. Trying to think of a credible source, I visited the website of the National Academy of Sciences; the front-page greeted me with a technical report on Terrorism Spent Nuclear Storage from 2006, and even less helpfully, a study from 2004 recommending everyone living near nuclear power plants should stock up on potassium iodide pills -- exactly what Americans should not do at the moment given that these pills are actually needed in Japan. The Centers for Disease Control and Prevention website was barely better. There was very good information on radiation but it was not updated to reflect current issues. Reputable news organizations were somewhat more helpful in terms of analyses of the crisis, but were unhelpful to misleading when it came to understanding the actual risks.
This represents a societal epistemological bankruptcy. Epistemology refers to the process by which we know what we know; and currently most of the ways we know about energy issues, about nuclear power, about fossil fuels and about the climate crisis are in a deeper crisis than the reactors in Fukushima. A confluence of developments has meant that a sane conversation on energy issues appears difficult to impossible for our society to manage. Lack of reasonable discussion leads to avoidance of the topic by politicians and the general public, which then means that powerful interests make these decisions almost by fiat -- and this often translates into "carry on as before."
Behavioral research increasingly confirms what one might suspect: when confronted with a long-term catastrophic problem which requires short-term unpleasant consequences, many people will try to avoid making a decision altogether even if it makes the problem worse over the long run. Complexity of information and choices, too, creates avoidance behavior. Avoidance, however comforting, only makes matters worse.
The Cost of "Carry-on As Before"
To take a concrete example of the dangers of avoiding real discussions about existing problems, let's look at the root cause of the current crisis in Fukushima: loss of water in the spent fuel rod pools. Needing to keep these rods in constantly cycling water is one of the least safe ways to handle spent fuel. There are newer, safer designs, but that would require rebuilding old plants or building new ones, something the public does not want to countenance. Thus, we continue to operate the least-safe designs we have.
Further, spent-fuel rod pools in Fukushima were located on the upper floors of the plant, above the reactor. Let's step back and think for a moment. Imagine you have some goldfish in a jar. Where do you place the jar? Not high up, unless your fish have mortally offended you (made funny faces at you?). You'd keep your jar of fish somewhere level, low, and hopefully away from other obvious sources of danger, like, say, nuclear reactors.
So, why, then, is spent fuel stored in a pool in an upper floor? Because it's a patch, not a solution. Spent fuel was not supposed to be kept in the nuclear power plants for years, as is now routinely done everywhere in the world. Remember the debate about the Yucca Mountain nuclear waste repository where spent fuel is supposed to be permanently stored? Years of political wrangling have led to inaction on that front. I make this point not to argue whether the Yucca repository was the best option; however, lack of action or active exploration of alternatives means that we have 33 states which have at least one site where nuclear waste is stored in the plant, often right next to the reactors.