The plant "may be experiencing nuclear meltdown", Kyodo and Jiji reported before the explosion, while public broadcaster NHK quoted the safety agency as saying metal tubes that contain uranium fuel may have melted.(AFP)
See http://www.geigercounters.com/Danger.htm for example. Occupational acceptable exposure is 25x that of non-occupational.
Exposure to 1.015 mSv / hour for a year would give a dose equivalent of 8.9 Sv - the excess relative risk of cancer for low dose chronic radiation exposure is about 0.97 per Sv - so the exposure to that level for a year would drastically increase cancer risk.
Obviously, people won't be allowed into the areas where radiation levels were that high.
I saw a report of a worker acutely exposed to >100 mSv; that single event would be enough to increase that worker's lifetime risk of cancer by about 10%.
http://www.tepco.co.jp/en/press/corp-com/release/11031219-e....
So when they say around the reactor the dose in an hour is about the same as you get a year, then this is about equivalent to two scans in a hospital.
Note: this is talking about low levels where the only influence radiation has is increasing the chance of cancer. If there are very high doses >100mSv involved, there will be direct radiological damage which can be strongly compared to damage from burning.
http://www.guardian.co.uk/world/blog/2011/mar/12/japan-tsuna...