In reply to Rick Fletcher.

Rick; thanks for your information & links via Twitter. I have concluded at this time that the risk of an explosion and a major radiation burst is quite small. My key questions, to which I'll try to find some answers are:

How severe are the radiation leaks at the reactor?
What is the half-life of this material?
How far does this radiation spread and what will affect its spread?
What will affect the increase/decrease of these leaks?

I'm also noting that anti-nuke organizations are taking advantage of these incidents to influence policy in other countries.