The Japan situation is problematic but still in flux. I worked recently with a PhD student of mine to evaluate the 4 proposed governmental scenarios, which ranged from a phase out nuclear energy through to an expansion to about 50% of supply by 2035. The original paper is here:
http://www.sciencedirect.com/science...01421513000049
and the blog post covering the results here:
http://bravenewclimate.com/2013/02/0...ns-over-style/