James Hansen and Steven Chu

James Hansen is a NASA climate scientist. He is thought to be one of first scientists who warned the world against perils of global warming.
Steven Chu is the current secretary of US Department of Energy and a Nobel Physics prize laureate.
Both are prominent scientists who are fighting to reduce greenhouse gas emissions.
So I thought they were my friends.
However, their recent writings are testimonies of their pro-nuclear energy stance.
Take a look at

1) James Hansen's new book,
Hansen, J. (2009). Storms of My Grandchildren: The Truth about the Coming Climate Catastrophe and Our Last Chance to Save Humanity. New York, NY: Bloomsbury USA. (http://www.stormsofmygrandchildren.com/)

2) Steven Chu's WSJ article,
Chu, S. (2010, March 23). America's New Nuclear Option. Wall Street Journal. (http://bit.ly/9CBw67)

Do they, the smartest people in our time, know something which I, just one student who is struggling with his own dissertation topic, don't understand?
Or, are they missing some important issues in equity, justice, or ecology?