New Fire at Japan Nuclear Plant; How Much Radiation is Safe?

The latest from Japan featuring reports from CNN's Anderson Cooper, Dr. Sanjay Gupta and Elizabeth Cohen and interviews with Matthew Wald (The New York Times' nuclear expert), Senator David Vitter (R - Louisiana), James Acton (physicist with the Nuclear Policy Program of the Carnegie Endowment), John Ritch (Director of the World Nuclear Association and former U.S. ambassador to the International Atomic Energy Agency), Petra Nemcova (2004 Thailand tsunami survivor) and Nick Kristof (The New York Times). CNN's Arwa Damon reports from Libya on the tensions there.