Meanwhile - on the ground - teams of TEPCO workers began working in shifts to bring the melting down plant under control. These shifts were essentially suicide missions - as radiation levels were well above lifetime dosages. During that March - an estimated 900,000 terabecquerels of radiation were released into the air. That's roughly one-sixth of the radiation released during the Chernobyl nuclear crisis - but again - that was just during the month of March. Between then and December of 2011, when TEPCO finally said the plant was stable, more than 300 workers were exposed to lethally high levels of radiation - and millions of gallons of highly radioactive sea water were dumped into the ground and into the ocean.The effects of this radioactive dump are still not known.

In February of this year - TEPCO began pouring cement around the plant as part of the decommissioning process - a process that operators believe could take as long as 30 years. But despite assurances from TEPCO that the plant is stable - evidence shows the nuclear crisis is still far from resolved. The Unit 4 reactor building, with tons of radioactive fuel and waste still stored in its roof, is leaning - and in danger of toppling over and triggering a chain-reaction radioactive fire that could blow exponentially more radiation in the atmosphere than Chernobyl And radiation levels at reactor one recently reached all-time highs. Yet - Japan is moving forward with nuclear power. Just this month - a reactor at the Oi nuclear plant was turned on - marking the first time a Japanese nuclear reactor was operational since the March earthquake.

But the question is - have the lessons of Fukushima been learned? And not just in Japan - where the crisis continues and could yet worsen - but also in the United States? That's the topic for tonight's Bigger Picture discussion.... Joining Thom for Conversations with Great Minds are...Paul Gunter - the Director of Reactor Oversight Project at Beyond Nuclear - and 2008 recepient of the Jane Bagley Lehman Award for environmental activism - who's been on the front lines fighting back against nuclear power for more than thirty years now. And - Kevin Kamps - Radioactive Waste Watchdog at Beyond Nuclear - who's testified before the officials at the highest levels U.S. Federal Agencies dealing with radioactive Waste Management - including the Department of Energy, the Nuclear Regulatory Commission, and the EPA.