Would a New Nuclear Plant Fare Better than Fukushima? 

Workers in protective gear conduct a cooling operation by spraying water at the damaged No. 4 unit of the Fukushima Daiichi nuclear complex in Japan on March 22. Newer nuclear plant designs rely on integrated "passive safety" systems for cooling in the event of power loss, but they are not yet deployed.

Photograph courtesy Tokyo Electric Power Company via Kyodo/AP