I feel for all of the people who are in need of help in Japan and other areas. After looking at this catastrophe, it makes me wonder if nuclear power is really a viable option for the energy crisis.

SOMA, Japan -- Dangerous levels of radiation leaking from a crippled nuclear plant forced Japan to order 140,000 people to seal themselves indoors Tuesday after an explosion and a fire dramatically escalated the crisis spawned by a deadly tsunami.

France's nuclear watchdog is now warning the situation at Fukushima's No. 1 nuclear plant now rates at six on a seven-point scale of gravity, according to AFP.

"Right now it's worse than Three Mile Island," professor emeritus of nuclear engineering at University of California at Berkeley Donald Olander said. But it's nowhere near the levels released during Chernobyl.

The 1986 Chernobyl incident in the Ukraine was a level seven, while the 1979 accident at the Three Mile Island nuclear plant was a level five.

On Three Mile Island, the radiation leak was held inside the containment shell -- thick concrete armor around the reactor. The Chernobyl reactor had no shell and was also operational when the disaster struck. The Japanese reactors automatically shut down when the quake hit and are encased in containment shells.