Not quite three Chernobyls, hell, it's not even one.

Well if you consider the amount of exposed fuel the guess is quite close. There is about 270 tons of fuel in the reactors and at least as much more in the waste pools. It sounds like the biggest criticality event so far, just dragged out across longer time period.

"The Daiichi complex in Fukushima, Japan ... had a total of 1760 metric tons of fresh and used nuclear fuel on site last year, according to a presentation by its owners, the Tokyo Electric Power Company (Tepco). The most damaged Daiichi reactor, number 3, contains about 90 tons of fuel, and the storage pool above reactor 4, which the Nuclear Regulatory Commission's (NRC's) Gregory Jaczko reported yesterday had lost its cooling water, contains 135 tons of spent fuel. The amount of fuel lost in the core melt at Three Mile Island in 1979 was about 30 tons; the Chernobyl reactors had about 180 tons when the accident occurred in 1986."


http://news.sciencemag.org/scienceinsider/201...html?rss=1