Kyodo News has the report:

The Nuclear Safety Commission of Japan released a preliminary calculation Monday saying that the crippled Fukushima Daiichi nuclear plant had been releasing up to 10,000 terabecquerels of radioactive materials per hour at some point after a massive quake and tsunami hit northeastern Japan on March 11.

The disclosure prompted the government to consider raising the accident's severity level to 7, the worst on an international scale, from the current 5, government sources said. The level 7 on the International Nuclear Event Scale has only been applied to the 1986 Chernobyl catastrophe.

...

The commission says the release has since come down to under 1 terabecquerel per hour and said that it is still examining the total amount of radioactive materials released.

These are some of the first estimates of the scale of the radiation released by the damaged reactors—and the amounts are staggeringly large. Three Mile Island, by comparison, was a paltry incident.

I'll reiterate the obvious: It's unwise to travel anywhere near these reactors—about a sixty mile radius. One should avoid eating foods—particularly iodine-rich foods—grown in the areas contaminated. The amount of radioactive material reaching the United States is tiny; unless you are in the immediate vicinity of the plant, there is little to no risk.