Let's do the math, shall we?:

"Some experts go further, suggesting that Japan may have a design on the shelf.

"I'd be surprised if they didn't," said Frank Barnaby, a British nuclear physicist and nonproliferation advocate who's studied Japan's nuclear energy industry. "They have stocks of plutonium. They have the know-how. All that is lacking is the political decision."

Japan is third, after the United States and France, in nuclear power output. Its 54 reactors produce as much as 35 percent of the electricity consumed here, and its 43 tons in plutonium stockpiles are among the largest in the world. A nuclear bomb can be built with 17 or 18 pounds of plutonium."

[ 43 tons X 2000lbs/ton / 18lbs/bomb = 4778. But I'm sure you figured that out already. -ed. ]