"Japan disclosed Monday that its nuclear accident was more severe in its first days than it had previously admitted -- casting new light on how Tokyo's early handling of the disaster briefly sent its relations with the U.S. into one of the tensest periods in years.
Japan's Nuclear and Industrial Safety Agency on Monday more than doubled its estimate for the amount of radiation released from the plant in the first week of the March disaster and said holes may have formed around pipes attached to reactor containment vessels. It also said it believes that reactor cores at some of the units at the complex melted much faster than the plant operator previously suggested.
U.S. and Japanese officials say differences over the accident's severity nearly boiled over in the days after the March 11 earthquake and tsumami that disabled cooling systems at the Fukushima Daiichi nuclear. That, in turn, prompted a scramble to repair an alliance seen as critical to security in East Asia."
Chester Dawson, Mitsuru Obe and Peter Landers report for the Wall St. Journal June 7, 2011.
"Radiation Understated After Quake, Japan Says" (New York Times)
"Japan Says It Was Unprepared for Nuclear Disaster" (AP)