"Japan Concedes Severity of Blast"

"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.

SEE ALSO:

"Radiation Understated After Quake, Japan Says" (New York Times)

"Japan Says It Was Unprepared for Nuclear Disaster" (AP)

"Japan Makes New Nuclear Safety Vows After Quake Disaster" (Reuters)

"Japan To Restart Nuclear Reactors After Inspections" (Monsters & Critics)

"UN Nuclear Agency Chief: Missions To Japan To Continue; Information at Start Not Enough" (AP)

"Japan Doubles Fukushima Radiation Leak Estimate" (BBC News)

"Japan Says It Was Unprepared for Nuclear Disaster" (CBS News)

"Japan to Make Nuclear Regulator More Independent" (Wall St. Journal)

"World Officials To Discuss Nuclear Power After Japan Quake" (BBC News)

"Japan Nuclear Plant Moves Radioactive Water" (Bloomberg)

"America's Nuclear Spent-Fuel Time Bombs " (Huffington Post)