Associated Press – 2008-09-01 21:55:28

http://www.military.com/news/article/us-ends-probe-of-nuke-sub-in-japan.html?wh=wh

TOKYO (August 30, 2008) — Japan has received a final US report concluding that small amounts of radiation escaped from a faulty valve on an American nuclear-powered submarine during Japanese port visits but posed no health or environmental threat, the Foreign Ministry said.

The US Navy disclosed in early August that the USS Houston had leaked water containing radiation during several calls to Sasebo and Okinawa in southern Japan and Yokosuka near Tokyo between July 2006 and April 2008.

US Deputy Chief of Mission James P. Zumwalt submitted the report Friday, saying the Navy investigation concluded that the leakage in the three ports totaled 0.6 micro curies, or less than one-millionth of a curie, which posed no danger to Japan, the Foreign Ministry said in a statement obtained Saturday. The ministry provided a copy of the report.

“The trace levels of radioactivity would have no adverse effect on human health, marine life, or the environment,” the US report said. “The radiation exposure dose would be less than that received from a routine chest X-ray.”

The report said the US Navy was improving the valve’s quality before sending the submarine back into operation.

It said the Navy, after reviewing records dating back to 2004, concluded that “the valve had been steadily leaking” from June 2006 until the submarine entered dry dock in July, when the problem was discovered for the first time. About a gallon of water spilled onto a crew member on July 17 when a fitting came loose. The report also said no similar leakage had occurred in the past 50 years.

US officials were not available for comment Saturday.

The incident has caused a stir in Japan weeks ahead of the arrival of the nuclear-powered aircraft carrier USS George Washington, to be permanently based in Yokosuka, near Tokyo. The George Washington is to arrive in late September after a fire aboard the vessel in May delayed its departure – another incident that irked many Japanese.

The presence of nuclear submarines is particularly sensitive in Japan, the only country to have been attacked by US atomic bombs in the closing days of World War II.

The Navy has said the Houston also released tiny amounts of radiation in Guam, Pearl Harbor, and during port visits in Singapore, Port Kelang, Malaysia and Saipan.

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