WASHINGTON, March 14, 2011 — The U.S. 7th Fleet has temporarily repositioned its ships and aircraft away from Japan’s Fukushima Dai-Ichi Nuclear Power Plant after detecting low-level contamination in the air and on its aircraft operating in the area.
The source of this airborne radioactivity is a radioactive plume released from the power plant, officials said.
In a statement announcing the decision, officials emphasized that the maximum potential radiation dose received by anyone aboard a ship that passed through the area was less than the radiation exposure received from about a month of exposure to natural background radiation from sources such as rocks, soil and the sun.
The USS Ronald Reagan was operating about 100 miles northeast of the power plant at the time. Using sensitive instruments, precautionary measurements of three helicopter aircrews returning to the ship after conducting disaster relief missions near Sendai identified low levels of radioactivity on 17 air crew members.
The low-level radioactivity was easily removed from affected personnel by washing with soap and water, officials said, and no further contamination was detected afterward.
But as a precautionary measure, officials said, USS Ronald Reagan and other U.S. 7th Fleet ships conducting disaster response operations in the area have moved out of the downwind direction from the site to assess the situation and determine what appropriate mitigating actions are necessary.
“We remain committed to our mission of providing assistance to the people of Japan,” the 7th Fleet statement said.
U.S. Department of Defense
Office of the Assistant Secretary of Defense (Public Affairs)