NEW : Commander : ` ` We are being very conservative in our recommendations '' The Navy is limiting outdoor activities and installing ventilation systems . Workers are scrambling to cool down fuel rods and prevent a full meltdown in three reactors at the earthquake-hit Fukushima Daiichi plant . The Navy says the radioactivity detected comes from the nearby Daiichi plant . Workers at the plant are scrambling to avoid a full meltdown .
NEW : Commander : ` ` We are being very conservative in our recommendations '' The Navy is limiting outdoor activities and installing ventilation systems . The Navy says the radioactivity detected comes from the nearby Daiichi plant . Workers at the plant are scrambling to avoid a full meltdown .