NEW : Tokyo Electric plans a new structure to support the No . 4 unit 's spent nuclear fuel pool . Robots probe darkened reactor buildings for signs of radiation, and robots will be used in future years as part of an effort to remove contaminated water from the reactors. Radiation readings in one town are halfway to the government 's evacuation threshold . Tokyo Electric says it will take 6 to 9 months to wind down the nuclear crisis .
NEW : Tokyo Electric plans a new structure to support the No . 4 unit 's spent nuclear fuel pool . Robots probe darkened reactor No . 3 . Radiation readings in one town are halfway to the government 's evacuation threshold . Tokyo Electric says it will take 6 to 9 months to wind down the nuclear crisis .