on 17 april, remote control robots were used to enter the reactor building and performed a series of inspections. on 27 april, tepco revised its estimate of damaged fuel in unit 3 from 25% to 30%. radiation measurements of the water in the unit 3 spent fuel pool were reported at 140 kbq of radioactive caesium-134 per cubic centimeter, 150 kbq of caesium-137 per cubic centimeter, and 11 kbq per cubic centimeter of iodine-131 on 10 may.