The Fukushima Aiikuen orphanage sits on 7 hectares of wooded hills — that's about the area of 15 or 16 soccer pitches — on the outskirts of the city of Fukushima. There's an outdoor sports field, a campsite and plenty of lawns for the 91 children living there to play on. In the two years since the start of the ongoing Fukushima nuclear disaster, however, they've gone mostly unused.

That's because orphanage director Hisao Saito, 60, has cut outdoor playtime from five to two hours per day for elementary-age children at the facility; for the preschoolers, he has nearly eliminated it.

He says he wants to lower their exposure to radiation, but he worries about the side effects.