Shortly after 3.30pm on the afternoon of March 11, 2011, Yukiteru Naka watched from the window of his new hilltop house in Tomioka, Japan, as a tsunami broke over the roofs of the Fukushima Daini nuclear power station a kilometre down the coast.

As a nuclear engineer, he knew just how serious this could be.

Last Saturday, he stood forlornly outside his empty dream home with his Geiger counter in his hand, admitting he has no idea when he will ever be allowed to return. Although his house survived the huge wave because of its altitude, it was badly contaminated by the subsequent nuclear accident at Daini's sister plant Fukushima Daiichi, 10 kilometres to the north.

Radiation levels in his garden are now about three microsieverts an hour, 37 times higher than in Tokyo 200 kilometres away.

Naka's home is in the Japanese government's designated restricted zone, which means he is allowed to return briefly during the daytime but not to stay overnight. Just across the road is the more contaminated "no return" zone where residents will not be allowed home.

He has been forced to relocate with his wife 130 kilometres away to the city of Koriyama. Naka has also had to move his nuclear engineering firm, which has been contracted to work in the Fukushima plants.

Near his house, the town of Tomioka is deserted, patrolled only by solitary ghost-like officials in masks and white radiation coveralls. The tsunami smashed the railway station, gutted shops and wrecked homes - all still unrepaired because they are contaminated.

Roads are barred by high fences, buildings taped off with warning signs while large red read-outs from solar-powered monitors constantly log the radiation levels. Visitors to the small stretch of the town's famed cherry tree avenue that is still open are warned to leave after 15 minutes because of radioactive hotspots.

All around, red plastic sticks mark the areas scheduled for decontamination and topsoil removal. Big black bags bulging with the radioactive earth that has already been dug up line the roadsides, with hundreds piling up at a huge shoreline construction site, awaiting a permanent storage solution.

Another Tomioka resident forced to leave by the nuclear accident is Tomuko Endo. She used to breed cows as a business but all six died of starvation after she was evacuated.

The stress has kept her husband in hospital for the last three years. She managed to save her cat which survived for 45 days on its own killing rats and birds - and has been decontaminated. Endo now lives in a one-room hut in a temporary government evacuation centre in Koriyama with 550 other households.

Koriyama is 55 kilometres from Fukushima Daiichi and outside the official evacuation zones. But even here, parents are still worried about allowing their children to play outside.

Tokiko Noguchi decided to leave the city after the accident, but returned because her daughter, now 15, missed her friends. But when she went to school, she had to wear protective clothing. The school banned outdoor play and kept the windows shut, even on hot sunny days. A large radiation monitor was installed in the playground.

Noguchi decided she had to do something. With the support of the environmental group Green Cross International, she set up the 3a family centre to give children a place to play inside. The centre also arranges medical check-ups for children and parents, lobbies central and local government, and tests food for radioactive contamination.

Yohei Suzuki, who helps at the centre, also returned so his children could be with their friends. "I decided with a friend to measure radioactivity and decontaminate it." He has set up a GPS-linked monitoring network across the city, and recorded levels up to twice as high as the government's monitors. That's because, he says, the ground around the official monitors has been cleaned.

Further away from the site of the nuclear accident in the city of Fukushima, authorities have built a huge indoor play centre, complete with sand pit, to help children avoid the radioactivity outside. "I was haunted by the contamination after the accident," says Miyuki Sano, who has a six-year-old daughter.

"I fear the contamination will never disappear. As a mother, I don't want my daughter to play outside."