More than three years after Japan’s Fukushima nuclear disaster more than 120,000 people from the region are living in nuclear limbo with once close-knit families forced to live apart.

Japan’s nuclear watchdog on Wednesday gave the green light for two nuclear reactors at Kyushu Electric Power’s Sendai plant in south-west Japan to restart, but communities are anxious over the safety aspects. The nuclear industry in Japan has been mothballed since the meltdown.

At a temporary housing complex in Fukushima prefecture one resident, Iiko Kanno, said she now spends her days reading, growing vegetables and counting the days until she is reunited with her grandchildren. As with many of her neighbours, Kanno’s family has been torn apart by the nuclear meltdown, which happened in March 2011.

“It wasn’t until about a month after the nuclear disaster that we got the order to evacuate,” Kanno said of her contaminated former home, Iitate, a picturesque, but now abandoned, village 24 miles north-west of the Fukushima Daiichi nuclear power plant. “Our family’s vegetable farm was worthless, and we were told it was no longer safe to stay in Iitate.”

Most of Iitate’s 6,000 residents stayed in the village after the disaster, convinced they were safe since their homes were outside the 12-mile (20km) evacuation zone imposed by the government.

The local authorities did not order an evacuation until several weeks later, after a radiation expert discovered multiple radioactive hotspots at levels higher than those considered safe for human habitation.

About 150 residents ended up in the temporary complex on the outskirts of Fukushima city, living in cramped wooden lodges surrounded by cherry, peach and apple trees.

Three and a half years after the disaster, Iitate remains uninhabited, apart from decontamination workers and residents desperate to save their irradiated farms.

In spending her twilight years in imposed isolation, and with little prospect of returning to her hometown, Kanno, 78, is far from alone among the estimated 120,000 people from the Fukushima area who continue to live in nuclear limbo.

A survey conducted this year by the prefectural government found that almost half of the households forced to evacuate were living apart, while almost 70% had relatives suffering from physical and mental health problems.

Of the total, 48.9% of households said family members were living in two or more locations. Of that number, 58.6% said relatives who had once lived together had been scattered across three or more sites.

In the same survey, 67.5% of households said they had relatives who were showing signs of physical or psychological distress. More than half of those afflicted said they had lost interest in activities they once enjoyed or that they had trouble sleeping.

Kanno’s plight is typical of many Fukushima families who lived together in large rural homes before the disaster.

Her husband and mother died in the 12 months before north-east Japan was struck by the magnitude 9.0 earthquake, which triggered a tsunami that killed almost 19,000 people and caused the world’s worst nuclear accident since Chernobyl. Her 43-year-old son, Futoshi, moved to Saitama, near Tokyo, with his wife and their young son.

“In Iitate it was normal for three generations of the same family to live under one roof,” she said. “My son initially found work in Fukushima city, but he and his wife didn’t want to bring up their children in an area with high radiation. They won’t bring him here to see me, so I only get to see them at the new year and on other special occasions.”

Her daughter and three other grandchildren, who lived in a nearby town in Fukushima, are now some distance away, in Niigata prefecture. Her daughter’s husband, a teacher, still works in Fukushima and commutes to his family’s new home every weekend.

For people of Kanno’s generation, the prospect of playing next to no part in her grandchildren’s upbringing is almost unimaginable. “If we had been able to stay in Iitate we would all be living together now,” she says. “I was practically brought up by my grandparents, and my parents helped raise my children. But radiation has made that impossible now.”

Kanno was depressed for months after the accident, and is still unable to sleep without medication. “If I don’t take it, I lie awake gazing at my grandson’s photo, wondering how much I’ll get to see of him before he’s an adult.”

Iitate’s mayor, Norio Kanno, has vowed that decontamination work will make the village inhabitable again, possibly by 2016. But residents say the problem of cleaning the village’s mountainous terrain, which sends radioactive particles into residential areas below after rainfall, makes that unlikely.

So far only a few hundred people from two districts on the eastern edge of the evacuation zone have been given permission to return permanently.

“It could be years before we can return, so families had to make a tough choice,” says Hanako Hasegawa, an Iitate resident who helps at a drop-in centre for evacuees.

Her husband makes brief returns to clean the home they once shared with their children and grandchildren, while other residents have seen their abandoned homes become overrun with mould and vermin.

“People who go back return saying it’s a sad place to be now,” says Hasegawa. “Yet they still go back to weed the garden and tidy homes they will probably never live in.”

The once close-knit residents are now part of Japan’s nuclear diaspora. Most stay in parts of Fukushima prefecture not affected by the evacuation order; the remainder are scattered among all but two of Japan’s 46 other prefectures, according to village records. Four have made new lives overseas. Hasegawa, whose family ran a dairy farm, are dispersed across four locations.

Typically, fathers leave in search of work and children move out of Fukushima with their mothers, while grandparents stay put, reluctant to venture far from their hometowns near the end of their lives. The average age of the residents of this temporary housing complex is 66; of those in their 70s and 80s, about 20 are living alone.

“If my son didn’t bring my granddaughter here, I would never get to see her,” Hasegawa says. “There are lots of older people here in the same situation. Younger members of the family come for special occasions, like festivals and sports days, then leave straight after.”

Kanno and her neighbours keep fit with morning calisthenics, and try to maintain community ties fractured by the events at Fukushima Daiichi, a two-hour drive away, with tea afternoons, craft workshops and coach trips.

“The nuclear accident turned everything upside down,” she said. “Even if the evacuation order is lifted, no young people or children will go back. We have asked everyone – the village office, decontamination workers, environment ministry bureaucrats – when it will be safe to return. But no one can give us an answer.”