As Japan prepares to mark the anniversary of the deadly earthquake and tsunami that swept the northern Pacific coastline three years ago, some of the smallest children in Koriyama, a short drive from the crippled Fukushima nuclear plant, barely know what it’s like to play outside –- fear of radiation has kept them indoors for much of their short lives.

Though the strict safety limits for outdoor activity set after the meltdowns at the nuclear plant have now been eased, parental worries and ingrained habit mean many children still stay inside.

And the impact is now starting to show, with children experiencing falling strength, lack of co-ordination and emotional issues like shorter tempers, officials and educators say.

“There are children who are very fearful. They ask before they eat anything, ‘does this have radiation in it?’ and we have to tell them it’s OK to eat,” said Mitsuhiro Hiraguri, director of the Emporium Kindergarten in Koriyama, about 55 kilometres west of the Fukushima nuclear plant. “But some really, really want to play outside. They say they want to play in the sandbox and make mud pies. We have to tell them no, I’m sorry. Play in the sandbox inside instead.”

The 9.0-magnitude earthquake and tsunami that hit on March 11, 2011, killed 15,884 people and left 2636 people still unaccounted for. Huge waves swamped cooling systems of the Fukushima Dai-ichi nuclear plant, which went through reactor meltdowns and explosions that spewed radioactive materials to the vast farm region. The plant remains volatile and engineers say it will take four decades to dismantle the crippled reactors.

The nuclear accident was the world’s worst in 25 years, spewing radiation over a swathe of Fukushima, an agricultural area long known for its rice, beef and peaches.

A 30-kilometre radius around the plant was declared a no-go zone, forcing about 160,000 people from homes where some had lived for generations. Other areas, where the radiation was not so critically high, took steps such as replacing the earth in parks and school playgrounds, decontaminating public spaces like sidewalks, and limiting children’s outdoor play time.

In Koriyama, the city recommended shortly after the disaster that children up to two years old not spend more than 15 minutes outside each day. Those aged three to five should limit their outdoor time to 30 minutes or less.

These limits were lifted last October, but many kindergartens and nursery schools continue to adhere to the limits, in line with the wishes of worried parents. One mother at an indoor Koriyama playground was overheard telling her child: “Try to avoid touching the outside air”.

Though thyroid cancer in children was linked to the 1986 Chernobyl nuclear accident, the United Nations said last May that cancer rates were not expected to rise after Fukushima.

Meanwhile, very low levels of radiation from the nuclear disaster will likely reach ocean waters along the United States west coast next month, scientists say. Current models predict that the radiation will be at extremely low levels that won’t harm humans or the environment, said Ken Buesseler, a chemical oceanographer at the Woods Hole Oceanographic Institution, who is calling for more monitoring.

2014 Fairfax Media