Armed with a small plastic Geiger counter, a teenage girl in a neat, dark uniform and trainers carefully takes a radiation reading among the familiar apparatus of a modern science classroom.

Three years after the Fukushima nuclear meltdown ravaged the Tohoku region in the north of Japan, it continues to bring science to life in horrifying ways at schools throughout the region. Pupils around the world are taught what Geiger counters are for but few will have used one to measure potentially hazardous levels of radiation in their lessons.

Today, on the third anniversary of the 2011 disaster, the instrument records 0.046 microsieverts at Fukushima First Junior High in Fukushima city, about 40 miles from the stricken power plant. That is an average radiation recording here and far below the official safe annual limit of up to one millisievert, or 1,000 microsieverts, as recommended by the International Commission on Radiological Protection.

The 15-year-old matter of factly states that she has previously taken “very high” radiation readings at school. But just how dangerous the nuclear fallout was, and still is, remains hotly disputed by government officials and experts.

The ongoing fear and confusion has turned radiation into a new taboo. Few parents or teachers can answer children’s questions about whether they are safe or not and how to protect themselves and their loved ones. Owing to the stigma surrounding the issues, the teenager’s parents have asked her to talk to TES anonymously, although later today she speaks publicly at a school memorial service marking the event that forced her family to flee from their home in the city of Minamisoma, 16 miles from the nuclear plant.

“I didn’t even know the word radiation before this happened,” she says. “I knew there was a nuclear plant near my house but I didn’t know what would happen if there was a meltdown.”

Knowledge is power

The girl sits on a pale green chair in the school’s counselling room, where pupils normally come for help with issues such as bullying. Thanks to Save the Children Japan (SCJ), pupils at schools like this have been able to discuss radiation in new education workshops.

Most 15-year-olds here were at their elementary school graduation ceremonies on 11 March 2011 when the massive earthquake hit, causing buildings to shake violently and sending desks crashing to floor. A boy (whose parents also don’t want him to be named) smiles but says: “I thought it was the end of the world. I was really scared for my life. I thought I would have to leave Fukushima.

“I knew nothing about radiation before the disaster. Now I know it is difficult to protect against and is harmful to the body. I know mushrooms get more contaminated than other foods too. I like mushrooms,” he says, clearly disappointed that he needs to eat fewer of them to reduce his chances of suffering from cancer and other health problems.

In the corridor outside, the student joins his friends in looking at a photographic timeline of harrowing images charting the disaster.

Going home to a ghost town

In the coastal city of Iwaki, about 25 miles south of the power plant, a 17-year-old pupil flicks through pictures taken on her mobile. They show her and her relatives in protective suits making a heartbreaking visit to their abandoned home in Okuma, the town where the stricken nuclear plant is located.

She says: “Our house is a mess. I would like to go home but it is in one of the most highly contaminated parts of Okuma so I don’t know if that will ever be possible.”

Showing a photograph of her old school, she adds: “It looks like it is stuck in a moment of time. Nothing has moved since that day. Everything was left after the graduation ceremony.”

The student says she also found the SCJ cooking demonstration useful, learning which foods are more prone to contamination so she can help protect herself by choosing ingredients with a lower level of risk. SCJ launched the workshops to help children deal with the consequences of the disaster after it became clear that mandatory lessons - just two hours per year - did not give pupils enough of an opportunity to ask questions and voice concerns.

Initial government teaching guidelines stuck mainly to pure science with only brief reference to the meltdown. These have now been revised in the wake of criticism to include more detail of the disaster and its consequences. SCJ programme manager Kazuyo Igarashi says: “It’s very difficult for teachers to deal with this issue. Two hours a year is nothing. Radiation has been reducing and many people here are now leading normal lives again but many children are still thinking about what happened and are anxious about their future.”

The workshops are led by Akifumi Ueda, a biology graduate who works with the non-governmental organisation Citizen Science Initiative Japan to promote sustainable development of science and technology.

“Some students are very worried about cancer,” he says. “In the workshops we help them to understand that we can’t tell who will get cancer and who won’t, but that they can help to control the impact radiation has on their health through the way they live their lives, making an effort to minimise the radiation by actively selecting foods.”

Students are also warned to avoid highly contaminated hot spots, such as mountainous areas where trees absorb more radiation. But some experts warn that the stress people feel is a greater threat to their health than the radiation itself.

“In the workshops we give pupils information,” Ueda adds. “For example, about how different experts believe different health problems relate to different levels or types of radiation. When advice is contradictory pupils have to go back to the source. It’s important that they learn to judge for themselves what information is reliable and to make up their own minds.”

Learning lessons from Chernobyl

Even when the earthquake and tsunami killed thousands in 2011, Yasuhide Kanno feared the worst was yet to come.

The science teacher was at university in 1986 when an explosion at Chernobyl caused the world’s worst nuclear accident to date, inspiring him to research the risks. Nearly three decades on, terrified that the natural disaster would trigger an equally catastrophic meltdown at the nearby nuclear power plant, he began monitoring radiation levels at Fukushima First Junior High.

“I was really scared even before it happened. On the day of the meltdown I was riding my motorbike home from school with a Geiger counter in my pocket. At home I took a reading of five microsieverts inside, which is very high. I washed all my clothes and my hair and called my colleagues to tell them it was dangerous.”

On the third anniversary of the tragedy, he rubs his eyes before laughing briefly as he describes the challenges of teaching pupils about radiation.

“There are too many. There is no standard for this in the curriculum so I had to start from scratch. To what extent radiation is safe or not, nobody knows. I can’t tell pupils that it’s not safe, or that it is safe. I can only teach the facts of what radiation is.”

Implementation of the mandatory two hours of lessons on radiation each year remains patchy, he says. Schools in Fukushima are leading the way, but contradictory reports on risks make it a complex task.

Mr Kanno, 47, is one of several teachers who signed up for a new workshop launched late in 2013 by Save the Children Japan.

He admits: “I was searching for a radiation expert because I was feeling the limitations of my own knowledge and wanted to collaborate with someone to accelerate pupils’ understanding.

“The workshop really helped children to express their emotions and anxieties about the disaster and to focus on concerns like health.”

It also helped to win over the children’s families. “Before the workshops, parents complained about radiation lessons - they were concerned that we would upset pupils by reminding them about the terrible experience,” he explains.

“Complaints have reduced following the workshop. I think everyone feels less uneasy.”

In 2012 Mr Kanno joined a delegation of Japanese professionals to Belarus to learn lessons from Chernobyl.

He says: “They are still teaching pupils, from kindergarten to high school, about radiation 27 years on. “Radiation education is a long-term issue which future generations will need to know about.”