Toshihide Tsuda, professor of environmental epidemiology at Okayama University, found that the rate of children suffering from thyroid cancer in Fukushima Prefecture in Japan was as much as 20 to 50 times higher than the national average as of 2014, three years after the Fukushima nuclear disaster.

His findings were published in the electronic edition of the journal of the International Society for Environmental Epidemiology late last year, but was refuted by the Fukushima prefectural government and other experts as it doubted the cases are related to the nuclear crisis and the government attributed to the surge to "over diagnosis."

"Unless radiation exposure data are checked, any specific relationship between a cancer incidence and radiation cannot be identified," Shiochiro Tsugane, director of the Research Center for Cancer Prevention and Screening, was quoted by a local report as saying.

More than 160 teenagers in Fukushima Prefecture were diagnosed with thyroid cancer, including suspect cases, since the Fukushima Daiichi nuclear power plant was crippled by the monstrous quake-triggered tsunami in March 2011. And the number almost certainly increase with the passage of time.

At the fifth anniversary of the Fukushima nuclear crisis, the parents of the children who were diagnosed with thyroid cancer in Fukushima formed a mutual help group to demand the government provide convincing evidence that their children's sufferings were not related to the nuclear crisis.

In fact, the International Society for Environmental Epidemiology sent a message to the Japanese government suggesting it to conduct detailed and continuous research on residents' health in Fukushima, but the government here did not respond to the advice, according to Tsuda who urged the government to face up to the aftermath of the nuclear issue.

Meanwhile, overseas nuclear experts are also surprised by the irresponsible and indifferent attitude of the Japanese government toward the nuclear refugees.

Oleksiy Pasyuk, an expert on energy policy at the National Ecological Center of Ukraine, told Xinhua that one of the main mistakes made by Japan in the aftermath of the accident was that the government had not stocked enough medicinal iodine tablets, which can prevent the absorption of radioactive material into the human body.

"No iodine tablets were distributed to residents living in the plant's vicinity, who may have been exposed to radiation -- it was an essential lesson, which they had to learn from Chernobyl," Pasyuk said last month at the 30th anniversary of the Chernobyl nuclear disaster.

The Fukushima disaster is the worst nuclear crisis since the Chernobyl catastrophe in 1986, but the Japanese government has failed to learn the lessons from the Chernobyl over the past 25 years.

The management of the Fukushima plant had been warned in advance about the risks of failure of the emergency electricity generators and the subsequent failure of the cooling systems in a seismically active region, said Olga Kosharna.

The expert with the State Nuclear Regulatory Inspectorate of Ukraine said that "if they had re-ionizers of hydrogen or holes in the roof, there would be no explosion and no such severe radiation effects. There has been a human error."

"Japanese mentality is hierarchical -- all are awaiting instructions from the top chief to start acting and it is time-consuming. Besides, there was no independent nuclear agency, which examines the technical state of the plant and decides whether to stop the functioning of the reactors or suspend its operating license," Kosharna told Xinhua.

More than five years on, the debate over the aftermath of the world's worst nuclear disaster in three decades are continuing, but Prime Minister Shinzo Abe told the international community in 2013 when Japan bid for the 2020 Olympic Games that the crisis was "totally under control."

The fact is obvious that about 200 tons of highly-contaminated water flows freely into the Pacific Ocean everyday and the nuclear power plant operator Tokyo Electric Power Company (TEPCO) still can not prevent the contaminated water from leaking from its makeshift containers.

TEPCO in March launched its ambitious project of freezing soil to create an ice wall to decrease toxic water leaking into the ocean. Local reports said that the project is expected to reduce the water to about 50 tons, but added that the effects are still unclear, as such a project is unprecedented on such a huge scale.

According to research by Fukushima University, about 3,500 trillion becquerels of radiative cesium-137 were discharged into the sea with the toxic water since the disaster broke out and the radiative material has reached the western coast of northern America.

Meanwhile, about a hundred thousand evacuees are still displaced and live in cramped temporary housing camps due to the uncontrolled nuclear disaster.

However, in the face of such troubles regarding the ongoing Fukushima Daiichi nuclear power plant crisis, the Japanese government is eager to reboot the country's idled nuclear plants.

The Sendai nuclear power plant in the Kyushu area was reopened last November despite the eruption of a nearby volcano. It is also close to Kumamoto Prefecture, which was hit by waves of strong earthquakes, including one measuring a magnitude of 6.7 and another registering M7.3, last month.

The majority of the Japanese public oppose the restarting of the country's nuclear power plants and only about 30 percent are supportive. More than 60 percent of Fukushima prefectural residents are dissatisfied with the government's countermeasures against the nuclear disaster.