The crisis at the plant resulted from an earthquake and tsunami March 11.
Some experts believe the Fukushima crisis is more serious than that resulting from an explosion at Ukraine's Chernobyl power plant 25 years ago, the Mainichi Daily News reported Monday.
"It's graver than Chernobyl in that no one can predict how the situation will develop," said Atsushi Kasai, a former senior researcher with the Japan Atomic Energy Research Institute.
In addition to danger from leaking radioactivity, Japanese citizens are also at risk of psychological illnesses, officials said.
"Research institutes from various countries conducted detailed surveys on the health of people affected by the Chernobyl crisis," said Yoshihisa Matsumoto, Tokyo Institute of Technology associate professor of radiobiology. "The Japanese government should arrange for checks on the mental and physical health of local residents and nuclear plant workers."
Tokyo-Sendai bullet train service resumed Monday for the first time since the earthquake.
Sendai is the capital of Miyagi Prefecture, one of the areas hit hardest in the disaster.
Reconnection of the train service was expected to speed up reconstruction activities in the disaster region and facilitate faster access for officials to the Japanese capital, Kyodo News reported.
The crisis at the Fukushima plant has been rated a maximum Level 7 on a scale established by the International Atomic Energy Agency and the Organization for Economic Cooperation and Development in 1992.
The Yomiuri Shimbun said Monday the amount of radiation released from the damaged plant is greater than first reported.
Plant operator Tokyo Electric Power Co. said it could be as long as four months before it is able to control radiation leakage from the crippled reactors.
The latest confirmed death toll from the earthquake-tsunami rose to 14,300 as of 4 p.m. Sunday, the National Police Agency reported. The agency said 11,999 people remained missing.
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