By ELAINE KURTENBACH
2013-05-28 02:47 PM
Education Minister Hakubun Shimomura, whose agency oversees such research, said Tuesday the government will tighten oversight of such research. He criticized a "low level of safety awareness" at the facility in Tokaimura, north of Tokyo.
"It is crucial for a nuclear research facility to give top priority to safety measures," Shimomura said. "Their lack of safety awareness and insufficient safety management systems apparently have invited the problem," he said.
Japan's nuclear industry has been in crisis since the March 2011 accident at the tsunami-hit Fukushima Dai-ichi nuclear plant, the worst since Chernobyl in 1986. The government has revamped its regulatory regime and is drafting stricter safety standards, as troubles continue to mount.
Shimomura said the government would set up a panel to discuss reform and safety compliance at the Japan Atomic Energy Agency after the accident Thursday at the Hadron Experimental Facility of the JAEA's Japan Proton Accelerator Research Complex in Tokaimura, where at least two previous radiation accidents have occurred.
Researchers were trying to generate particles by directing a proton beam at some gold when their equipment overheated, causing the evaporation and release of radioactive gold, the government-run JAEA said in a statement. The leak originally was thought to have been contained inside the lab, but it spread to other areas when a ventilation fan was switched on.
Out of 55 people tested, 22 had no excess exposure and 33 received radiation dosages of up to 1.7 millisieverts. That is about the average annual background dose for someone living in Japan. Nuclear workers generally are limited to 100 millisieverts of exposure over five years.
Japan's Nuclear Regulation Authority rated the accident as "Level 1," or third from the lowest level on a 9-level international scale. The March 2011 accident at the tsunami-hit Fukushima Dai-ichi nuclear plant, the country's worst ever atomic energy disaster, was rated a 7 on the international scale.
No radiation was released to the outside environment in Tokaimura, but the accident's handling and a failure by the JAEA to report the leak until more than a day later has also raised concerns over the degree of safety awareness and transparency in the industry.
Also Tuesday, a zoning reclassification ended a "no-go zone" designation for areas contaminated with radiation from the Fukushima Dai-Ichi plant. However, most of the area is designated "difficult to return to" and remains off-limits.
Some 150,000 Fukushima residents are still displaced due to the disaster.
Associated Press writer Mari Yamaguchi contributed to this report.