Japan is vowing to implement better government oversight and safety practices after another accident at one of its nuclear facilities.
At least thirty people were exposed to minor excess radiation last week at the Hadron Experimental Facility in Tokaimura, north of Tokyo, which is part of Japan Atomic Energy Agency's Proton Accelerator Research Complex.
The leak caused a slight increase in radiation levels outside the site, according to the Nuclear Regulation Authority, but said it would have “no impact on the general public.”
Japan's nuclear industry has not fully recovered since a tsunami sparked the massive disaster at the Fukushima Dai-ichi nuclear plant in March 2011.
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"It is crucial for a nuclear research facility to give top priority to safety measures," Education Minister Hakubun Shimomura said. "Their lack of safety awareness and insufficient safety management systems apparently invited the problem."
At the time of last week's accident, scientists were "directing a proton beam at some gold when their equipment overheated, causing the evaporation and release of radioactive gold" according to JAEA.
When researchers turned on ventilation fans to address the radiation, regulators say it spread to other parts of the complex.