Radiation readings around tanks holding contaminated water at the crippled Fukushima nuclear plant have spiked more than 20 percent to their highest level, Japan's nuclear regulator said, again raising questions about the clean-up of the worst atomic disaster in 27 years.
Readings just above the ground near a set of tanks at the Fukushima Daiichi plant showed radiation as high as 2,200 millisieverts (mSv), the Nuclear Regulation Authority (NRA) said on Wednesday. The previous high in areas holding the tanks, 1,800 mSv, was recorded on Saturday.
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Both levels would be enough to kill an unprotected person within hours. The NRA has said the recently discovered hotspots are highly concentrated and easily shielded.
The tanks sit on a hill above the Pacific Ocean at the Fukushima plant, which was devastated by a tsunami generated by a massive earthquake in March 2011, triggering the worst nuclear crisis since Chernobyl a quarter of a century earlier.