Source:
Asahi ShimbunTokyo Electric Power Co. concealed data showing spikes in radiation levels at the Fukushima No. 1 nuclear power plant in March, one day before a hydrogen explosion injured seven workers.
The Asahi Shimbun obtained a 100-page internal TEPCO report containing minute-to-minute data on radiation levels at the plant as well as pressure and water levels inside the No. 3 reactor from March 11 to April 30.
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Both levels were well above the upper limit of 250 millisieverts for an entire year under the plant's safety standards for workers. But the workers who were trying to bring the situation under control at the plant were not informed of the levels.
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The TEPCO data also showed high levels of hydrogen may be emitting from the damaged core of the No. 3 reactor on March 13, when TEPCO started injecting seawater to cool the reactor.
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Read more:
http://www.asahi.com/english/TKY201105130370.html
Via
http://enenews.com/tepco-concealed-radiation-data-before-explosion-at-no-3-reactor-workers-not-informed-of-extremely-high-levels