Tokyo Electric Power Co. (9501) is re-analyzing 164 water samples collected last year at the wrecked Fukushima atomic plant because previous readings “significantly undercounted” radiation levels.
The utility known as Tepco said the levels were undercounted due to errors in its testing of beta radiation, which includes strontium-90, an isotope linked to bone cancer. None of the samples were taken from seawater, the company said today in an e-mailed statement.
“These errors occurred during a time when the number of the samplings rapidly increased as the result of a series of events since last April, including groundwater reservoir leakage and a major leak from a storage tank,” according to the statement.
It will run new tests of the samples taken from April to September 2013 and will publish corrected beta radiation readings. Outside experts were being sought in Japan and internationally to cross-check analysis results and review Tepco’s measurement methods, the company said.
The measurement errors were halted in October 2013 after testing manuals were clarified and other steps taken to ensure accuracy, Tepco said.
Shinji Kinjo, leader of a disaster task force at Japan’s Nuclear Regulation Authority, said his office hadn’t been aware of the measurement errors. The regulator’s oversight of the utility is based on Tepco’s measurements, he added.
Earlier today, Tepco suspended the removal of spent nuclear fuel rods at Fukushima plant after a cooling system failed due to a damaged power cable, the company said in a separate e-mailed statement. Work resumed at the reactor No. 4 spent fuel pool after activation of a backup system.
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