Workers with Kansai Electric Power Co. (KEPCO) in Japan discovered a puddle of radioactive water on the floor of the Takahama 4 nuclear reactor.
An alarm sounded when coolant in the chemical and volume control system was passed through a boron thermal regeneration system before an increase of the reactor coolant system temperature. Water supply to the boron thermal regeneration system ended and a worker began field inspection. He found a puddle on the floor in front of the condensate demineralizer.
In addition to the puddle, workers found water had leaked on the floor of the auxiliary condensate building. In total, workers believe about 34 litres of water leaked, and KEPCO said the estimated amount of radioactivity in the puddle is below one-two hundredth of Japan’s threshold level. An investigation into the cause of the leak is underway.
Both units shut down in 2011 following the disaster at the Fukushima Daiichi nuclear power plant. Takahama 3 restarted at the end of January, and refueling started at Unit 4 at the same time.
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