Sea radiation from Fukushima seen triple Tepco estimate

TOKYO Fri Sep 9, 2011 11:19am EDT

The upper point of Unit 2 water intake is seen before the installation of concrete plates for mitigation of radioactive contamination in the ocean at the tsunami-crippled Fukushima Daiichi Nuclear Power Station in Fukushima prefecture, in this handout photo taken and released July 5, 2011. REUTERS/Tokyo Electric Power Co/Handout

The upper point of Unit 2 water intake is seen before the installation of concrete plates for mitigation of radioactive contamination in the ocean at the tsunami-crippled Fukushima Daiichi Nuclear Power Station in Fukushima prefecture, in this handout photo taken and released July 5, 2011.

Credit: Reuters/Tokyo Electric Power Co/Handout

TOKYO (Reuters) - Radioactive material released into the sea in the Fukushima nuclear power plant crisis is more than triple the amount estimated by plant operator Tokyo Electric Power Co, Japanese researchers say.

Japan's biggest utility estimated around 4,720 trillion becquerels of cesium-137 and iodine-131 was released into the Pacific Ocean between March 21 and April 30, but researchers at the Japan Atomic Energy Agency (JAEA) put the amount 15,000 trillion becquerels, or terabecquerels.

Government regulations ban shipment of foodstuff containing over 500 becquerels of radioactive material per kg.

Takuya Kobayashi, a researcher at the agency, said on Friday the difference in figures was probably because his team measured airborne radioactive material that fell into the ocean in addition to material from contaminated water that leaked from the plant.

He believed Tepco excluded radiation that originally came from airborne material. The report does not include cesium-134 as the research group initially lacked resources to measure it, meaning the amount of estimated radioactive material will increase with further calculations.

The March 11 earthquake and tsuanmi knocked out reactor cooling systems at Fukushima Daiichi, 240 km (150 miles) north of Tokyo, triggering meltdowns and radiation leaks.

Huge amounts of contaminated water accumulated during efforts to cool the reactors, with much of it reaching the sea, and radiation has been found in fish, seaweed and other seafood.

Tepco edged closer this week to its near-term goal of bringing the reactors to a state of cold shutdown by January, with the temperature at the second of three damaged units falling below boiling point.

(Reporting by Yuko Takeo; Editing by Michael Watson)

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Comments (1)
bamdamajam wrote:
Dude, you have got to give better units. A becquerel is the decay of one nucleus. It’s kinda meaningless unless you give a mass and a time frame. For example the table I’m sitting at has 300 becquerels per hour per kilogram. Really good data would be the number of becquerels per minute per kilogram of sea water per radioactive isotope. Don’t get lost in them big numbers.

Sep 09, 2011 11:56am EDT  --  Report as abuse
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