Tritium in Japanese precipitation following the March 2011 Fukushima Daiichi Nuclear Plant accident.
Tritium concentrations in Japanese precipitation samples collected after the March 2011 accident at the Fukushima Dai-ichi Nuclear Power Plant (FNPP1) were measured. Values exceeding the pre-accident background were detected at three out of seven localities (Tsukuba, Kashiwa and Hongo) southwest of the FNPP1 at distances varying between 170 and 220 km from the source. The highest tritium content was found in the first rainfall in Tsukuba after the accident; however concentrations were 500 times less than the regulatory limit for tritium in drinking water. Tritium concentrations decreased steadily and rapidly with time, becoming indistinguishable from the pre-accident values within five weeks. The atmospheric tritium activities in the vicinity of the FNPP1 during the earliest stage of the accident was estimated to be 1.5×10(3) Bq/m(3), which is potentially capable of producing rainwater exceeding the regulatory limit, but only in the immediate vicinity of the source.
Isotope Hydrology Section, Division of Physical and Chemical Sciences, International Atomic Energy Agency, Vienna International Centre, 1400 Vienna, Austria. t.matsumoto@iaea.org
Takuya
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Matsumoto
Teruyuki
T
Maruoka
Gen
G
Shimoda
Hajime
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Obata
Hiroyuki
H
Kagi
Katsuhiko
K
Suzuki
Koshi
K
Yamamoto
Takehiro
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Mitsuguchi
Kyoko
K
Hagino
Naotaka
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Tomioka
Chinmaya
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Sambandam
Daniela
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Brummer
Philipp Martin
PM
Klaus
Pradeep
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Aggarwal
D062406:Fukushima Nuclear Accident; D011834:Radiation Monitoring; D011848:Radioactive Pollutants / Q000032:analysis*; D011891:Rain / Q000737:chemistry*; D013997:Time Factors; D014316:Tritium / Q000032:analysis*
D011848:Radioactive Pollutants; D014316:Tritium