Abstract:
On March 11, 2011, a catastrophic tsunami induced by a magnitude 9.0 earthquake caused the terrible Fukushima Daiichi Nuclear Power Plant (FDNPP) accident, leading to the release of a large amount of radionuclides into the environment. The published studies on plutonium isotopes in the environment after the FDNPP accident were reviewed in this paper. The total atmospheric released amounts of Pu from the FDNPP accident were estimated to be 10
9 Bq, that is only 1/10 000 of that released from the Chernobyl accident. The Pu isotopes were released from the damaged reactors, not from the spent fuel pools in the FDNPP. The Pu isotopic ratios (
240Pu/
239Pu,
241Pu/
239Pu) and activity ratios of
A(
238Pu)/
A(
239+240Pu) were significantly different from that of global fallout, serving as powerful fingerprints for Pu source identification. To date, the plutonium isotopes from the accident in the terrestrial environment within the 30 km zone around the FDNPP site have been widely observed and there are no strong positive correlations between the Pu isotopes contamination levels and the distances from the FDNPP site. The influence of the FDNPP accident on Pu distributions in the marine environment is limited. No detectable Pu contamination from the accident is observed even in the near coastal (5 km off the FDNPP site) marine sediments.