Timeline of the Fukushima Daiichi nuclear disaster pumps could be retrofitted to deliver concrete for that purpose. Prior to the elevation to level 7 by the Japanese authorities James Acton, Associate of the Nuclear Policy Program at the Carnegie Endowment for International Peace, was of the opinion that "Fukushima is not the worst nuclear accident ever but it is the most complicated and the most dramatic, was a crisis that played out in real time on TV. Chernobyl did not." A survey of radiation in seawater outside unit 2 shows radioactive isotope concentrations (iodine-131, caesium-134 and caesium-137) falling for the third consecutive day since the leak was
Radiation effects from the Fukushima Daiichi nuclear disaster radioactive caesium. In addition to the large releases of contaminated water (520 tons and 4.7 PBq) believed to have leaked from unit 2 from mid-March until early April, another release of radioactive water is believed to have contaminated the sea from unit 3, because on 16 May TEPCO announced seawater measurements of 200 Bq per cubic centimeter of caesium-134, 220 Bq per cubic centimeter of caesium-137, and unspecified high levels of iodine shortly after discovering a unit-3 leak. At two locations 20 kilometers north and south and 3 kilometers from the coast, TEPCO found strontium-89 and strontium-90 in the seabed