Timeline of the Fukushima Daiichi nuclear disaster of caesium-137 by the Atmospheric Chemistry and Physics journal—an estimate about 42 percent of that released into the atmosphere in the Chernobyl explosion in 1986. Caesium-137 has a half-life of 30 years. TEPCO reports the completion of a cover for the reactor unit 1, which is 54 metres high, 47 metres wide and 42 metres deep. The cover has a built-in ventilation system that is supposed to filter radioactive material. Boric acid is injected into reactor number 2 after the discovery of xenon in its containment vessel. The presence of xenon may be an indication that a self-sustained fission reaction
Radiation effects from the Fukushima Daiichi nuclear disaster Commission (NSC) of Japan published the results of the recalculation of the total amount of radioactive materials released into the air during the incident at the Fukushima Daiichi Nuclear Power Station. The total amounts released between 11 March and 5 April were revised downwards to 130 PBq for iodine-131 (I-131) and 11 PBq for caesium-137 (Cs-137). Earlier estimations were 150 PBq and 12 PBq. On 20 September the Japanese government and TEPCO announced the installation of new filters at reactors 1, 2 and 3 to reduce the release of radioactive materials into the air. Gases from the reactors would be