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
On-Line Isotope Mass Separator more than 60 physics experiments are active there. Radioactive nuclei are produced at ISOLDE by impinging a high energy beam of protons on a stationary target. There are a number of target materials depending on the desired final species. Collisions between the proton beam and the target produce a variety of fragments, which are extracted and filtered to yield the desired isotope. The time required for extraction places a lower limit on the half life of isotopes which can be produced by this method. Once extracted, the isotopes are directed either to one of several detectors, an isotope harvesting area,