The main result of the investigation is that the emissions from the power plant started earlier, lasted longer and are therefore higher than assumed in most studies conducted before. The total release amounts to 36 PBq which equals 40% of the Chernobyl emissions. About 20% of the cesium was deposited on Japanese territory while about 80% was deposited in the water.
Regarding the radioactive noble gas Xenon‐133, the results indicate an emission of 16700 Peta‐Becquerel (1 Becquerel is one radioactive decay per second, 1 Peta‐Becquerel equals 1015 Bq).
This is the largest civilian noble gas release in history, exceeding the Chernobyl noble gas release by a factor of 2.5. There is strong evidence that emissions started already on 11 March 2011 at 6:00 UTC, which is immediately after the big earthquake.
Xenon‐133 is neither ingested nor retained in the inhalation process and therefore of less health concern, but it is important for understanding the accident events.