Deciphering the measured ratios of iodine-131 to cesium-137 at the fukushima reactors

Abstract

We calculate the relative abundance of the radioactive isotopes Iodine-131 and Cesium- 137 produced by nuclear fission in reactors and compare it with data taken at the troubled Fukushima Dai-ichi nuclear power plant. The ratio of radioactivities of these two isotopes can be used to obtain information about when the nuclear reactions terminated.