Chien-Shiung Wu
In a typical nuclear reactor fueled with uranium-235, the presence of 135Xe as a fission product presents designers and operators with problems due to its large neutron cross section for absorption. Because absorbing neutrons can detrimentally affect a nuclear reactor's ability to increase power, reactors are designed to mitigate this effect; operators are trained to properly anticipate and react to these transients. In fact, during World War II, Enrico Fermi suspected the effect of Xe-135, and followed the advice of Emilio Segrè in contacting his student Chien-Shiung Wu. Wu's soon-to-be published paper on Xe-135 completely verified Fermi's guess that it absorbed neutrons and disrupted the B Reactor that was being used in their project.