CHERNOBYL

Reactor Poisoning

When nuclear power took its first stumbling steps in laboratories in the 1950s, the nuclear reaction would inexplicably stop after about a day. The reactor consisted of a small amount of nuclear fuel cooled by air. After a few days, it could be restarted, only to stop again. Over and over. What was happening? Reactor poisoning! Some decay products absorb neutrons very effectively and prevent the nuclear reaction. Xenon-135 is one example. At Chernobyl, these "poisoning" substances prevented the reactor from reaching full power. For a little while.