Got it! "Sunburst" by Phyllis Gotlieb!
After reading through half of this list, I recognized the title (the german version of this wikipedia article also lists best known work). I ordered it right away (used, but who cares), man I cannot wait. Nostalgia ahoy!
For anyone interested, a short introduction:
A nuclear accident ravages a small town outside of Chicago, resulting
in a government quarantine isolating it from the rest of the world. A
generation later, with the quarantine still in place, strange
mutations have affected the minds of the town's children -- mutations
which could either spell the next stage in human evolution, or
something far more sinister. As the children's psychic powers begin to
manifest themselves in more demented and destructive forms, the kids
escape their compound. Now it is up to Shandy Johnson and her friends
to track down the runaways. Possessing similar powers, Sandy and her
friends find themselves facing increasingly frightening confrontations
with their escaped peers. First published in 1964 and again in 1978,
Sunburst has lost neither its edge nor its relevance. Predating the
near-misses and disasters at Three Mile Island and Chernobyl, Gotlieb
reminds us of the tremendous forces we have at our fingertips --
powers that humans use daily but do not fully comprehend
PS I asked this question as a guest, is there any way to merge accounts or something?