Which specific group of neutrons, which are born a short time after a fission event rather than immediately, allow a reactor's power to be safely controlled by humans?

The specific group of neutrons that allow a reactor's power to be safely controlled by humans are called delayed neutrons. While the vast majority of neutrons, known as prompt neutrons, are emitted immediately, or instantaneously, during a nuclear fission event, a small but vital fraction are released after a measurable delay. These delayed neutrons do not come directly from the fission process itself but are instead produced by the radioactive decay of certain unstable atomic nuclei, called fission products, which are created when a heavy nucleus like uranium-235 splits. These particular fission products are known as delayed neutron precursors. After ....