Thermonuclear fusion and spallation reactions (α, n)
Nuclear Reactor Physics - Nuclear Reactions

For some heavy nuclei, such as curium 244, α decay competes with neutron-producing spontaneous fission.

Reactions (α, n) occur on light elements such as oxygen 17 and oxygen 18 present in UOx and MOx oxidic fuels, or light elements in vitrified waste. The number of neutrons emitted per reaction (α, n) when slowing down a particle α emitted (at a given energy) by a given heavy isotope in the medium under consideration (UO ₂ , PuO ₂ , SiO ₂ ...) is called the yield (α, n)