A constituent that absorbs neutrons and thereby reduces their availability for a nuclear fission chain reaction. Effectiveness depends on isotope, neutron spectrum and spatial distribution, not just one thermal cross section.
The reduction of reactor reactivity caused by neutron absorption by xenon-135. In a simplified model its abundance is fed by radioactive iodine decay, while its removal is by radioactive decay and neutron capture. Changes in these pathways can delay its response to a change of neutron flux.
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Neutron poison refers to substances that can absorb neutrons and thereby reduce the number of neutrons available to sustain a nuclear chain reaction. These materials are crucial in nuclear reactors for controlling the fission process. By absorbing neutrons, neutron poisons help to manage the reactor's reactivity and ensure safe operation. Common neutron poisons include: - **Boron**: Often used in the form of boron carbide or dissolved in water, it is effective due to its high neutron capture cross-section.