Neutron capture

[1] Neutron capture plays a significant role in the cosmic nucleosynthesis of heavy elements.

[1] Neutron capture on protons yields a line at 2.223 MeV predicted[2] and commonly observed[3] in solar flares.

The thermal energy of the nucleus also has an effect; as temperatures rise, Doppler broadening increases the chance of catching a resonance peak.

In particular, the increase in uranium-238's ability to absorb neutrons at higher temperatures (and to do so without fissioning) is a negative feedback mechanism that helps keep nuclear reactors under control.

The energy of neutron capture thus intervenes[clarification needed] in the standard enthalpy of formation of isotopes.

Other neutron absorbers used in nuclear reactors are xenon, cadmium, hafnium, gadolinium, cobalt, samarium, titanium, dysprosium, erbium, europium, molybdenum and ytterbium.

However, it is found in the same ores as zirconium, which shares the same outer electron shell configuration and thus has similar chemical properties.

The latter, being essentially transparent to neutrons, is prized for internal reactor parts, including the metallic cladding of the fuel rods.