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Which materials are used for nuclear reactor control rods?
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nuclear fission
Italian-born physicist Enrico Fermi explaining a problem in physics, c. 1950. He was awarded the 1938 Nobel Prize for Physics.
Nuclear reactor control rods are composed of materials with a high neutron-capture cross section, allowing them to effectively absorb neutrons and regulate the rate of nuclear fission within a nuclear reactor.1
Common materials used for these rods include:
- Boron: Often used in the form of boron carbide.213
- Rare-earth elements: Specifically europium and dysprosium, which are preferred for their durability as neutron absorbers.4
- Other metals: Cadmium and hafnium are also utilized for their high absorption capabilities.1
Additionally, materials such as gadolinium may be used as "burnable poisons" to help regulate reactivity over the lifetime of the fuel core. These rods are essential for maintaining a steady-state chain reaction, adjusting power levels, and safely shutting down the reactor when necessary.241