The bits of debris and corrosion that become radioactive as they go through the reactor are called

• A. Contaminants
• B. Decay products
• C. Activation products
• D. Fission fragments

Answer: (C)

Inside a reactor, materials such as debris and corrosion are bombarded by a steady flux of neutrons. When stable atoms in those materials capture neutrons or undergo other nuclear reactions, they become radioactive. The new radioactive species created this way are called activation products. This is different from contaminants, which are impurities that may be radioactive because of contamination rather than processing, and from decay products, which are formed when existing radionuclides decay rather than being produced by neutron irradiation. It’s also distinct from fission fragments, which are the radioactive pieces produced when fuel nuclei undergo fission. Activation products are the radioactive species generated directly by neutron irradiation of materials in the reactor, including debris and corrosion.