Radionuclides in the coolant consist of which groups?

• A. Fission Products
• B. Activation Products
• C. Fission Products and Activation Products
• D. Naturally Occurring Isotopes

Answer: (C)

Radionuclides in the coolant come from two main sources: fission products and activation products. When fuel undergoes fission, a wide range of fission fragments are produced, many of which are highly radioactive and can dissolve into or be carried by the coolant. Neutrons in the reactor also activate materials in contact with the coolant—such as structural metals and impurities—creating activation products that become radioactive. Together, these two groups account for the radioactive content in the coolant. Naturally occurring isotopes may be present, but the activity associated with reactor operation is dominated by both fission products and activation products.