Which isotope is the result of activation of corrosion products?

• A. Ar-41
• B. Co-60
• C. H-3
• D. Na-24

Answer: (B)

Activation of corrosion products refers to radioisotopes formed when trace metals from plant materials become activated by neutron flux in the reactor. The most common product from this pathway is cobalt-60, produced when cobalt impurities in stainless steel capture a neutron. Co-60 emits strong gamma radiation and is a major contributor to dose rates from activated corrosion products in the plant. The other isotopes listed arise from different activation routes not tied to corrosion products: Ar-41 comes from activation of argon in the coolant or air, H-3 (tritium) from reactions involving hydrogen in water, and Na-24 from sodium in materials. So cobalt-60 best fits the activation of corrosion products.