The Kinetics of ⁶⁰Co Uptake on and Release from Stainless Steel With and Without ⁶⁵Zn Addition Under Boiling Water Reactor Conditions

In water-cooled reactors measures to minimize the radiation fields due to the transport and deposition of ⁶⁰Co are important to ensure low occupational doses of radiation. For example, it is now accepted practice to add zinc to boiling water reactor coolant to minimize ⁶⁰Co transport and pickup by surfaces. This paper describes a study of the kinetics of ⁶⁰Co deposition on Type 316 stainless steel in neutral, partially deoxygenated water at 563 K and 10.2 MPa with and without zinc traced with ⁶⁵Zn. The effect of zinc addition on the corrosion rate of preoxidized stainless steel was also studied using relatively high concentrations of additive. General observations and a mathematical model of the corrosion rate provide insights into the possible mechanisms involved.