Reactivity Contributions of Various Materials in Topsy, Godiva, and Jezebel

This report brings together an extensive accumulation of reactivity contribution data for the various critical assemblies at Pajarito. Corresponding values of effective absorption and transport cross sections are derived, and relationships between critical mass and volume fraction of diluents are obtained in terms of these cross sections. In some favorable cases, inelastic scattering contributions to the effective absorption cross sections are estimated.