Work on the preparation of graphite spheres containing thorium oxide for use as breeder elements in the Pebble Bed Reactor-Steam Power Plant is described. Graphite spheres of varying density were infiltrated with thorium nitrate solutions, followed by denitration to thorium oxide.

Absolute (p,n) cross sections have been measured for Ti47, V51, Cr52, Co59, and Cu63 at energies between 4 and 6.5 Mov. These data plus earlier measurements of the cross section for inelastic proton scattering have been used to estimate total proton absorption cross sections for V51 and Co59. An optical model calculation using parameters giving a good fit to elastic scattering measurements predicts an absorption cross section in good agreement with the measurements for Co59. For V51, some sets of parameters gave good agreement with the measured absorption cross section, but the fit to the elastic scattering data was only fair.