An analytical procedure for 0.04 to 1.6 percent ruthenium in plutonium metal was developed. Determination of ruthenium in metallic plutonium was investigated as part of a program for securing analytical procedures for various metals in plutonium. However, results of the investigation are given in this report with emphasis on the determination of ruthenium in plutonium chloride solutions. Specifically, this report is primarily concerned with the separation and determination of 40 to 400 micrograms of ruthenium in a hydrochloric acid solution of 25 to 100 milligrams of plutonium.

Recent measurements on the long counter efficiency in which comparisons were made with the (n, p) scattering cross section, additional variations in efficiency were found which varied slowly with neutron energy but were still correlated with the total neutron cross section of carbon. Because of these variations in efficiency there are errors in the fission cross sections reported in LA-1714. Corrections to these data have been given here.

As an alternative to recovering Ba140 from the spent MTR fuel assemblies a new enriched-uranium fuel pin was designed for irradiation. Two specimens, each containing about 3 g. of uranium (93% enriched), were irradiated to 1.3% and about 18% burnup. Examination after irradiation indicated that design improvements were needed; photographs are presented to illustrate the damage incurred during irradiation. A simple inorganic chemical process using precipitation and filtration techniques was developed to separate Ba140 from other fission products and uranium.