Recent technological advancements have stimulated interest in lanthanide compounds as neutron absorbers. Specific fabrication procedures were developed for incorporating chemically stable europium oxide in stainless steel base neutron absorbers. The irradiation of europium oxide -stainless steel base absorbers to neutron absorptions as high as 6 x I021/cm3 resulted in no deleterious effects. The excellent performance of the europium oxide-stainless steel combination in the control rods of the SM-1 and SM-1A reactors further demonstrated their potential in pressurized water reactors. Arc fusion was found superior to conventional high-temperature heat treating for the production of either bulk or dense dispersoids of the lanthanide oxides. Europium molybdate and titanate are attractive compounds that resist attack by water. In addition to its superior resistance to corrosion by water at high temperature, europium molybdate has a substantial europium density. However9 like europium oxide9 it is only compatible with stainless steels having low silicon contents. Europium titanate has a lower europium density but acceptable resistance to water and superior compatibility with conventional stainless steels.