Research and development related to the Nevada nuclear waste storage investigations. Progress report, July 1-September 30, 1980

Sorption of americium and plutonium was measured in a controlled, oxygen-free atmosphere and in air on a series of tuff samples. Sorption of plutonium was greater in the controlled atmosphere than in air. Sorption of both elements is higher on zeolitized tuff than devitrified tuff. Sorption of strontium, cesium, barium, cerium, and europium is being measured on tuff samples of mineralogies not previously studied, and samples from the USW-G1 drill hole have been selected for study. Work on the dependence of the sorption ratio on element concentration (barium and europium) and on solution-to-solid ratios is reported. Progress on controlling Eh and making Eh measurements is presented. Some tuff-water systems exhibit reduced or negative Eh values under oxygen-free conditions. Development of a method for encasing cores for flow studies is discussed. Field geologic mapping is being conducted in the Lunar Crater volcanic field of central Nevada. Mineralogy-petrology studies are being conducted on core samples from the USW-G1 exploration hole in Yucca Mountain. Zeolite heating tests of core samples from UE25a-1 show density, volume, and weight changes that correlate with alteration of mineral assemblages. Hydrogen-deuterium ratios in water evolved from a clinoptilolite specimen from Yucca Mountain have been measured. Jacket seals leaked during the first attempt at high temperature exposure in the hydrothermal soak tests. Revised seals using temperature-cured epoxy are being developed. Data from strength tests for various types of tuff conducted at ambient pressure and 400{sup 0}C for 16 h are presented. A densely welded specimen showed a 40% reduction in strength