No abstract

Column and batch experiments were conducted in fiscal year 1998 at Pacific Northwest National Laboratory' to evaluate the effect of varying concentrations of NaOH on the sorptive, physical, and hydraulic properties of two media: a quartz sand and a composite subsurface sediment from the 200-East Area of the Hanford Site. The NaOH solutions were used as a simplified effluent from a low-activity glass waste form. These experiments were conducted over a limited (0-to 10-month) contact time, with respect to the 10,000-to 100,000-year scenarios described in the Immobilized Low-Activity Waste-Performance Assessment (ILAW-PA).Whe? these two solids were put in contact with the NaOH solutions, dissolution was evident by a substantial increase in dissolved Si concentrations in the leachates. Incremental increases in NaOH concentrations, resulted in corresponding increases in Si concentrations. A number of physical and hydraulic properties also changed as the NaOH concentrations were changed.It was observed that quartz sand was less reactive than the composite sediment. Further, moistureretention measurements were made on the quartz sand and composite sediment, which showed that the NaOH-treated solids retained more water than the non-NaOH-treated solids. Because the other chemical, physical, and hydraulic measurements did not change dramatically after the high-NaOH treatments, the greater moisture retention of the high-NaOH treatments was attributed to a "salt effect" and not to the formation of small particles during the dissolution (weathering).The distribution coefficients (Kds) for Cs and Sr were measured on the NaOH-treated sediments, with decreases from -3,000 to 1,000 and 1,300 to 300 mL/g noted, respectively, at the 0.01-to 1.0-M NaOH levels. There was no apparent trend for the Sr I

No abstract

The fatigue behavior of optical glass fibers was determined in air at 23°C and 55% relative humidity by the dynamic-fatigue test technique in which strength is measured as a function of stressing rate. The good correlation found between the fatigue test data and fracture-mechanics theory indicates that failure is controlled by slow crack growth of preexisting flaws and that fracture-mechanics theory can be used in making failure predictions for optical glass fibers.

The effectiveness of proof testing as a method of improving component reliability was studied by comparing the inert strength distributions of soda-lime-silicate glass before and after proof testing. The effects of unloading rate from the proof stress, hold time at the proof stress, and proof-test environment were examined. The results indicate that the proof test must be conducted with rapid unloading rates and good environmental control to be effective. The theoretical implications of these results are discussed.