Grout to meet physical and chemical requirements for closure at Hanford grout vaults. Final report

摘要

The US Army Engineer Waterways Experiment Station (WES) developed a grout based on portland cement, Class F fly ash, and bentonite clay, for the Hanford Grout Vault Program. The purpose of this grout was to fill the void between a wasteform containing 106-AN waste and the vault cover blocks. Following a successful grout development program, heat output, volume change, and compressive strength were monitored with time in simulated repository conditions and in full-depth physical models. This research indicated that the cold-cap grout could achieve and maintain adequate volume stability and other required physical properties in the internal environment of a sealed vault. To determine if contact with 106-AN liquid waste would cause chemical deterioration of the cold-cap grout, cured specimens were immersed in simulated waste. Over a period of 21 days at 150 F, specimens increased in mass without significant changes in volume. X-ray diffraction of reacted specimens revealed crystallization of sodium aluminum silicate hydrate. Scanning electron microscopy used with X-ray fluorescence showed that clusters if this phase had formed in grout pores, increasing grout density and decreasing its effective porosity. Physical and chemical tests collectively indicate a sealing component. However, the Hanford Grout Vault Program was cancelled before completion of this research. This report summarizes close-out Waterways Experiment Station when the Program was cancelled.