Humid air corrosion of YMP waste package candidate material

The Yucca Mountain Site Characterization Project is evaluating candidate materials for high level nuclear waste containers (Waste Packages) for a potential deep geologic repository at Yucca Mountain, Nevada. The potential repository is located above the water table in the unsaturated zone. The rock contains nominally 10% by volume water and gas pressure in the emplacement drifts of the repository is expected to remain near the ambient atmospheric pressure. The heat generated by the radioactive decay of the waste will raise the temperature of the waste packages and the surrounding rock. Waste Package temperatures above the ambient boiling point of water are anticipated for the waste emplacement scenarios. Because the repository emplacement drifts are expected to remain at the ambient atmospheric pressure, the maximum relative humidity obtainable decreases above the boiling point of water. Temperatures of the Waste Packages and the surrounding rock are expected to reach maximum temperature within 100`s of years and then gradually decrease with time. Episodic liquid water contact with the WPs is also expected; this will result in the deposition of salts and mineral scale