Nuclear Energy Research Initiative (NERI) Program. Technical progress report

Engelhardt, G.R. ; MacDonald, D.D.

SRI International, Menlo Park, CA (United States)

关键词: Critical Temperature;    Water Vapor;    Hydroxides;    Atmospheric Pressure;    Nuclear Energy;   

DOI  :  10.2172/761589
RP-ID  :  None
RP-ID  :  FG03-99SF21884
RP-ID  :  761589

美国|英语

来源: UNT Digital Library

【 摘 要 】

During the past quartile the authors have explored the thermodynamics of various metal hydroxide and oxyhydroxide dehydration reactions of iron, nickel, and chromium with the objective of estimating the critical temperature, T{sub cr}. This is the temperature at which the oxide is in equilibrium with the oxyhydroxide or hydroxide and water vapor under the expected repository conditions of temperature and pressure. Because localized corrosion requires the presence of an ionically conducting phase on the surface (to support oxygen reduction) T{sub cr} is also the temperature below which ''wet'' corrosion first becomes possible. Past analyses have assumed that wet corrosion requires the presence of a layer of bulk water on the surface and hence that corrosion is not possible at temperatures above the boiling temperature of bulk water under the prevailing atmospheric pressure. Furthermore, significant elevation of the boiling temperature may occur if the aqueous phase becomes concentrated in salts. Because of the hydration of hygroscopic corrosion products, which may occur at significantly higher temperatures than the boiling temperature of water, and because of boiling temperature elevation effects, the past assumption needs to be reevaluated. This is the primary goal of this work.