The crevice corrosion of Alloy 22 in the Yucca Mountain nuclear waste repository

Abstract

How would you……describe the overall signifi cance of this paper?This paper demonstrates that much research and understanding has been done in the last fi ve years regarding the localized corrosion resistance of Alloy 22. This information is crucial for predicting the lifetime performance of the high-level nuclear waste containers of Yucca Mountain.…describe this work to a materials science and engineering professional with no experience in your technical specialty?This is a review of results obtained using electrochemical and corrosion tests to assess the environmental and metallurgical variables that affect the localized corrosion resistance of the nickel-based Alloy 22 (N06022). The main experimental result discussed here is the repassivation potential value, a parameter used to predict if Alloy 22 may be prone or not to suffer localized corrosion. …describe this work to a layperson?This work deals with the degradation of an alloy (metal) due to its interaction with the environment. This process is called corrosion (rusting) in which a metal reverts back to oxides of minerals by a mechanism of oxidation. This metal is planned to be used as a barrier between nuclear waste and the environment in a mountain in Nevada. The susceptibility of Alloy 22 (N06022) to crevice corrosion may depend on environmental and metallurgical variables. This paper summarizes the current fi ndings regarding the effect of many of these variables, such as pH, other inhibitive species and types of crevicing material, geometry, and applied torque. There are still contradictory results regarding the effect of metallurgical factors such as the presence of weld seams. Crevice corrosion stifl ing and arrest must be considered in evaluating the life expectancy of components made of Alloy 22.

Crevice corrosion of nickel-based alloys considered as engineering barriers of geological repositories

“…Groundwaters contain a wide variety of species and they may be contaminated with other species during the construction of the repository site. [49][50][51] There is a considerable amount of research on the effect of these species as potential anodic inhibitors of chloride-induced crevice corrosion of alloy 22. 29 E R,CREV of alloy 22 is independent of solution pH in a wide range of pH values.…”

“…29 E R,CREV of alloy 22 is independent of solution pH in a wide range of pH values. 26,51 Complete inhibition of crevice corrosion occurs at pH ≥ 12.5 at any chloride concentration. 55 Such a high pH value is not expected in Yucca Mountain concentrated groundwaters.…”

“…Some authors report a detrimental effect, 30,65 whereas others report a negligible effect. 28,40,51,66 These apparently contradicting researches are based on different testing techniques and crevice former materials (solid PTFE vs. PTFE-wrapped ceramic). Crevice geometry may be the main cause of reported differences.…”

“…The tighter the crevice is the lower the current density needed for crevice corrosion stabilisation is. It may be speculated that the anodic response of solubilised and thermally aged material is similar at low current densities (PTFE-wrapped ceramic crevice formers) 28,40,51,66 but differ at high current densities (solid PTFE crevice formers). 30,65 Container fabrication processes.…”

Susceptibility of 316L stainless steel to crevice corrosion in submersible solenoid valve

“…It is normally considered that crevice corrosion will occur if corrosion potential of a metal in a given environment exceeds repassivation potential [33,34]. As shown in Fig.…”