Title: Cohesive Relations for Surface Atoms in the Iron-Technetium Binary System

Abstract

Iron-technetium alloys are of relevance to the development of waste forms for disposition of radioactive technetium-99 obtained from spent nuclear fuel. Corrosion of candidate waste forms is a function of the local cohesive energy () of surface atoms. A theoretical model for calculating is developed. Density functional theory was used to construct a modified embedded atom (MEAM) potential for iron-technetium. Materials properties determined for the iron-technetium system were in good agreement with the literature. To explore the relationship between local structure and corrosion, MEAM simulations were performed on representative iron-technetium alloys and intermetallics. Technetium-rich phases have lower , suggesting that these phases will be more noble than iron-rich ones. Quantitative estimates of based on numbers of nearest neighbors alone can lead to errors up to 0.5 eV. Consequently, atomistic corrosion simulations for alloy systems should utilize physics-based models that consider not only neighbor counts, but also local compositions and atomic arrangements.

Authors:

Taylor, Christopher D. ^[1]

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+ Show Author Affiliations

1. Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM 87544, USA

Publication Date:

Sun Oct 16 00:00:00 EDT 2011

Sponsoring Org.:

USDOE

OSTI Identifier:

1198039

Grant/Contract Number:  

AC52-06NA25396

Resource Type:

Published Article

Journal Name:

Journal of Metallurgy

Additional Journal Information:

Journal Name: Journal of Metallurgy Journal Volume: 2011; Journal ID: ISSN 1687-9465

Publisher:

Hindawi Publishing Corporation

Country of Publication:

Country unknown/Code not available

Language:

English