THE SCHOOL OF MATERIALS SCIENCE AND ENGINEERING

GEORGIA INSTITUTE OF TECHNOLOGY

Under the provisions of the regulations for the degree

DOCTOR OF PHILOSOPHY

on Wednesday, January 9, 2018

12:00 PM
in Love 295

will be held the

DISSERTATION PROPOSAL DEFENSE

for

Kevin Jeremy Chan

“Effects of Carbon on Corrosion in Molten Fluoride Salt”

Committee Members:

Prof. Preet Singh, Advisor, MSE

Prof. Chaitanya Deo, NRE/MSE

Prof. Joshua Kacher, MSE

Prof. Hamid Garmestani, MSE

James R. Keiser, Ph.D., ORNL

Abstract:

The fluoride salt cooled high temperature reactor (FHR), as a Generation IV reactor concept is intended to provide breakthrough improvements in economics and safety. This is accomplished by using molten fluoride salt as the coolant, however managing corrosion of structural alloys in this environment is a challenge. Reactor core components made of graphite and other carbonaceous materials present significant surface area to the molten salt coolant, and indirectly interact with structural alloys. The resulting carbon-metal interactions can contribute to corrosion because chromium, and several other alloying elements form stable carbides at FHR operating temperatures. An understanding of the role of carbon on corrosion in molten fluoride salts will inform decisions related to the design and operation of FHRs.

In the proposed work, targeted exposure tests of materials in molten eutectic LiF-NaF-KF (FLiNaK) salt in the presence of graphite will be used to study carbon effects on corrosion in FHRs. Salt chemistry and materials will be varied to accomplish research aims. The first aim is to characterize the corrosion of candidate Ni based alloys and austenitic stainless steels during corrosion in molten fluoride in the presence of graphite. The second aim is to determine the mechanism of carbon transport through the molten fluoride salt from graphite to alloy surfaces. The third aim is to investigate molten fluoride corrosion barrier properties of chromium carbide, which can be applied as a coating or generated by pre-carburization on alloy surfaces.