Oxide evolution on Alloy X-750 in simulated BWR environment
Journal article, 2016

In order to simulate the environment experienced by spacer grids in a boiling water reactor (BWR), specimens of the Ni-based Alloy X-750 were exposed to a water jet in an autoclave at a temperature of 286 degrees C and a pressure of 80 bar. The oxide microstructure of specimens exposed for 2 h, 24 h, 168 h and 840 h has been investigated mainly using electron microscopy. The specimens suffer mass loss due to dissolution during exposure. At the same time a complex layered oxide develops. After the longest exposure the oxide consists of two outer spinel layers consisting of blocky crystals, one intermediate layer of nickel oxide interspersed with Ti-rich oxide needles, and an inner layer of oxidized base metal. The evolution of the oxide leading up to this structure is discussed and a model is presented.

BWR

NiFe2O4

Nickel based alloys

High temperature water

Oxide formation

Alloy X-750

Corrosion

Author

Silvia Tuzi

Chalmers, Physics, Materials Microstructure

Kenneth Göransson

Westinghouse Electric Sweden AB

Seikh Mohammad Habibur Rahman

Chalmers, Chemistry and Chemical Engineering, Energy and Material, Environmental Inorganic Chemistry

Sten Eriksson

Chalmers, Chemistry and Chemical Engineering, Energy and Material, Environmental Inorganic Chemistry

Fang Liu

Chalmers, Physics, Materials Microstructure

Mattias Thuvander

Chalmers, Physics, Materials Microstructure

Krystyna Marta Stiller

Chalmers, Physics, Materials Microstructure

Journal of Nuclear Materials

0022-3115 (ISSN)

Vol. 482 19-27

Subject Categories

Chemical Sciences

DOI

10.1016/j.jnucmat.2016.09.026

More information

Latest update

11/1/2018