Steam oxidation of FeCrAl coated Zircaloy-2

A NEITZCH Jupiter 441 simultaneous thermal analysis with a water vapor furnace was installed and calibrated for temperature and di fferential scanning calorimetry (DSC). Bare and FeCrAl coated Zircaloy-2 nuclear fuel cladding and FeCrAl coated single crystal Yttria stabilized Zirconia (YSZ) samples were oxidized in an argon/steam environment at 700 C and 1100 C. FeCrAl coated Zircaloy-2 was also heated to 1200 C in an inert environment. Real-time thermo gravimetric analysis (TGA) and DSC data was taken during the steam oxidation. Glancing angle and 2 theta-omega X-ray di raction (XRD) scans were taken of the samples pre- and post- exposure. Scanning electron microscopy, energy-dispersive X-ray spectroscopy, and Auger electron spectroscopy (AES) depth profiling was performed. The TGA showed that the coated Zircaloy-2 samples experienced significantly less weight gain as compared to the bare Zircaloy-2 samples, indicating a slower rate of oxidation. AES and XRD showed that at 700 C this decrease was due to the formation of a protective alpha -alumina layer. Chromium segregated below the alumina layer to form a secondary layer. Finally it was observed that iron di fused into the base Zircaloy-2. At 1100 C a eutectic interaction between the zirconium and iron on the Zr exists and is postulated to have caused the evaporation of the coating and loss of protection. The FeCrAl on YSZ samples did not exhibit this phenomenon, however a spinel oxide was formed at 1100 C as opposed to alpha-alumina.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Nuclear, Plasma, Radiolgc Engr

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2016

Author dc:creator

• Mouche, Peter A.

Contributors dc:contributor

• Heuser, Brent J.

• Oxidation
• Cladding
• Nuclear
• Accident
• Coating
• FeCrAl
• Steam

Statement dc:rights

• Copyright 2016 Peter Mouche

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/90650

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/90650