Hydride Induced Embrittlement
on Zircaloy-4
Doug Ogletree
Glen Rose ISD
Dr. Lin Shao (Texas A&M University)
Dr. Wayne Kinnison (Texas A&M University--Kingsville)
Radiation and Materials
Science Group
This lab group works with particle accelerators.
Accelerators are used to simulate the reactor
environment, speed up materials’ development and
obtain fundamental understanding of those materials.
The team members are:
Ion Beam Laboratory at
TAMU
P.I.: Lin Shao
Visiting Faculty: Wayne Kinnison (TAMUK), Zhongyu Li (HEU)
Lab Manager: Mark Hollander
Graduate Students: Michael Martin, Assel Aitkaliyeva (INL), Di
Chen, Michael Myers(LLNL), George Wei, Tianyi Chen, Robert
Balerio, Jing Wang, Michael General, Josey Wallace
Undergraduate Students: Richard Vega, Travis Smith, Lloyd
Price, Lance Hill, Leanne Kristek, McIan Amos, Silas Marrs
Overview
My research project involves the cladding material
that covers fuel rods in a nuclear reactor. The
material of interest in this project is Zircaloy-4.
The long term water-cooling of spent fuel rods, which
are clad with zirconium alloys and come from nuclear
reactors, elevates the requirement for their resistance
to oxidation-related nodular corrosion.
Furthermore, oxidative reaction of zirconium with
water releases hydrogen gas, which partly diffuses
into the alloy and forms zirconium hydrides.
Overview
The hydrides are less dense and are weaker
mechanically than the alloy; their formation results in
blistering and cracking of the cladding – a
phenomenon known as hydrogen embrittlement.
My Assignment
The project is interested in studying the effect of
hydrogen accumulation in Zircaloy-4 and how it
causes the material to become brittle over time and
try to understand how to lengthen the materials
stability.
Methods
I have prepared samples of Zircaloy-4 to implant
hydrogen ions at various energy levels, which will
result in the protons being implanted at different
depths in the sample.
I will characterize the samples using nano- and microindentation techniques.
I will measure the depth of the indentations as a
function of the applied force to help provide some
insight into the embrittlement of the alloy.
Work Performed
Soon after meeting the lab group, I got to first
observe how to cut materials using a high precision
saw.
Polishing My Samples
Next we polished the Zirc-4 using a polishing machine.
Special Training
Radiation Facility at Texas A&M University
I was then trained on how to operate the accelerator.
Result of training on the 140 kV ion accelerator using
120 keV He ions.
Next Steps
I will run SRIM software to get data on Zircaloy-4 to determine
fluence levels.
I will use nano-indentation on one of my samples to determine a
baseline.
I will begin the implantation of protons into the metal using
different fluences.
http://www.youtube.com/watch?v=qjStle6_N8I
I will do the indentation measurements on the irradiated
samples.
Finally, I will observe the irradiated samples using SEM.
Summary
It is now up to individual power plants to safely take
care of the spent nuclear fuel on site.
This will require storage for a long period of time.
This raises safety issues for the general population.
Therefore, this project will be one small piece in
helping determine the continued use of Zircaloy-4 as
a safe cladding material.
Acknowledgements

TAMU E3 Program

National Science Foundation

Nuclear Power Institute

Dr. Lin Shao

Dr. Wayne Kinnison

Michael Martin

Richard Vega

Michael General

Josey Wallace