Oxygen concentration measurement in liquid lead-bismuth eutectic Page: 2 of 7
This article is part of the collection entitled: Office of Scientific & Technical Information Technical Reports and was provided to Digital Library by the UNT Libraries Government Documents Department.
The following text was automatically extracted from the image on this page using optical character recognition software:
Oxygen Concentration Measurement in Liquid Pb-Bi Eutectic
T. W. Darling, Ning Li
Los Alamos National Laboratory, Mail Stop K764, MST-10, Los Alamos, New Mexico 87544
Abstract - Liquid lead-bismuth (Pb-Bi) eutectic (LBE) may see extensive use as a coolant fluid, and
perhaps also as a spallation target, in next generation nuclear energy systems. While it is not as reactive
as alkali metal liquids, it does present a long term corrosion problem with some materials, notably
stainless steels. Mitigation of the corrosion problem may be achieved by producing and maintaining a
protective oxide on exposed surfaces, through control of the concentration of dissolved oxygen in the LBE.
We have developed an oxygen sensor based on available zirconia-based solid electrolytes used in the
automotive industry, which represents a relatively inexpensive source of reproducible and reliable
components. We will present the design considerations and characteristics of our sensor unit, and describe
its use in the LBE test loop at Los Alamos for measurement and control of dissolved oxygen concentration.
Liquid metals in general are reactive,
tending to dissolve, amalgamate or alloy with,
other metals. Liquid lead-bismuth alloy is known
to be particularly aggressive towards iron and
nickel, major components of stainless steels. The
long term reliability of piping containing such is
determined by its resistance to being dissolved,
eroded or corroded by the liquid. This resistance
is greatly enhanced if a protective layer of oxide
exists on the metal surfaces in contact with the
liquid. Monitoring such a layer inside the
system is difficult, but the oxygen chemistry is
sufficiently well known that if we measure the
temperature and the concentration of oxygen
dissolved in the liquid lead bismuth, we can
control the conditions for maintaining the oxide
layer. Extensive work in Russia at the IPPE
supports this proposition. Measurements of
oxygen levels in the liquid lead-bismuth may be
made by measuring the voltage developed across
doped zirconia ceramics when a difference in
oxygen concentration also exists across them.
The material is relatively expensive and
construction of reliable temperature-cycling
joints is difficult. The automobile industry has
many years of experience in these ceramics for
exhaust line oxygen sensors. These
commercially available elements have many
advantages: consistent materials properties; a
convenient conical shape; a formed flange for
mechanically holding and sealing the element.
We describe our initial results using an
automobile-style YSZ oxygen sensor unit to
measure oxygen levels in a LBE test system as a
precursor to use in the large LBE materials test
loop at Los Alamos.
II. MATERIALS AND OPERATING
The measurement of relative oxygen
concentration in liquid metals using solid
electrolyte membranes is well established.3'4
Solid electrolytes are materials which are
permeable to specific ions. In the case of a
sintered ceramic of zirconia, Zr02, 02- ions may
pass through the solid if the temperature is above
about 350C. The oxygen ions move by hopping
between defect sites.The number and
effectiveness of these sites is enhanced by
stabilizing (or partially stabilizing) the crystal
structure of the Zr02 into a cubic or monoclinic
structure by the addition of 8-18% yttria, Y203.
This is usually called YSZ or PSZ.
Since charge moves along with the ions, there is
also some electrical conductivity at high
temperatures. At these high temperatures, it is
even possible that electrons from bonding
Here’s what’s next.
This article can be searched. Note: Results may vary based on the legibility of text within the document.
Tools / Downloads
Get a copy of this page or view the extracted text.
Citing and Sharing
Basic information for referencing this web page. We also provide extended guidance on usage rights, references, copying or embedding.
Reference the current page of this Article.
Darling, T. W. (Timothy W.) & Li, N. (Ning). Oxygen concentration measurement in liquid lead-bismuth eutectic, article, January 1, 2001; United States. (https://digital.library.unt.edu/ark:/67531/metadc925971/m1/2/: accessed April 18, 2019), University of North Texas Libraries, Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.