Examination of Factors Affecting the Quality of Vacuum Induction-Melted Uranium Page: 5
This report is part of the collection entitled: Technical Report Archive and Image Library and was provided to UNT Digital Library by the UNT Libraries Government Documents Department.
Extracted Text
The following text was automatically extracted from the image on this page using optical character recognition software:
CONFIDENTIAL
5
EXAMINATION OF FACTORS AFFECTING THE QUALITY
OF VACUUM INDUCT ION-MELT ED URANIUM
Roy W. Endcbrock, Ellis L. Foster, Jr. ,
and Ronald F. Dickerson
Uranium melting was investigated to determine what reactions, variable in
nature, could be detrimental to ingot purity at soundness. Experiments were con-
ducted with 104b uranium charges in a vacuum induction furnace 1200 liters in
volume. A special manifold allowed sampling of the furnace atmosphere for mass
spectrometer analyses at appropriate times after the furnace was isolated from the
vacuum system. If ells were made with a selected production grade of pure uranium.
The program included (l) exploratory melts in graphite with and without dgO
crucible dressings, (2) melts in graphite and sirconia crucibles under dry and wet
furnace conditions, (3) replicate experiments in which known quantities of hydrogen,
nitrogen, CO, oxygen, COp HjO, and argon were each admitted to the furnace to
determine pressure-time relationships and residual-gas compositions, and (4) a
demonstration of the water-gas reaction within the furnace.
The MgO crucible dressing tended to peel during initial outgoes in g. During the
melting cycle, JdgO was reduced and formed a black magnesium deposit within the
furnace. Cases and, especially, water vapor adsorbed by graphite components were
difficult to remove. To lower the outgas rate at 2500 F from 3 to 0.45 H per min, it
woe necessary to heat the crucible for 5-1/2 hr in the 2500 to 3100 F temperature
range at I x ICT* of mercury. Water and graphite at elevated temperatures pro-
duced hydrogen and CO, the products of the water-gas reaction. A secondary
reaction between CO and uranium resulted in a furnace atmosphere that wot mainly
hydrogen. Temperature variations between surface and subsurface metal were large.
Optical temperature determinations were affected by dross and varied considerably
with dross thickness. The integrity of the surface drois was a controlling factor of
the composition and amount of reactive gas remaining over the melt and of the
ability to reproduce data.
From a thermodynamic viewpoint, small changes in CO partial pres sure over the
melt will result In large changes in the carbon-oxygen level of the melt, and the
contribution of CO to contamination can be greater through this mechanism than by
the direct CO-uranium reaction.
INTRODUCTION
Uranium fuel slugs for production-type reactors must meet rigid quality specifi-
cations for acceptance. Fuel-slug quality, however, is directly dependent upon the
quality of the ingot from which slugs are fabricated. Metal quality is related to a vari-
ety cf chemical and physical effects which manifest themselves in variable degrees of
mefcil soundness and purity and which appear to originate in the melting and casting
phases of processing. The over-all study of the cause-and-effect relationship of the
processing parameters that contribute to metal rejection is complex as is attested by
thu amount of continuing research directed toward a better understanding of these proc-
ess variables.
CONFIDENTIAL
• • • , , , »» •• • ••• • ••• M
• •• . • • • • » • •• •• ••
.... . , •••••••••
... . • ••• • •• ••
... . . « •• • ••• •• • •
•• ... • ••• • • •• «• • • • ••• • •
Upcoming Pages
Here’s what’s next.
Search Inside
This report 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 Report.
Endebrock, Roy W.; Foster, Ellis L. & Dickerson, Ronald F. Examination of Factors Affecting the Quality of Vacuum Induction-Melted Uranium, report, July 3, 1958; Columbus, Ohio. (https://digital.library.unt.edu/ark:/67531/metadc714197/m1/3/: accessed April 24, 2024), University of North Texas Libraries, UNT Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.