skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Alternative Crucibles for U-Mo Microwave Melting

Abstract

The crucibles used currently for microwave melting of U-Mo alloy at the Y-12 Complex contain silicon carbide (SiC) in a mullite (3Al 2O 3-2SiO 2) matrix with an erbia coating in contact with the melt. Due to observed silicon contamination, Pacific Northwest National Laboratory has investigated alternative crucible materials that are susceptible to microwave radiation and are chemically compatible with molten U-Mo at 1400 1500C. Recommended crucibles for further testing are: 1) high-purity alumina (Al 2O 3); 2) yttria-stabilized zirconia (ZrO 2); 3) a composite of alumina and yttria-stabilized zirconia; 4) aluminum nitride (AlN). Only AlN does not require an erbia coating. The recommended secondary susceptor, for heating at low temperature, is SiC in a “picket fence” arrangement.

Authors:
 [1]
  1. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1400354
Report Number(s):
PNNL-26479
DN2006000; TRN: US1800573
DOE Contract Number:
AC05-76RL01830
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS; MICROWAVE RADIATION; MELTING; CRUCIBLES; ALLOYS

Citation Formats

Kirby, Brent W. Alternative Crucibles for U-Mo Microwave Melting. United States: N. p., 2017. Web. doi:10.2172/1400354.
Kirby, Brent W. Alternative Crucibles for U-Mo Microwave Melting. United States. doi:10.2172/1400354.
Kirby, Brent W. Fri . "Alternative Crucibles for U-Mo Microwave Melting". United States. doi:10.2172/1400354. https://www.osti.gov/servlets/purl/1400354.
@article{osti_1400354,
title = {Alternative Crucibles for U-Mo Microwave Melting},
author = {Kirby, Brent W.},
abstractNote = {The crucibles used currently for microwave melting of U-Mo alloy at the Y-12 Complex contain silicon carbide (SiC) in a mullite (3Al2O3-2SiO2) matrix with an erbia coating in contact with the melt. Due to observed silicon contamination, Pacific Northwest National Laboratory has investigated alternative crucible materials that are susceptible to microwave radiation and are chemically compatible with molten U-Mo at 1400 1500C. Recommended crucibles for further testing are: 1) high-purity alumina (Al2O3); 2) yttria-stabilized zirconia (ZrO2); 3) a composite of alumina and yttria-stabilized zirconia; 4) aluminum nitride (AlN). Only AlN does not require an erbia coating. The recommended secondary susceptor, for heating at low temperature, is SiC in a “picket fence” arrangement.},
doi = {10.2172/1400354},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Fri Mar 31 00:00:00 EDT 2017},
month = {Fri Mar 31 00:00:00 EDT 2017}
}

Technical Report:

Save / Share:
  • Silicon carbide (SiC) crucibles were used to melt aluminum and copper in conventional and tuned microwave cavities at a microwave frequency of 2450 MHz. SiC crucibles were also used to vitrify and homogenize mixtures of nuclear waste and glass frit.
  • A new material, Tribocor 532N (an alloy of 50 wt % niobium-30 wt % titanium-20 wt % tungsten (50Nb-30Ti-20W) nitrided at >1800/degree/C), has been shown to be an excellent crucible/susceptor for melting and casting uranium and its alloys in a noncarbon environment. Testing has progressed from very small-scale initial tests to intermediate-scale foundry tests with performance better than graphite containment. Lifetime tests of Tribocor 532N indicate an improvement of more than an order of magnitude as compared to graphite. The Tribocor 532N is far superior to oxide-based ceramics and experiences no cracking from thermal cycling, is capable of directly susceptingmore » in an induction field for induction heating, and is stable with graphite---allowing any portion of a graphite stack to be replaced interchangeably with Tribocor 532N. Tribocor 532N can be coated with standard paint, and it performs equally well with the more economical zirconia coating instead of yttria, while also being compatible with erbia coatings that are suitable for enriched uranium. Since Tribocor 532N contains no carbon, a Tribocor crucible should introduce less carbon during melt cycles and enable more recycled metal to be used without increasing carbon levels. The long lifetime projections for Tribocor 532N make the material economical. A large-scale crucible of Tribocor 532N will be tested. 14 refs., 11 figs., 7 tabs.« less
  • 24p. Bottom-pour Ta and CaF/sub 2/-coated steel melt crucibles for Pu and Pu-rich alloys were developed. The controlled pour is effected by melting a Pu plug in the bottom spout of the crucible after the desired temperature and vacuum conditions are obtained. A description is given of the development of the crucibles which have replaced ceramic crucibles for casting work on the kilogram scale. (auth)
  • Flame-sprayed magnesium zirconate was evaluated as a crucible coating and mold coating for the vacuum melting and casting of uranium. The quality of the metal was affected by the use of this coating. Slug-to-good-slug yields were decreased when the coating was used on crucibles and were increased when the coating was used on molds. Carbon and hydrogen levels in ingots melted in magnesium zirconate-coated crucibles were decreased, but not significantly. (auth)