Vitrification of High Chrome Oxide Nuclear Waste in Iron Phosphate Glasses
A simulated high level waste (HLW) containing 4 mass% chrome oxide, whose overall composition is representative of the high chrome oxide wastes at Hanford WA USA, was easily vitrified in a phosphate glass at temperatures ranging from 1150 °C, for waste loadings of 55 mass%, to 1250 °C for waste loadings of 75 mass%. Even at these high waste loadings, these wasteforms had an excellent chemical durability. The best chemical durability was achieved when the O/(Si + P) atomic ratio was between 3.5 and 3.8. These wasteforms were also resistant to crystallization although trace amounts of crystalline Cr2O3 were present in wasteforms containing more than 70 mass% HLW. It is concluded that up to 45 mass% of the total HLW at Hanford, especially that containing as high as 4.5 mass% chrome oxide, could be directly vitrified into an iron phosphate glass, that meets all of the current chemical durability requirements by simply adding 25-35 mass% P2O5 to the waste and melting the mixture at 1150-1250 °C for a few (<6) hours.
W. Huang et al., "Vitrification of High Chrome Oxide Nuclear Waste in Iron Phosphate Glasses," Journal of Nuclear Materials, Elsevier Inc., Jan 2004.
The definitive version is available at http://dx.doi.org/10.1016/j.jnucmat.2004.01.021
Materials Science and Engineering
Keywords and Phrases
High Chrome Oxide; Iron Phosphate Glass; Nuclear Waste; Vitrification
Article - Journal
© 2004 Elsevier Inc., All rights reserved.