• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.18 no.1
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• pp.31-41
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• 2020

We studied the anisotropic shrinkage and deformation characteristics of large size sintered bodies in the manufacturing of glass-ceramic composite wasteform. We used uranium-bearing waste, generated from the treatment of spent uranium catalyst. Sintered specimens were prepared in several forms, comprising a circular disk, and a quarter disk in several diameters of up to 40 cm. Regardless of form or size, the sintered bodies had high isotropic shrinkage when they were fabricated using green bodies prepared at 60 MPa. The average anisotropy rate and average shrinkage rate were 1.6%, and 37.4%, respectively. We confirmed that the glass-ceramic composite wasteform in a large scale disk-type for packing in a 200 L drum could be fabricated with a tolerable anisotropy shrinkage. This has resulted in a significant reduction in the volume of radioactive waste to be disposed of with highly stable wasteform.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.2
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• pp.91-97
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• 2013

Pyrolysis and surface recession of charring composites are progressed primarily in the thickness direction. The unmixing-mixing scheme is applied to describe the in-plane and through-thickness behaviors of porous composites. The extended unmixing-mixing equations are based on transverse isotropy of unidirectionally fiber-reinforced composites. The strain components of gas pressure in pores, thermal expansion, and chemical shrinkage are included in the constitutive model. By analyzing micromechanical representative volume elements of porous composites, the validity of the derived equations are examined.