Crush strength of encapsulated microspheres

Technical Report · Thu Dec 15 04:00:00 EST 1988

OSTI ID:6500067

Marra, J E

The use of coated microsphere fuels has been suggested for the Savannah River Plant's (SRP) operating reactors as well as for the Low-Temperature Heavy-Water (LTHW) New Production Reactor (NPR). A program is underway to examine the feasibility of incorporating coated microsphere fuels into the well developed powder metallurgy (PM) fuel fabrication process. The coated microspheres were developed for use in the High-Temperature Gas-Cooled Reactor (HTGR). The reference fuel (Triso-coated) for the HTGR consists of an uranium oxycarbide kernel encapsulated in a porous pyrolytic carbon buffer, a dense pyrolytic carbon inner layer (IPyC), a SiC layer, and a dense pyrolytic carbon outer layer (OPyC). For the microspheres to contain gaseous fission products, less than one particle in 1000 can fail during fabrication and/or irradiation. Early SRL efforts have shown that conventional Triso-coated particles do not survive fabrication by PM/sup 2/. Measurements of the crush strength of coated microspheres show that removal of either the pyrolytic carbon buffer or the outer pyrolytic carbon layer lowers the fracture resistance of the microspheres. These results indicate that Triso coated microspheres are more likely to fracture during fabrication of SRP fuel if the microspheres are down sized by removal of either of the pyrolytic carbon layers.

• Research Organization: Du Pont de Nemours (E.I.) and Co., Aiken, SC (USA). Savannah River Lab.
• DOE Contract Number: AC09-76SR00001
• OSTI ID: 6500067
• Report Number(s): DPST-88-1006; ON: DE89006759
• Country of Publication: United States
• Language: English

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FAILURES
FRACTURES
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