Interfaces in Ceramic Nuclear Fuels

Internal interfaces such as grain boundaries, pore surfaces and phase boundaries play a major role in determining the mechanical and to some extent thermal properties of most ceramic bodies. Other important interfaces are those between regions of different density, chemical composition or stress state. One major problem of the ceramic engineer is to prevent the ceramic component from failing at these interfaces under service conditions. The nuclear ceramist has to face most problems encountered by his non-nuclear colleague, but the need to predict and allow for radiation-induced changes as well as those due to temperature and stress effects during service life often makes his task more difficult. This paper explores some of these problems, using the interfaces in selected all-ceramic nuclear fuels as examples.