Performance prediction of high density nuclear fuel plate containing U-7%Mo/Al

In recent several years, the Center for Nuclear Fuel Technology (PTBN) - BATAN is conducting research and development on new research reactor fuel of U-Mo/Al dispersion containing 7 g U/cm³ as a substitute for the actual U₃Si₂ fuel of 2.96 g.U/cm³ . The major advantages of this fuel are higher U content than the U₃Si₂ and easier management, i.e. reprocessing of the spent fuel, while the main drawback is the manufacture of powder that is more difficult because it is more ductile and its thermal conductivity degrade faster during in reactor service. The first difficulties have been solved by hydriding process. Performance prediction should be foreseen in order to obtain permit for irradiation testing of the new fuel. The prediction has been performed on hot spot location by taking into account some effects of fission swelling of fuel particles, formation of interfacial reaction layer, meat densification which feedback to fuel temperature and plate swelling the principal safety parameters of normal operation. The results show that at lower burnup the dominant effect is fission solid swelling but at higher burnup it is replaced by fission gas swelling. At 60% burnup (10.2 x 10⌃21 fission/cm³ ) fuel particle swelling reaches 75.79% and at total burnup swelling rises to 103.1%, which corresponds to 11.6% and 17.2% plate pillowing. The interfacial reaction layer at full burnup is 5.7 µm. Plate pillowing at 60% burnup is below the limit acceptance but plate pillowing at full burnup is beyond the limit acceptance. (author)