A Historical Review of Cermet Fuel Development and the Engine Performance Implications

摘要

This paper reviews test data for cermet fuel samples developed in the 1960's to better quantify Nuclear Thermal Propulsion (NTP) cermet engine performance, and to better understand contemporary fuel testing results. Over 200 cermet (W-UO_2) samples were tested by thermally cycling to 2500°C (2770 K) in hydrogen. The data indicates two issues at high temperatures: the vaporization rate of UO_2 and the chemical stability of UO_2. The data show that cladding and chemical stabilizers each result in large, order of magnitude improvements in high temperature performance, while other approaches yield smaller, incremental improvements. Data is very limited above 2770 K, and this complicates predictions of engine performance at high I_(sp). The paper considers how this material performance data translates into engine performance. In particular, the location of maximum temperature within the fuel element and the effect of heat deposition rate are examined.