SASSYS SAS4A-FPIN2 LIQUID-METAL REACTOR TRANSIENT ANALYSIS CODE SYSTEM FOR MECHANICAL ANALYSIS OF METALLIC FUEL-ELEMENTS/

The metal fuel version of the FPIN2 fuel element mechanics model has b een incorporated into the SASSYS/SAS4A code system. In this implementa tion, SASSYS/SAS4A provides the fuel and cladding temperatures, and FP IN2 performs the analysis of fuel and cladding deformation. The FPIN2 results aid in the understanding of accident progression by providing the estimates of the axial expansion of fuel, time and location of cla dding failure, and the condition of the fuel at the time of failure. T he validation of the integrated SASSYS/SAS4A-FPIN2 model has been perf ormed using the data from in-reactor TREAT tests for the prototypic bi nary and ternary fuels of the Integral Fast Reactor concept. The integ rated model calculations are compared with available experimental data for the six fuel elements in these rests, and good agreement is obtai ned for the key parameters related to transient behavior of the metall ic fast reactor fuel elements.