Benchmark Comparison of the Oregon State TRIGA® Reactor Between MCNP® and Serpent 2

The results of a recently developed Serpent 2 model of the Oregon State TRIGA® Reactor (OSTR) are compared to the results from the OSTR MCNP® model and measured values for reactor steady state behavior. This benchmark comparison is performed using fresh fuel isotopic data and measured reactivity values at the beginning of the current core life in 2008 to negate burnup uncertainties in calculated values. Reactivity bias, integral control rod reactivity worths, core excess reactivity, shutdown margin, the fuel temperature coefficient of reactivity, and kinetic parameters calculated by Serpent 2 and MCNP® are compared to the measured values. The results from the Serpent 2 model strongly agree with both MCNP® results and measured values and are within one standard deviation of each other in all cases, with the exception of the Serpent 2 calculated total control rod reactivity worth, which slightly under-predicts the total rod worth when compared to the measured value despite the MCNP® and Serpent 2 calculated total rod worth values being within each other’s 1σ standard deviations.