Sensitivity and uncertainty analysis of core criticality for the transformational challenge reactor

Sensitivity and uncertainty analysis is an important part of the overall TCR reactor design effort. The sensitivity and uncertainty of the calculated Keff of the TCR core was assessed and demonstrated in this work. With the scqueniial calculations using TSUNAMI-3D, TSUNAMI-IP, and USLSTATS, the SDF of this core was produced, a set of potentially applicable critical experiments were identified. and the bias and bias uncertainty in the calculated keff of the TCR core were determined by using data from the set of critical experiments. Given the uniqueness of the TCR core design, there is only a small number of critical experiments that have a high (i.e., above 0.8) similarity index to this core, which partially caused the bias and bias uncertainty to be relatively large, as observed in this work. The bias and bias uncertainty in the calculated keff, for this and future TCR core designs, that can be quantified using the methodology tested in this exercise, will be factored into the core design activities to ensure there will be sufficient reactivity margin to start up the reactor and also sufficient control rod/shroud worth to shut down the reactor.