An integral assessment has been performed to quantify the predictive capabilities of FAST, a
thermal-mechanical nuclear fuel performance code designed to analyze fuel behavior from beginning
of life to burnup levels allowed by the U.S. Nuclear Regulatory Commission (NRC). FAST
code calculations are shown to compare satisfactorily to a preselected set of experimental data
with both steady-state and anticipated operating occurrence (AOO) conditions and design basis
accident (DBA) transient operating conditions.
This document describes the assessment of FAST-1.2, the latest version of FAST, released March
2023.