Serpent-2 and OSCAR-4 computational tools compared against McMaster nuclear reactor improved operational data history for U-235 fuel inventory tracking, local power tracking and validation of multiplication factor

The tracking of fuel inventory is important for safety and for knowledge of the flux distribution. In a research reactor, tracking of the reactor core fuel composition using simulation code is crucial for fuel management strategy, such as by optimizing the core pattern for sample irradiation purposes and for providing an economical fuel cycle length. Operational data history for the McMaster Nuclear Reactor (MNR) is a valuable asset for comparing and validating simulation code. A previous study examined U-235 content using the nodal diffusion code Overall System for CAlculation of Reactors (OSCAR-4) against standard MNR operational data and recommended considering the Pu-239 content in the energy production in the standard operational data. In this work, a new method was implemented by introducing a Fuel Inventory Correction (FIC) factor for improving the U-235 operational data records. U-238 and Pu-239 code-to-code tracking comparisons were also employed. The maximum difference between U-235 at end of life (EOL) and the updated operational data history was 2.43% and 6.97% for Serpent 2 and OSCAR-4, respectively. The FA power profile tracking showed a similar response whenever fuel shuffling and/or refueling occurred, with a maximum different of 16% (30 kW) in one cycle. The multiplication factors for the two sets of code differed systematically, averaging 0.9982 and 1.0051 for Serpent 2 and OSCAR-4, respectively.