Monte Carlo calculation analysis of PWR-type fuel assembly mockup cores loaded with Gd₂O₃-UO₂ fuel rods in B&W 1810 series critical experiments

ABSTRACT

To extend the information on the validation of the JENDL-4.0 nuclear data library, continuous-energy Monte Carlo calculation was applied to the analysis of the twenty-two PWR-type fuel assembly mockup cores in the Babcock and Wilcox (B&W) 1810 series critical experiments which provided the benchmark data for the validation of the nuclear tools about using Gd₂O₃-UO₂ fuel rods. The critical analysis results showed that the effective neutron multiplication factors (k_eff) ranged from 0.99933 to 1.00040 and the average value was 0.99969. The k_eff values were scrutinized against the numbers of the Gd₂O₃-UO₂ fuel rods, the insertion of the Ag-In-Cd absorber rods and the B₄C absorber rods, and partially loading the 4.020 wt% UO₂ fuel rods. The analysis results of the core radial fission rate distributions of the six cores indicated that the calculations generally well reproduced the measurements of the fuel rods in the central fuel assemblies. It was observed that the relative differences between the calculated and measured fission rates of the Gd₂O₃-UO₂ fuel rods were larger than those of the neighboring UO₂ fuel rods. This trend was examined by comparing with the results of the precedent studies of the Monte Carlo and deterministic transport calculations.

KEYWORDS:

• B&W 1810 series critical experiment
• Gd₂O₃-UO₂ fuel rod
• boron concentration
• fission rate distribution
• critical analysis
• continuous-energy monte carlo code
• JENDL-4.0

Disclosure statement

No potential conflict of interest was reported by the author(s).

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