Izvorni znanstveni članak

Influence of Spacer Grids Homogenization on Core Reactivity and Axial Power Distribution

Radomir Ječmenica, ; University of Zagreb, Faculty of Electrical Engineering and Computing Unska 3, 10000 Zagreb, Croatia
Davor Grgić, ; University of Zagreb, Faculty of Electrical Engineering and Computing Unska 3, 10000 Zagreb, Croatia
Mario Matijević ; University of Zagreb, Faculty of Electrical Engineering and Computing Unska 3, 10000 Zagreb, Croatia

Sažetak

The paper presents the influence of spacer grid homogenization during cross section
generation on core reactivity and axial power distribution. Homogenization calculation was
performed at fuel assembly level using FA2D code. The first approach is to smear uniformly all
centrally located spacer grids along 120 inches of fuel assembly and carry out 2D transport
calculation. The second approach is to smear spacer grid within 6 inches of fuel assembly and
perform homogenization calculation. That composition is then assigned to closest 6 in axial
subdivision of the core calculation. The last analysed option is to do additional localization of
spacer grids and carry out homogenization within 2 inches of fuel assembly height. The additional
subdivision is afterward performed of the closest regular axial core subdivision in nodal core
calculation. The core calculation was performed using modified PARCS 2.5 code for NPP Krško
cycle 29. The normalized axial power distributions obtained by PARCS for three different ways of
spacer grid homogenization are then compared to quantify the influence of modelling. Similar
comparison was performed for critical boron concentration. As expected larger influence is present
for axial power distribution (more details for fine localization), with some influence on axial power
offset and global reactivity.

Ključne riječi

homogenization, spacer grids, FA2D, PARCS, axial power distribution, axial offset

Hrčak ID:

247101

URI

https://hrcak.srce.hr/247101

Datum izdavanja:

28.10.2019.

Posjeta: 366 *