Abstract:
The integral fuel burnable absorber (IFBA) coated with zirconium diboride (ZrB
2) on the surface of UO
2 pellets is used for the reactivity control of fuel assemblies in light water reactors. The SCIENCE code package developed by AREVA has the capability of simulating IFBA assembly. However, the simulation accuracy requires calibration. The Westinghouse RFA-2 assemblies with and without IFBA rods were modeled by APOLLO2-F code. The infinite multiplication factor
k∞ and IFBA value were studied and the corresponding results with Westinghouse were compared and analyzed. The different treatment methods of the fuel and cladding temperature and differences in the database were also studied. The deviation of IFBA value may affect reactor core parameters and power distribution, and its impact was assessed by analyzing the ZrB
2 density correction factor. The preliminary results show that
k∞ and IFBA value calculated by SCIENCE code agree well with Westinghouse results and the former is about 2% lower than the latter at low burnup zone. The maximum of assembly relative power deviation is about 1% in the core loaded with 8 assemblies with 104 IFBA rods. The changes of boron concentration, power peak factor
FQ and enthalpy rise factor
FΔH can be ignored. The lead using assembly with 28 or fewer IFBA fuel rods can be directly calculated using the SCIENCE code.