Development of SARAX code system for full-range spectrum adaptability in advanced reactor analysis.

• The SARAX code system was extended for full-range spectrum adaptability. • The assembly calculation is based on the improved Tone's method with MOC solver. • The high-efficient 2-D hyperfine group method was developed. For better self-shielded cross-section generation in advanced reactor analysis with full-range spectrum adaptability, the 2-D subassembly calculation capability has been recently developed with several new methods in the SARAX code system. The improved Tone's method was implemented in the 2-D resonance self-shielding by incorporating the MOC to accurately estimate the heterogeneity effect. The 2-D hyperfine group method with on-the-fly collision probability and the adjacent region flux approximation was developed to perform the 2-D slowing-down spectrum calculation. For better consideration of spectral transition effects due to different mean free path of neutrons, the local super-subassembly model and the whole-core equivalent model can be built with the super-homogenization technique. Verification results showed that for different subassembly calculations, the eigenvalue and self-shielded cross-sections of major actinides agreed with the OpenMC solutions. For core calculations of TRIGA and the reactor with irradiation tunnel, the k-effective and power distribution also agreed well with the OpenMC. [ABSTRACT FROM AUTHOR]