Comparison of EQL0D V2 and V4 Procedures by Means of Equilibrium U-Pu and Th-U Cycles in 16 Selected Reactors

Abstract Three papers related to the equilibrium fuel cycle in 16 selected reactors were submitted to ICONE 31 conference. In this first paper, the major equilibrium cycle characteristic obtained by EQL0D v4 are compared to the previous results simulated by EQL0D v2. These older simulations were accomplished for infinite lattice and neglected fission products. Therefore, the results presented in this paper apply the same simplification to enable a cross-comparison. The impact of leakage from finite core and of the fission products are addressed in the second and third paper from this series. The same 16 reactors are simulated, 8 with thermal and 8 with fast neutron spectrum as in the existing study. EQL0D v2 simulations use only the ENDF/B-VII.0 library, while EQL0D v4 can choose between eight different libraries. To allow cross-comparison, results are presented for the ENDF/B-VII.0 cross-section library. To demonstrate the new capabilities, results are also shown for the ENDF/B-VIII.0 library. Even though, the EQL0D v2 and v4 substantially differ in the treatment of cross-sections provided by the Serpent 2 code and rely on different version of this code, their results are very similar. The excess reactivity, its nuclide-wise break-down and other parameters like migration area are in good agreement. The difference between EQ0D v4 results for ENDF/B-VII.0 and ENDF/B-VIII.0 cross-section libraries is larger. This disparity is mainly caused by the lower 233U capture cross-section in the newer library, which results in decreased build-up of higher actinides nuclides.