Cross-Section Generation Using TXT2NTAB Code for Uncertainty Propagation with Burnup Dependence

Abstract

One of the challenges of study the neutronics of reactor is to generate reliable parameterized libraries, which contains information to simulate the core in all possible operational and transient conditions. These libraries must include tables of cross-sections and other neutronics and kinetics parameters and are obtained by simulating all the assemblies in a transport code. At lattice level, one can use branch calculations to change "instantaneously" the feedback parameters as a function of burnup. When using random sampling for the lattice calculations, one can obtain statistical information of the output parameters and use it in a core simulation to characterize the accuracy of the data estimating uncertainties when simulating a heterogeneous system at different scales of detail. This work presents the methodology to generate NEMTAB libraries from data obtained in SCALE code system to be used in PARCS simulations. The code TXT2NTAB is used to reorder the cross-sections tables in NEMTAB format and generate another NEMTAB of standard deviation. With these libraries, the authors perform a steady state calculation for an LWR to propagate several uncertainties at the core level. The methodology allows to obtain statistical information of the most important output parameters: multiplication factor (keff), axial power peak (Pz) and axial peak node (Nz).