Implementation and verification of a point kinetics module in the subchannel code KTF

Abstract

Consulta en la Biblioteca ETSI Industriales(9120)

[EN] In this document the integration and verification of a point kinetics module within the KTF code is reported. This work was performed in an internship of 6 months at INR as part of the final master project under the Erasmus program of the Technical University of Valencia.The point kinetics module was taken from the COBRA-TF version developed and maintained at Pennsylvania State University (PSU). This module takes into account the thermal-hydraulic feedback with the reactivity coefficients, the decay heat deposition and a programmed time-dependent reactivity insertion via input (i.e. to simulate control rod insertions/extraction). With the new module, KTFis able to describe the core behavior during postulated transients e.g. RIAs, flow reduction, etc. where a interaction between the core neutronics and the thermal hydraulics plays an important role. . The use of the point kinetics approximation is justified when the spatial distribution of the power density is not time dependent and hence point kinetics gives a good estimation ofthe total power evolution versus time. The work reported is divided inthree Chapters. The first Chapterconsists in the validation of the mathematical method implemented in the point kinetics module (PKM from now on) taken from COBRA-TF against the numericalsolution for some simple problems. The PKM is based on the analytical solution of the point kinetics equations.The validation wasdone for different reactivity changes, i.e. constant, jump, and ramp modes. In the second Chapter, a code to code comparison between COBRA-TF and KTF is presented to show the performance of the PKMimplementation in KTF compared to the one implemented in COBRA-TF. A comparison of results obtained for 4 different scenarios is given and discussed. In the last Chapter the KTF PKM is compared with the equivalentTRACE Point kinetic model by the analysis of loss of flow transient scenario in a PWR core. Finally, several auxiliary tools have been developed to facilitate the post processing of the data and the discussion of the obtained results.