2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/190984We work in a chiral invariant quark model, with a condensed vacuum, characterized by only one parameter. Bound state equations for the nucleon and Delta are solved in order to obtain an updated value of their radii and masses. Nucleon-nucleon S-Wave scattering is studied in the RGM framework both for isospin T=1 and T=0. The phase shifts are calculated and an equivalent local potential, which is consistent with K-N scattering, is derived. The result is a reasonable microscopic short range repulsion in the nucleon-nucleon interaction.23 pages in latex revtex, 4 Postscript figuresNuclear Theorytext