ADAPTIVE TIME-STEP CONTROL FOR THE MODAL METHOD TO INTEGRATE THE MULTIGROUP NEUTRON DIFFUSION EQUATION A. Carreño, A. Vidal-Ferràndiz, D. Ginestar and G. Verdú EPJ Web Conf., 247 (2021) 07010 Published online: 22 February 2021 DOI: 10.1051/epjconf/202124707010