DEVELOPMENT OF 3D PIN-BY-PIN CORE SOLVER TORTIN AND COUPLING WITH THERMAL-HYDRAULICS P. Mala, A. Pautz, H. Ferroukhi and A. Vasiliev EPJ Web Conf., 247 (2021) 02034 Published online: 22 February 2021 DOI: 10.1051/epjconf/202124702034