THE UK NATIONAL THERMAL-HYDRAULICS FACILITY: MOTIVATIONS, DESIGN AND PLANNING STATUS M Dahlfors, J Joannou, A Brummitt, M J D Rushton, S C Middleburgh and W E Lee EPJ Web Conf., 247 (2021) 20006 Published online: 22 February 2021 DOI: 10.1051/epjconf/202124720006