Dr. Deborah Hill is the Criticality Technical Leader and a Senior Fellow for Criticality Safety within the NNL Safety, Security & Safeguards team. Deborah has been with NNL and its precursors for over 20 years and is currently responsible for the content and quality of the technical work undertaken by a team of twelve criticality specialists, as well as developing and promoting the wider NNL technical capability in her role as a Senior Fellow. Deborah has a BSc and PhD in Physics from the University of Warwick and is a Chartered Physicist. She held the position of Chair of the UK Working Party on Criticality from 2006 – 2015 and is currently the Chair of the American Nuclear Society Nuclear Criticality Safety Division.