COLLOQUIUM: What is the Fusion Nuclear Science Facility, What Does it Do, Why do We Need It...the Critical First Step Toward Power Plants

For fusion research to take the step beyond ITER it will have to embrace the fusion nuclear science along with fusion plasma science.   The hardware that surrounds and supports the plasma will become part of the challenge for research and development since fusion power plants will rely on these structures to recover the power emitted, breed the tritium fuel, provide neutron and gamma shielding, and provide the magnetic fields and the vacuum environment the plasma requires.  The Fusion Nuclear Science Facility (FNSF) is a fusion nuclear device that is considered as the first step in a two-step pathway from ITER to commercial power plants in the U.S.   The project reported here is exploring a conventional aspect ratio facility to better understand its characteristics and how it moves the demonstration of sustained fusion energy production toward our present vision of power plants.  In order to address this facility several technical strategies and choices had to be established, including the need for a fusion break-in step, the importance of power plant relevance, the practicality of a single primary blanket approach, the need for a fusion core component qualifications, the need for a plasma strategy, and a series of technical decisions that stem from these.   A series of missions that must be accomplished to reach an electricity producing power plant are described, and several metrics are proposed for measuring their progress.  A program is postulated for the FNSF to expose the steps required to advance these missions, and force the consideration of allocating time to plasma operations, inspections, and maintenance.  The operating point (its geometry) is used in detailed analysis of the plasma and engineering systems to establish the credibility of such a facility at its smaller size, identify the benefits/penalties of specific technical decisions, uncover vulnerabilities and approaches to provide margin, and help in establishing targeted R&D for the FNSF.