Optimization of a water-cooled divertor for the European power plant conceptual study

In this paper, a water-cooled divertor concept is assessed and optimized according to operating conditions foreseen for the water-cooled lithium lead (WCLL) blanket concept in the frame of the European Power Plant Conceptual Study (PPCS). In a power reactor, the potential performances of a divertor concept are judged not only by its capability to sustain high heat flux, but also by the availability of the extracted heat for power conversion. A water-cooled divertor is the preferred option when used with a WCLL blanket because it simplifies the reactor coolant system design and reduces the required R&D by using the same coolant for all components. A Cu-alloy tube is used as heat sink, armored by a tungsten monoblock. A swirl tape is inserted in the tube, as a turbulence promoter. This concept needs limited extrapolations from todayʹs plasma physics assumptions insofar it allows high surface heat fluxes (up to 15 MW m−2). At the same time, it permits the divertor power to contribute in the thermodynamic cycle of the plant with an overall maximum gross thermal efficiency of about 33% similar to that of a pressurized water reactor.