Advancements in DEMO WCLL breeding blanket design and integration

The water-cooled lithium–lead breeding blanket is a candidate option for the European Demonstration Power Plant(DEMO) nuclear fusion reactor. This breeding blanket concept relies on the liquid lithium– lead as breeder–multiplier,pressurized water as coolant, and EUROFER as structural material. The current design is based on DEMO 2015specifications and represents the follow-up of the design developed in 2015. The single-module-segment approach isemployed. This is constituted by a basic geometry repeated along the poloidal direction. The power is removed by meansof radial–toroidal (i.e., horizontal) water cooling tubes in the breeding zone. The lithium–lead flows in a radial–poloidaldirection. On the back of the segment, a 100-mm-thick plate is in charge of withstanding the loads due to normal operationand selected postulated initiating events. Water and lithium–lead manifolds are designed and integrated with a consistentprimary heat transport system, based on a reliable pressurized water reactor operating experience, and the lithium–leadsystem. Rationale and features of the single-module-segment water-cooled lithium–lead breeding blanket design arediscussed and supported by thermo-mechanic, thermo-hydraulic, and neutronic analyses. Preliminary integration withthe primary heat transfer system, the energy storage system, and the balance of plant is briefly discussed. Open issues, areasof research, and development needs are finally pointed out.