Multiphysics Optimization for Water-Cooled Breeding Blanket Design Enhancement

The commercial feasibility of the first fusion power plant generation adopting D-T plasma is strongly dependent upon the self-sustainability in terms of tritium fueling. Within such a kind of reactor, the component selected to house the tritium breeding reactions is the breeding blanket, which is further assigned to heat power removal and radiation shielding functions. As a consequence of both its role and position, the breeding blanket is heavily exposed to both surface and volumetric heat loads and, hence, its design requires a typical multiphysics approach, from the neutronics to the thermo-mechanics. During last years, a great deal of effort has been put in the optimization of the breeding blanket design, with the aim of maximizing the tritium breeding and heat removal performances without undermining its structural integrity. In this dissertation, a derivative-free optimization method named “Complex method” is applied for the design optimization of the European DEMO Water-Cooled Lithium Lead breeding blanket concept. To this purpose, a potential tritium production performances-based objective function is defined and a multiphysics model of the blanket is developed inside COMSOL environment in order to solve the coupled thermo-mechanical problem, while the optimization algorithm implemented in MATLAB leads the design towards a minimum optimum point compliant with the prescribed requirements. Once the optimized design is obtained, its nuclear, thermal-hydraulic and structural performances are assessed by means of specific neutron transport and multiphysics simulations, respectively. Finally, the structural integrity is verified by means of the application of the RCC-MRx design criteria.