I. Palermo

Tritium production assessment for the DCLL EUROfusion DEMO

The viability of a fusion reactor is preeminently conditioned by the tritium self-sufficiency. An assessment of different parameters representing the tritium production, as the tritium breeding ratio (TBR), the tritium production rate (TPR) density and their poloidal and radial variations along the PbLi breeder zones has been performed for the last DCLL DEMO designs developed in the frame of the EUROfusion Programme. The final overall value of 1.104 obtained allows accomplishing the fuel self-sufficiency requirement. This TBR value includes not only the contribution of the breeding blanket (BB) modules but also of the back supporting structure (BSS). The BSS design resulted fundamental to reach the 1.1 criterion. Lastly, the influence of the integration in the reactor of the heating and current drive (H&CD) systems that will penetrate the breeder volume has been evaluated. Assuming different configurations for them, the TBR loss has been determined. All the calculations have entailed the use of the particle transport Monte Carlo code MCNP5.

Neutronic design studies of a conceptual DCLL fusion reactor for a DEMO and a commercial power plant

Neutronic analyses or, more widely, nuclear analyses have been performed for the development of a dual-coolant He/LiPb (DCLL) conceptual design reactor. A detailed three-dimensional (3D) model has been examined and optimized. The design is based on the plasma parameters and functional materials of the power plant conceptual studies (PPCS) model C. The initial radial-build for the detailed model has been determined according to the dimensions established in a previous work on an equivalent simplified homogenized reactor model. For optimization purposes, the initial specifications established over the simplified model have been refined on the detailed 3D design, modifying material and dimension of breeding blanket, shield and vacuum vessel in order to fulfil the priority requirements of a fusion reactor in terms of the fundamental neutronic responses. Tritium breeding ratio, energy multiplication factor, radiation limits in the TF coils, helium production and displacements per atom (dpa) have been calculated in order to demonstrate the functionality and viability of the reactor design in guaranteeing tritium self-sufficiency, power efficiency, plasma confinement, and re-weldability and structural integrity of the components. The paper describes the neutronic design improvements of the DCLL reactor, obtaining results for both DEMO and power plant operational scenarios.