Parametric thermal analysis for the optimization of Double Walled Tubes layout in the Water Cooled Lithium Lead inboard blanket of DEMO fusion reactor

Pietro Arena,Pietro Alessandro Di Maio,Alessandro Del Nevo,Ruggero Forte,Giulio Nevone

doi:10.1088/1742-6596/1224/1/012031

Abstract

Within the roadmap that will lead to the nuclear fusion exploitation for electric energy generation, the construction of a DEMOnstration (DEMO) reactor is, probably, the most important milestone to be reached since it will demonstrate the technological feasibility and economic competitiveness of an industrial-scale nuclear fusion reactor. In order to reach this goal, several European universities and research centres have joined their efforts in the EUROfusion action, funded by HORIZON 2020 UE programme. Within the framework of EUROfusion research activities, ENEA and University of Palermo are involved in the design of the Water-Cooled Lithium Lead Breeding Blanket (WCLL BB), that is one of the two BB concepts under consideration to be adopted in the DEMO reactor. It is mainly characterized by a liquid lithium-lead eutectic alloy acting as breeder (lithium) and neutron multiplier (lead), as well as by subcooled pressurized water as coolant. Two separate circuits, both characterized by a pressure of 15.5 MPa and inlet/outlet temperatures of 295 °C/328 °C, are deputed to cool down the First Wall (FW) and the Breeder Zone (BZ). The former consists in a system of radial-toroidal-radial C-shaped squared channels where countercurrent water flow occurs while the latter relies in the use of bundles of poloidal-radial Double Walled Tubes (DWTs) housed within the breeder.A parametric thermal study has been carried out in order to assess the best DWTs’ layout assuring that the structural material maximum temperature does not overcome the allowable limit of 550 °C and that the overall coolant thermal rise fulfils the design target value of 33 °C. The study has been performed following a theoretical-numerical approach based on the Finite Element Method (FEM) and adopting the quoted Abaqus FEM code. Main assumptions and models together with results obtained are herewith reported and critically discussed.

Highlights

In the future, nuclear fusion power reactors might represent a very interesting alternative to the conventional power plants using fossil fuels for electric energy generation
Within the framework of EUROfusion research activities, ENEA and University of Palermo are involved in the design of the Water-Cooled Lithium Lead Breeding Blanket (WCLL BB), that is one of the two BB concepts under consideration to be adopted in the DEMO reactor
The WCLL BB inboard segment design equipped with a “beer box” SP grid configuration has been considered, that relies on the use of both horizontal and vertical SPs extending for the whole radial length of the module, from First Wall (FW) to Back Plate (BP), and delimiting several toroidal-radial cells articulated in central and lateral units (CUs and Lateral Unit (LU)), each provided with its own bundle of Double Walled Tubes (DWTs)

Summary

Introduction

Nuclear fusion power reactors might represent a very interesting alternative to the conventional power plants using fossil fuels for electric energy generation. Within the roadmap leading to the realization of net electric power from nuclear fusion reactions on an industrial scale [1], the DEMOnstration (DEMO) fusion reactor will have the role of proving the technical feasibility of such a power plant assessing, at the same time, its economic competitiveness on the worldwide energy market.

Published under licence by IOP Publishing Ltd

Vertical SP

CU Layout

Conclusions