Assessment of the importance of neutron multiplication for tritium production

Abstract

One of the major requirements for a fusion power plant in the future is tritium self-sufficiency. For this reason the scientific community has dedicated a lot of effort to research activity on reactor tritium breeding blankets. In the framework of the international project DEMO, many concepts of breeding blanket have been taken into account and some of them will be tested in the experimental reactor ITER by means of appropriate test blanket modules (TBMs). All the breeding blanket concepts rely on the adoption of binary systems composed of a material acting as neutronic multiplier and another as a breeder. This paper addresses a neutronic feature of these kinds of systems. In particular, attention has been focused on the assessment of the importance of neutrons coming from multiplication reactions for the production of tritium. A theoretical framework has been set up and a procedure to evaluate the performance of the multiplier-breeder systems, under the aforementioned point of view, has been developed. Moreover, the model set up has been applied to helium cooled lithium lead and helium cooled pebble bad TBMs under irradiation in ITER and the results have been critically discussed.

Identification of blanket design points using an integrated multi-physics approach

“…As a matter of fact, in order to achieve the main functions of the BB several analysis fields have to be investigated during the conceptual design [1,2]. These functions consist of: 1) recovering the heat generated in the plasma and transferring it to the coolant, 2) breeding the tritium burnt in fusion reaction [3] and 3) shielding the Vacuum Vessel and superconducting coils from thermal and nuclear radiations [4]. As the BB is a complex multi-physics reactor component, the main R&D campaigns basically involve analyses of different kinds, such as neutronics, thermal-hydraulics [6] and structural mechanics [7].…”