TritiumStopp

Motivation

The project focuses on a specific topic: protecting materials in contact with tritium in nuclear fusion power plants from tritium permeation. Tritium is an extremely valuable resource; the breeding reaction provides very limited reproduction rates, so supercritical tritium loss could become a bottleneck in the realization of fusion power plant concepts, a risk that has been underestimated thus far. Thin oxide, nitride, or diamond-like barrier layers have the potential to reduce tritium permeation in wall materials to negligible levels. However, only vague and poorly comparable data on freshly deposited layers is currently available. In addition to the question of the long-term barrier effect, it is unclear to what extent the barrier effect persists under the stress conditions of fusion power plant operation. The main question, in addition to the mechanical and thermal effects, is to what extent neutron irradiation causes atomistic and microstructural changes in the coatings that permanently damage their barrier effect.

Aims and Procedure

This project involves systematically investigating different thin-film variants to study the long-term stability of the permeation barrier effect under the aforementioned stress factors. These investigations will be conducted systematically using a measuring station and deuterium irradiation, accompanied by comprehensive before-and-after material diagnostics. The metal nitride, oxide, and diamond-like carbon layer variants are examined. Recognizing the importance of the initial structure of the coatings, various deposition processes are employed, and the coating parameters are varied. Attention is always paid to the practical applicability to real components of the fusion power plant. One aim of the project is to demonstrate implementation concepts differentiated according to the respective location of use.

Innovation and Perspective

First, we aim to gain fundamental material science findings on cause-and-effect mechanisms regarding layer type, structure, morphology, and defects that affect the barrier effect against tritium permeation. On the other hand, the goal is to gain knowledge that can be directly applied to the design of practical power plant concepts. Although the topic is specifically related to the issue of tritium fusion power plants, the results are also valuable for all conventional hydrogen applications involving permeation.