Page 342 - Fundamentals of Magnetic Thermonuclear Reactor Design

318 Fundamentals of Magnetic Thermonuclear Reactor Design

use the electrically insulating barrier at the duct wall/liquid metal interface. All
modules, excluding the Russian and the Korean ones, use the barrier to limit
tritium loss due to diffusion.

10.6 BLANKET DESIGN PROBLEMS

The key problems of the blanket design, addressed by the R&D programme and
calling for innovative solutions are as follows:

l Creation of new materials, identification of their basic characteristics and
working out of relevant blanket fabrication processes
l Off-reactor tests, to be carried out as part of the functional system design
optimisation
l Tests using reactor as a laboratory to understand how materials and func-
tional systems respond to neutron fluxes and
l Testing of functional systems in facilities producing neutrons through a
fusion reaction, such as ITER, IFMIF (the International Fusion Materials
Irradiation Facility), and CTF (the fusion Component Test Facility).
Let us take a closer look into the main aspects of this R&D programme.
Structural, moderating and reflecting materials:

l Development of low-activation materials that perform well at high tempera-
tures, have strong mechanical properties and can withstand intensive neu-
tron irradiation.
l Obtaining of thermal physics and strength properties of such materials in
required temperature and fast-neutron fluence ranges.
l Ensuring compatibility between a structural material and a coolant.
l Decrease of tritium absorption rate, and reduction of tritium trapping by ma-
terials providing them with specific capabilities and/or systematic removal
of trapped tritium.
l Mastering of processes that support commercial handling of radioactive
structural materials.
l Blanket comprehensive design optimisation ensuring, among other things,
reduction in metal consumption.
Ceramic breeding materials:
l Adjustment of processes for granulating and packaging 1–5-mm pebbles to
a maximum attainable compaction.
l Development of materials that can demonstrate adequate thermal physics
and mechanical properties in design temperature, durability and neutron flu-
ence ranges.
l Breeding process research and development of relevant databases.
l Adjustment of optimised tritium extraction processes, and identification of
relevant operating temperature ranges.