G8 Multilateral Research Funding Nu-FuSE

The primary focus of fusion energy research over the past decades has
been on magnetic confinement devices called tokamaks. The UK's JET
facility is currently the largest tokamak in the world but will be surpassed
by the international ITER device, now under construction in France.
Providing computational resources in support of ITER is a dedicated High
Performance Computer for Fusion (HPC-FF) at Jülich, Germany, which will
soon be expanded at Rokkasho, Japan in the International Fusion Energy
Research Center within the ``broader approach" framework between
Japan and the EU. Operation is planned to start in 2012. Simulation is
required in three principal areas: plasma physics, the powerful controlling
plasma-solid interaction/interface, and materials science. We have
constructed a consortium involving six countries (France, Germany, Japan,
Russia, UK and USA) with expertise in all three of these applications
domains as well as the underpinning computational science techniques.
We propose to use these skills to undertake an integrated research
programme focussed on investigating the scaling of key codes which have
relevance for providing experimentally validated predictive capabilities for
magnetic fusion systems.
On the path towards an economical magnetic confinement fusion reactor
integrated numerical models can speed up technological but also physical
progress, even mitigating possible bottlenecks.
Our proposal concentrates on codes for three scientific areas, the plasma
itself, the materials from which a reactor will be built, and the physics of the
plasma edge.
Previous research on materials and plasmas has been conducted
independently, and a key aspect of the proposal is to ensure that scientists
working in these areas are well versed in all the issues affecting putative
devices. We will train a cohort of young scientists who are genuinely
expert in "Fusion Energy", as opposed to the current division of expertise
between plasma physicists, reactor engineers and materials scientists.
This group will comprise both the researchers paid for by the project, and
the students funded by the constituent universities to work alongside them.
It will also bring together the international group of senior scientists (PIs)
from different fields united in the goal of supporting a practical fusion
energy device. The collaborative training courses will ensure that
expertise in one area is matched by an understanding of the other.
Particularly in materials science, researchers are using codes developed
to treat a wide range of materials. The issues relevant for fusion are more
specific, and there is plenty of
scope for both algorithmic and parallelisation developments to lead to
significant speed-ups.
By concentrating on community codes, we will ensure that the exascale
developments of the project are of benefit to a wide range of external
users, in addition to the scientists working on the project itself.

Current worldwide energy consumption has risen 20-fold during the 20th century and the growth rate shows no
sign of saturation. Of the current 15 TW load 80-90% is derived from fossil fuels, but with peak oil imminent and
coal supplies limited, a sea change in energy production is vital. Renewables will make a contribution to future
energy production, but they are generally unrelated to seasonal and geographical demands - while nuclear fission
raises significant environmental and political worries. Nuclear fusion, on the other hand, promises a low pollution
route to generate a large fraction of the world's energy needs sustainably. However, the scientific and engineering
challenges in designing such a reactor are formidable and commercial power plants are not expected before 2050.
Real progress therefore needs to be made now if fusion is to be relevant as coal and oil decline.


Fusion power is famously always 30 years in the future. To some extent this is due to the stop-start nature of funding over the
last few decades, but also due to the formidable difficulties encountered both in physics and engineering. Many of these were
"unanticipated" in the sense that they are irrelevant to smaller devices. Materials is the classic case, for fusion devices to date
the radiation dose is negligible compared with the lifetime-limiting doses in fission reactors. Even at ITER, the doses are not extreme, and since
continuous operation for many years is not envisaged, checking and repair is possible. But a commercial fusion tokamak reactor
would produce far more, and more energetic radiation, in the form of very high neutron dose. The timescales for R&D, licensing
and formal testing mean that it is perfectly possible that a wholly new class of materials could take 20-30 years to be usable: so this
process needs to start now, which means proceeding by simulation and extrapolation of experimental results without the necessary experimental verification.


It is not yet known which area of physics (or interaction between areas) will prove the rate limiter in progress towards a commercial reactor. Consequently it is important to make progress on all fronts to identify possible bottlenecks in as-yet unbuilt devices. Any advances in understanding could speed implementation of the fusion programme by several years. This is the major impact of the project.