Memorandum 108
Submission from High Power laser Energy
Research project (HiPER)
OVERVIEW OF
NUCLEAR FUSION
ENERGY
The process of "nuclear fusion" involves
the combination of two atomic nuclei to form a single, larger
nucleus. If the initial atoms are small (ie near the start of
the periodic table), then energy may be released during this process,
because the larger atom will be more stable. That is, it has an
effectively lower rest mass. As shown by Einstein (E= m c2), a
change in mass will lead to the creation of a large amount of
energy.
THE FUSION
PROCESS
Fusion is the process which powers the Sun.
It is not encountered in everyday life on Earth because extreme
temperatures are required (many millions of degrees) in order
for the positively charged atoms to have sufficient speed to overcome
their mutual repulsion. The temperatures are so high that the
matter turns into a plasma, in which the electrons are stripped
from their nucleus. The fact that high temperatures are needed
gives rise to the common name for this approach being thermonuclear
fusion. The Sun delivers the initial energy to create a plasma
using the power of gravity. On Earth we need to find other solutions.
The most advantageous fusion reaction for terrestrial
studies is the combination of two Hydrogen isotopes (Deuterium
and Tritium) to form a Helium nucleus plus a neutron. For energy
production, we need to create a propagating fusion reaction-that
is, one which sustains itself once we have initiated the reaction.
This can be achieved by using the Helium nucleus to deposit its
energy into its neighbouring atoms, thus providing sufficient
heat to start the next reaction. The neutron is used to drive
the power plant-it is captured in an absorbing blanket surrounding
the system which heats up because of the energy deposited by the
neutron. This is then simply used to heat water to power a conventional
steam turbine for energy production.
Fusion is the opposite process to nuclear "fission"
(the process used in nuclear power plants), where heavy elements
such as Uranium are split into two daughter nuclei.
The benefits of fusion can be summarised as:
(1) Abundant fuel and energy security: the raw
products can be found naturally (Deuterium comes from seawater
and Tritium can be created in situ within the fusion device itself).
(2) The energy released is very high, meaning
it is a naturally efficient system (multi-GW power plants are
the predicted scale for fusion reactors).
(3) The process is significantly cleaner than
other bulk power production techniques: There is no greenhouse
gas production, and there are no long-lived radioactive products,
although there is activation of the reaction chamber that can
persist for ~100 years.
(4) The process is inherently safe (little or
no stored energy, so no potential for runaway reactions).
Thermonuclear fusion has been studied for approximately
50 years. The proof of principle (demonstrating the validity of
the underlying science) has been achieved in defence programmes
(in the 1980s). What remains is to find a route to produce a stable,
efficient and cost effective power plant. There are two principal
routes being explored, both of which are at a high stage of maturity,
albeit still requiring multi-decade investment to develop to the
stage of a viable reactor. The two routes are:
(1) Magnetically confined Fusion Energy (MFE).
Here, large low density plasmas made up of Deuterium and Tritium
fuel are created in toroidal (doughnut-shaped) chambers called
"tokamaks". The operation is essentially "steady
state" rather than pulsed. The Joint European Torus (JET)
based at the Culham Laboratory in Oxfordshire is the world's largest
example and has demonstrated the scientific basis of magnetic
confinement fusion. The international community has agreed to
fund the next generation machine (ITER), to be sited in Cadarache,
France towards the end of next decade. Its cost is of order $5B
construction, and a similar sum for operation. See http://www.iter.org/index.htm
(2) Inertially confined Fusion Energy (IFE).
Here, high power pulsed lasers are used to compress a small pellet
of Deuterium and Tritium to achieve very high densities (>30
times the density of lead) over a very short timescale (< 1
nanosecond). The National Ignition Facility in the USA is currently
under construction with a mission to demonstrate the scientific
basis of IFE (ie sustained, scalable thermonuclear burn). See
.http://www.llnl.gov/nif/project/.
Costs are similar to MFE. A significant amount of IFE research
is also carried out within the UK, based on experiments at the
Central Laser Facility at the Rutherford Appleton Laboratory,
Oxfordshire. This approach has the benefit of applicability to
other scientific goals (astrophysics, material science, particle
acceleration). With the advent of new laser technology leading
to significantly reduced costs, an entirely civilian approach
to IFE is now feasible, and forms the basis of the HiPER project
(see below).
HIPER SUMMARY
HiPER is a UK initiative for Europe to take
a world leading position in the demonstration of Inertial Fusion
Energy and the science of extreme conditions. This approach to
energy and science is made feasible by the advent of a revolutionary
approach to laser-driven fusion known as "Fast Ignition".
HiPER will make use of advanced laser technology in a unique configuration,
allowing fusion fuel to be compressed and then ignited to induce
a propagating burn wave yielding significant energy gain (Q~100).
At present, the HiPER project is a consortium
of seven European countries at the national level (Czech Republic,
France, Greece, Italy, Portugal, Spain, with the UK taking the
coordinating role), two regional governments (Madrid and Aquitaine),
industry, plus scientists from four other countries (Poland, Germany,
Russia, USA) and international links to Japan, China, Republic
of Korea and Canada. The project has completed a two-year conceptual
design phase, and has just entered a three year "preparatory
phase" in April 2008 as part of the EC's stewardship of the
ESFRI roadmap facilities. This phase is co-funded by the UK. Assuming
success in this phase, construction is envisaged for the latter
half of next decade.
The facility will mark the culmination of a
UK-led strategic alliance of laser capabilities across Europe,
which includes all the major existing facilities and a significant
intermediate step (PETAL), currently under construction near Bordeaux
at a cost of ~€80M.
The timing of the HiPER preparatory phase has
been designed to take full advantage of international work in
this area. Three strands of work are being planned to converge
early next decade:
- IGNITION DEMONSTRATION: It is expected
that net energy production from laser fusion will be demonstrated
in the USA in the early part of the next decade on the National
Ignition Facility (and subsequently on Laser Megajoule in France).
This will mark the culmination of over 40 years' research, and
a commitment of many billion dollars.
- FUTURE PATH: Alongside this, there has
been significant investment in laser facilities around the world
targeted at developing an advanced route to fusion ignition. This
route is designed to increase the efficiency of the fusion yield
using a substantially smaller facility. If successful, this will
provide the confidence to proceed with engineering analyses for
commercially viable energy production and will provide the technological
basis for a broadly-based science programme. These facilities
(in USA, Europe and Asia) are designed to provide the scientific
evidence for how this field should develop. They are too small
to achieve fusion gain themselves, but should within the next
five years provide sufficient information to allow the future
path to be adequately defined.
- INTEGRATED PLAN: The HiPER project is designed
to capitalise on this work. The design phase has established the
overall strategic requirements. The preparatory phase will provide
the structural and technological groundwork to allow the next
big step to proceed without delay, whilst ensuring that construction
decisions are only taken after validation of the proposed approach.
This preparatory phase will place Europe in a clear leadership
position.
The conceptual work done on HiPER has already
had a significant influence on the international community. We
note that the US are now actively working on fast ignition relevant
modifications to NIF to follow on from the initial demonstrations
of energy gain. Meanwhile, we have started discussions with the
Japanese on the potential for an international approach to the
next step. These changes can be capitalised upon as part of the
HiPER project, and could enable HiPER to take a generational leap
in capability (to high repetition rate operation) based on close
coordination with our international partners.
EXPECTED SCIENTIFIC
AND ECONOMIC
IMPACT
HiPER has been designed to marry together the
establishment of European leadership in the science of extreme
conditions with the key societal challenge facing mankind: a long-term
supply of abundant clean energy.
This is a field in which the UK can honestly
claim to be a true world leader. We have the world's most powerful,
most intense laser (Vulcan-PetaWatt), and are set to retain this
leadership for the next few years with the emergence of the high
intensity Astra-Gemini (2007) and Vulcan-10PW (2010-11) facility
developments. This leadership has provided us with the scientific
and technological knowledge and international reputation to propose
and lead the HiPER project.
The science case has been developed by over
50 senior scientists from 11 nations during the past two years.
It offers a compelling argument for a step-change in laser capability
for European academics. Its proposed science programme covers
a broad spectrum in this rapidly developing field, with a facility
capability that will offer unprecedented, internationally unique
tools. The topical fields range from laboratory astrophysics,
the study of extreme states of matter, planetary science, creation
of relativistic particle beams, and fundamental quantum physics.
It is clear that HiPER will open up entirely
new areas of research, providing access to physics regimes which
cannot be explored on any other science facility. Its user base
will be greatly expanded compared to existing laser laboratories,
consistent with this increase in scientific breadth.
The energy mission is aimed at establishing
the case for the exploitation of laser driven fusion. The project
is timed so that decisions can be made following the upcoming
demonstration of energy production from lasers (in ~2012 in the
USA and subsequently in France). HiPER will develop the route
to viable power generation by addressing the key R&D challenges-both
scientifically and technologically. Its "Fast Ignition"
approach promises a factor 5-10 reduction in scale (and thus cost)
of the capital plant, whilst severing the principal link to classified
applications. This allows academia and industry to take a lead
role for the first time.
Work in the current "preparatory phase
project" will concentrate on establishing the most appropriate
route to moving forwards in this area. It will assess the likely
technical solutions and associated risks to allow informed decisions
on the required R&D and facility specification for subsequent
phases.
Multiple energy solutions are demanded by a
risk-balanced strategy for energy supply, with fusion able to
offer the "holy grail" of energy sources-limitless fuel
with no carbon or unmanageable radioactive by-products, energy
security, and a scale able to meet the long term demand. Laser
fusion is highly complementary to ITER, and is based on a scientifically
proven approach (inertial confinement).
There are significant industrial opportunities
for the UK and Europe as part of the HiPER project-in the design
and build phase, the operational phase, and from the ensuing technical
spin-out opportunities. With regard to the future energy applications
of HiPER, the scale of the potential economic impact is clear.
HiPER would secure UK/European leadership in
a field which is rapidly developing in Asia and the USA. No comparable
laser system is underway anywhere in the world-HiPER will be a
highly effective international attractor to the UK.
ENGINEERING REQUIREMENTS
The scale of the scientific and engineering
challenge to achieve fusion energy is very significant. It covers
a broad array of disciplines, each requiring a clear, long-term
development plan. This demand a coherent approach linking: academic
training to ensure adequate community skills; early industrial
engagement to ensure opportunities for the UK are not missed;
identification and funding for the required Research, Development
and prototyping; and close collaboration between academia and
industry to identify optimum solutions.
The technical areas requiring development include:
- Remote handling and robotics in harsh environments.
- Advanced material science for reactor vessel
components.
- Microscale and nanoscale facbrication and
characterisation (of the fuel pellets).
- Advanced laser technology.
- Manufacture of at high volume, low cost
of large scale (metre-diameter) optics.
- Adaptive and active optics.
- Radiation hardened electronics.
- Remote injection and tracking technology
(of the pellet targets).
- Cryogenic (~20K) vacuum technology.
- Thermal system management.
- Structural engineering.
- Fluid dynamics (for liquid wall chambers).
- Waste management and tritium extraction.
- Automated alignment and component replacement.
FUNDING
Technical work associated with the three-year
preparatory phase has direct funding or in-kind commitments amounting
to ~€70M from: European Commission, UK, France, Czech Republic,
Greece, Spain, Italy, Poland, Portugal and the Republic of Korea,
plus formal agreements with institutions in Germany, Canada, USA,
Japan and China.
€13M of this is direct funding provided
from the EC and the national partners (over three years) to fulfil
specific project requirements of the preparatory phase.
The cost of construction and operation will
be assessed during the course of the preparatory phase and depends
on key technology down-selection choices in the next few years.
However, it is clear that it is in the billion-Euro class of facilities.
TIMELINE
- Conceptual design study [UK funding, scientists
from 12 nations involved] (2005-06).
- Included on ESFRI European roadmap (October
2006); UK endorsement as Coordinators (January 2007).
- Preparatory Phase Project [National and
EC funding] (April 2008 to March 2011).
- Detailed Engineering Phase (estimate 2011-14).
- Construction Phase (estimate 2014-20).
June 2008
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