Fusion is the holy grail of electricity generation. When the technology is available it will become the main workhorse of electricity generation, especially if the costs per KW are very low. It will most likely replace existing GHG emitting power stations (coal and natural gas), and may make other renewable solutions obsolete. If the cost of electricity becomes very low it may create a paradigm shift in our use of energy and in the American way of life.
The catch is that we do not know if or when fusion will be possible, whether it could be commercialized and at what speed and costs. It could be that the first experiment will be successful within a decade, but it could take as long as the end of the century. Our forecast is for the first successful fusion in the lab in 10-15 years. Commercial implementation: another 10-15 years.
This leads us to the following conclusions:
- Do not build any assumption of Fusion availability into the U.S. energy policy
- Fusion could provide the U.S. with a tremendous strategic advantage. The first nation to implement a commercial fusion power plant will win the energy race and will enjoy the economic fruits for decades.
- It can also be part of an ultimate solution package for global warming.
- We should continue with our heavy investment in R&D on the subject and increase it if necessary.
- Once a breakthrough is achieved, the U.S. energy policy will have to be revolutionized.
The United States must convert its “Fusion Energy Sciences” program within the Department of Energy into a “Fusion Energy” program so that essential technology can be developed in the U.S. with government support in parallel with the development of fusion science. For example, the development of commercially viable reactor materials is as important to the successful achievement of economically competitive fusion reactors as configuration optimization in magnetic confinement fusion or fuel capsule design optimization in inertial confinement fusion. If the U.S. is to benefit economically from the commercialization of fusion, it is important for U.S. innovators and corporations to own the key patents for as much of the technology as possible.
Fusion energy, including magnetic and inertial fusion, is one of only a few sufficient candidate sources of energy for the future of the world (including fission, solar, wind and sustainably-engineered biomass energy). By sufficient is meant indefinitely sustainable energy, including energy for acquisition and distribution of water, for at least 10 billion people living with at least the current impact level of global warming, at a cost less than the 20 % of the world GDP at any time (10% shares of GDP each for water and electricity). Higher costs expended for water and energy would mean less GDP available for other necessary human development and quality of life.
Two major facilities, ITER and NIF, should prove the scientific basis for fusion ignition, in which alpha particle self-heating exceeds the plasma energy losses. However, ignition is a necessary but far from sufficient prerequisite for fusion energy, which also requires an engineering basis for long power plant investment lifetime (e.g., 30 years) and affordable economics (e.g., unit costs of energy production that would scale to less than 10 % of the world’s GDP to meet the above world energy needs, with acceptable safety and environmental characteristics. By acceptable safety and environmental impacts is meant that the work days lost or deaths per GWe-yr are preferably less, but not substantially more, than other sufficient and affordable energy candidates. None of the sufficient energy options listed above have yet demonstrably met all these demanding criteria.
It is likely that energy, water and food demands of a still-growing world population will force an urgency on the time to develop any or all of the sufficient energy options, so development time, total development cost, and economic competitiveness are ultimately crucial questions to be answered through research and development (R&D). R&D time scales for fusion energy, ultimately crucial questions as with other energy options, can only be discovered after extensive additional research and development. A description of the scope of energy R&D needed for many approaches to either magnetic or inertial fusion, but not the time scales or total R&D costs, can be found at the following URL: http://fire.pppl.gov/snowmass02.html#Snowmass02Section
Despite the fact that the US is the world leader in inertial fusion expertise, IFE has not received as much R&D funding as MFE, in part because many critics remain skeptical of NIF ignition, and because NNSA has not put priority on high pulse rate R&D for its defense mission, allowing more critics to wonder if high average power inertial fusion energy can be achieved. NIF ignition provides the earliest possible confirmation of inertial fusion ignition in the laboratory, and thus the success of the NIF Ignition Campaign is a necessary but not sufficient condition for success of all inertial fusion energy options.
What is most needed at this point in the fusion energy sciences research program is a strategic plan for the development of fusion as an energy source. Such a plan should state that it is the goal of the US program to build a fusion demonstration power plant in the US by no later then 2040. The plan should be supported with sub goals with specific milestones with needed dates and budgets. The plan will also need to address what aspects the US will emphasize within the world-wide fusion research program. The plan should integrated together both magnetic and inertial approaches for fusion energy.
The fastest, lowest risk, most cost effective path to fusion energy is to pursue an integrated approach and to foster competition between concepts.
An integrated approach is needed because development of a viable energy source requires linking the science, technology, and engineering as a coherent system. The demonstration of fusion energy is important, but equally essential is the development of materials and methods to efficiently heat, contain, and harness that energy. Ultimately it is the integrated system that determines if fusion can contribute to the world’s energy needs.
Fostering competition encourages innovation, accelerates progress, and decreases risk. Inertial Fusion, which has developed a vast scientific base due to its application for weapons research, has some distinct advantages over the magnetic approach. Credible technologies for the energy components have been investigated in sub scale systems. Inertial Fusion may lead to a faster, more attractive path to energy and should be part of a fusion energy program.
After a ten month process involving a large fraction of the magnetic fusion community, and culminating in a June 8-12 Workshop, a report has been issued entitled “Research Needs for Magnetic Fusion Energy Sciences.” The process was chaired by Richard Hazeltine (U.Texas) with David Hill (LLNL) as vice-chair.
The 422 page report and 14 page Executive Summary is posted at http://fire.pppl.gov and also at http://burningplasma.org/web/renew.html
The report asserts, “The realization of fusion power would change the economics and ecology of energy production as profoundly as petroleum exploitation did two centuries ago.” It states, “The worldwide fusion community broadly agrees that the science has advanced to the point where an aggressive action plan, aimed at the remaining barriers to practical fusion energy, is warranted.” However, it says, “the program faces new challenges; above all it is challenged to demonstrate the timeliness of its promised benefits.”
Now that we know it will be 15 years or more for ITER to begin serious experiments with deuterium and tritium fusion reactor fuel, it behooves the United States to build a modest size net power-producing magnetic confinement device based upon the latest theoretical and experimental advances. At the very least, we should design a ~100 MW net fusion power system using the state-of-the-art understanding of fusion temperature magnetically confined plasmas and estimate how much it would cost and how long it would take to build. We might discover that the United States could already be designing or even building a demonstration power plant by the time ITER starts producing net power by fusion reactions. However, as argued by Sethian earlier, that does mean that we will need to be developing other parts of a fusion power plant in parallel with the high temperature fusion plasma science, including first-wall and breeding blanket materials and reliable high field superconducting magnets. Such an integrated program will require the Department of Energy to move from a fusion energy science program to a fusion energy program. Considering that we we spend hundreds of billions of dollars each year to import oil, the cost of developing fusion as a practical, clean energy source is a small price to pay to achieve true energy self-sufficiency in the long run.
The realization of fusion energy is still decades away. If 50 years of fusion research has taught us anything, it is that fusion is a very difficult problem. Anything to make it easier should be very, very seriously considered. One thing which might help is using the potential energy of the fusion neutron to breed ten times more nuclear fuel, rather than using its kinetic energy to boil water. This is the fusion fission hybrid. The concept dates back to the very dawn of the fusion project. Andrei Sakharov proposed it in 1950, and Hans Bethe advocated it in 1979. Both advocated it as a means to produce fuel for other, separate nuclear reactors, rather than as a single reactor to produce and burn fissile material. Over the years, others have advocated it, but so far the idea has not really caught on, at least in the United States. Since 1998, I have been its principal American advocate. Ralph Moir of LLNL has been a consistent advocate of it for 35 years. He has set up a web site where much information on the hybrid, including several of my own scientific papers are archived. Its web address is : http://www.ralphmoir.com/.
The only bullet that is completly rational is – “Do not build any assumptions on (future)availability…” , and the other questionable bullet is on spending – “….and increase it if necessary.” The other bullets are primarily “Motherhood”.
Both of these comments require some justification which ,very briefly, follows: First on “Futures”.
Since the concept of magnetic confinment fusion was first declasified – “The First United Nations Conference on the Peaceful Uses of Atomic Energy – 1955″, there has been major R&D in US and the World. At that time Dr. Homi Bhabha (Chairman of the Conference), when asked about the future of fusion, said “Comercial in 30 Years”. In the next cnference, 1958, to the same question – “…27 years”. The prediction of comercialization has been circa 30 years from that time to today, 55 years. Post ITER is the same time frame or longer.
This continued future has not been the result of low budgets – several hundreds of millions of dollars yearly over this total period, culminating with an “estimate” of 30 billion dollars for ITER to its operational date – circa 2016.
The engineering problems of a fusion power plant are incredible and there has been neglible discussion of two technical concerns which were identified in my paper for the 1958 Atoms for Peace conference. The lifetime of the fusion inner wall is probably a faction of typical power plant lifetime, 40 years or more. Ten Mev neutrons can do incredible damage. Replacement of repair could be an insurmontable problem.
The issue is the neutrons that are captured in the wall, just beyound the wall, or possibly in the cryogenic magnet coils. Many of these captures will convert the original element to a radiactive one. Depending upon the characteristic of the newly formed elements, their half-life, the type of radiation, and the quantity, maintenance on the wall and the many complex systems may not be possible. I have seen no calculations on either the lifetime of the wall or the level of residual radiation.
Lastly, based on the design concept of ITER, the capital cost of a fusion plant must be a multiple of the current fission alternative.
With ITER going forward some of these issues may be resoved, but in my view it is still only a slight hope fora future energy source.
Robert W. Kupp