CREATING SUNS ON EARTH

Abstract

Concerns about climate change and energy security have prompted some countries to revive dormant nuclear fission power programs to meet growing energy demands and reduce carbon dioxide emissions. However, this so-called nuclear renaissance based on fission would have major drawbacks in the areas of safety, security, and nonproliferation. Nuclear fusion, however, is portrayed by its proponents as mitigating these drawbacks, and scientists continue to pursue fusion's promise with two large-scale projects: the International Thermonuclear Experimental Reactor (ITER), and the Laser Inertial Fusion Engine (LIFE) reactor. Although supporters often hail fusion as proliferation resistant, the technology could be used to create weapons-usable fissile material. This article explains how fissile material could be created in ITER or LIFE and analyzes other nonproliferation implications of fusion; the authors discuss the various challenges faced by ITER and LIFE.

Keywords:

• Fusion
• fissile material
• energy security
• nonproliferation policy

An oft-repeated joke in certain circles is that nuclear fusion is fifty years away—and will always be fifty years away. Despite the progress of the last fifty years, many scientists believe that energy generation based on fusion remains at least that far in the future. However, increased funding from the nuclear weapon states for stockpile stewardship programs along with recent technological advances have led to an increase in funding for fusion research. Many states have also been reevaluating nuclear power because of energy security and environmental concerns; however, most of this talk revolves around fission reactors. Fission reactors may be better suited to reduce carbon dioxide emissions than traditional fossil fuel power plants, but the technology has major drawbacks in terms of safety, security, and proliferation.

Proponents of nuclear fusion believe that fusion technology mitigates some of these drawbacks. As a result, scientists continue to advocate for nuclear fusion research. The International Thermonuclear Experimental Reactor (ITER), currently under construction in France, is intended to demonstrate the potential of fusion reactors based on the tokamak design; the technology being tested at the National Ignition Facility (NIF) in Livermore, California, is intended to be a precursor to the Laser Inertial Fusion Engine (LIFE), a hybrid fusion-fission design concept. Scientists are studying other pathways to fusion, but ITER and NIF employ the two most advanced nuclear fusion concepts: magnetic confinement and laser inertial confinement.

Both reactor concepts require massive investments and pose immense technical challenges that must be resolved before fusion can be considered a reliable and cost-effective method to produce energy. Because of these challenges, fusion power has remained elusive, in contrast to fission power, which went from initial discovery to industrial deployment in little more than a decade. Although fusion has proven to be a much more difficult technology, it remains enticing for several reasons: it produces much less radioactive waste than fission, is based on abundant resources, and has no risk of catastrophic reactor meltdown.

Despite the promise of nuclear fusion, a host of economic, political, technological, and proliferation challenges must be addressed in order for fusion-based energy production to become a reality. Many of these challenges have received little analysis. This article explains the basics of magnetic confinement and laser inertial confinement fusion and how these technologies are used in the context of the ITER and LIFE projects, addresses the advantages and disadvantages of the two technologies, and provides policy recommendations. Because fusion technology is often advertised as inherently proliferation resistant, this article also discusses the nonproliferation implications that arise from nuclear fusion in general and from ITER and LIFE, specifically. While the International Atomic Energy Agency (IAEA) has no plans to safeguard future fusion plants (and indeed it is too early for such plans; the reactor designs used in LIFE and ITER remain conceptual), this article demonstrates that nuclear fusion technology does pose proliferation challenges.1

Fusion: The Basics

Both the ITER and LIFE fuel cycles will utilize deuterium and tritium—two different isotopes of hydrogen—for fusion. When deuterium and tritium are fused, the reaction yields helium (an alpha particle) and a neutron, together carrying a total kinetic energy of 17.6 million electron volts (MeV); 14.1 MeV are transported by the ejected neutron and the remaining 3.5 MeV by the alpha particle. Deuterium is fairly abundant in nature; however, tritium is rare and must be produced artificially by either breeding it in a fission reactor or bombarding lithium with neutrons. Most fusion reactor designs utilize the bombardment method by incorporating lithium in the reactor wall with the aim of breeding tritium.

ITER and Magnetic Confinement Fusion

Fusion basically attempts to recreate conditions in the sun, yet the levels of pressure and density present in the core of a star cannot be replicated on Earth. One alternative is to heat ionized gas to temperatures greater than hundreds of millions of degrees Celsius so that fusion can occur. This highly unstable gas, referred to as plasma, has been the focus of magnetic confinement fusion research.2 In the late 1950s, scientists at the Kurchatov Institute in Moscow devised a unique fusion reactor: the tokamak (toroidalnaya kamera i magnetnaya katushka, or “toroidal chamber and magnetic coil”).3 Plasma cools immediately upon touching reactor walls; the tokamak design circumvents this problem by containing the plasma with powerful magnetic fields, preventing it from coming into contact with the vessel—hence the term “magnetic confinement fusion.” In the chamber, a torus that forms a D in vertical cross-section, a magnetic cage creates helical field lines around which the plasma's particles gyrate (see Figure 1). The electrically charged neutrons slow down after penetrating the reactor wall, then heat up a thermodynamic vector fluid, like water or gas, which drives a heat-exchange system or turbine to generate electricity.4

FIGURE 1  Basic tokamak in cross-section.

Illustration by Georgia Wulff, based on an image from Princeton Plasma Physics Lab.

ITER, an international consortium of eight partners (the European Union, China, India, Japan, Russia, South Korea, the United Kingdom, and the United States) is based on magnetic confinement fusion and is intended to conclusively prove that this type of energy generation is technically viable. The consortium hopes that ITER will be the last step before tokamak-based commercial fusion power plants are built. ITER has several objectives. It hopes to generate ten times as much energy as it consumes (a Q value of around 10); to achieve a plasma that sustains itself without massive external heating (a “burning” plasma); to test a variety of technologies that could be used in a future commercial fusion power plant; and to conduct experiments with lithium-based tritium breeding. The project is to span thirty-five years. Initial cost estimates were €11 billion: €5 billion for the construction phase, €5 billion for the operational period, and around €1 billion for decommissioning; however, design changes and increased raw material prices have driven costs up by at least one-third.5

ITER will be the largest tokamak fusion device in the world. The 840 cubic meters (m³) of plasma will have an outer radius of 6.2 meters (m) and an inner radius of 2.0 m, and an operating temperature of 20 kiloelectron volts. The fusion power will be a maximum of 500 megawatts (MW), with an input heating power of 50 MW. Confinement is based on three magnetic coils, a central solenoid (CS) field coil, six poloidal field (PF) coils, and 18 wedged toroidal field (TF) coils.6 The TF and PF coils are used to shape and control the plasma. The CS coil is used to preheat the plasma with a field strength of 13.5 tesla (T) and a resulting plasma current of approximately 15 MW. Eight cryopumps located around the torus cool the superconducting magnets, which surround the primary vacuum vessel, with supercritical helium cooled to 4 Kelvin (-453 degrees Fahrenheit). The inside of the toroidal vessel is covered by the blanket, which shields the vessel and the magnets from the neutron flux and heat created by the fusion reaction, with eight equatorial ports for remote access, maintenance, heating, and diagnostics. The blanket is comprised of 440 individual segments, each with a detachable first wall. Besides shielding the vessel and magnets, the blanket modules will also be used for tritium breeding. The entire machine is encased in a 14,000 m³ cryostat, cooling the contained vessel to around 70 Kelvin (-334 degrees Fahrenheit) in a secondary vacuum.7

ITER proposes to achieve ignition—a sustained nuclear fusion burn with more energy generated than introduced (a positive Q efficient)—by utilizing a specific sequence: after the TF coil has been turned on, a small amount of gas is injected into the chamber, and the primary transformer circuit (the CS coil) generates an electric field in the gas, which ionizes the mixture and thus transforms it into plasma, while the created current heats the plasma to about 30 million degrees Kelvin (around 54 million degrees Fahrenheit). The PF coil is active during ohmic heating as well and with the TF coil confines the plasma. Additional heating is then provided through radiofrequencies in the tens of megahertz to hundreds of gigahertz range, transmitted by antennae in the equatorial ports, and through neutral beam injection, in order to achieve the temperatures necessary for fusion.8 Over time, the plasma is gradually contaminated with impurities (helium-ash) from the particle collisions, which could eventually inhibit the fusion process. Consequently, a device called a “divertor” was designed to limit the production of impurities and to remove them. Essentially an exhaust pipe, the divertor is a circular, trench-shaped structure at the base of the torus that sucks up impurities, neutrons, and helium nuclei from plasma with a high Q ratio. This design also allows the immense heat load to be spread onto the divertor plates on the divertor modules.

ITER is also designed to have six test blanket modules to experiment with different material combinations to breed the fusion fuel; the first blanket tests are scheduled to begin in 2016. A study done by the European Fusion Development Agreement foresees four different blanket module designs. All of these ideas are conceptual and utilize a variety of different materials for the blanket and the coolant that flows within the blanket module. The breeding blanket is made of reduced activation ferritic martensitic steel (a variety of steel under development that can withstand very high temperature and radiation conditions) in which liquid lithium-lead flows. Lithium serves as the breeding material; lead functions as a neutron multiplier.

NIF, LIFE, and Inertial Confinement Fusion

After the laser was invented in 1960, scientists at Lawrence Livermore National Laboratory (LLNL) quickly realized that it might be possible to create energy by using powerful laser pulses to compress and ignite deuterium-tritium fuel. In 1962, LLNL initiated its first laser fusion project and in 1972 formed the Inertial Confinement Fusion (ICF) Program. Starting in 1972, the ICF Program built a series of lasers—named Janus, Cyclops, Shiva, and Nova—each larger and more powerful than the last.9 These projects laid the groundwork for the development of NIF, the construction of which was completed in March 2009. NIF is a giant complex of 192 laser beams focused on a BB-sized deuterium-tritium target.10

NIF will attempt to achieve ignition by simultaneously firing dozens of laser beams through a system of optic amplifiers. After passing through the amplifiers, each beam carries a tremendous amount of energy. A complex system of mirrors routes the beams into a spherical configuration, focusing the beams on the center of a chamber that contains a target fuel pellet (see Figure 2).11

FIGURE 2  LIFE fusion-fission chamber for 37.5-MJ hot-spot ignition (HSI) target driven by a 1.4-megajoule (MJ), 350-nanometer (nm) laser. Source: Edward I. Moses et al., “A Sustainable Nuclear Fuel Cycle Based On Laser Inertial Fusion Energy,” Fusion Science and Technology 56 (August 2009), p. 551. © August 2009, American Nuclear Society, La Grange Park, Illinois. Reprinted with permission.

NIF will initially use a method called indirect drive to heat a copper-doped, beryllium coated deuterium-tritium fuel pellet. Indirect drive does not directly target the fuel pellet. Instead, lasers would heat the inner walls of a gold cavity (housing the fuel pellet) called a hohlraum. This should create super-hot plasma within the hohlraum that radiates a bath of X-rays, causing the outer surface of the fuel pellet to rapidly heat and implode. This would form a central “hot spot,” where fusion would set in and the compressed fuel burn before it can disassemble.12 When bathed and compressed by the hohlraum's X-rays, the design is supposed to raise the temperature of the fuel pellet to 180 million degrees Fahrenheit, causing the deuterium and tritium to fuse.13

If ignition occurs, the next logical step for the NIF team is to lobby for funding to continue the development of the LIFE concept: a plan to utilize the knowledge gained from NIF to further develop technology usable for laser inertial fusion power generation. The current LIFE reactor design plan envisions 500 MW of pure fusion power. The vast majority of power (80 percent) would come from the ejection of the 14.1 MeV neutrons, with the rest of the energy coming from X-rays and ions. This process generates approximately 10¹⁹ 14.1MeV neutrons per shot (about 10²⁰ neutrons per second). The ejected neutrons pass through a layer of beryllium pebbles that generate 1.8 neutrons for every neutron they absorb. The newly generated neutrons have a significantly lower energy spectrum, making them ideal for fission energy generation.14 The moderated neutrons are then driven into a 1-meter-thick subcritical fission blanket. The blanket contains fission pellets immersed in a molten salt called “flibe” (2LiF+BeF) that carries away the heat released by the fusion-fission reaction. The steam released would drive turbines to produce electricity.15 Overall, the blanket effectively “boosts” the fusion reaction by a factor of four to ten. This boost increases the initial fusion power reaction up to an average of 2,000–3,000 MW for a period of years to decades (see Figure 3).

FIGURE 3  The energy and materials flow for the LIFE reactor. (DU is depleted uranium; SNF is spent nuclear fuel.) Source: Edward I. Moses et al., “A Sustainable Nuclear Fuel Cycle Based On Laser Inertial Fusion Energy,” Fusion Science and Technology 56 (August 2009), p. 548. © August 2009, American Nuclear Society, La Grange Park, Illinois. Reprinted with permission.

History of Fusion

The development of fusion projects such as ITER and NIF has been slowed by immense technological problems, cost overruns, and the practical reality of securing and maintaining funding. After thermonuclear fusion was initially demonstrated in 1951, politicians were eager to provide support; however, enthusiasm quickly faded when technological problems emerged.16 Magnetic confinement fusion was declassified in 1958; yet for most of the 1960s, U.S. fusion research was minimal. Federal budget levels hovered around $30 million annually, largely because of technical problems like plasma leakage and insufficient confinement times.17 In 1968, Russian scientists made great advances in magnetic fusion, which reignited enthusiasm in the United States. Soon, fusion devices began proliferating throughout the United States: MIT, Oak Ridge National Laboratory, Princeton University, and the University of Texas at Austin, among other locations, all built research reactors. Federal funding for fusion rose accordingly, from $63 million in 1974 to $316 million in 1977.18

During this time the political climate also began to shift in favor of large-scale fusion research projects. Representative Mike McCormack (Democrat of Washington), an outspoken fusion proponent and chairman of the Committee on Science and Technology's Subcommittee on Energy Research, began to rally support for the next big step: advancing magnetic fusion from the research stage to a functioning power production prototype plant. McCormack authored the Magnetic Fusion Energy Engineering Act, which passed the U.S. Senate and House with large majorities in August 1980. At the heart of the bill was a plan to build a $1.6 billion fusion power demonstration plant in the United States by 2000. In the short term, the bill also provided funds to establish a Center for Fusion Engineering (CFE) for fusion research and to build a Fusion Engineering Device (FED) to test ignited and burning plasmas. Politics intervened when Ronald Reagan won the presidential election. Reagan not only favored breeder reactor concepts over magnetic fusion, but also implemented federal budget cuts of 12 percent across the board, effectively putting the CFE and FED into hibernation. Federal budget levels for fusion dropped markedly afterward, and magnetic fusion research remained dead in the water for most of the 1980s, with several large-scale projects collapsing.19

During his two terms, President Bill Clinton allocated just $250–$350 million a year for all magnetic fusion research before terminating the program in 1999. This was remarkable because several fusion projects around the world such as the Tokamak Fusion Test Reactor (Princeton), the Joint European Torus (United Kingdom), the JT-60 (Japan), and the T-15 (Russia) were showing signs of a maturing technology.20 From 1999 onward, U.S. federal funding was bundled for research on all fusion concepts, including inertial confinement and other concepts such as stellarators and Z-pinch systems. In 2003, under the George W. Bush administration, the United States resumed funding of ITER, having left the project in 1999, and allocated $40 million–$60 million annually to the joint project, which had an annual overall budget of $300 million–$400 million. The 2009 budget included $421 million for fusion research, of which an estimated $401 million was actually spent.21

Using fusion to generate power will depend on securing reliable funding for research, in addition to solving the technological problems that still plague the projects. Long-term political support for an eventual LIFE project could be particularly problematic for three main reasons. First, funding for NIF is protected by its ostensible role in the U.S. Stockpile Stewardship Program, which ties NIF to the defense and nuclear weapons complexes and their relatively reliable funding. LIFE, on the other hand, would not benefit from a national defense connection and would therefore have a more difficult time securing funds.

Second, since its inception, NIF has been dogged by complaints of significant cost overruns, secrecy, and mismanagement. Recent revelations in an October 2009 report by the Office of Field Financial Management (OFFM) in the National Nuclear Security Administration (NNSA) have further strengthened critics' suspicions. According to the OFFM report, managers at LLNL shifted expenses associated with NIF to other projects, understating the true cost of NIF by $80 million in fiscal 2008–2009.22 This revelation, combined with NIF's 300 percent cost overrun, is unlikely to inspire confidence in policy makers to trust LLNL to responsibly manage funding for a LIFE program.

Third, there is a perception in some corners that upper management at the Department of Energy (DOE) may not be particularly excited about NIF and LIFE. Those who doubt DOE's support point to Secretary Steven Chu's withdrawal from a scheduled speaking engagement at the May 29, 2009 dedication ceremony for NIF.23 Secretary Chu has also written a reasoned and not particularly enthusiastic analysis of fusion, describing it in 2005 as something that deserves continued research, but warning (in the context of future energy solutions) that the United States should not “put all our eggs in one basket.”24 However, David Crandall, chief scientist of the NNSA, says that the DOE has not taken a position on future energy projects based on hybrid fusion targets with fission blankets.25 According to Crandall, during his time in the Office of Fusion Energy, from 1983 to 1995, there was reluctance within the DOE and the fusion community to consider hybrid fusion systems—due to the perception that these systems would undermine the advantages of pure fusion. However, Crandall believes that although these concerns are still valid, “the value of a neutron source as a driver for subcritical fission, and the potential for easing some requirements on a fusion energy source through hybrids have led to renewed interest in the topic.” Based on his talks with scientists and DOE leadership, he does not see a broad consensus on the value (or lack thereof) of fusion-fission. Crandall also notes that the NIF dedication ceremony took place early in Secretary Chu's tenure and scheduling him during that time was difficult; reading anything into his absence may be unreasonable. According to Crandall, “NIF construction is an NNSA accomplishment and the DOE was well and appropriately represented by NNSA Administrator [Thomas] D'Agostino, who has the continuing confidence of the President.”26

If NIF continues to have the support of DOE and a LIFE demonstration reactor is eventually green-lighted, it could follow the phased funding path recently outlined by the ITER project. In order to ensure continued support and to mitigate concerns raised by governments involved in the ITER project, a new phased construction approach was agreed upon during an ITER council meeting in Mito, Japan in June 2009. The new plan foresees a basic device built by 2018, essentially consisting of simply the vacuum vessel, the superconducting magnetic coils, and the cryogenic system. ITER would have to first demonstrate plasma generation and progress with this bare-bones reactor, after which other systems would be integrated.

Technical Problems

In addition to problems with sustained political support and funding, ITER and LIFE face huge technical challenges. ITER will be the first fusion facility in which the components face a true fusion neutron-spectrum; how well the components will handle neutron bombardment in ITER-produced conditions remains to be seen. For example, the optical and electrical diagnostic systems that will be used to monitor ITER's operation could be damaged over time by the increasing radiation. There is also the possibility that the structural joints that connect the magnetic support structure and the reactor vessel with the underlying heat sink could develop weak points due to continued exposure to high temperatures and radiation.

Another problem is that the constant neutron bombardments could induce nuclear reactions within the reactor vessel's wall that would lead to helium atoms accumulating within the steel of the vessel and the surrounding support structure. Researchers speculate as to whether these helium “bubbles” would simply vanish into the surrounding area or if their presence would lead to swelling, cracks, or voids in the reactor vessel and support structure.27 Sebastian Balibar, a prominent French physicist and outspoken critic of ITER and fusion, believes the problem of helium accumulation in the vessel and structural materials will never be resolved.28

Problems also persist in the area of plasma control. During ongoing experiments at the Axially Symmetric Divertor Experiment (ASDEX) Upgrade tokamak at the Max Planck Institute for Plasma Physics (IPP), the plasma often begins to swing uncontrollably (a phenomenon referred to as “quenching”) and comes too close to the wall; the subsequent cooling abruptly ends the fusion reaction. Quenching happens relatively often, especially during the ignition phase, because plasma is highly sensitive and unstable. A potential way to improve stability during ignition is to mix in nitrogen, resulting in an increase in temperature and energy generation, a process observed by researchers at IPP during unpublished experiments in early 2009.29 Thus far, scientists have been unable to explain the stabilizing effect of nitrogen. Even if the plasma remains stable throughout the ignition phase, experiments at ASDEX also show that the magnetic cage must be constantly adjusted by changing the electrical currents, otherwise the plasma breaks out of confinement.30

Edge-localized modes (ELM)—sudden instabilities in the border region (edge) of the plasma closest to the reactor wall—also make plasma control difficult. If these sudden bursts come into contact with the reactor vessel, they could potentially damage the innermost wall of the vacuum vessel. Based on observations of these instabilities at the ASDEX tokamak, IPP physicists have suggested that it is possible to suppress large-amplitude ELMs by introducing small, resonant magnetic field perturbation coils around the torus. But this is just a first step in addressing the problem of ELMs and their adverse effects on plasma control.31 Other physicists believe that tiny ELMs, occurring every millisecond within the ionized gas, release huge bursts of energy (up to 20 gigawatts) across the entire reactor lining. These dramatic outbursts may lead to the wall and structural materials having to be replaced more frequently than previously estimated. Consequently, maintenance and material costs would increase dramatically. Potential solutions to the ELM problems do exist, for example, shooting frozen hydrogen pellets (not deuterium or tritium) into the plasma every 25 milliseconds to provoke mini-ELMs before the energy level created by these phenomena would lead to structural damage. To prevent ELMs from developing at the edge of the plasma, researchers have also suggested “poking holes” in the magnetic bottle that confines the plasma by including extra coils that produce a tiny magnetic field at the edge of the bottle (about 1/10,000 of the larger field). These smaller fields create perturbations at the edge of the field that would allow for a tiny but controlled leakage of plasma, essentially allowing miniscule amounts of plasma to touch the wall, but below the threshold of instability or of fusion reaction shutdown.32

Probably the biggest technical challenge that ITER needs to overcome is finding suitable materials for its demanding operational conditions, which are characterized by immense temperatures and high neutron fluxes. Almost all components that are in close proximity to the plasma (such as the reactor wall, shield modules, blanket modules, and divertor) will have to withstand extreme conditions and have low activation properties. A variety of materials are under consideration, including variations and alloys of beryllium and tungsten, the aforementioned reduced activation ferritic martensitic steel, vanadium alloys, and silicon-carbide composites, but as of yet the materials required for a continuously operating tokamak plant simply do not exist.

NIF and the laser inertial confinement path to fusion are likewise plagued by questions of technical feasibility. Some scientists do not believe NIF will obtain ignition, which could be a deathblow to the LIFE concept. Perhaps the most pessimistic analysis has been presented by Stephen E. Bodner, former head of the laser fusion program at the U.S. Naval Research Laboratory. In a March 2009 analysis, Bodner said that NIF's 2004 design specifications called for the delivery of 1.8 megajoules (MJ) of third-harmonic laser energy to a focal spot 0.5 x 1.0 millimeters (mm) in size (already increased from the original contract specifications). NIF's initial design also called for the use of optical smoothing techniques at 270 gigahertz (GHz) of bandwidth.33 According to Bodner, NIF scientists have been unable to meet these design specifications. Initial testing in 2007 at 1.8 MJ and at 270 GHz of smoothing bandwidth resulted in a focal spot size of 1.64 x 1.91 mm, well outside of the design specifications. A focal spot of this size would likely hit the hohlraum entrance or directly strike the spherical fuel pellet, resulting in an ignition failure.34

In order to narrow the focal spot to an acceptable level, Bodner says that NIF scientists were forced to drop the laser power to 1 MJ and have effectively abandoned plans to utilize 1.8 MJ of laser energy. Instead, the new point design aims for 1.221 MJ of laser energy. There is no experimental data on NIF's performance at 1.2 MJ, so whether this new, lower-power design will be focused and strong enough to create ignition remains to be seen. Of additional concern, Bodner says that NIF has a nonlinear optical problem that destroys the transverse near-field phase quality, which inhibits increasing laser energy above 1 MJ.35

However, Erik Storm, a NIF scientist and one of the leaders of the LIFE concept, says that these criticisms are inaccurate. According to Storm, there were never any problems with near-field phase quality; he also says that during an early January 2010 test, NIF fired 1.2 MJ of energy in a NIF ignition pulse-shape, where laser power, focal spot parameters, bandwidth, and other variables met the requirements established by the target design team.36 The NIF team has so far chosen to operate at 1.2 MJ, Storm says, because not all of the beams have the latest and most damage-resistant optics installed. According to Storm, improvements in surface-finishing technology in the last few years have resulted in optics that can accept fluence levels of 1.8 MJ with acceptable damage (from an optics maintenance perspective). The new optics have already been installed on 25 percent of NIF's beams, and test shots with individual and quad beam groupings have delivered the energy equivalent of more than 1.8 MJ with correct pulse shape, focal spot parameters, bandwidth, and beam balance requirements. Once the new optics have been installed on all 192 beams, NIF could do routine shots at energy fluences providing 1.8 MJ. Thus, the decision to operate NIF at lower energies was simply a strategic economic and operating cost decision, Storm says.37 Regardless of the reason, the question will be settled after NIF installs the new optics and tries to fire 1.8 MJ shots and achieve ignition, probably by the end of 2010.

Even if NIF succeeds in achieving ignition and research into the LIFE concept moves forward, LIFE reactors would face structural problems similar to ITER's. For example, questions remain about how the structural elements of the reactor core will hold up under a pulsed-periodic, high-energy load and the corresponding neutron flux. The radiation stability of the blanket also remains to be seen.38 The high-energy neutrons expelled from the rapid fusion reaction shots will damage any material they come into contact with. These reactions rearrange atoms in the metals surrounding the reactor core, creating impurities, brittleness, and weakness. As a result, the entire reactor core would frequently need to be replaced.39 LIFE planners acknowledge this deficiency and plan to mitigate radiation da mage through the use of oxide dispersion strengthened (ODS) ferritic steels, refractory metals such as tungsten, and other unspecified materials. According to their calculations, ODS ferritic steels have a potential neutron damage limit of 150–300 displacements per atom (dpa). LIFE's first layer wall is anticipated to receive approximately 35 dpa per year, meaning even with advanced materials the chamber would still need to be replaced every four to eight years.40 How much periodic chamber replacement threatens the economic viability of a LIFE reactor remains unclear because the cost estimates have not been released. Based on NIF's experiences, it is safe to say that the actual cost may be significantly higher than the initial estimates.

In addition, the striking of high-energy neutrons against the surrounding materials also results in “induced radioactivity,” similar to the radioactivity caused by a fission reaction. Like other forms of nuclear energy, operation and maintenance of LIFE would require robots to service the reactor core and dispose of radiological waste.41 When the reactor core is decommissioned, the material will be highly radioactive. But the irradiated components cool much more quickly than in a fission reactor; after approximately 100 years, a human can safely approach.42 This is a significantly shorter time period than the thousands of years of storage required for fission. A 100-year storage timeline would allow for rotating interim storage solutions, whereas fission waste will eventually require long-term storage in underground repositories.43

Yet LIFE's technical challenges are far greater than just issues related to neutron flux and induced radioactivity. Some of the problems must be overcome by technologies not yet invented. For example, the current technique for obtaining inertial confinement fusion demands near perfection of the symmetry of the spherical ablator. The distribution of energy fired by the lasers must also be extremely precise.44 A LIFE plant will also require a laser that can fire approximately 10 shots per second. The current optical lasers employed by NIF require several hours of cool down between shots, so as not to crack the optics. A technique called fast ignition, while still theoretical, may resolve this issue. Scientists are investigating fast ignition with the Mercury Laser at LLNL and the proposed high-power energy research experimental laser in Europe.45 In addition, scientists continue to debate the design and construction of the fission blanket, as well as how to extract and recycle tritium from the blanket.

For some of the problems facing LIFE, technological solutions already exist. These technologies, however, must be improved prior to use in the LIFE cycle. For example, a LIFE plant firing 10 shots per second would require millions of deuterium-tritium fuel pellets for continuous operation. Each fuel pellet requires exacting standards and uniform manufacturing. Developers of the Pebble Bed Modular Reactor (fission) design are working on a similar issue through the manufacturing of many millions of sub-millimeter fuel kernels know as Triso fuel.46 The experience gained from this process could be adapted to LIFE fuel pellets.

In addition, questions remain about energy storage and removal. LIFE plants would need to store and discharge enormous volumes of energy with each shot. Capacitor technology would need additional improvement to provide safe operation. Also, after the shot and subsequent energy generation, LIFE needs an electrical grid that can sustain the energy output. Plans call for plants with outputs of 1,500–3,000 MW, requiring high-power transmission lines and modern electrical grids. This would mostly restrict the first wave of LIFE plants to urban areas in developed countries, likely limiting the LIFE team's dream to roll out 1,000–2,000 GW of installed fusion energy by 2100.47

Nonproliferation Implications of Fusion Technology

ITER's Fissile Material–Free Fuel Cycle

A major concern with fission reactor technology is the need for fissile fuel, which can be misappropriated for weapons uses. Most fission reactors require 3–5 percent uranium-235 (U-235) low-enriched uranium (LEU) fuel.48 While this is not nuclear weapons–usable, some research reactors use up to 93 percent U-235, which is highly enriched uranium (HEU), that is, weapon-grade uranium. As seen with the concern over Iran's enrichment program, any country purportedly starting enrichment for civilian use can also adapt the technology to produce weapon-grade material. After irradiating natural uranium, LEU, or HEU in a reactor, a country can also reprocess the spent fuel to obtain weapons-usable plutonium-239 (Pu-239). Nearly every nuclear weapon state has done this.

A tokamak fusion power plant will not need fissile material to produce energy, which is beneficial to nonproliferation goals. Because many of the associated dual-use facilities would not be needed for a tokamak fusion power plant, the likelihood of weapons development is lessened. Although deuterium and tritium can be utilized as components in advanced nuclear weapons, they cannot be used to acquire a first-generation fission bomb. There will also be little to no spent nuclear fuel in a magnetic confinement reactor, lessening the likelihood that a state would decide to pursue reprocessing. However, in theory an operator could introduce fertile isotopes such as uranium-238 (U-238) for neutron bombardment into the tritium breeder blanket, yielding fissile material suitable for use in nuclear weapons; any nuclear fusion power plant would have to make arrangements to safeguard against this.

Plutonium Breeding and Safeguarding at a LIFE Plant

Although the fast neutrons from the fusion reaction burn waste in the breeder blanket, they also breed fissile material. In fact, the first several years of a LIFE plant's operation is called the “breed-up phase,” during which U-238 is transmuted into fissile Pu-239 and plutonium-241. After approximately ten years of operation, a LIFE plant reaches its peak plutonium production phase, and the plutonium created would not significantly decline until thirty-five to forty years into operation.49 Therefore, the large amounts of plutonium contained in the blanket would be a proliferation concern throughout the lifespan of a LIFE plant.

LIFE would be an excellent plutonium production machine largely because the fast neutrons pass through a beryllium layer surrounding the fusion target chamber. The beryllium multiplies the number of neutrons by approximately 1.8. This reaction “softens” the neutron spectrum, resulting in neutron energies more effective at producing tritium and plutonium (as well as fission), raising the same proliferation concerns as conventional fast-neutron or breeder reactors.50 However, extracting the fuel from the blanket would be quite difficult and relatively easy to safeguard. The fissile material would be widely dispersed in millions of individual fuel pebbles, which according to LIFE design plans would be tagged as individual accountable items and therefore hopefully difficult to divert.51 Still, fuel pebbles would be removed for inspection at a rate of 2–3 per second, resulting in a cycle time of approximately thirty days per pebble. Therefore, with such a rapid removal rate, the IAEA would need to develop a safeguard regime for LIFE plants to prevent the misuse of the blanket for fissile material production.52 Bruce Moran, head of the IAEA's Concepts and Approaches Section, said in an e-mail message that the IAEA has no plan to safeguard a LIFE or any other future fusion reactor because the IAEA considers the potential development of fusion technology a low priority.53

Theoretically, the neutron bombardment that makes energy generation possible in a LIFE reactor could also be used in a tokamak reactor to transmute thorium-232 to uranium-233 or U-238 to Pu-239. The high neutron flux and the energetic environment in the tokamak wall would yield very pure (99 percent) Pu-239. Regardless of whether a potential state would really chose the route of building a tokamak reactor to acquire fissile material, the technology must be evaluated based purely on the question of whether such a scenario is feasible; otherwise, fusion cannot be promoted as a proliferation-resistant technology. Fabio Balloni of the Interdisziplinäre Arbeitsgruppe Naturwissenschaft, Technik, und Sicherheit (Interdisciplinary Working Group on Science, Technology, and Security) at the Technical University–Darmstadt used the Monte Carlo n-particle Transport Code as the basis for calculating whether a tokamak fusion plant could be used to breed fissile material, based on the blanket configuration introduced earlier. In his scenario, Balloni assumed the replacement of the liquid lithium-lead within six of the blanket modules in a 20-degree section of the full 360-degree tokamak torus, with natural uranium or LEU with an enrichment level of 3.75 percent U-235. For the simulation, Balloni used variables of 0.1 percent, 0.5 percent, 1 percent, and 10 percent to replace the liquid lithium-lead alloy in the blankets with the two different isotopic compositions. Although replacing the breeding material with U-238 would increase potential plutonium production, there are two limiting factors: possible fissioning of the U-238 or U-235 would threaten structural integrity of the tokamak due to overheating; and in order to continue fueling the fusion reactor, a certain amount of tritium needs to be part of the fuel cycle. Balloni's experiments showed that the maximum exchangeable fraction lies at 1 percent; in this case LEU is necessary to guarantee continued tritium production in amounts required to continually fuel the reactor. His simulation yielded sobering results, as can be seen in Table 1. Replacing 1 percent of liquid lithium-lead with natural or LEU results in almost 65 kilograms (kg) of plutonium, even if only a 20-degree segment of the blanket is utilized. Using the entire 360 degree torus results in more than 1,100 kg of plutonium. When using just 0.1 percent, the amounts of plutonium generated are still of proliferation concern. The simulation is based on continuous operation of the reactor, which is a rather unrealistic assumption, but there is no doubt that a fusion reactor could be used to breed plutonium in large amounts. Another factor that has to be considered is that the lithium-lead in the blanket is in liquid form, while the U-238 is not, so the blankets would have to undergo an appropriate redesign—a rather daunting technical feat.

TABLE 1  Burn-up scenarios.

	Natural Uranium		LEU (U-235 at 3.75 percent)
Percent LEU	20° (kg Pu)	Total (kg Pu)	20° (kg Pu)	Total (kg Pu)
0.1	9.04	162.18	9.1	163.8
0.5	37.91	682.38	38.5	693
1.0	64.87	1,167.66	65.32	1,175.76
Computer simulation of burn-up scenarios for six blanket modules in a 20-degree segment or the entire tokamak and the resulting Pu-239 production capacity, in kilograms per year. Source: Fabio Balloni, Matthias Englert, and Wolfgang Liebert, “Proliferation Risks of a Future Fusion Reactor—Possible Plutonium Production,” FONAS Newsletter, No. 9, April 2009.

Balloni also suggested methods to prevent the breeding of fissile material in the blankets, including measuring fission neutrons with a neutron detector when removing the blankets for tritium extraction or maintenance, measuring the gamma rays emitted by fission products, or simply weighing the blankets before installation by the IAEA or a another safeguarding agency.54 It is crucial that ITER operators realize that these theoretical safeguarding measures must be tested at the tokamak in France, so that when the time comes (if fusion-based power generation actually does become reality), operators can ensure that the plant will not be used for any proliferative purposes.

Deep Burn and Reduced Waste

What differentiates a fusion plant greatly from a fission power plant is the advantage of reduced radioactive waste. Waste resulting from a tokamak fusion plant can be stored aboveground, and after approximately twelve years most of the radioactivity would decay. Remote handling procedures for waste contained in fuel assemblies have been established for fission reactors; however, in a tokamak fusion reactor, the diffusion of tritium and the radioactivation of the first wall and divertor assemblies could create challenging waste management and disposal problems, especially because components have to be replaced continually during the reactor's operational lifetime.

In a LIFE plant, waste concerns would theoretically be minimized because of the efficiency of hybrid fusion-fission and the ability to import waste for transmutation. Utilizing a heavy hydrogen blanket with natural uranium could burn 3.5–4 percent of the uranium, making it eight to ten times more efficient than standard RBMK- and VVER-type reactors.55 Also, while a standard light water fission reactor extracts 1 percent of the energy in LEU fuel, a LIFE plant could potentially extract up to 99 percent of the energy in supplied fuel. Therefore, a 1,500-MW plant could operate for fifty years on a much smaller amount of fuel than traditional light water reactors.56 Conceptual planners predict that a LIFE plant would produce approximately 5 percent of the nuclear waste of a comparable light water reactor.57

Because LIFE could potentially achieve such a deep, efficient burn, it could also transmute the stockpiles of civilian and military spent nuclear fuel and depleted uranium into relatively harmless waste; after forty years of operation, the U-238 would be significantly depleted and cease to create additional plutonium. At that point, a LIFE plant would burn down the actinides remaining in the blanket.58 Theoretically, long-lived actinides generated by other nuclear power plants could also be placed in the blanket and transmuted to much shorter-lived fission products, which could reduce the need for long-term underground waste repositories.

Concerns Regarding Tritium in the ITER Fuel Cycle

Tritium is of interest in a nonproliferation context because it is used in sophisticated nuclear weapon designs, including boosted fission weapons, “dial-a-yield,” and thermonuclear warheads. Only a few grams of tritium can significantly increase the yield of some fission weapon designs.59 During implosion, deuterium-tritium gas is injected into the hollow core of the plutonium sphere at high pressures, and the resulting fusion reaction induces further fission reactions, thus increasing (boosting) the weapon's yield. Dial-a-yield weapons work similarly by injecting variable amounts of tritium into the pit before delivery, providing the option to select a yield based on target selection. Tritium can also be used in enhanced radiation weapons or neutron bombs that have a comparatively low yield but a very large flux of high-energy neutrons relative to a pure fission weapon that produces the same overpressure, or blast. Enhanced radiation weapons typically use about 20–30 grams of tritium.60

On its own, tritium is useless to any country aspiring to clandestinely develop nuclear weapons; however, for a country that has already developed simple fission weapons based on large warheads, tritium is decisive in developing smaller, more efficient warheads with higher yields, which may allow the use of more capable delivery systems beyond gravity bombs or crude ballistic missiles. Tritium allows threshold countries to pursue modern, miniaturized warheads with selectable yields that can be integrated into a delivery system with multiple independently targetable reentry vehicles. Tritium can thus be seen as crucial to the vertical proliferation of a country just beginning a nuclear weapons program.61 By participating in an international fusion program, countries might gain necessary experience with handling weapons-relevant amounts of tritium that they would not otherwise have received.

ITER and LIFE designs both utilize substantial amounts of tritium; ITER will use approximately 17.5 kg of Canadian tritium over its thirty-five-year operational lifetime, which will be present in the reactor complex and the neighboring tritium building in a variety of forms. Unfortunately, accounting for tritium poses some problems. Measuring tritium is inherently difficult; it is one of the most challenging isotopes to detect because it emits only beta rays that have exceptionally low energy.62 The beta decay of tritium can be used to measure the amount of tritium—depending on the aggregate state either by mass spectrometer, gas chromatography, or calorimetry (measuring the decay heat). The tritium circulating in the ITER fuel cycle will be measured daily, which is an exceptionally strict accounting regime; however, this method has one major flaw: the burn-up rate of tritium within the plasma is very difficult to measure, even though ITER's design provides for a variety of neutron cameras and neutron spectrometers designed to gauge the amount of tritium contained in the ionized gas. Joerg Reckers, a physicist at the Center for Science and Peace Research at the University of Hamburg, used detailed computer simulations to estimate what effect the difficulty of measuring tritium burn-up within the plasma would have on ITER's overall accounting of tritium. His results were somewhat worrisome: according to Reckers, the detection probability of a loss of 171 grams of tritium within the first ten years of ITER operation is just 20 percent.63 If one considers that a 1-gigawatt fusion power plant would use 50–180 kg of tritium annually, the severity of the problem becomes strikingly clear.64 Reckers suggested improving the measurement precision of ITER's tritium control regime by adding micro-gas-chromatographs at the base of the reactor vessel where tritium, along with the helium ash, is collected by the cryopumps—a feature absent in current ITER design specifications. In order to guarantee that fusion power plants truly are more proliferation resistant and secure than fission plants, ITER needs to function as a real-world test for effective tritium control, something that is currently not part of ITER's official goals.

Safety and Sabotage

ITER and LIFE plants are inherently safer than conventional nuclear fission plants, primarily because the reactor always remains in a subcritical state. This eliminates the possibility of a meltdown and corresponding release of radioactive material into the surrounding environment. Because the deuterium-tritium fuel is supplied continuously in very small amounts, the ITER and LIFE reactors have only enough fuel for a few seconds of fusion reaction. The injection of fuel pellets can be quickly stopped, instantly ending the fusion reaction. Even in the event of a malfunction, the amount of fuel contained in the reactor core is insufficient to cause off-site harm.65 This compares favorably to fission plants, which are vulnerable to terrorist attack and sabotage.66 (This article uses the IAEA's definition of sabotage: “Any deliberate act directed against a nuclear facility, nuclear transport cask, or nuclear material which could directly or indirectly endanger the health and safety of the worker, the public, and the environment by exposure to radiation.”)67

The primary target for radiological sabotage at a fission power plant would be the special nuclear materials: spent fuel, fresh fuel, and the reactor core.68 At a fission power plant, the least radioactive—and therefore least worrisome—of the special nuclear materials is the fresh fuel. The most worrisome is the spent fuel because it contains the toxic alpha, beta, and gamma ray emitting fission products and long-lived actinides resulting from irradiation in the reactor core. In the United States, spent fuel usually spends at least one year cooling in an on-site spent fuel pool pond before it is moved to on-site dry cask storage.69 In both cases, the spent fuel is at risk for sabotage. Containment structures cover only the reactor core, meaning an attack on a spent fuel pool could release radioactive material into the surrounding environment. In addition, nuclear power plants place dry casks outdoors, greatly enhancing their vulnerability to terrorist attack. In contrast, an ITER or LIFE power plant would produce only a fraction of the spent fuel created by a fission reactor. As such, the amount of high-level waste would be greatly reduced and therefore easier to protect, reducing the risks stemming from a terrorist attack.

At a fission plant, a saboteur could also cause a loss of coolant accident (LOCA), resulting in a core meltdown; a fusion plant, however, is intrinsically safe from a meltdown even in the event of sabotage. In the case of a tokamak reactor, the low amount of radioactivity should greatly decrease the danger from a LOCA. If the cooling circuit of a future fusion plant fails completely, the radioactivity in the vessel and structural materials would continue to generate heat, but most experts agree that melting and a subsequent release of radioactive gas is impossible.70 Power production would stop as soon as fueling stops. The resulting temperature drop in the plasma would immediately end the fusion reaction; should the magnetic superconductors fail, the plasma would touch the vessel wall, which immediately stops the fusion reaction.

Even if all cooling circuits in a potential tokamak fusion plant stop operating, and if all active safety operations fail, and if there is no intervention for a prolonged period of time, the amount of tritium released into the environment would be very small. The tokamak structure inherently provides a three-layered defense against the release of tritium: the gas would have to penetrate the vacuum vessel, then the cryostat, and finally the building that houses the reactor. The temperature increase in a LOCA could theoretically lead to tritium being transported oustide the plant by erosion dust circulating loose in the vessel, but it would be trapped by the heat sink outside of and underneath the vessel. In this case, the amount of radiation released would be about 1.2 millisieverts (mSv). Even if the electric circuits fail and the heat sink, which is based on pumps providing convective circulation, do not catch the released tritium, the amount of radiation released would be around 18 mSv, which is below the 50 mSv evacuation level set by the International Commission on Radiological Protection.71

However, it would be unreasonable to assert that a tokamak fusion plant does not present any risk of radiation release or accident. Lithium would be present in substantial quantities in a pure fusion plant; consequently, a lithium fire could break out, resulting in considerable radiation release. Additionally, the neutral beam injections systems could create the need for large openings in the vacuum vessel, thereby increasing the risk of radiation release. A tokamak fusion system is highly complex, even when compared to fission systems; the risk of industrial accidents involving radiation release during construction, operation, and decommissioning should be considered significant.

In a LIFE plant, a saboteur would have to continue deuterium-tritium fuel injections while simultaneously interrupting the flow of flibe (molten salt coolant) to the blanket in order to cause the blanket to meltdown. This scenario is possible in theory but highly unlikely because of the immense technical and logistical challenges. Nonetheless, the blanket would contain radioactive material that would be susceptible to a bomb or other explosive attack. As such, LIFE plant designs should incorporate a containment vessel and institute physical protection measures for the reactor core.

Economics

Fusion is an expensive undertaking; the ITER project initially called for €11 billion to be spent over thirty-five years, but leading figures at the ITER Development Agency recently said costs will almost certainly increase. This has led critics to question not only the financial viability of the ITER project, but also the feasibility of fusion-based power and the possibility of producing economically competitive energy. French physicist Sebastian Balibar has likened ITER to the International Space Station, which many view as a failed investment because it cost well over $100 billion and has yielded insubstantial scientific progress.72

Unlike ITER, LIFE is still in the conceptual stage and does not have a specific cost estimate. In this respect, ITER and future tokamak projects have a distinct advantage: technologies and processes for ITER are largely established, and costs can be quantified, whereas many technologies for LIFE are not yet invented or are still in the experimental stages. However, proponents of LIFE hope that as lasers become increasingly efficient, the ratio of nuclear energy to laser energy released will continue to increase. Due to economies of scale, laser costs will decrease as production increases. The resulting reduction in laser energy might allow the capacity of the experimental reactor to be reduced to tens of megawatts, meaning that a prototype LIFE plant could be built on a smaller scale than a commercial project, which would reduce economic risk. This offers a distinct advantage over a tokamak prototype, which is very expensive and requires gigawatts of energy and full-scale construction to maintain its high-temperature plasmas.73

Considering the magnitude of the world's future projected energy needs, the investment in ITER (and potential investment in LIFE) does not seem excessive, especially in comparison with expenses spent on fossil fuels. For example, coal—an energy inefficient, highly polluting, and finite resource—is subsidized by the German government at a rate of €2.5 billion per year.74 In the United States, the fossil fuel industry has benefited from approximately $72 billion in federal subsidies over the past seven years.75 The entire thirty-five-year ITER budget, including construction, operation, and decommissioning costs, is less than what the world spends today on oil in three days.76 Kaname Ikeda, general director of the ITER organization, recently said that even in the worst-case scenario the costs for ITER would be significantly less than a single day's cost of energy generation in Europe.77 British physicist Llewellyn Smith, who heads the U.K. fusion development program, has argued that humankind must invest in various new types of energy generation, including wind, solar, and biofuels, simply because guaranteeing energy security is such a massive task. ITER's price tag may seem high, but it should be recalled that its budget will be spent over thirty-five years and funded among eight partners.

ITER vs. LIFE

The question still remains, however, which fusion energy program should be pursued—if any. Laser inertial confinement fusion is tied to the U.S. Stockpile Stewardship Program (SSP), and therefore many of the program details are classified and much of NIF's findings are unavailable to the broader scientific community. Conversely, a primary advantage of magnetic confinement fusion is that it is entirely independent from military and nuclear weapon programs, making it a far more open technology. Scientists are able to read all of the technical literature and can visit the facilities without being subject to national security restrictions.78 This open, internationalized model allows a far greater number of scientists to collaborate; repeatedly in ITER's design and now construction stages, participating nations cooperated to overcome technical and economic obstacles. It would therefore be highly beneficial for the advancement of LIFE if it could be internationalized and separate from the U.S. weapons and stockpile stewardship programs. This may not be too difficult because many of the necessary technologies are already unclassified; it is more a question of resolving intellectual, proprietary, and patent protections.79

Another major advantage of the ITER reactor is that its technology is more advanced and farther along than that of LIFE. The major technical and material problems are well defined and generally understood, freeing physicists to devote their time and energy to refining established processes and routines to make them more efficient. The LIFE reactor, on the other hand, depends on the development of multiple technologies that do not exist or are still in the experimental stages. However, ITER scientists still project that it will be 2040 before a reliable magnetic confinement fusion power plant could introduce power into the electric grid, and the project's recent cost hikes and delays make this timeline questionable.80

One can only speculate as to the cost of electricity generated by fusion. A series of computer simulations performed by ARIES, a joint project between the physics departments of several major U.S. universities, projects an electricity base price of 4.7 cents per kilowatt-hour in a potential tokamak power plant, which would be competitive with other electricity sources. Unfortunately, these projections depend on overcoming many technical challenges and should be taken with a grain of salt.81 It is simply too early to tell whether laser internal confinement fusion or magnetic fusion will succeed; however, it seems clear that future research into creating energy through inertial confinement fusion is largely dependent on the success or failure of NIF. According to NNSA's chief scientist, “Until there is fusion burn in the laboratory with sufficient detail for reliable conception of hybrids, I don't think any DOE position is likely nor any DOE sponsored program of work.”82

If NIF does not achieve ignition, then substantial taxpayer funding for the LIFE concept does not seem justifiable. If, on the other hand, NIF achieves ignition, then laser inertial confinement and magnetic confinement technologies should be pursued with equal vigor until it becomes clear which is more economical, will contribute the most to global energy security, and will lessen the likelihood of nuclear proliferation.

Conclusion

Creating conditions similar to those in the core of a sun is a daunting scientific and economic challenge, yet the potential of fusion energy is too great to dismiss because of these difficulties. The primary reason for the continued support of fusion is that its successful application may yield substantial benefits; for example, the amount of nuclear waste created is far less than that which is derived from nuclear fission. The deuterium-tritium fuel cycle yields little radioactive waste; if properly constructed, fusion reactors will not have long-lasting decommissioning costs when compared to fission power reactors.83

Still, the history of nuclear fusion brings with it a great deal of warranted skepticism. Immense unsolved technical and economic challenges give ammunition to critics who question the validity and concept of fusion energy. However, scientists have made enormous leaps in fusion research, and technological innovations of great magnitude are always associated with a certain degree of risk. As W.J. Nuttall points out in his book Nuclear Renaissance, one cannot “exclude the possibility that one day the power of the hydrogen bomb could be harnessed peacefully, just as the power of the atom bomb was harnessed in the 1950s.”84 Fusion power would be a “game-changer” on many levels, from climate change to nuclear waste and energy security; it may also ease certain proliferation concerns.

To succeed, any fusion project will require sustained, long-term political and public support. As fusion technology matures, backers will need to show steady technical progress in order to avoid disruption of funding. Fusion proponents should also avoid using overly optimistic cost estimates and timelines. Otherwise, the public and policy makers will see just another over-budget, impractical pork project. Proponents should use conservative cost estimates and realistic timelines, even if they seem shocking. In the long term, fusion will have a higher chance of survival if leaders decide to support it based on cautious assessments.

From a nonproliferation standpoint, ITER is an ideal project to evaluate and test the proliferation resistance of future fusion plants. Unfortunately, these objectives are not currently included in the ITER project, nor in the LIFE plans. This requires swift action on the part of the funding partners in order to be remedied. It should not be too difficult to find physicists from each of the participating nations to form a commission tasked with security and safeguarding issues; a good starting point would be the Interdisciplinary Working Group on Science, Technology, and Security at the Technical University–Darmstadt, or the Center for Science and Peace Research at the University of Hamburg.

All precautions should be taken to ensure that fusion technology truly is a safe and secure alternative to fission. Too often, fusion is promoted as inherently safe from a proliferation standpoint, which is not technically true. Consequently, it is necessary to address safeguarding issues now, instead of in forty or fifty years, when energy generation based on fusion could theoretically be used; otherwise, fusion could run into the same kind of problems that weigh down fission-based energy. Being aggressive and addressing these complicated issues as soon as possible will better prepare policy makers and the public for a day when fusion power could be a viable and cost-effective alternative to fission.

ACKNOWLEDGEMENTS

The authors would like to express their gratitude to Aaron Stein, who provided valuable research, insights, and editing assistance during the drafting of this paper.

Notes

1. Bruce Moran, section head, Concept and Approach, IAEA, Division of Concepts and Planning, e-mail correspondence with authors, June 12, 2009.

2. Olaf Stampf, “Die Sonne auf Erden” [The Sun on Earth], Der Spiegel, December 29, 2008, p. 118.

3. Adam McLean, “The ITER Fusion Reactor and Its Role in the Development of a Fusion Power Plant,” Radiation Protection Management 22, No. 5 (2005).

4. M.Q. Tran, “Opportunities and Challenges for Industry in the Construction of ITER,” EFDA Support Unit Garching, 2005, p. 5.

5. Ian Sample, “ITER: Flagship Fusion Reactor Could Cost Twice as Much as Budgeted,” Guardian, January 29, 2009.

6. Kenneth J. Korane, “The Future of Fusion Heats Up,” Future Technology, September 15, 2005, pp. 102–103.

7. Tran, “Opportunities and Challenges for Industry in the Construction of ITER,” p. 6.

8. Chris Llewellyn Smith, “Fusion: JET, ITER and Beyond,” Nuclear Engineering International, February 20, 2006, p. 10; Korane, “The Future of Fusion Heats Up.”

9. LLNL, “Laser Programs: The First 25 Years … 1972–1997,” UCRL-TB-128043, <lasers.llnl.gov/science_technology/pdfs/Lasers_1972_1997.pdf>; Ann Parker, “Empowering Light: Historic Accomplishments in Laser Research,” Science & Technology Review, September 2002, <www.llnl.gov/str/September02/September50th.html>.

10. LLNL, “About NIF and Photon Science,” <lasers.llnl.gov/about>.

11. LLNL, “How NIF Works,” <lasers.llnl.gov/about/nif/how_nif_works/index.php>.

12. LLNL, “How NIF Works,” <lasers.llnl.gov/about/nif/how_nif_works/index.php>.

13. W.J. Nuttall, Nuclear Renaissance: Technologies and Policies for the Future of Nuclear Power (New York, NY: Taylor & Francis Group, 2005), pp. 244–46.

14. LLNL, “How LIFE Works,” <lasers.llnl.gov/about/missions/energy_for_the_future/life/how_life_works.php>.

15. LLNL, “How LIFE Works,” <lasers.llnl.gov/about/missions/energy_for_the_future/life/how_life_works.php>.

16. “‘George’ Shot is Pivotal,” in “Quest for the Hydrogen Bomb,” AtomicArchive.com, <www.atomicarchive.com/History/hbomb/page_12.shtml>.

17. Dale Meade, “50 Years of Fusion Research,” presentation at Symposium on Fusion Engineering 2009, San Diego, June 1, 2009.

18. T.A. Heppenheimer, The Man-Made Sun: The Quest for Fusion Power (Boston: Little, Brown & Co., 1984), pp. 180–82.

19. T.A. Heppenheimer, The Man-Made Sun: The Quest for Fusion Power (Boston: Little, Brown & Co., 1984). pp. 203–35.

20. Meade, “50 Years of Fusion Research.”

21. All budget numbers are based on the officially released budgets of the U.S. government; see U.S. Government Printing Office, <www.gpoaccess.gov/USbudget>.

22. William Stenseth, “Review of LNL Self-Constructed Asset Pool (SCAP) Special Allocation Indirect Rates and Reduced Management Fee,” memorandum to LNNL from NNSA, October 2009, <www.trivalleycares.org/new/govdocs/OFFM%20Inspection%20report%20on%20NIF.pdf>; “Report Finds Livermore Disguised Fusion Lab's True Cost,” Global Security Newswire, December 11, 2009, <gsn.nti.org/gsn/nw_20091211_8200.php>.

23. During the writing of this paper, the authors were told by a fusion critic that NIF and fusion lacked high-level DOE support. Also see Helian Unbound (an anonymous blogger), “The Big NIF Dis,” June 22, 2009, <helian.net/blog/2009/06/22/inertial-confinement-fusion/the-big-nif-dis>.

24. Steven Chu, “Biological Solutions to the Energy Crisis,” AAPPS Bulletin 15 (August 2005), p. 7, <www.lbl.gov/Publications/Director/assets/docs/biological-solution-1-AAPPS-Taiwan-July-2005.pdf>.

25. David Crandall, chief scientist, NNSA, e-mail correspondence with authors, February 1, 2010.

26. David Crandall, chief scientist, NNSA, e-mail correspondence with authors, February 1, 2010.

27. Tony James, “Big Science,” Engineering & Technology 2 (June 2007), pp. 38–39.

28. Sebastian Balibar, “Die Kernfusion ist ein Mythos” [Fusion is a Myth], Die Welt, May 21, 2007, p. 8.

29. Stampf, “Die Sonne auf Erden,” p. 120.

30. Stampf, “Die Sonne auf Erden,” p. 120.

31. Gamini Seneviratne, “Fusion Talks Focus on Life after ITER,” Nuclear News, December 2008, p. 51.

32. Roger Hingfield, “Flaw in the 7 Billion Pound ITER Fusion Power Plan,” The Telegraph, March 12, 2008.

33. Stephen Bodner, “NIF Laser Fails to Meet the Minimum Specifications Required for Their Ignition Target Designs,” March 28, 2009, <www.trivalleycares.org/new/NIF_analysis_4_30.pdf>.

34. Stephen Bodner, “NIF Laser Fails to Meet the Minimum Specifications Required for Their Ignition Target Designs,” March 28, 2009, <www.trivalleycares.org/new/NIF_analysis_4_30.pdf>.

35. Stephen Bodner, “NIF Laser Fails to Meet the Minimum Specifications Required for Their Ignition Target Designs,” March 28, 2009, <www.trivalleycares.org/new/NIF_analysis_4_30.pdf>.

36. Erik Storm, LIFE project manager, e-mail correspondence with author, January 20, 2010.

37. Erik Storm, LIFE project manager, e-mail correspondence with author, January 20, 2010.

38. Basov, “Nuclear Reactor with a Laser Fusion Neutron Source,” pp. 129–36.

39. Charles Seife, Sun in a Bottle: The Strange History of Fusion and the Science of Wishful Thinking (London: Penguin Books, 2008), p. 168.

40. Edward I. Moses et al., “A Sustainable Nuclear Fuel Cycle Based On Laser Inertial Fusion Energy,” Fusion Science and Technology 56 (August 2009), p. 552.

41. Basov, “Nuclear Reactor with a Laser Fusion Neutron Source,” pp. 129–36.

42. Seife, Sun in a Bottle, pp. 168–69.

43. IAEA, “The Long Term Storage of Radioactive Waste: Safety and Sustainability: A Position Paper of International Experts,” 2003, <www-pub.iaea.org/MTCD/publications/PDF/LTS-RW_web.pdf>.

44. High-Power Laser Energy Research (HiPER), “Fast Ignition Fusion,” <www.hiper-laser.org/fusion/fastignition.asp>.

45. For the status of the Mercury and HiPER lasers, see LLNL, “The Mercury Laser: Ten Shots a Second,” <lasers.llnl.gov/programs/psa/fusion_energy/mercury.php>; and European High-Power Laser Energy Research, <www.hiper-laser.org>.

46. Nuttall, Nuclear Renaissance, p. 161.

47. For LLNL's plans for a LIFE rollout see LLNL, “Life Project Plan,” <lasers.llnl.gov/about/missions/energy_for_the_future/life/project_plan.php>.

48. The exception is the Canadian CANDU reactor, which runs on natural uranium; however, CANDU reactors are not particularly efficient and produce excellent weapon-grade plutonium in the spent fuel.

49. Moses et al., “A Sustainable Nuclear Fuel Cycle Based On Laser Inertial Fusion Energy,” p. 556.

50. Moses et al., “A Sustainable Nuclear Fuel Cycle Based On Laser Inertial Fusion Energy,” p. 556.; N.G. Basov, V.I. Subbotin, and L.P. Feoktistov, “Nuclear Reactor with a Laser Fusion Neutron Source,” PINSA-A 64, No. 2 (1998), pp. 129–36; Nuttall, Nuclear Renaissance, p. 257.

51. Moses et al., “A Sustainable Nuclear Fuel Cycle Based On Laser Inertial Fusion Energy,” p. 560.

52. Nuttall, Nuclear Renaissance, p. 257.

53. Bruce Moran, section head, Concept and Approach, IAEA, Division of Concepts and Planning, e-mail correspondence with authors, June 12, 2009.

54. Fabio Balloni, “Proliferation Risks Associated with Fusion Power Plants,” presentation at the Interdisziplinäre Arbeitsgruppe Naturwissenschaft, Technik, und Sicherheit (IANUS) Group (Interdisciplinary Working Group on Science, Technology, and Security), Technical University–Darmstadt.

55. Basov, “Nuclear Reactor with a Laser Fusion Neutron Source,” pp. 129–36.

56. LLNL, “LIFE: Benefits and Challenges,” <lasers.llnl.gov/missions/energy_for_the_future/life/benefits_challenges.php>.

57. Moses et al., “A Sustainable Nuclear Fuel Cycle Based On Laser Inertial Fusion Energy,” p. 559.

58. Moses et al., “A Sustainable Nuclear Fuel Cycle Based On Laser Inertial Fusion Energy,” p. 559.

59. Andre Gsponer and Jean Pierre Hurni, “ITER: The International Thermonuclear Experimental Reactor and the Nuclear Weapons Proliferation Implications of Thermonuclear Fusion Energy Systems,” Independent Scientific Research Institute, February 2, 2008, p. 15.

60. Martin B. Kalinowski, International Control of Tritium for Nuclear Nonproliferation and Disarmament (Boca Raton, FL: CRC Press, 2004), pp. 9–11.

61. Martin B. Kalinowski, International Control of Tritium for Nuclear Nonproliferation and Disarmament (Boca Raton, FL: CRC Press, 2004), p. 43.

62. Martin B. Kalinowski, International Control of Tritium for Nuclear Nonproliferation and Disarmament (Boca Raton, FL: CRC Press, 2004), p. 5.

63. Joerg Reckers, “Tritiumbilanzierung im ITER Fusionsreaktor” [Tritium Accounting in the ITER Fusion Reactor], doctoral diss., University of Hamburg, Physics Department, September 2007.

64. Different people suggest different estimates. Martin Kalinowski estimates around 180 kgs; Manfred Gugel of the Research Center Karlsruhe suggests around 50 kgs; Wolfgang Liebert of the IANUS group, around 100 kgs.

65. Nuttall, Nuclear Renaissance, p. 251.

66. Nuttall, Nuclear Renaissance, p. 251.

67. James W. Purvis, “Sabotage at Nuclear Power Plants,” Sandia National Laboratories, August 24, 1999, <www.osti.gov/bridge/servlets/purl/9593-cl8jIh/webviewable/9593.pdf>.

68. James W. Purvis, “Sabotage at Nuclear Power Plants,” Sandia National Laboratories, August 24, 1999, <www.osti.gov/bridge/servlets/purl/9593-cl8jIh/webviewable/9593.pdf>.

69. Nuclear Regulatory Commission, “Spent Fuel Pools,” and “Dry Cask Storage,” <www.nrc.gov/waste/spent-fuel-storage/pools.html>; and <www.nrc.gov/waste/spent-fuel-storage/dry-cask-storage.html>.

70. Smith, “Fusion: JET, ITER and Beyond,” p. 10.

71. “A Conceptual Study Of Commercial Fusion Power Plants: Final Report of the European Fusion Power Plant Conceptual Study,” April 13, 2005, pp. 31–32.

72. Balibar, “Die Kernfusion ist ein Mythos,” p. 8.

73. Basov, “Nuclear Reactor with a Laser Fusion Neutron Source,” pp. 129–36.

74. Stampf, “Sonne auf Erden,” p. 120.

75. “U.S. Tax Breaks Subsidize Foreign Oil Production,” Environmental Law Institute, September 18, 2009.

76. Stuart Nathan, “Fusion Future,” The Engineer, February 12, 2007, pp. 24.

77. Norbert Lossau, “Ist die Fusionsenergie unbezahlbar?” [Is Fusion Energy Impossible to Pay For?] Die Welt, September 17, 2008, p. 31.

78. Seife, Sun in a Bottle, p. 163.

79. Erik Storm, project manager, LIFE, e-mail correspondence with author, September 27, 2009.

80. ITER, “ITER & Beyond,” <www.iter.org/proj/Pages/ITERAndBeyond.aspx>.

81. Farrokh Najmabadi et al., “The ARIES-AT Advanced Tokamak: Advanced Technology Fusion Power Plant,” Fusion Engineering and Design 80 (2006), p. 19.

82. David Crandall, NNSA chief scientist, e-mail correspondence with authors, February 1, 2010.

83. Nuttall, Nuclear Renaissance, p. 251.

84. Nuttall, Nuclear Renaissance, p. 296.