Nonelectric Applications of Fusion

This is the final report of a panel set up by the U.S. Department of Energy (DOE) Fusion Energy Sciences Advisory Committee (FESAC) in response to a charge letter from Dr. James Decker, Acting Director of the DOE Office of Science. In that letter, Dr. Decker asked FESAC to consider whether the Fusion Energy Sciences program should broaden its scope and activities to include non-electric applications of intermediate-term fusion devices. This report, submitted to FESAC July 31, 2003, and subsequently approved by them (Appendix B), presents FESAC's response to that charge.     

Frontiers in Fusion Research

Presentations that were made at a Fusion Power Associates symposium, Frontiers in Fusion Research, are summarized. Discussions include the science frontiers of burning plasma physics, magnetic fusion concepts, inertial fusion concepts, and fusion technology.     

Ion beam propagation and focusing

Inertial confinement fusion with ion beams requires the efficient delivery of high energy (1 MJ), high power (100 TW) ion beams to a small fusion target. The propagation and focusing of such beams is the subject of this paper. Fundamental constraints on ion beam propagation and focusing are discussed, and ion beam propagation modes are categorized. For light ion fusion (LIF), large currents (2–33 MA) of moderate energy (3–50 MeV) ions of low atomic number (1A12) must be directed to a target of radius 1 cm. The development of pulsed power ion diodes for LIF is discussed, and the necessity for virtually complete charge neutralization during transport and focusing is emphasized. Fornear-term LIF experiments, the goal is to produce pellet ignition without the standoff needed for the ultimate reactor application. Ion diodes for use on Sandia National Laboratories Particle Beam Fusion Accelerators PBFA-I (2–4 MV, 1 MJ, 30 TW, operational) and PBFA-II (2–16 MV, 3.5 MJ, 100 TW, scheduled for operation in 1985) are discussed. Ion beam transport from these diodes to the pellet is examined in reference to the power brightness . While values of =2–5 TW/cm²/sr have been achieved to date, a value of 100 TW/cm²/sr is needed for breakeven. Research is now directed toward increasing , and means already exist (e.g., scaling to higher voltages, enhanced ion diode current densities, and bunching), which indicate that the required goal should be attainable. Forfar-term LIF applications, the goal is to produce net energy gain with standoff suitable for a reactor. This may be achieved by ion beam transport in preformed, current-carrying plasma channels. Channel transport research is discussed, including experiments with wire-initiated, wall-initiated, and laser-initiated discharge channels, all of which have demonstrated transport with high efficiency (50–100%). Alternate approaches to LIF are also discussed, including comoving electron beam schemes and a neutralized beam scheme. For heavy ion fusion (HIF), moderate currents (10 kA) of high energy (10 GeV) ions of high atomic number (A200) must be directed to a target of radius 0.3 cm. Conventional accelerator drivers for HIF are noted. For a baseline HIF reactor system, the optimum transport mode for low charge state beams is ballistic transport in near vacuum (10^–4–10^–3 Torr lithium), although a host of other possibilities exists. Development of transport modes suitable for higher charge state HIF beams may ultimately result in more economical HIF accelerator schemes. Alternate approaches to HIF are also discussed which involve collective effects accelerators. The status of the various ion beam transport and focusing modes for LIF and HIF are summarized, and the directions of future research are indicated.     

Fusion Power: Looking to the Future

Presentations that were made at a Fusion Power Associates symposium, Fusion Power: Looking to the Future, are summarized. The topics included overview and personal perspectives, status of ITER, stellarators, inertial confinement and innovative concepts. Also included is a summary of work on laser fusion at Osaka University.     

Report of the Integrated Program Planning Activity for the U.S. Department of Energy Fusion Energy Sciences Program

This report of the Integrated Program Planning Activity (IPPA) has been prepared in response to a recommendation by the Secretary of Energy Advisory Board that, Given the complex nature of the fusion effort, an integrated program planning process is an absolute necessity. We therefore undertook this activity to integrate the various elements of the program, to improve communication and performance accountability across the program, and to show the interconnectedness and interdependency of the diverse parts of the national Fusion Energy Sciences Program. This report is based on the September 1999 Fusion Energy Sciences Advisory Committee's (FESAC) report Priorities and Balance within the Fusion Energy Sciences Program. In its December 5, 2000, letter to the Director of the Office of Science, the FESAC reaffirmed the validity of the September 1999 report and stated that the IPPA presents a framework and process to guide the achievement of the 5-year goals listed in the 1999 report. The report also outlines a process for establishing a database for the fusion research program that will indicate how each research element fits into the overall program. This database will also include near-term milestones associated with each research element and will facilitate assessments of the balance within the program at different levels.     

Pilot plant: An affordable step toward fusion power

Progress is reported on a study to define a pilot plant to demonstrate the production of high grade heat in a fusion power plant configuration at the lowest possible capital cost. We are considering several driven reactor tokamak designs with fusion power production levels in the 15–50 MWth range, using demountable copper coils. We conclude that it is acceptable for such facilities to be net consumers of electricity as a trade-off to achieve low capital cost, which we estimate to be in the $1 billion range. These designs are based on currently accepted physics models. Even lower cost designs may be possible, if we depart somewhat from the current physics database.     

Fusion in the Era of Burning Plasma Studies: Workforce Planning for 2004–2014

This is the final report of a panel set up by the U.S. Department of Energy (DOE) Fusion Energy Sciences Advisory Committee (FESAC) in response to a charge letter from Dr. Raymond Orbach (Appendix A), asking FESAC to addressed the issue of workforce development in the U.S. fusion program. This report, submitted to FESAC March 29, 2004 and subsequently approved by them (Appendix B), presents FESAC's response to that charge.     

Symposium on Cost-Effective Steps to Fusion Power

A summary is provided of the keynote address, and other papers not otherwise published in this issue, presented at Fusion Power Associates symposium Cost-effective Steps to Fusion Power, held January 25–27, 1999 in Marina del Rey, CA.     

Report of the First Fusion Energy Sciences Committee of Visitors

This is the final report of a Committee of Visitors (COV) set up by the U.S. Department of Energy (DOE) Fusion Energy Sciences Advisory Committee (FESAC) in response to a charge letter from DOE Office of Science Director Raymond Orbach (Appendix A). In that letter, Dr. Orbach asked FESAC to assess matters pertaining to program decisions for the DOE's fusion theory and computation programs. This report, submitted to FESAC on March 29, 2004, and subsequently approved by them (Appendix B), presents FESACs response to that charge.     

The “18 Year” Alternative: A Business Proposal to Develop Commercial Fusion Energy by 2021—The Fusion Power Corporation

This policy essay asserts that the 35 year plan recently adopted by the U.S. Department of Energy's Fusion Energy Sciences Advisory Committee is too risk averse and too costly. An alternative 18 year schedule is proposed. All dollar amounts shown below are undiscounted, and are only intended to be indicative of approximate future costs.     

Report of the U.S. Department of Energy Fusion Energy Sciences Advisory Committee (FESAC) Panel Reviewing the Theory and Computing Program

This Panel was set up by the Fusion Energy Sciences Advisory Committee (FESAC) at its November 2000 meeting for the purpose of addressing questions from the Department of Energy concerning the theory and computing/simulation program of the Office of Fusion Energy Sciences. Although the Panel primarily addressed programmatic questions, it acknowledges that the theory and computing in fusion energy sciences has a stellar record of research successes. (A recent FESAC report entitled Opportunities in the Fusion Energy Sciences Program listed a number of theory and computing research highlights.) Last year the National Research Council performed an assessment of the quality of the fusion energy sciences program—including theory and computing—and concluded that the quality of its research is on a par with that of other leading areas of contemporary physical science.     

Plasma Science and Its Applications

An overview is provided of the papers presented at Fusion Power Associates annual meeting and symposium on the topic Plasma Science and Its Applications, held June 3–5, 1998 in Washington, DC. Only those papers not otherwise contained in the current issue of the JFE are covered.     

A Review of the U.S. Department of Energy's Inertial Fusion Energy Program

This is the final report of a panel set up by the U.S. Department of Energy (DOE) Fusion Energy Sciences Advisory Committee (FESAC) in response to a charge letter from Dr. Ray Orbach (Appendix A). In that letter, Dr. Orbach asked FESAC for an assessment of the present status of inertial fusion energy (IFE) research carried out in contributing programs. These programs include the heavy ion (HI) beam, the high average power laser (HAPL), and Z-Pinch drivers and associated technologies, including fast ignition (FI). This report, presented to FESAC on March 29, 2004, and subsequently approved by them (Appendix B), presents FESAC's response to that charge.     

Connections between physics and economics for Tokamak fusion power plants

A simplified physics, engineering, and costing model of a tokamak fusion reactor is used to examine quantitatively the connection between physics performance and power-plant economics. The material contained herein was generated as part of a broader study of the economic, safety, and environmental impact of fusion based on a range of confinement schemes, fusion fuels, blanket/shield configurations, power-conversion schemes, and commercial end products. Only a DT-fuelled tokamak reactor that produces electricity through an intermediate heat exchange and a conventional thermal-electric conversion cycle is considered; a self-cooled lithium-metal blanket with vanadium-alloy structure, steel shield, and superconducting magnets is used for all cases studied. An optimistic extension of Troyon scaling is applied to a high-elongation ( = 2.5) and low-safety-factor (q =2.3) plasma with =0.1 and efficient (I P _CD =0.2 A/W) current drive. This 1200-MWe (net) power plant provides an economically competitive base case with which to compare other approaches to tokamak fusion power. The base case chosen for comparisons represents an optimistic extrapolation of present tokamak physics and technology. Troyon scaling with a coefficient B a/I equal to 0.04 is applied; the impact of an ad hoc but pessimistic scaling that diminished the Troyon coefficient with plasma elongation was also examined. Additionally, a constant current-drive efficiency, =nI R _T /P _CD =0.2 A/W, atT=10 keV plasma temperature is assumed; although representing an aggressive R&D target relative to present experience, the realization of bootstrap currents for the basecase, and especially for the second-stability-region tokamak, can significantly reduce this problem. The impact and reoptimization for a constant normalized current-drive efficiency, =nI R _T/P _CD, was also examined. Although the focus of this study has been the optimistic basecase tokamak, comparisons are made with tokamaks based on (a) operation in the second-stability region (=0.2, increased aspect ratio, reduced elongation), (b) super high-field but low-beta operation, (c) very low aspect ratio and highly elongated spherical torus, and (d) a direct application of the present database using a long-pulsed, low-beta tokamak. The economic impact of a range of base-case parameters and operating variables is examined, including current-drive efficiency, beta, stability limits, advanced magnets, economy of scale, blanket/shield lifetime, blanket thickness, and plant lead time. It is found that a range of tokamak options, relative to the optimistic base case selected for this study, may provide economically competitive power plants. Areas where physics and technology advances are needed to achieve this attractive end product are quantitively elucidated for all tokamak options considered.     

Spherical Torus Pathway to Fusion Power

Spherical Torus (ST) as an example of confinement concept innovation to enable a potentially attractive pathway to fusion power is discussed. Given the anticipated high performance in small size, the ST plasma could be used to stimulate innovation also in engineering, technology, and material combinations to provide a smarter, cheaper, faster pathway. This pathway could complement the mainline program based on the tokamak in making the desired progress in fusion energy sciences. The ST pathway could include a small VNS (Volume Neutron Source) with low fusion amplification (Q 1–2) for Fusion Energy Development (energy technology) and a small Pilot Plant with high Q (15–30) to practice Fusion Power Demonstration. Success in these steps also enhances the possibility for competitive non-electric applications of interest to society in time scales shorter than electric power generation. The scientific basis for these possibilities will be tested in the U.S. by the Proof of Principle experiment NSTX (National Spherical Torus Experiment) presently being built, and could be completed by a Proof of Performance and Optimization experiment such as a small DTST (Deuterium-Tritium Spherical Torus). Utilization of facilities and equipment already available in the U.S. would minimize the time and cost for these experiments and accelerate the approach to the stage of Fusion Energy Development.     

A Plan for the Development of Fusion Energy

This is the final report of a panel set up by the U.S. Department of Energy (DOE) Fusion Energy Sciences Advisory Committee (FESAC) in response to a charge letter dated September 10, 2002 from Dr. Ray Orbach, Director of the DOE's Office of Science. In that letter, Dr. Orbach asked FESAC to develop a plan with the end goal of the start of operation of a demonstration power plant in approximately 35 years. This report, submitted March 5, 2003, presents such a plan, leading to commercial application of fusion energy by mid-century. The plan is derived from the necessary features of a demonstration fusion power plant and from the time scale defined by President Bush. It identifies critical milestones, key decision points, needed major facilities and required budgets. The report also responds to a request from DOE to FESAC to describe what new or upgraded fusion facilities will best serve our purposes over a time frame of the next twenty years.     

Nuclear fusion from crack-generated particle acceleration

Summary In summary, the high-voltages necessary to accelerate deuterons to energies sufficient to produce modest numbers (10⁴–10⁵/sec) of d-d neutrons appears to be possible as a result of cracking or fracture of the metal lattice in the cold fusion experiments.This mechanism requires neither massive electrons nor exotic nuclear reactions to explain the apparent cold fusion d-d neutron production results. Instead, it is possible that high voltage electrostatic fields, known to be associated with cracking, can reside across a crack gap long enough for the deuterons to be accelerated to sufficiently high energy to produce the d-d reactions. Interestingly, the electrostatic acceleration is quite similar to that of laboratory accelerators except for its submicron scale. Clearly, much work is still required to determine whether such a crack-generated acceleration mechanism, a quasi-particle mechanism, some combination of these, or some other, as yet unidentified mechanism is responsible for the nuclear effects seen in cold fusion experiments.Presented at the Workshop on Cold Fusion Phenomena, Sante Fe, New Mexico, May 23–25, 1989.     

Report of the Fusion Simulation Project Steering Committee

The Fusion Simulation Project (FSP) is envisioned as a 15 year, $20M/year multi-institutional project to develop a comprehensive simulation capability for magnetic fusion experiments with a focus on the International Thermonuclear Experimental Reactor (ITER). The FSP would be able to contribute to design decisions, experimental planning and performance optimization for ITER, substantially increasing ITERs likelihood of success and its value to the US Fusion Program. The FSP would be jointly supported by the DOE Office of Fusion Energy Sciences and the DOE Office of Advanced Scientific Computing Research. The potential for developing this simulation capability rests on the exponential growth of computer power over the last 50 years, the progress in physics understanding developed by the international fusion program and the continued progress in computational mathematics that enables the use of the new ultra-scale computers to solve difficult mathematical problems. The initial concept for the FSP was developed by the Fusion Energy Sciences Advisory Committee Integrated Simulation and Optimization of Fusion Systems Subcommittee (J. Dahlburg and J. Corones, et al., J. Fusion Energy, 20(4), 135–196.). The DOE asked the FSP Steering Committee to develop a project vision, a governance concept and a roadmap for the FSP. The Committee recommends that the FSP consist of three elements: a production component, a research and integration component, and a software infrastructure component. The key challenge is developing components that bridge the enormous distance and time scales involved with the disparate physics elements of tokamak performance. The committee recommended that this challenge be met through Focused Integration Initiatives that would first seek to integrate different physics packages with disparate distance and time scales. An example is the integration of Radio Frequency (RF) Current Drive and Magnetohydrodynamics (MHD) components to produce an integrated capability to simulate the use of RF current drive to suppress MHD instabilities. This report also defines the requirements for a governance structure. The FSP Steering Committee judged that the project begin with a conceptual design phase lasting one or two years and be followed by a staged ramp-up over a few years to the full funding level.     

Thin-foil electrochemical cells: High-sensitivity fusion tests andin-situ ion beam measurements of deuterium loading

Electrochemical cells constructed with a thin Pd or Ti foil electrode mounted at one wall of the cell have been used both to test for the existence of cold fusion and to measure directly DPd loading ratios in an operating cell. The first type of experiment used a surface-barrier particle detector positioned a few millimeters from the foil to provide a very sensitive monitor for possible fusion-generated protons at 3.02 MeV. The detection limit for this arrangement is estimated to be 10^–24 fusions/deuterium/s, assuming a bulk fusion effect. These experiments included cells with 5- and 25-m-thick Pd foils, 10-m Ti foils, parallel experiments with 0.1M LiOD (heavy water) in one cell and LiOH (light water) in another, current densities up to 0.5 A/cm², and run times as long as 22 days. No evidence for fusion products was seen. The second type of experiment using these cells, both as an adjunct to the fusion tests and to provide new information, was the use of external beam nuclear reaction analysis to monitor directly the loading and unloading of deuterium in the foil of an operating cell. Using a 1.5-MeV³He ion beam in air, the deuterium in the outer 2 m of the exposed Pd foil was measured for the first time using the D(³He,p) nuclear reaction. The maximum DPd ratios observed using this technique were 0.8–0.9.     

Radiation Safety Considerations for LHD Experiments

For experiments with the Large Helical Device (LHD) which is now under construction at the Toki site in Japan, radiation safety issues were discussed. In the course of plasma experiments, radiations such as X-rays, induced -rays, and neutrons increase. From a safety point of view, these radiation exposures to the environment should be controlled to limit the annual dose to less than 50 Sv at the site boundary. In order to meet this, an area monitoring system named RMSAFE (Radiation Monitoring System Applicable to Fusion Experiments) has been developed and partly installed. This can discriminate and measure radiations including burst-like emissions due to plasma shots from natural radiations. For the present period, this system is operating to monitor the natural radiation levels before the LHD operation. It was observed that the radiation levels strongly depend on rain levels and ground state. An indoor area monitoring system has already been implemented on site, to measure radiations from NBI and ECH test shots, and it shows good monitoring ability. Also, thermoluminescence dosimetry has been applied. The importance of investigating the radiological behavior under natural conditions with continuous monitoring is shown.