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PREPUBLICATION COPY—SUBJECT TO FURTHER EDITORIAL CORRECTION 177 178 Preface and Acknowledgments 179 180 In the fall of 2010, the Office of the U.S. Department of Energy’s (DOE’s) Under 181 Secretary for Science asked for a National Research Council (NRC) committee to investigate the 182 prospects for generating power using inertial confinement fusion (ICF) concepts, acknowledging 183 that a key test of viability for this concept—ignition1—could be demonstrated at the National 184 Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL) in the relatively near 185 term. The committee was asked to provide an unclassified report. However, DOE indicated that 186 to fully assess this topic, the committee’s deliberations would have to be informed by the results 187 of some classified experiments and information, particularly in the area of ICF targets and 188 nonproliferation. Thus, the Panel on the Assessment of Inertial Confinement Fusion Targets 189 (“the panel”) was assembled, composed of experts able to access the needed information (for 190 member biographies, see Appendix A). The panel was charged with advising the Committee on 191 the Prospects for Inertial Confinement Fusion Energy Systems on these issues, both by internal 192 discussion and by this unclassified report. The statement of task for the panel is given in Box P.1. 193 Box P.1 Statement of Task for the Panel on the Assessment of Inertial Confinement Fusion Targets A Panel on Fusion Target Physics (“the panel”) will serve as a technical resource to the Committee on Inertial Confinement Energy Systems (“the Committee”) and will prepare a report that describes the R&D challenges to providing suitable targets, on the basis of parameters established and provided to the Panel by the Committee. The Panel on Fusion Target Physics will prepare a report that will assess the current performance of fusion targets associated with various ICF concepts in order to understand: 1. The spectrum output; 2. The illumination geometry; 3. The high-gain geometry; and 4. The robustness of the target design. The panel will also address the potential impacts of the use and development of current concepts for Inertial Fusion Energy on the proliferation of nuclear weapons information and technology, as appropriate. The Panel will examine technology options, but will not provide recommendations specific to any currently operating or proposed ICF facility. 194 195 The panel interpreted the terms used in its statement of task in the following way. 196 “Illumination geometry” not only is interpreted to mean the physical arrangement and timing of 197 laser or particle beams incident on the target but also is generalized to mean “delivering driver 198 energy to the target.” In this way, the magnetic forces in pulsed-power schemes are also 199 included. “High-gain geometry” is interpreted as designs that enable the energy incident on the 200 target to be converted efficiently into fuel burn and high yield.2 “Spectrum output” is interpreted 201 to include all of the types of emissions (photons, ions, neutrons, and debris) from the fusion 202 target and their energy spectra. Depending on the type of reaction chamber used (solid wall, 1 The operative definition of ignition adopted by the panel, “gain greater than unity,” is the same as that used in the earlier National Research Council NRC report: Review of the Department of Energy's Inertial Confinement Fusion Program,Washington, D.C.: National Academy Press (1997). 2 High yield is defined broadly as much more than 10 times the fusion energy produced as driver energy delivered to the target. 1
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PREPUBLICATION COPY—SUBJECT TO FURTHER EDITORIAL CORRECTION 203 wetted wall, liquid wall, gas-filled, evacuated, and so on) these emissions may or may not reach 204 the chamber wall; however, a detailed discussion of the effects on the wall is beyond the scope of 205 this report. “Robustness of the target design” is interpreted in two ways: (1) the inherent 206 “physics robustness,” which relates to the performance margins of the design being large enough 207 compared to the physics uncertainties that reliable performance can be assured under ideal 208 conditions, and (2) “engineering robustness,” which relates to the target’s ability to deliver 209 reliable performance even under nonideal conditions such as variations in driver energy, target 210 manufacturing defects, errors in target positioning, or driver beam misalignment. 211 This unclassified report contains all of the panel’s conclusions and recommendations. In 212 some cases, additional support and documentation required the discussion of classified material, 213 which appears in classified appendixes in a separate version of this report. ICF is an active 214 research field, and scientific understanding continues to evolve. The information discussed here 215 is accurate as of the date presented to the panel (see Appendix B), though in some cases more 216 recent updates are included; if so, this is noted in the text. 217 This report was reviewed in draft form by individuals chosen for their diverse 218 perspectives and technical expertise in accordance with procedures approved by the National 219 Research Council’s Report Review Committee. The purpose of this independent review is to 220 provide candid and critical comments that will assist the institution in making its published 221 report as sound as possible and to ensure that the report meets institutional standards for 222 objectivity, evidence, and responsiveness to the study charge. The review comments and draft 223 manuscript remain confidential to protect the integrity of the process. 224 We wish to thank the following individuals for their review of this report: 225 226 Bedros Afeyan, Polymath Research Inc., 227 Roger Bangerter, E.O. Lawrence Berkeley National Laboratory (retired), 228 Michael Corradini, University of Wisconsin, 229 Jill Dahlburg, Naval Research Laboratory, 230 Richard Garwin, IBM Thomas J. Watson Research Center, 231 David Hammer, Cornell University, 232 Frank von Hippel, Princeton University, 233 Arjun Makhijani, Institute for Energy and Environmental Research, 234 David Overskei, Decision Factors Inc., 235 Robert Rosner, University of Chicago, and 236 Douglas Wilson, Los Alamos National Laboratory. 237 238 Although the reviewers listed above have provided many constructive comments and 239 suggestions, they were not asked to endorse the conclusions or recommendations, nor did they 240 see the final draft of the report before its release. The review of this report was overseen by 241 Louis J. Lanzerotti, New Jersey Institute of Technology. Appointed by the NRC, he was 242 responsible for making certain that an independent examination of this report was carried out in 243 accordance with institutional procedures and that all review comments were carefully 244 considered. Responsibility for the final content of this report rests entirely with the authoring 245 committee and the institution. 246 2
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PREPUBLICATION COPY—SUBJECT TO FURTHER EDITORIAL CORRECTION 247 The panel also thanks the NRC staff for its dedicated work, in particular Sarah Case, who 248 got the panel started off on the correct path, and Greg Eyring, who persevered in getting both the 249 classified and the unclassified reports over many hurdles. 250 251 John F. Ahearne, Chair 252 Panel on Assessment of Inertial Confinement Fusion Targets 3