Inertial fusion energy (IFE) has been a concept since the 1970s, and the National Research Council (NRC) has performed several reviews of the Department of Energy’s (DOE’s) programs for inertial confinement fusion (ICF)—the essential concept underlying IFE—since that time (NRC, 1986, 1990, and 1997). This report of the Panel on Fusion Target Physics supports and informs a broader study on the prospects for IFE being undertaken by a separate NRC committee.1 The broader study is motivated by a desire on the part of DOE, the sponsor, to determine a clearer path forward for the IFE concept, in view of the prospect that a key test of viability for this concept—ignition—can be demonstrated at the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL) in the relatively near term.
To address its statement of task (see the Preface), the panel heard from many sources, listed in Appendix B, and visited several laboratories involved in U.S. efforts in ICF and IFE—LLNL, Sandia National Laboratories, Lawrence Berkeley National Laboratory, the University of Rochester Laboratory for Laser Energetics, and the Naval Research Laboratory—and heard from representatives of additional programs at the Los Alamos National Laboratory.
The panel’s focus in this study is IFE targets, including both direct-drive and indirect-drive targets. To distinguish its role as clearly as possible from that of the main study committee, the panel drew a conceptual sphere around the outside of the target and considered anything crossing the surface of the sphere (energy
1 The Committee on the Prospects for Inertial Confinement Fusion Energy Systems.
coming in, reaction products going out) as well as physics processes taking place inside the sphere, to be within its purview. In addition, the panel considered the technical feasibility of fabricating various target concepts to be within its charge, but deemed the mass manufacturing of high-performance, cost-effective targets for future power plants to be part of the main committee’s responsibility. Inevitably, there were certain topics at the interface between the charges of the panel and the main committee, such as the survivability of the injected target in the extreme environment of the reaction chamber. In such cases, the panel felt that it was preferable that the panel and committee reports should overlap rather than risk the possibility that important topics might be left out.
Chapter 2 provides a brief technical background on IFE and a discussion of key concepts related to ICF targets and their role in IFE. In Chapter 3, the proliferation risks of specific target designs are discussed, as well as the broader proliferation risks associated with IFE plants and research facilities. Chapter 4 evaluates the current status of various targets, considering the results of actual experiments on their performance as well as the analytical and predictive capabilities of available codes and simulations. This analysis is used to characterize the state of our current understanding of fusion target physics and to identify the major issues that remain to be resolved. The classified version of this report contains additional appendixes discussing classified material that the panel considers relevant to its conclusions and recommendations.