A program is needed that attempts to answer whether there is any TA that appears to be practical as well as economically viable. Only certain combinations of targets, drivers, and chambers seem to be possible in this sense. While the emphasis today and in the near future should be on scientific issues related to driver and target performance, working only on these problems could easily lead to solutions that are not compatible with practical commercial driver and chamber options. Such a serial approach could lead to dead ends and would also extend the timescale to the possible practical implementation of IFE.
Technology R&D is not done in a vacuum, and certain answers from the technology research will be beneficial to the overall IFE program in its earlier phases. The design of a FTF and a DEMO cannot be accomplished absent critical technology developments even in the conceptual stages. If the IFE program is to continue advancing, there must be supporting technology developments all along the event pathways. And, perhaps most importantly, if there is to be a meaningful IFE program, it is vital that there be a skilled workforce to investigate the myriad of technology problems over the coming decades. These trained technical experts will not be available unless there is meaningful and challenging R&D for them to carry out early on. That will be possible only if there is a long-term sustained technology element included in the IFE program. Such a program element can be enhanced by identifying synergistic opportunities between the magnetic fusion energy and IFE programs and incorporating them in both programs.
Conclusion 4-13: The appropriate time for the establishment of a national, coordinated, broad-based inertial fusion energy program within DOE is when ignition is achieved.
Conclusion 4-14: There is a compelling need for a sustained, long-term engineering science and technology component in a national inertial fusion energy program.
Such a program would require a sustained effort that is initially devoted primarily to an improved understanding of target physics, particularly the relationship between absorbed energy and gain. Once the target physics is understood, modest gain has been achieved, and there is confidence that reactor-scale gain can be achieved, funding would then be ramped up and devoted primarily to technology development of the three TAs, including target manufacture, driver modules, chamber design, and materials. TA (driver) down-select should occur as part of the technology development phase. The committee’s order-of-magnitude estimate for accomplishing this in a two-step approach is given in Table 4.4.