Recommendation 4-7: The achievement of ignition with laser-indirect drive at the National Ignition Facility should not preclude experiments to test the feasibility of laser-direct drive. Direct drive experiments should also be carried out because of their potential for achieving higher gain and/or other technological advantages.
Conclusion 4-6: It is essential for the IFE program to develop reliable models and improve the physics understanding of the phenomena underlying experimental tests of the target physics. Knowledge gained through experimental tests should be used to validate and improve the models, so that there can be reasonable confidence that the predictions are not restricted to the parameter space explored in the experimental tests. Models will be important for optimizing designs from both a technological and economic perspective.
Conclusion 4-7: Achieving higher gains has the potential to provide improved technical margins and potential economic advantages for the system as a whole. If calculations are confirmed, fewer targets would be needed to produce a given amount of power, or the driver repetition rate or driver energy could be reduced, thereby reducing costs.
An important question is which facilities will need to be built to successfully reach the goals of the IFE program. Table 4.3 is based on the data provided in the discussions in Chapters 2 and 3 on the TAs respecting what has been done and what is under way in IFE, as well as what the magnetic fusion energy program provides and what needs to be done to reach the conceptual design stage of DEMO and commercial deployment of IFE. In addition to a number of smaller test facilities (i.e., IREs), it assumes that there will be an additional two major facilities: (1) a Fusion Test Facility (FTF), a staged facility with repetitively targeted deuterium-tritium (DT), high-gain capsules that would bring all aspects of the technology of IFE up to TRL 6 using a prototypical driver that would be determined by the IFE program, and (2) the end point of the IFE development program, DEMO, which would complete the TRL process.
As shown in Table 4.3, NIF and FTF are absolutely critical to move the TAs and their technological components from TRLs of 4 or less to 6 for the CD-0 DEMO decision process. Note also that it has been assumed in Table 4.3 that certain technologies (e.g., materials, handling) will be developed, at least in part, using existing MFE facilities, as described in Chapter 3.