FAQs about the CPP report

The APS DPP CPP represented the first phase of a long range strategic planning process for DOE Fusion Energy Sciences. As we delve into the second phase, led by a subcommittee of FESAC, it is important to make sure that everyone has a complete understanding of the work done during the first phase that is summarized in the CPP report, as this report forms the basis for the work of the subcommittee. The leadership of the CPP process (the CPP Co-Chairs, Program Committee and Expert Groups) have received several questions over the previous months about the CPP report that we would like to address. This FAQ document is intended to ensure that everyone has access to the information exchanged in response to these questions and was put together as a collaboration between the CPP Co-Chairs and members of the FESAC Long Range Planning (LRP) Subcommittee. Some of the questions are intended to address commonly heard misunderstandings or misconceptions and have simple objective answers. Other questions probe the reasons or justifications behind elements represented in the consensus CPP report. Answers to these questions are written in an attempt to reflect the consensus that emerged during the CPP process, but we recognize that the answers do not represent every single point of view that was raised.

This FAQ is intended to help lay the groundwork for gathering input from the broader community on strategies for overall program balance across the FES portfolio. The CPP accomplished a great deal, resulting in community-led prioritization of individual sub-areas of the FES portfolio and the identification of many cross-cutting opportunities. However, there was not sufficient time to allow conversations between the sub-areas in order to: (1) enable each community to better understand the research needs and priorities of the other and (2) have meaningful discussion on how a strategic plan can address balance across the whole FES portfolio. The FAQs, along with past and future webinars on the CPP report, are intended to help with the first need. The LRP subcommittee is organizing focus groups to help address the second need. These small groups will also offer additional opportunities to have conversations around cross-cutting scientific opportunities that may not have been captured under the four CPP cross-cutting areas (Theory/Computation, Diagnostics, Workforce and Enabling Technology). We anticipate additional questions about the CPP report to arise during these discussions and we intend to update this FAQ as they arise.

Note that the order of the questions & answers does not represent relative importance.

No, the report does not propose that the FPP should be the primary goal of FES. The report states that research categorized as “Fusion Science and Technology” should advance the goal of achieving a low-cost FPP, and that research in this category should be evaluated and prioritized accordingly. However, there is equal weight given in the report to general plasma science and high energy density physics, which do not (and should not) have the goal of an FPP as a motivating factor.

No, the FST community wants to focus on research and development, advancing the science and technology needed to design and build a pilot plant in the 2040’s. Developing a pilot plant will push the frontiers of plasma science (confining far-from-equilibrium plasmas, controlling instabilities, understanding plasma-material interaction and finding ways to tame disruptions, ELMs, etc) and fusion nuclear science and technology (developing robust magnet technology, finding structural materials that can withstand intense neutron bombardment, establishing the ability to breed tritium fuel for fusion, etc).

Developing new technologies requires significant progress in our scientific understanding, and vice versa. While Fusion Materials and Technology (FM&T) area is essential to develop practical fusion energy, this area has received less support from DOE FES than it requires. In the planning process and report, the FST community has recognized the need for enhanced focus on and investments in that field to lay the groundwork for the FPP. The large number of recommendations in the FM&T area reflects the substantial progress needed in science and technology to reach the FPP goal, and it does not necessarily reflect budgetary recommendations. These define a plan that will evolve based on the results of research. See also the answer to question: "How do the recommendations within FST address the “low-cost” aspect of an FPP? How is our program different from EU DEMO?".

There was great enthusiasm in the FST community for making fusion energy a reality. There seemed to be broad understanding that having a perfect plasma by itself or a perfect material by itself does not make a reactor; these aspects are inextricably intertwined and the science of both must be advanced to achieve fusion energy. Currently, FES is the only DOE office that supports science related to fusion energy. This is similar to how fission energy research, including for materials and technology, is supported by the NE office. For example, research on understanding material degradation to extend fission plant life times or research for developing new materials for small modular reactors would be funded by NE. In addition, many of the fusion materials and technology items are currently at low technology readiness levels that require basic and fundamental science research. These are reasons why the CPP report recommends actions to advance plasma science, actions to advance associated materials science and technology, and actions to encourage coordination and communications between these aspects of the field.

There was not time to delve into program balance or prioritization between these areas during the CPP process. The CPP report is therefore not intended to convey relative priority or relative importance, and relative length or ordering of the two sections in the CPP report should not be interpreted as such.

NNSA has a stockpile stewardship mission and fundamental science is not a primary focus. The science associated with HEDP has been highlighted in a number of recent reports from the plasma community, including the NAS “Opportunities in Intense Ultrafast Lasers” or “Reaching for the Brightest Light” report, the DOE FES Frontiers in Plasma Science Report, and in the NAS Plasma 2020 Decadal Report. The science of HEDP, and the alternative fusion concepts within, is at the forefront of our field and we want to ensure that this is supported. DOE FES, as a steward of plasma science, should step up to support this important science, and can in fact leverage many of the investments that NNSA has already made to support the FES mission. At the same time, we should continue to engage NNSA and other agencies, including NSF, DOE HEP and DOD to support this important field of scientific discovery and technology development and to leverage their contributions.

The National Ignition Facility (NIF) is an NNSA-funded facility to pursue HED and Inertial Confinement Fusion (ICF) experiments to achieve the high-pressure, and high-energy-density regimes found in an operating nuclear weapon without underground nuclear testing. The development of IFE, towards the goal of an energy source, is distinct from the NNSA’s mission. Key differences include that a credible approach towards IFE requires high target gain and high repetition rate drivers, and low-cost mass-produced targets. IFE concepts can also potentially utilize novel driver technologies or energy-coupling schemes, which are not within the scope of NNSA’s work.

Everything in the FST section is there because it is either necessary or desirable to achieve the goal of a low-cost fusion pilot plant (FPP) at an acceptable level of risk for this community. A great deal of work was already done by the community to combine, condense, and select key elements from the large number of white papers that were submitted in order to write the FST chapter. However, it is understood that not all of these recommendations can be carried out immediately even under highly optimistic budget scenarios. Given necessary budget constraints, the report intends to convey how initiatives should be sequenced both through the order of the Strategic Objectives and through the stated Values. In general, sequencing should be consistent with making rapid progress toward enabling the stated FPP deliverables at low capital cost, and decisions should be clearly justified on this basis.

The field of plasma science is incredibly diverse and broad with the capability to advance science and benefit society across so many areas. To attempt to capture this breadth, many recommendations were needed. During the CPP, great effort was taken to merge the related topics that emerged from the GPS and HEDP parts of the process so that the list was as concise as possible. While prioritization was considered within the HEDP and GPS groups separately, the community did not reach the point of prioritization across the two areas.

The report makes it clear that the U.S. should distinguish itself by pursuing innovation that allows an FPP concept that projects a reactor that is commercially viable in the U.S. market (largely, this requires low capital cost). This is reflected in the recommendations in several ways. First, the report states that we should not down-select to an FPP concept at this point, and that we should continue to pursue stellarators, alternates, and IFE concepts until a low-cost FPP design is found. Second, there are numerous recommendations to pursue high-risk but potentially transformative technologies that are not being explored by international partners. Third, the recommendation for FPP design studies emphasizes engagement with private industry from an early stage, and using techno-economic analysis to guide research priorities.

No, the report tries to be clear that this is not the role of the FPP design study. Rather, the role of this team (or teams) is to provide a common basis for systems studies, costing, and techno-economic analysis. This output should be used by FES (and others) to ensure that research priorities are aligned with the goal of achieving a low-cost FPP. The report is clear that this should be a multi-institutional effort.

As discussed extensively in Appendix B, closing some of the scientific gaps (i.e., unknowns or open questions) towards building an FPP requires capabilities that are beyond what present devices can achieve. The FST community has voiced that building an FPP without this new device would carry too high of a risk for the FPP, and has therefore shown consensus behind starting the pre-conceptual designs for the new tokamak (NTUF). The FST community also carefully weighed the options of a new device versus an upgrade to an existing device and felt that answering the necessary scientific questions would require a new device rather than an upgrade. Also, the community considered four possible major capabilities for such a new device and selected two of them as the most urgent. There are no cost estimates for this new tokamak yet, and it is the role of the FESAC LRP subcommittee to ensure a balance across the program under constrained budget scenarios. As with all the items in the report, the sequencing, cost, benefit, and risk needs to be considered for how this element of the plan would fit with all the others.

There are a few reasons why you might not see your comment or input reflected in the final report. One reason could be if your white paper or initiative was very specific to your own research or your institution. The purpose of the report was to lay out critical research topics that should be addressed, but not to be prescriptive on exactly how they should be addressed, where research projects should be located, or which people should be funded to address them. Another reason that you might not see your comment is that we tried to be inclusive and focus on consensus topics. We read and seriously considered every comment that was submitted and compared those comments against the vast body of feedback and information we had from the whitepapers, workshops, Expert Groups, and more. In cases where the suggestion helped better explain a topic or represent the consensus view, we incorporated it into the report. Consensus does not mean that everyone got exactly what they wanted in the report, but that we listened to all voices and tried to come to agreement. Consensus also does not mean a majority vote. There are numerous topics in the report that have only a few experts who research in those areas. By encouraging those experts to speak out in the web meetings and in person workshops, the scientists outside those topics were able to learn the value of the research and support it in the final report even when it was not their personal area.

Both the DPS and FST topics have basic and fundamental science questions to research and the report supports this. At the same time, there are numerous research topics within DPS and FST that have potential technology or commercial applications. FES is certainly not the only Office of Science that supports both basic and applied research. In fact, there is a long history of successful technology transfer of research that was started by DOE and then transferred to industry.

Following the 2013 report, the Panel Co-Chairs of the 2013 National Research Council Report on IFE (Ronald Davidson & Gerald Kulcinski) released a clarification of their positions regarding the interpretation of the NRC Report, which is consistent with the proposal for a modest IFE program now and which indicates the scientific need for that program. From that clarification, key statements include:

1. 1. 1. Individual Findings and Recommendations in the NRC Report on IFE should not be interpreted in isolation, but rather they should be interpreted w/in the context of the other Findings and Recommendations in the NRC Report.

      2. In the absence of achieving ignition in the laboratory in the near term, it was our intention that promising IFE concepts, driver approaches, and technologies be peer-reviewed and pursued by the DOE at modest levels and with improved coordination, not that such efforts be summarily terminated. As stated in the report, the IFE effort would benefit greatly from a plan and an approach to program governance that can make difficult decisions but is able to retain the strengths of the institutions active in IFE research.

      3. If ignition is achieved in laboratory experiments, it was our intention that a robust nationally coordinated IFE program be established by DOE, with compelling priorities and a down-selection process among promising driver approaches implemented as outlined in the NRC Report. For example, in conjunction with the MFE program, common technologies such as tritium breeding, materials, environmental impacts, etc., could be leveraged in support of IFE.

In other words, the NRC report supported continual support of an IFE research program, cautioned against downselecting too early, and stated that DOE should coordinate a robust national IFE program (which was and still is currently spread across multiple agencies and offices) upon the achievement of ignition. These views are supported by and reflected in the CPP-DPP report. The scientific rationale for this program is delineated in the CPP report, and focuses on the points under (b) above.

While the CPP report reflects the conclusion of the 2018 NAS Burning Plasma Strategy report that full partnership in ITER remains the best option for accessing burning plasmas at the scale of a power plant, and the charge letter instructs this strategic planning process to assume that the US remains a member of ITER, the urgency voiced by the community during the CPP process prohibits waiting for these results before initiating the many additional R&D activities needed for proceeding with an FPP. This approach parallels that of many other countries' strategic plans, which uniformly envision design of a national DEMO or other next-step ITER successor facilities beginning before ITER DT operations. The CPP report includes a number of recommendations (e.g. in FST-PR-B and FST-SO-D) on actions the US program can take to maximize the chances of ITER’s success. Both the NAS and CPP reports also identify a number of areas where full engagement with ITER before the start of burning plasma operation will provide advances in areas such as materials and nuclear engineering that will be directly relevant to many different possible FPP concepts, and not just to helping advance the tokamak physics basis. Additionally, FST-SO-D.1 specifically recommends “Leverag[ing] all opportunities to access, prepare for, and study burning plasma physics...", which includes engagement with private industry to study burning plasmas in other smaller-scale facilities they would operate. Finally, it is important to emphasize that the plan detailed in the CPP report is fundamentally research-driven, with follow-on strategic planning activities recommended to occur every 5-7 years. This process allows the community to dynamically respond and adjust priorities as our understanding of the scientific and technical challenges for realizing economic fusion power is advanced.