Bringing Fusion to the U.S. Grid (2021) / Chapter Skim
Currently Skimming:
4 Innovations and Research Needed to Address Key Fusion Pilot Plant Goals
4 Innovations and Research Needed to Address Key Fusion Pilot Plant Goals
Pages 55-82
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 55... ...
This enthusiasm is manifest in the recent fusion community planning process1 and the numerous private startup companies that have garnered significant investment and are working to further the development of numerous fusion confinement and potential power plant concepts. However, research aimed at developing a fusion-based power plant has, to date, focused mainly on the plasma physics and confinement itself, including the plasma, the divertor and first wall, as well as the magnets and heating systems.
|
From page 56... ...
However, as noted in the Fusion Energy Sciences Advisory Committee report on Transforma tive Enabling Capability for Efficient Advance Toward Fusion Energy,2 numerous recent advances in advanced materials and manufacturing, high-temperature and/ or high-field magnets, and tritium processing offer the potential to significantly increase the TRL to enable construction and mitigate risks towards the initial operation of a compact pilot plant. The divertor, first wall, and blanket systems for operation in a fusion power reactor represent a significant materials development challenge resulting from the neutron-induced degradation, thermal mechanical loading, and corrosive envi ronment.
|
From page 57... ...
An integrated strategy is needed to develop and test the integrated first wall and breeding blanket concepts in time for readiness for deployment of a compact fusion pilot plant. There are two inter-related motivations for innovations and research in fusion energy.
|
From page 58... ...
magnets was identified as a key enabling technology that pro vides a potential path, when combined with advanced operating scenarios, to a compact fusion pilot plant with high fusion power density, and high poloidal beta enabling high bootstrap current fraction. Input to the committee stated that there are numerous other fusion confinement concepts that may provide a pathway to electricity generation.
|
From page 59... ...
To achieve practical applications to replace present electrical generating pro cesses with fusion will require substantial progress in producing, maintaining, and heating of a burning plasma, while keeping it confined without damaging the engineered systems surrounding the plasma. Fusion performance can be character ized by the fusion energy gain, or the closely related triple product of ion density, ion temperature, and energy confinement time.
|
From page 60... ...
The specific innovations required to advance a concept toward readiness for a pilot plant vary significantly with the characteristics of the concept. For brevity and concreteness, the remainder of this subsection focuses on the tokamak, as it is closest to readiness in terms of triple product, and was identified as the leading magnetic fusion concept in the 2019 Burning Plasma report.
|
From page 61... ...
the fusion triple product, or fusion gain, which must be large enough for the plasma to produce net electricity and be predomi nantly self-heated by fusion products (i.e., "burning plasma")
|
From page 62... ...
However, the high operating density of a compact fusion device is likely beneficial for enhancing radiative cooling and to achieve detached plasma state. Another challenge is taming the transient heat flux including those due to edge localized modes (ELMs)
|
From page 63... ...
High-Temperature Superconducting Magnets It has been known for many decades that access to high magnetic fields is an important requirement for the achievement of magnetic fusion energy. Further more, for virtually all magnetic fusion concepts, the fields must be generated by superconducting magnets.
|
From page 64... ...
This provides confidence in RAFM structural materials for use in a fusion pilot plant, although the degradation service limit above this fluence is not yet established. However, RAFM materials have not been fully demonstrated in the complex environmental loading conditions of a fusion pilot plant, which include multiple combined degradation modes including neutron degradation, He and H2 gas generation from nuclear transmutation, injected ions and permeating tritium, sig nificant and potentially time-varying heat flux, complex mechanical loading, and magnetic fields and corrosive coolants, including the effects of radiolysis.
|
From page 65... ...
Zinkle and L.L. Snead, 2014, Designing radiation resistance in materials for fusion energy, Annual Review of Materials Research 44:241-267; permission conveyed through Copyright Clearance Center, Inc.
|
From page 66... ...
Thus, robust mechanical property, corrosion, fabrication, and irradia tion effects databases will need to be established that meet the requirements of appropriate regulatory authorities, including those consisting of high-temperature and time-varying stress state. This necessitates significant materials R&D to enable the design and function of all in-vessel and ex-vessel structural and functional materials in the fusion pilot plant environment.
|
From page 67... ...
The implantation of helium into materials can cause blistering and spallation that can produce material loss. The maturity of materials for applications in high heat flux and ion implantation applications in advanced fuel cycles is at a low TRL that necessitates further R&D, which should be defined as part of a more detailed technology roadmap for such fusion concepts.
|
From page 68... ...
Examples of areas requiring further R&D include high-frequency gyrotrons to enable electron cyclotron heating and current drive at high magnetic field, antenna structures compatible with high neutron and heat flux, and beam injection systems compatible with tritium breeding blankets. Solutions for the plasma heating systems and actuators for a fusion pilot plant are not in hand.
|
From page 69... ...
This is an essential capability for a D-T fusion pilot plant, and advances in these areas are required to meet the ambitious goals of a fusion pilot plant in the 2035-2040 timeframe. There are presently many blanket concepts being considered to meet the simul taneous demands of fusion power removal, neutron shielding, and tritium breed ing.
|
From page 70... ...
Direct internal recycling technologies, blanket tritium inventory reduction, or other similar methods to reduce the tritium inventory will need development before a fusion pilot plant. Finding: Improvements in tritium accountability methods that can be applied in continuously operating fusion plants are needed and should be demon strated in a fusion pilot plant.
|
From page 71... ...
Technologies should be demonstrated prior to the con struction of the tritium plant of a D-T fusion pilot plant. Finding: Tritium emissions from a fusion energy pilot plant need to be con trolled to meet applicable NRC guidelines.
|
From page 72... ...
Change cannot happen without a visible and obvious emphasis. Recommendation: The participants in the development of the pilot plant should execute the recommendation of the Community Planning Process to "Embrace diversity, equity, and inclusion, and develop the multidisciplinary workforce required to solve the challenges in fusion and plasma science." A continued tight coupling between the ongoing research teams in the fusion program and the pilot plant teams will be needed.
|
From page 73... ...
Experience gained at these facilities in addressing issues related to tritium handling and neutron production can benefit the fusion pilot plant effort and add diversity in perspective. DOE Fusion Energy Sciences has operated national facilities at national labo ratories, industry, and universities.
|
From page 74... ...
MODELS FOR PUBLIC-PRIVATE PARTNERSHIPS Over the last several decades, fusion energy research has involved government sponsored programs, and for larger research efforts, international collaboration with the ITER being the largest and most sustained example. However, over the last two decades multiple private-sector efforts have been initiated to develop fusion energy concepts.
|
From page 75... ...
However, it is important to note that SpaceX would likely not have been successful in such a short timeframe without access to NASA's technical expertise and key infrastructure including launch range facilities. In the same way, it remains essential that DOE sustain a strong base program in fusion energy science and technology, including supporting infrastructure and research at national laboratories and universities, and pursuing development of a fusion pilot plant as recommended in this report.
|
From page 76... ...
Recommendation: The Department of Energy should evaluate and identify the best model for public-private partnerships to accelerate development and reduce government cost for a fusion pilot plant. Note that the different phases of the development, including conceptual design and technology roadmap, detailed engineering design, construction and operation, may in volve different or incremental public private partnership models, including fixed-price payment for milestones.
|
From page 77... ...
If the U.S. fusion pilot plant is a tokamak, then there are sev eral specialized systems from the U.S.
|
From page 78... ...
• D-T fuel cycle technologies. The knowledge and application of the ITER tritium plant design directly supports the development of a fusion pilot plant in that the processing rate of hydrogen isotopes is much greater than current facilities use and scale-up as well as validation of many components will be completed as part of constructing the ITER fuel cycle.
|
From page 79... ...
The knowledge gained by participating in the ITER project is one of the key motivations for the United States to continue its support. Recommendation: The Department of Energy should assure maximum pos sible access to ITER information for the members of the fusion pilot plant design teams.
|
From page 80... ...
L Snead, 2014, Designing radiation resistance in materials for fusion energy, Annual Review of Materials Research 44:241-267, https://doi.org/10.1146/annurev matsci-070813-113627.
|
From page 81... ...
20. Fusion Energy Sciences Advisory Committee, 2018, "Fusion Energy Sciences Advisory Committee Report: Transformative Enabling Capabilities for Efficient Advance Toward Fusion Energy," up dated February 15, https://science.osti.gov/-/media/fes/fesac/pdf/2018/TEC_Report_15Feb2018.
|
From page 82... ...
Grid 35. Federal Register, 2020, "Cost-Sharing Partnerships with the Private Sector in Fusion Energy," https://www.federalregister.gov/documents/2020/04/20/2020-08312/cost-sharing-partnerships with-the-private-sector-in-fusion-energy.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.