Bringing Fusion to the U.S. Grid (2021) / Chapter Skim
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3 Goals for a Fusion Pilot Plant
3 Goals for a Fusion Pilot Plant
Pages 25-54
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From page 25... ...
The first hurdle is net plasma gain, Qp -- that is, the ratio of fusion power to input power to the plasma, must exceed unity. It is selfevident that this objective is the minimum required for a power plant, but it is also an important threshold in fusion science since this also represents the minimum where the fusion plasma can start to heat itself in order to sustain the temperatures necessary for fusion.
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From page 26... ...
The lower limit for a pilot is set by two considerations. First, cost certainty requires a minimum power generation scale such that the extrapolation to FOAK fusion power plant is reliable and reasonable.
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From page 27... ...
Phase 2: Production of fusion power and electricity for an environmental cycle of the components that are degraded by the fusion energy production expected in an annual operation cycle of a FOAK fusion power plant. Operation during an environmental cycle results in material erosion and migration of plasma-facing surfaces, fuel/ash transport and retention, sensors, plasma actuators, and material damage caused by energetic n eutrons in D-T systems.
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From page 28... ...
While an environmental cycle is not strictly defined numerically, because it can vary across design approaches, based on our present knowledge base it likely represents a significant (on the order of one full power year) operational time before maintenance/repair would be required in a FOAK fusion power plant.
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From page 29... ...
• Establish lower bound on mean time to failure of structural components Blanket • D emonstrate power extraction • D emonstrate tritium generation with TBR materials • Demonstrate ability to generate and > 0.9 averaged over an environmental recover tritium with sufficiently low cycle tritium losses such that external • Demonstrate tritium losses <1 percent tritium inventory is maintained for of tritium consumption averaged over an power operations and remain within environmental cycle regulatory limits • Establish lower bound limit on mean time to failure of blanket structural materials due to environmental degradation NOTE: Phase 3 has the same goals as Phase 2 with the addition of more environmental cycles and/or modified materials and components. will also need to demonstrate effective remote maintenance and component replacement in order to provide greater certainty for the maintenance time and operation and maintenance costs of the FOAK fusion power plant.
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From page 30... ...
The duration of plasma operation and heat exhaust would be increased within Phase 1b in order to demonstrate the ability to reach a steady rate of fusion power, capture the fusion energy, and demonstrate the capability to generate electricity. From a material and components viewpoint Phase 1 demonstrates solutions to the so-called "zero dpa (displacements per atom)
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From page 31... ...
The helium ash must be removed at a steady state rate from the fusion plasma system and replaced with the fusion fuels, to maintain a constant fusion power. The helium is eventually removed as a neutral gas particle at near room temperature in a region outside of the fusion plasma, typically a pump adjacent to plasma-facing components where the helium ions are neutralized into helium atoms.
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From page 32... ...
The coupled issues of ash removal and the evolving viability of PFCs due to helium bombardment will be a critical requirement to demonstrate in all fusion pilots, regardless of configuration or fuel cycle. Conclusion: The ash removal concept has to be demonstrated in a pilot plant and should be applicable to the FOAK fusion power plant.
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From page 33... ...
and energy multiplier (M, thermal power/fusion power) of idealized deuterium-tritium (D-T)
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From page 34... ...
and some molten salt reactors use fluoride salt coolants that contain lithium and produce tritium at rates comparable to heavy water reac tors. Because these advanced fission reactors require systems for tritium control and recovery, they may have capability to extend tritium supplies and also demonstrate tritium control and recovery technologies that can be used in fusion power plants.
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From page 35... ...
Smith, 2017, Tritium resources available for fusion reactors, Nuclear Fusion 58:026010, © 2017 EURATOM. There are presently many blanket concepts being considered to meet the simul taneous demands of fusion power removal, neutron shielding, and tritium breed ing.
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From page 36... ...
. Furthermore, they define the required minimum "starting" inventory of tritium fuel, which is important for the plant's power availability in case of a shutdown or for the start of a new fusion power plant.
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From page 37... ...
Alternative Fuel Cycles to D-T The technology challenges that face alternative fuel cycles are less defined because most research efforts to date have concentrated on the D-T cycle. Nonetheless, alternate fuel cycles have been proposed and studied such as D-D and p-11B that have abundant terrestrial fuel sources, and D-3He, which would likely require a lunar source of He-3 for a FOAK fusion power plant.
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From page 38... ...
. As well, Figure 3.3 shows that alternate fuels have a lower fraction of fusion power released as neutrons.
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From page 39... ...
RELIABILITY AND AVAILABILITY The pilot plant should provide operational and test data needed to assure reliability for the subsequent FOAK fusion power plant, which must be capable of operating with high availability (eventually greater than 85 percent)
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From page 40... ...
has been devoted to structural materials performance under neutron irra diation for these components, but design and integration into a functioning fusion power plant is highly complex and is one of the primary objectives of a pilot plant. Finding: A fusion pilot plant will need to demonstrate the ability to effi ciently perform remote maintenance and replacement in support of the design of a power plant, taking into account details of the consequences of the fusion environment, such as material activation and tritium retention in components.
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From page 41... ...
, an independent federal agency, regulates the Nation's civilian use of nuclear materials. This authority was granted to the NRC by Congress through the Atomic Energy Act of 1954, as amended, hereinafter referred to as the AEA.9 In 2009, the NRC determined, "as a general matter, that the NRC has regulatory jurisdiction over commercial fusion energy devices whenever such devices are of significance to the common defense and security, or could affect the health and safety of the public."10 The NRC has not yet established a framework for fusion power reactors but is required to do so by December 31, 2027, per the Nuclear Energy Innovation and Modernization Act (NEIMA)
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From page 42... ...
Fusion power plants cannot have a chain reaction. As a result, safety issues associated with fusion are different from those associated with fission reactors and stem from control of relatively short-lived radioactive material, such as tritium and longer-lived radioisotopes generated by neutron activation of metallic materials in the structures.20 If the NRC were to treat fusion reactors as "utilization facilities," it would not need to use 10 CFR Part 50.
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From page 43... ...
As such, the regulatory framework would be tailored to the hazards posed by fusion and would only impose regulatory requirements that the Commission deems as necessary to provide reasonable assurance of adequate protection of public health and safety and to promote the common defense and security and to protect the environment. Finding: A regulatory process that minimizes unnecessary regulatory burden is a critical element of the nation's development of the most cost-effective fusion pilot plant.
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From page 44... ...
The cost of the decommissioning depends on the complexity of the process and the amount and type of waste requiring disposal and is accounted for in the decommissioning plan and in the regulatory require ments. The classification of the waste depends on the concentration and form of the materials.25 The NRC requires that operations of a facility be conducted in a manner that minimizes contamination as a means of reducing the complexity of the decommissioning process.26 The TFTR tokamak D-T fusion experiment was successfully decommissioned in 2002.27 Advances in radiological decommissioning techniques are being made every year in the areas of remote tooling for segmenta tion and packaging of large, highly activated reactor components and likely can be applied to the future decommissioning of a fusion power reactor.28 Finding: Decommissioning of a fusion facility is not expected to present sig nificant or new challenges due to the vast experience in decommissioning of materials facilities and nuclear power plants in the United States.
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From page 45... ...
Recommendation: The Nuclear Regulatory Commission should establish the regulatory framework, including the decommissioning stage, for fusion power plants as well as the pilot plant. ECONOMIC CONSIDERATIONS As one considers new generation pilot electrical plants and their economic value, we can look at how pilot plants have been funded in the past, their generating scale, and what has driven the economic value seen by the participants in developing these pilot plants.
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From page 46... ...
title=Shippingport_ Atomic_Power_Station&oldid=964406210; Texas Clean Energy, Kemper County Energy, and Callide Oxyfuel data from World Nuclear Organization, https://www.worldnuclear.org/information-library/energy-and-the-environment/clean-coal-technologies.aspx; Solar PV Grid Scale data from Lawrence Berkeley Laboratory; Ivanpah Solar Power Facility data from Wikipedia, https:// en.wikipedia.org/w/index.php? title=Ivanpah_Solar_Power_Facility&oldid=977491449; Vogtle Electric Generating Plant data from Wikipedia, https://en.wikipedia.org/w/index.php?
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From page 47... ...
Given that electricity is fundamental to modern society, the financial health of this service provider should be in the state's interest. Looking at past pilot plants in the United States from Texas, Mississippi, California, and Virginia (Table 3.2)
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From page 48... ...
These examples help provide the proper context for a fusion pilot plant whose goal is to accelerate the development of a FOAK fusion power plant. Indeed, it is this stated goal of a pilot that differentiates it from fusion devices designed to ad dress purely technical or scientific challenges.
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From page 49... ...
The first consideration is total cost. The ability of individual investors and utilities to invest in a pilot plant and/or FOAK power plant depends on the overall cost estimate for the pilot facility.
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From page 50... ...
electrical marketplace, for a FOAK fusion power plant that even following a fusion pilot will be a relatively immature technology. The maximum FOAK cost should be evaluated periodically based on input from the energy marketplace, consistent with the final recommendation of Chapter 2.
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From page 51... ...
The levelized cost of energy (LCOE) for the FOAK fusion power plant will be defined in large part by the normalized generation construction costs, facility availability, and the operation and maintenance costs.
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From page 52... ...
The overall cost requirement on a pilot facility could also be reduced if the plant is sited near a utility location with synchronous condensers, storage, or standby generators, since these features are required to support a fusion pilot plant. The present cost risk for fusion is the thermal side of the plant, not the balance of plant, so the value should be considered based on the cost of the thermal side of the plant and using the minimum cost balance of plant design to provide electrical energy.
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From page 53... ...
Villari, 2019, A review of radioactive wastes production and potential environmental releases at experimental nuclear fusion facilities, Environments 7(1) :1-12, https://doi.org/10.3390/ environments7010006.
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From page 54... ...
Guarracino, C Poggi, and R Villari, 2019, A review of radioactive wastes production and potential environmental releases at experimental nuclear fusion facilities, Environments 7(1)
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