(searched for: Public Acceptance of ITER-Tokamak Fusion Power)
European Journal of Energy Research, Volume 1, pp 8-12; https://doi.org/10.24018/ejenergy.2021.1.4.18
One of the U.S. Electric Power Research Institute’s criteria for practical fusion power is public acceptance. In this analysis we consider the potential public acceptance of ITER-tokamak fusion power. Because ITER-like reactors are not likely to be commercially ready before mid-century, a forecast of public acceptance is very difficult. We break “the public” down into four entities: 1) Rank and file consumers, 2) Governments [local, state, & federal including regulators], 3) NGOs including environmental groups, and 4) Electric utilities. We assert that ITER-tokamaks will be evaluated in the context of fission power because both are nuclear processes. We observe that ITER-tokamak fusion will present radioactive hazards and be extremely expensive. Three possible futures for fission nuclear mid-century are: 1) full acceptance, 2) middling acceptance, and 3) rejection. If fission power is accepted mid-century, then ITER-tokamak fusion stands the best chance of being publicly acceptable, its largest drawback being very high cost. If fission power is of middling acceptance, then ITER-tokamak fusion might be marginally more acceptable because of its much shorter life radioactive waste. If fission power is unacceptable, then ITER-tokamak fusion acceptance will be very difficult.
Nuclear Fusion, Volume 61; https://doi.org/10.1088/1741-4326/abbf35
The tritium aspects of the DT fuel cycle embody some of the most challenging feasibility and attractiveness issues in the development of fusion systems. The review and analyses in this paper provide important information to understand and quantify these challenges and to define the phase space of plasma physics and fusion technology parameters and features that must guide a serious R&D in the world fusion program. We focus in particular on components, issues and R&D necessary to satisfy three 'principal requirements': (1) achieving tritium self-sufficiency within the fusion system, (2) providing a tritium inventory for the initial start-up of a fusion facility, and (3) managing the safety and biological hazards of tritium. A primary conclusion is that the physics and technology state-of-the-art will not enable DEMO and future power plants to satisfy these principal requirements. We quantify goals and define specific areas and ideas for physics and technology R&D to meet these requirements. A powerful fuel cycle dynamics model was developed to calculate time-dependent tritium inventories and flow rates in all parts and components of the fuel cycle for different ranges of parameters and physics and technology conditions. Dynamics modeling analyses show that the key parameters affecting tritium inventories, tritium start-up inventory, and tritium self-sufficiency are the tritium burn fraction in the plasma (fb), fueling efficiency (ηf), processing time of plasma exhaust in the inner fuel cycle (tp), reactor availability factor (AF), reserve time (tr) which determines the reserve tritium inventory needed in the storage system in order to keep the plant operational for time tr in case of any malfunction of any part of the tritium processing system, and the doubling time (td). Results show that ηffb > 2% and processing time of 1–4 h are required to achieve tritium self-sufficiency with reasonable confidence. For ηffb = 2% and processing time of 4 h, the tritium start-up inventory required for a 3 GW fusion reactor is ~11 kg, while it is 30% and 1% ≤ ηffb ≤ 2%, and achievable with reasonable confidence if AF > 50% and ηffb > 2%. These results are of particular concern in light of the low availability factor predicted for the near-term plasma-based experimental facilities (e.g. FNSF, VNS, CTF), and can have repercussions on tritium economy in DEMO reactors as well, unless significant advancements in RAMI are made. There is a linear dependency between the tritium start-up inventory and the fusion power. The required tritium start-up inventory for a fusion facility of 100 MW fusion power is as small as 1 kg. Since fusion power plants will have large powers for better economics, it is important to maintain a 'reserve' tritium inventory in the tritium storage system to continue to fuel the plasma and avoid plant shutdown in case of malfunctions of some parts of the tritium processing lines. But our results show that a reserve time as short as 24 h leads to unacceptable reserve and start-up inventory requirements. Therefore, high reliability and fast maintainability of all components in the fuel cycle are necessary in order to avoid the need for storing reserve tritium inventory sufficient for continued fusion facility operation for more than a few hours. The physics aspects of plasma fueling, tritium burn fraction, and particle and power exhaust are highly interrelated and complex, and predictions for DEMO and power reactors are highly uncertain because of lack of experiments with burning plasma. Fueling by pellet injection on the high field side of tokamak has evolved to be the preferred method to fuel a burning plasma. Extrapolation from the DIII-D penetration scaling shows fueling efficiency expected in DEMO to be <25%, but such extrapolations are highly uncertain. The fueling efficiency of gas in a reactor relevant regime is expected to be extremely poor and not very useful for getting tritium into the core plasma efficiently. Gas fueling will nonetheless be useful for feedback control of the divertor operating parameters. Extensive modeling has been carried out to predict burn fraction, fueling requirements, and fueling efficiency for ITER, DEMO, and beyond. The fueling rate required to operate Q = 10 ITER plasmas in order to provide the required core fueling, helium exhaust and radiative divertor plasma conditions for acceptable divertor power loads was calculated. If this fueling is performed with a 50–50 DT mix, the tritium burn fraction in ITER would be ~0.36%, which is too low to satisfy the self-sufficiency conditions derived from the dynamics modeling for fusion reactors. Extrapolation to DEMO using this approach would also yield similarly low burn fraction. Extensive analysis presented shows that specific features of edge neutral dynamics in ITER and fusion reactors, which are different from present experiments, open possibilities for optimization of tritium fueling and thus to improve the burn fraction. Using only tritium in pellet fueling of the plasma core, and only deuterium for edge density, divertor power load and ELM control results in significant increase of the burn fraction to 1.8–3.6%. These estimates are performed with physics models whose results cannot be fully validated for ITER and DEMO plasma conditions since these cannot be achieved in present tokamak experiments. Thus, several uncertainties remain regarding particle transport and scenario requirements in ITER and DEMO. The safety standard requirements for protection of the public and release guidelines for tritium have been reviewed. General safety approaches including minimizing tritium inventories, reducing tritium permeation through materials, and decontaminating material for waste disposal have been suggested.
Journal of Fusion Energy, Volume 35, pp 135-141; https://doi.org/10.1007/s10894-015-0053-y
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Journal of Nuclear Materials, Volume 367-370, pp 97-101; https://doi.org/10.1016/j.jnucmat.2007.03.236
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Fusion Technology, Volume 30, pp 1605-1612; https://doi.org/10.13182/fst96-a11963181
This paper examines the economics of magnetic fusion power generation, makes comparisons with other generation sources, and draws attention to some key issues. For other generation sources, the data presented are drawn from published references, but specific studies have been made for magnetic confinement systems. The magnetic fusion costs are benchmarked by comparison with those for ITER, since considerable effort has been invested in establishing the validity of the ITER costs. Estimated fusion generating costs are broadly comparable with fission and fossil fuel costs, and with the more promising of the renewables (not taking into account external cost factors and public acceptability issues). These external factors make it impossible to determine which generating source will be the most attractive in the mid-21st century, and may even preclude the use of some sources, making it strategically important to develop a range of options. Key factors in determining which energy sources are adopted in the 21st century are likely to be environmental and safety attributes. For the main magnetic fusion concepts under study in the world fusion programme the costs of electricity generation are similar when equivalent levels of physics and technology performance are assumed. The tokamak is the most developed concept. Other approaches have potential intrinsic physics or technology advantages over the conventional tokamak, that are yet to be fully demonstrated. Only very minor constraints on economic optimisation of designs are entailed by the requirement to preserve, during the optimisation, the full safety and environmental advantages of fusion. The overall conclusion is that the likely economic performance of fusion, combined with its excellent safety and environmental qualities, as shown in the SEAFP (Safety and Environmental Assessment of Fusion Power) study, make it a serious contender as one of the few major contributors to mid-21st century electricity generation.