Evaluation of feasibility and costs of alternative magnetic divertor configurations for DEMO

Ambrosino, R.; Castaldo, A.; Ha, S.; Loschiavo, V. P.; Merriman, S.; Reimerdes, H.

doi:10.1016/j.fusengdes.2019.04.095

Cited by 11 publications

(13 citation statements)

References 6 publications

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“…In our PROCESS simulations we have allowed the argon impurity fraction to vary, to facilitate reduced power to the divertor through argon ionisation and bremsstrahlung. Other advanced techniques developed for much smaller machines with much higher fluxes are also potentially available including long legged [68,69] or snowflake divertors [70] but they require additional plasma shaping coils which are exposed to large neutron fluxes, or raise demands (and costs) on the existing coil system [71,72] (e.g. in ITER, the current through the upper-most and lower-most solenoid modules would have to be increased by more than factor 10 [73] in order to produce a snowflake).…”

Section: Tritium Breedingmentioning

confidence: 99%

“…This very high flux necessitates thick radiation shielding (or breeding blanket) of ≈ 60 cm for the central column [153] (reducing the field on coil for a fixed reactor major radius), or frequent remote replacement of the central column magnets (on the order of every 3 years [157]). The small size also increases the power through the separatrix (above 30 MW m −1 in some designs [156,157]) necessitating the use of advanced divertor configurations [160] which would either make use of sacrificial, resistive, inboard coils (that are part of a higher order reactor design than that discussed in this work) or require heavily distorted TF coil architectures [71,72]. Large tokamak design studies of ITER-type plants have shown the cost of electricity is lower for large tokamaks, scaling proportionally to the electric power of the tokamak raised to the power -0.59 (i.e.…”

Section: Spherical Tokamak Power Plantsmentioning

confidence: 99%

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Training and Upgrading Tokamak Power Plants with Remountable Superconducting Magnets

L.¹,

Surrey²,

Naish³

et al. 2022

Preprint

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All high field superconductors producing magnetic fields above 12 T are brittle. Nevertheless, they will probably be the materials of choice in commercial tokamaks because the fusion power density in a tokamak scales as the fourth power of magnetic field. Here we propose using robust, ductile superconductors during the reactor commissioning phase in order to avoid brittle magnet failure while operational safety margins are being established. Here we use the PROCESS systems code to inform development strategy and to provide detailed capital-cost-minimised tokamak power plant designs. We propose building a 'demonstrator' tokamak with an electric power output of 100 MW e , a plasma fusion gain Q plasma = 17, a net gain Q net = 1.3, a cost of electricity (COE) of $ 1148 (2021 US) per MW h (at 75 % availability) and high temperature superconducting operational TF magnets producing 5.4 T on-axis and 12.5 T peak-field. It uses Nb-Ti training magnets and will cost about $ 9.75 Bn (2021 US). An equivalent 500 MW e plant has a COE of $ 608 per MW suggesting that large tokamaks may eventually dominate the commercial market. We consider a range of designs optimised for capital cost (as the reactors considered are pilot plants) consisting of both 100 MW e and 500 MW e plants with each of two approaches for the magnets: training and upgrading. With training magnets, the plant is cost-optimised for REBCO TF magnets. For a 100 MW e plant, the Nb-Ti training magnets typically produce 70 % peak field on the toroidal field coils compared to REBCO magnets, 65 % peak field on the central solenoid and cost ≈ 10 % of the total machine cost. Training magnets could in principle be reused for each of say 10 subsequent (commercial) machines and hence at 1 % bring only marginal additional cost. With upgrade magnets the plant is more expensive -first it is cost-optimised for Nb-Ti and then upgraded to REBCO coils. The upgrade increases the net electrical output from 100 to 280 MW e with an ≈ 25 % increase in reactor capital cost. We also evaluate likely advances in fusion technology and find that technologies on the horizon will probably not bring further large reductions in capital cost, and that REBCO magnets are generally stress-limited rather than current density limited. We conclude that: the fusion community should develop high B c2 alloys specifically for fusion applications; superconductors should be tested under operational-like radiation at cryogenic temperatures; and that we should proceed now with detailed design and construction of a prototype fusion power plant that integrates and de-risks all the key technologies including high temperature superconducting cables and joints using remountable training magnets, and hence is the last tokamak before commercialisation of fusion energy.

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Section: Tritium Breedingmentioning

confidence: 99%

Section: Spherical Tokamak Power Plantsmentioning

confidence: 99%

Training and Upgrading Tokamak Power Plants with Remountable Superconducting Magnets

L.¹,

Surrey²,

Naish³

et al. 2022

Preprint

View full text Add to dashboard Cite

show abstract

“…These shapes are generated to optimize the alternative configuration respecting the main parameters of the DEMO baseline SN configuration, as it is assumed as the starting point for the development of the ADCs. With respect to the previous version published in [3], this work starts from new 2D geometries generated to align the ADC machine geometries and configurations to the DEMO Single Null baseline 2017 [5].…”

Section: Design Requirements and Constraintsmentioning

confidence: 99%

“…Several divertor configuration concepts have been studied as alternatives to the conventional divertor, among which the configurations discussed in this work are the ones relying on the same physics basis as the baseline DEMO Single Null (SN) [3]. Within the EUROfusion Work Package DTT1/ADC, first assessment of possible alterative configurations, discussed in [3], focused mainly on the plasma-physics and plasma-control of ADCs, adopting as reference DEMO SN the baseline configuration developed in 2015 [4].…”

Section: Introductionmentioning

confidence: 99%

Preliminary engineering assessment of alternative magnetic divertor configurations for EU-DEMO

Marzullo

Ambrosino

Castaldo

et al. 2020

Fusion Engineering and Design

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“…This is beneficial for improved confinement. As a result, DN is a potential configuration for the European DEMO reactor [7]. In contrast to most (European) tokamaks, EAST has the flexibility to operate both in upper single null (USN) and in DN configurations.…”

Section: Introductionmentioning

confidence: 99%

Towards assessment of plasma edge transport in Neon seeded plasmas in disconnected double null configuration in EAST with SOLPS-ITER

Boeyaert

Wiesen

Wischmeier

et al. 2021

Nuclear Materials and Energy

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Evaluation of feasibility and costs of alternative magnetic divertor configurations for DEMO

Cited by 11 publications

References 6 publications

Training and Upgrading Tokamak Power Plants with Remountable Superconducting Magnets

Training and Upgrading Tokamak Power Plants with Remountable Superconducting Magnets

Preliminary engineering assessment of alternative magnetic divertor configurations for EU-DEMO

Towards assessment of plasma edge transport in Neon seeded plasmas in disconnected double null configuration in EAST with SOLPS-ITER

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