The European path towards
fusion electricity
Tony Donné

A.J.H. Donné | NIFS | Toki, JA| 15 September 2023

Thanks to:
Ambrogio Fasoli, Andreas Dinklage, Angel Ibarra, Antti Hakola, Arturo Alonso,
Athina Kappatou, Benoit Labit, Carlo Sozzi, Carlos Hidalgo, Chiara Bustreo, Christian Day,
Costanza Maggi, David Douai, David Keeling, Elena de la Luna, Elena Gaio,
Emmanuel Joffrin, Emmanuelle Tsitrone, Fabio Villone, Fernanda Rimini, Gerald Pintsuk,
Gianfranco Federici, Giuseppe Calabro, Gloria Falchetto, Hartmut Zohm, Ian Chapman,
Ivan Calvo, Jean-Philippe Hogge, Jeong-Ha You, Jerome Bucalossi, Jeronimo Garcia,
Joelle Elbez-Uzan, Joelle Mailloux, John Hillesheim, John Holden, Joseph Milnes,
Karl Tischler, Klaus Hesch, Lorenzo Boccacini, Luciana Barucca, Marco Wischmeier,Maria Teresa Porfiri, Matteo Baruzzo, Nicola Vianello, Oliver Crofts, Paola Batistoni,
Richard Kembleton, Rudolf Neu, Sara Moradi, Sebastijan Brezinsek, Sibylle Günter,
Tuomas Tala, Valentina Corato, Volker Naulin, Wolfgang Biel, Xavier Litaudon…… andmany others…also for kindly making slides available
A.J.H. Donné | NIFS | Toki, JA | 15 September 2023

EUROfusion
EUROfusion integrates R&D infusion science and technology
29 Countries
31 Research Institutions
164 Universities
800 MSc and PhD students
4000 Fusion Researchers &Support Staff
A.J.H. Donné | NIFS | Toki, JA | 15 September 2023

Short-term
Research onpresent andplannedfacilities,
analysis andmodelling

Medium-termLong-term
ITER

First plasma Full performance

Material research facilities

Consistentconcept

Commence
construction

IFMIF-DONES

Stellarator as fusion power plant?
Lower cost through concept improvements and innovations

DEMO

Electricity
production

Fusion Power Plants

European Fusion Research Roadmap – under revision

Milestone

A.J.H. Donné | NIFS | Toki, JA | 15 September 2023

Eight Roadmap Missions
1
2
3
4
5
6
7
8

• Plasma Regimes of Operation• Heat Exhaust Systems• Neutron Resistant Materials• Tritium Self-Sufficiency• Implementation of Intrinsic Safety Features• Integrated DEMO Design• Competitive Cost of Electricity• Stellarator
A.J.H. Donné | NIFS | Toki, JA | 15 September 2023

A revised approach to the Roadmap is neededInterest in fusion has grown enormously thanks to:• Fusion research successes at JET, NIF, W7-X, Medium-Sized
Tokamaks, and the almost completed ITER assembly• Realization that baseload electricity power plants are essential forenergy transition & security• Booming of private fusion efforts

Current Roadmap contains all the linked elements of a reactororiented program, but is mostly based on a sequential JET-ITERDEMO approach• Delays have impacted ITER, but also JT-60SA, IFMIF-DONES and DTT• Unique and valuable lessons learned from every stage of the ITER
project must be integrated into the Roadmap
A.J.H. Donné | NIFS | Toki, JA | 15 September 2023

Main elements of the Roadmap revision• Definition of the DEMO step
• Gaps to be addressed• Measures to accelerate theDEMO and FPP programs• Parallelization of ITER and
DEMO activities• Public-Private Partnerships
These points are in addition to the specific activities
for the ITER project, which remain central
A.J.H. Donné | NIFS | Toki, JA | 15 September 2023

Definition of the DEMO step – high level goals
Demonstration of performance of key technologies with tolerable failure
rates to achieve adequate levels of availability, and their integration
•
•
•
•
•

Net electricity output to grid of a few hundreds of MWs
Self-sufficient fuel cycle: supply tritium for itself & to start a new plant
Robust plasma operation scenario and power-exhaust system
Demonstration of intrinsic safety and tolerable impact of waste
Maintenance systems that ensure plant availability and accessibility

Tokamak configuration
Target: start operations /commissioning ~20 years after kick off

A.J.H. Donné | NIFS | Toki, JA | 15 September 2023

Definition of the DEMO step – requirements
Stakeholder requirements

Plant requirements

Net electrical power of 100s of MW

Pel,net ~ 300-500MW

Pulse length

tpulse >> dwell time (several hours)

Tritium self-sufficiency

Tritium Breeding Ratio TBR > 1

Blanket lifetime and radiation exposure~20dpa first phase (6-7y); ~50dpa second phase (16-17y)

Doubling time for FPP deploymenttD ≤ 10y

SafetyNo countermeasure to the population and to theenvironment in accidental conditions
Minimization of intermediate- and low-level radioactive
waste, and avoidance of high-level waste

A.J.H. Donné | NIFS | Toki, JA | 15 September 2023

Gaps to be addressed

A.J.H. Donné | NIFS | Toki, JA | 15 September 2023

Gain technical insights from ITER
• The work on EU DEMO benefits largely from theexperience gained from ITER
• ITER remains the crucial machine for thevalidation of the DEMO physics and part of thetechnology• RoX from ITER emphasises the importance ofsafety and licensing, design integration, quality,
shielding, fabricability, costs, RH• These play an important role in the design of
DEMO• There are still major technology gaps beyond ITER
• Low TRLs of DEMO enabling technologies for systems(i.e., breeding blanket, materials, RH) even after ITER
• The role of ITER in de-risking DEMO in the area of breedingblanket is questionable and risk mitigation options are studied

TRL Now

TRL after ITER

Water BoP (TRL 7-8)
Divertor RH (TRL 6)

Magnets Nb3Sn LTSC
Buildings
Vacuum Vessel
Cryopumps
Divertor and div RH (TRL 7-8)
ECH 170 GHz (TRL 6-7)
NB (1MeV)
DEMO Blanket RH
DEMO Blanket – TBM (TRL 4-5)

ECH 170 GHz (TRL 6)
Magnets Nb3Sn LTSC (TRL 6)
Divertor (TRL 4)
He BoP (TRL 4-5)
NB (1MeV) (TRL 3)
Blanket RH (TRL 3)
Blanket (TRL 2-3)

A.J.H. Donné | NIFS | Toki, JA | 15 September 2023

Search for the optimum DEMO design – EUROfusion approach
A system-oriented dimensioning process
If everyone is let to go on his
own way you end up having
something that does not work

• Many discussions to make fusion
smaller, cheaper, and faster, butthere is no magic bullet to solve theintegrated design problems.
• What makes a design sound:üRealistic physics and technology
assumptions
üA sound operating scenario and aconsistent strategy for the power
exhaust to be validated by ITER

*Dream Airplanes by C.W. Miller.
Optimal airplane design from theperspective of engineers of different
specialties 2010. Reston, VA:
American Institute of Aeronautics andAstronautics.
G. Federici “FPA 40th Annual Meeting, Washington DC, USA, Dec. 3-4, 2019üRobust design with margins
considering all the loads and theconstraints often coming fromsystem interdependenciesüEarly attention to nuclear design
integration and safety/licensingüSufficiently mature technologies
for all the systems

Lesson learnt from DEMO
pre-concept design
Still large plasma physics
uncertainties that impact
the design
Integration of multiple
design drivers acrossdifferent systems
Many systems
interdependencies with key
nuclear systems
Low technology readiness ofessential enabling
technologies

https://www.sciencedirect.com/journal/fusionengineering-and-design/special-issue/10RRZQ6LW4H

A.J.H. Donné | NIFS | Toki, JA | 15 September 2023

What defines the size of DEMO?
Key engineering constraints/ design drivers

Inboard space utilization is a crucial design aspect in tokamak design: trade-off plasma/shielding/magnets
C
L

RCS CSTFC

Key engineering drivers

Ro
RTF
B

Bmax

DVB

Central Solenoid: (pulsed machine – become
constraining at low aspect ratio)
TF coil radial build (see next slide)

Source: M. Coleman (DCT)

Shield/ breeding blanket (1.3-1.4 m inboard)
Plasma: divertor heat load at reattachment

R
Study to analyze sensitivity of machine size to plant electrical output, pulse duration• Reducing electricity output does not bring significant size reduction• The CS size increases as a function of the pulse duration but also at very low pulses
because of fatigue considerations

A.J.H. Donné | NIFS | Toki, JA | 15 September 2023

Use of high field coils
Impact of the TF coil field on the size of the machine
Pfus=2000 MW, pulse = 2 hrs, A=3.1

TF Inner Leg Space Allocation

C
L

RCS

CS

TFC
1

4
2

3
b

Ro
RTF
B

DVB

Breed BLKn-shieldVV
TH-Shield

ITER(for comparison)

a

Bmax

DVB

c

M. Siccinio, C. Bachmann. L. Giannini

R
Rule of thumb
1.3-1.4 m

Source: PROCESS M. Colemanàfor higher B-field, large structures are required to resist radial/vertical forces TF inner leg.
Alternative mechanical concepts are very challenging or do not bring significant improvements
A.J.H. Donné | NIFS | Toki, JA | 15 September 2023

USE OF HIGH FIELD COILS

Source: C. Bachmann

Alternative mechanical concepts for DEMO are challenging or do not bring improvements
Concepts of TF vertical pre-compression
Steel cables @ 1200 MPa
tension generate vertical+ radial pre-compression

Steel cable wound around TF
coil in assembly hall to generate
overall pre-compression of coil

C. Bachmann - Relevance of a highmagnetic field to the design of the EU
DEMO, submitted to Fusion Design andEngineering

C-clamp principle [P. Titus,
FNSF, TOFE-2020]:• Large pre-compression
rings cause a vertical precompression of the TF• Transfer of vertical loads
to the outboard side

Bucked + wedged concept:• Release TF inboard leg from EM forces
through transfer of radial force to CS• Reduce stress cycle on CS conductor• This relies on wedged inboard legs: only
possible if an assembly gap of ~3mm ±1mm between CS and TF can be ensured
which is very unlikely!

Assembly gap = 5mm

Assembly gap = 1mm

A.J.H. Donné | NIFS | Toki, JA | 15 September 2023

Re-baselining
Impact low aspect ratio•

It allows for a lower field (plasma, and TF coils).

•

It reduces the maximum heat flux at the divertor in case of reattachment.
This reduces the risk of the machine operation, enhancing the control
margins and, possibly, simplifies the whole design.

•

It allows for a higher k à a larger PF for a given machine radius. This is dueto the higher natural k, and to the fact that this reduces the relative
distance between plasma and passive structures, thus enhancing passive
stability.

Bo
[T]

Bmax
[T]

Heat Flux @reatt[MW/m2]

A=2.6

3.9

9.6

36.9

A=3.1

5.95

12.9

69.5

A=3.6

8.1

15.9

108.5

A=4.5

13.25

22.4

220.4

A.J.H. Donné | NIFS | Toki, JA | 15 September 2023

Industrial coil feasibility and cost issues
Benefits from coil designs that minimises TF structures• There is a practical limit to the max. thickness of the TF nose basedon manufacturability (given by size of forgings)• There is also a limit to weldability of segments and weld
deformation, which becomes hard to control in large and thickstructures. Mock-ups are required• For DEMO-sized machines, the cost of the structures alone (justthe coil case) is a significant fraction of overall cost of TF coils• In ITER, the material procurement and manufacture of the TF coilcases was what drove the schedule of TF coil deliveries (even withan intense three-supplier approach)• The same DEMO industrial study concluded a minimum of 12 years
for structure production, assuming two suppliers in parallel

Source: L. Giannini, M. Siccinio, M. Lungaroni

Pfus=2000 MW,
Pfus=500 MW,
pulsed = 2 hrs, R:7.5-8.5m
Steady state, R:6.5m
A.J.H. Donné | NIFS | Toki, JA | 15 September 2023

Performance and Reliability of Critical Core Technologies
Long lead times for R&D needed: (15-25 years)
Divertor targets

ü Impressive advances thanks to ITER R&D(1990’s-2000’s)
ü Fabrication of many (> 100) types of smalland medium-scale mock-ups (e.g., different
tube, mtls, geometries, armors andgeometries, fabrication methods, joints types)
ü Qualification/industrialization of key
processes High heat flux testing campaigns:
investigating degradation after repetitive
thermal loads in HHF tests stands (Gladis,
Judith, US, RF, JA EBs etc.)

Superconductor samples

Breeding blanket

ü Development and testing of many types ofconductors (mtls., void fraction, twist pitch etc.) incl.
HTS. Tests in SULTAN and EDIPO (EPFL-PSI as of 1992)

Most novel and complex systemü Qualification and industrialization of key components
and technologies
ü Model coil fabrication and testing e.g., FENIX (MFTF-B
choke coil in Nb3Sn ITER TF and CS 2000’s)üü

DPC Nb3Sn cable in CICC 1991
conduit 1985

üü
ü

ITER TF 1993

No breeding blanket has ever been
built or tested under relevant
integrated conditions.
• Still large uncertainties/ feasibility
concerns à very low TRL• Strong impact on machine
availability

ITER CS

DEMO

Sultan
LTS joint

Heat transfer across breeder/RAFM
plates and coolant pipes
High temp./pres. coolantsà strong
influence on reactor design
T generation and extraction in Li-basedsolid/ liquid breeders
n-irradiation damageà structural
material properties
Power and particles on first wall

HTS

There is a technology gap inthis area that needs to beurgently addressed

A.J.H. Donné | NIFS | Toki, JA | 15 September 2023

Magnet Systems

Source: Project Leader - Valentina Corato (ENEA)

Recent achievements
•
•
•
•
•

R&D on important DEMO magnets technologies
Qualification and industrialization of key components and technologies
Development and test of full-scale conductors (tests at EPFL-PSI), also joints
Development of conductor concepts based on HTS
DEMO design activities: winding pack design, thermo-hydraulics, quench
detection, etc.

TF conductor and winding pack design

Design and preliminary tests of HTS conductors
for the Central Solenoid (60kA@18T, 4.5K)

Conductor test sample

Qualification of cable termination

LTS joint
A.J.H. Donné | NIFS | Toki, JA | 15 September 2023

Magnet with HTS conductors
Strategy recommendations• HTS offer the promise of operating at both
higher magnetic fields and higher current
density (for Non-Insulated coils)
o Quench protection of NI coils for largescale magnets is an area in whichdevelopment and qualification is stillneeded (maturity level)• However, even if we do not operate at high fieldand start within conventional insulated coils, HTS
can still offer benefits:o Simplification of the magnet coolingscheme thanks to increased temperature
margin (indirect conduction cooling)o This in turn can greatly simplify coilconstruction and minimize High-Voltage
risks at the terminals by decoupling
coolant and current-carrying functions of
the conductor
ITER TF coil terminals
Leads, wires, and pipes with electrical breaks, all penetrating the ground plane

A.J.H. Donné | NIFS | Toki, JA | 15 September 2023

Breeding Blanket System

Source: Project Leader - Francisco Hernandez (KIT)

Recent achievements

WCLLa) Advanced stage in BB and TER
design with several studies aimed
at the optimisation of their overall
performancesb) Increased expertise in T-extraction
from PbLi (GLC, PAV)c) Increased capability to model
PbLi/water interaction throughdedicated numerical andexperimental activities

Slice - Elementary cell

PbLi FlowTEU OBFW cooling channels(7 x 7 mm²)

TEU IB

PumpingsystemBSSaa

Circumferential SG
Axial SGPT

LiPb Storage
Tanka

Breeding Blanket
segments

Radial SG

b
a

HCPB
a) Maturation of the BB and TER designs
for operation at high pressure purgegasb) The 1:10 RMSB mock-up
manufactured and under
qualification; Activities replacing thecryogenic process with getter beds iswell advancedc) Testing of a prototypical mock-up of afuel-pin in HELOKA ongoing; assemblyof FW with relevant fabrication routeand manifolds well advanced

Water
Manif

PbLi
Manifold

74 TC 0.5 mmcaPHTS loops
T [°C]

Fuel Pin mock-up

Gas-gas
HXs
Getterbeds

c

HELOKAvacuum tank

TER loopa

Breeding Blanket
segments

Circulators

b

RMSBs
HCPB TER with getter bedscb
1:10 RMSB mock-up

A.J.H. Donné | NIFS | Toki, JA | 15 September 2023

Tritium, Fuelling and Vacuum Systems
Recent achievements
Pellet Injection | Continuous and highly repetitive: Detailed design
ongoing based on a single screw extrusion, and a centrifuge toaccelerate DT pellets continuously and highly repetitive.

Source: Project Leader - Christian Day (KIT)

Direct Internal Recycling | Metal foil pumping: Lifetime of metal foil - Methods
developed to re-constitute pump performance following contamination

Supporting R&D
DesignSuperpermeation test facility HERMES.

Vacuum Pumping | Continuous: Three-stage mercury-based
pumping train (Diffusion pump + ejector pump + ring pump).

Test & Validate

Isotope Rebalancing: Temperature Swing Absorption combining materials
with normal and inverse isotope effect: Characterisation of candidate inverse
isotope effect alloys.

Supporting R&D

Nozzle set-up in the mercury lab
Serial testing of diffusion and ring pumps.

A.J.H. Donné | NIFS | Toki, JA | 15 September 2023

Divertor

Source: Project Leader (DEMO DIV) - Jeong-Ha You (IPP)

Recent achievements

High-heat-flux test to simulate strike-point sweeping on a divertor target

40 MW/m², 5000 loading cycles (pulse: 0.4 s, frequency: 0.63 Hz, coolant: 20 °C)
IR thermography (H beam irradiation)
500 pulses

5000 pulses

J.H. You et al. Nucl. Mater. Ener. 33 (2022)

Front face after the test (Tungsten: A.L.M.T.)(GLADIS, IPP Garching)

Front face topography measured by laser profilometry (visco-plastic deformation)

A.J.H. Donné | NIFS | Toki, JA | 15 September 2023

Remote MaintenanceSource: Project Leader - Oliver Crofts (UKAEA)

Recent achievements

Blanket handling
Further development of the Two
Port, High Payload, Precision Moverand co-operative handling control.
This mover holds the blanket at the
top and the bottom.
(UKAEA RACE, EK-CER, VTT, ENEA)

Service joining
Miniaturised inbore laser welding
head upgraded andtested to 2.2kW(UKAEA)

RMTF
Concept design developed for the Remote
Maintenance Test Facility to develop and test the
integrated performance of remote handlingequipment, control algorithms and sensor
technology for the precision handling of large
flexible loads.
Tender released for the initial test rig, TR0,
including test payload (UKAEA)
A.J.H. Donné | NIFS | Toki, JA | 15 September 2023

DEMO Remote handling and maintenanceDivertor maintenance and pipe module handling

Blanket maintenance

TARM handling system
Payload Oscillations

In-bore laser
weld tool and test rig
In-bore laser weld sample

Damped oscillations achieved
with control input-shaping

O. Crofts et al., EU DEMO Remote Maintenance System development during the PreConcept Design Phase, Fusion Engineering and Design 179 (2022) 113121
https://doi.org/10.1016/j.fusengdes.2022.113121

Pipe alignment testing

A.J.H. Donné | NIFS | Toki, JA | 15 September 2023

The IFMIF-DONES Facility
An accelerator based fusion-like neutron source to be mainly used forthe qualification of the materials to be used in the DEMO Reactor

High Flux Test Module:
20 dpa/fpy in 130 cm3
10 dpa/fpy in 400 cm3

Stripping reaction
15

Controlled Temperature:
250 < T < 550 ºC

A neutron flux of ~ 1015 n/cm2/s isgenerated with a neutron spectrum
up to 55 MeV energy

Heat removal byhigh velocity Li flux

A.J.H. Donné | NIFS | Toki, JA | 15 September 2023

LiPAc (Prototype Accelerator)

EUROfusion involved in commissioning of LIPAc (Japan) and
responsible for Engineering Design of IFMIF-DONES
A.J.H. Donné | NIFS | Toki, JA | 15 September 2023

IFMIF-DONES: Construction of First Auxiliary Buildings

The site is located at Escúzar– 18 km southwest from
Granada city – Spain
Operation starts ~2034
A.J.H. Donné | NIFS | Toki, JA | 15 September 2023

Measures to accelerate the DEMO program• Parallelization of activities to reduce the sequential coupling of
ITER milestones and DEMO decision points• Strengthening R&D in the identified gap areas• Increased effort in simulations for plasma and for engineering• Mutually beneficial new international collaborations• Development and maintenance of adequate workforce• Knowledge management• Streamlining licensing towards a regulatory framework for fusion
and rapidly identifying site
• Involvement of industry in DEMO design & construction (PPPs)
A.J.H. Donné | NIFS | Toki, JA | 15 September 2023

Measures to accelerate the FPP program beyond DEMO
• Dedicated test facilities to qualify
technologies for FPPs that will bedifferent from DEMO
• Investigations to increase
attractiveness of FPPs
• Stellarator FPP design studies• HTS magnets• Advanced structural materials• Alternatives to water as primarycoolant
A.J.H. Donné | NIFS | Toki, JA | 15 September 2023

Parallelization of ITER and DEMO and the role of ITER
ITER is a key milestone for fusion: crucial lessons
are drawn through all its phases• Info on how to design and constructcomponents at reactor scale in nuclear
environment, and on relevant licensing•

Vacuum vessel, cryogenics, magnets, H&CD systems• The ongoing assembly of ITER is giving
information to inform the DEMO design
process• ITER lessons during commissioning may not
influence DEMO design, but will be in timeand of highest value for DEMO commissioning
A.J.H. Donné | NIFS | Toki, JA | 15 September 2023

Parallelization of ITER and DEMO and the role of ITER••

ITER demonstration of Q=10 & burning plasma
regime will provide basis for DEMO scenarios
ITER TBM program will likely not be in time for
DEMO design•••

Emphasis on development & validation of blanket
technology before DEMO, so that DEMO can be
an integrated demonstrator and not a blanket
test facility

Yet, TBMs will yield crucial information for
DEMO on qualification, licensing,
manufacturing and integrated operation ofblankets in nuclear plasma environment
ITER’s experience with safety and waste
production, RH, civil engineering, the hot cell,the management of T and radioactive waste, isan essential reference for DEMO
A.J.H. Donné | NIFS | Toki, JA | 15 September 2023

Thus far I spoke a lot about
DEMO….. but support to ITER
should not be forgotten

A.J.H. Donné | NIFS | Toki, JA| 15 September 2023

Support for the ITER programme is key• EUROfusion continues to support ITER••

By dedicated experimental campaigns on ASDEX
Upgrade, COMPASS Upgrade, JET, MAST U, TCV,
WEST, W7-X and many linear devices
By detailed theoretical modelling using a.o.
a ~50 Pflops dedicated High Performance Computer

Some examples onfollowing slides
A.J.H. Donné | NIFS | Toki, JA | 15 September 2023

A.J.H. Donné | NIFS | Toki, JA | 15 September 2023

A.J.H. Donné | NIFS | Toki, JA | 15 September 2023

Shattered Pellet Injector (disruption mitigation)

A.J.H. Donné | NIFS | Toki, JA | 15 September 2023

Runaway Electron (RE) load characterization in JET§§§

Critical ITER topic: Be wall damage by RE events
Dedicated JET RE experiments to explore damage footprint (JPN 86801)§ RE power deposition on inner wall Be limiter tile during single event§ Post-mortem analysis: Be sectioning and metallography, microscopy, damage material properties
MEMOS-U simulations were validated to improve confidence in ITER predictions about potential Be tile
damage during RE events (in progress)

I. Jepu et al.

Octant 1

Octant 2

Octant 3

Octant 4

Octant 5

Octant 6

Octant 7

Octant 8

WPPWIE

A.J.H. Donné | NIFS | Toki, JA | 15 September 2023

Benign termination of runaway electron beam
• TCV disruption and runaway electron studies via EUROfusion• Control via gas injection to maximize power spread on wall
• Increased wetted area and conversion of magnetic energy to radiation prevents
localized heat flux from runaway electrons• Models developed using multimachine database to extrapolate technique toITER

A.J.H. Donné | NIFS | Toki, JA | 15 September 2023

World record plasma exposure in Magnum-PSI
T. Morgan, PFMC 2019
M. Balden, PFMC 2019

ITER relevant conditions (~1 Full Power Year):Target1200 C°
Heat load
20 MWm-2
Particle load 1.5 1025 particles m-2s-1
Duration:
18,5 hours= MAGNUM beam spot centre
D/He (1220°C) D (1225°C) H (615°C)
3×1029m-2 1×1030m-2 1×1029m-2

7
6
5
20
2
< 1.5×10 D/m

3
4
20<2×10 D/m2

D/He (1205°C)
5×1029m-22
1
20<4×10 D/m2

He (840°C)
2.5×1028m-2

3
7
6
5
4
18
2
20
< 5×10 D/m<5×10 D/m2

D (1215°C)
4×1029m-22
1
20<2.5×10 D/m2

A.J.H. Donné | NIFS | Toki, JA | 15 September 2023

Tungsten recrystallisation and softening studies
Critical ITER topic: W divertor operational window§ Study recrystallization and softening of W plasma-facing unit (PFU)
surfaces under WEST plasma loading§ Aim to benchmark models regarding recrystallization and softening
kinetics of W in view of ITER predictions§ Post-mortem analysis:§§

Loss of mechanical properties (Xh) -> Hardness measurements
Modification of the microstructure (X) -> EBSD measurements

WPPWIE
Tungsten PFU surface
after WEST plasma
Misalignment
0.4 mmSide view

A. Durif
A.J.H. Donné | NIFS | Toki, JA | 15 September 2023

Test of ITER-like divertor prototypes
WEST first phase of operation withITER prototypes (W monoblocks on
CuCrZr heat sink) in lower divertor
Long pulses up to 1 min with upper
actively cooled divertor

Damages observed on ITER-like plasma
facing unit after exposure• Cracking and melting on leadingedges (transients)• Hot Spots at toroidal gap
crossing, as predicted for ITER
A.J.H. Donné | NIFS | Toki, JA | 15 September 2023

Tungsten morphology changes in He plasmas••

Plasma loading in “W-fuzz growth regime”
Pre-formed W-fuzz in PSI-2 exposed in ASDEX-Upgrade H-modes
with ELMs

33.5 mm

He campaigns at JET and ASDEX-Upgrade to study W-fuzz
formation and erosion, a critical issue for ITER, and validate
relevant models

Samples after exposurein ASDEX-Upgrade

Initiallypolished
W samples

Initially
W-fuzzfrom PSI-2

Post-mortem analysis with SEM & FIB cuts
Further W growth in the scrape-off layer
Strike point
H-modePoloidalErosion at strike-line conditions

S. Brezinsek,
K. Krieger et al.

Toroidal

M. Rasinski et al.

Strike point
L-modeA.J.H. Donné | NIFS | Toki, JA | 15 September 2023

Laser-induced desorption diagnostic in JET§§§§

Critical ITER topic: Tritium retention and monitoring diagnostic
Transfer ex-situ laboratory technology (FREDIS) into the JET tokamak
Demonstrate in-situ laser-induced T desorption from Be layers and quantification via quadrupole mass
spectrometry of hydrogen isotopomers (H2, D2, T2, HD, TD)
Validate the technical approach for the T-monitor diagnostic in ITER§§§§

Design completed
Laboratory testing completed
Installation in preparation
Operation in early 2023

Measurement at innerdivertor where Be layers
identified by tile analysis

FZJ & UKAEA
M. Zlobinski et al.

A.J.H. Donné | NIFS | Toki, JA | 15 September 2023

Super-X divertor in MAST-U works
Super-X divertor compared toconventional divertor in L-mode• ~10 times reduction indivertor heat flux
• ~2 times reduction in
upstream density to detachouter divertors

A.J.H. Donné | NIFS | Toki, JA | 15 September 2023

X-point radiator control•

X-Point radiator (XPR) has promising features• Full detachment• Maximum power dissipation• Controllable•

Observed at Asdex-Upgrade, TCV, WEST, JET•

At JET•••••

Created with N2, Ne and Ar seeding
Movement tracked with bolometry camera
XPR location controlled within 4mm
ELMs diminish
First control of full detachment

43[RT22-05: M.Bernert, D.Brida, H.Reimerdes, N.Fedorczak +RT22-04: B. Sieglin, P.Fox, T.Bosman, M.Lennholm]
A.J.H. Donné | NIFS | Toki, JA | 15 September 2023

Fast-ion physics studies
Heating scenarios with MeV-range fast ions at JET
Dominant electron heating as in ITER
Access to high Ti
Destabilization of Alfvén Eigenmodes, which do notappear to be detrimental
Stabilizing impact on microturbulence
Non-linear interplay between fast ions, ITG and AEs[Y. Kazakov et al., Phys. Plasmas (2022)][S. Mazzi et al., Nature Physics (2022)]
A.J.H. Donné | NIFS | Toki, JA | 15 September 2023

Quasi-Continuous Exhaust regime
QCE regime obtained on JET building
on expts in ASDEX-Upgrade and TCV
Main features• no type-I ELMs
• high line-averaged and SOL density• only modest decrease of confinementcompared to type-I ELMy data base

Key access parameters• shaped plasma cross-section (k, d,closeness to double null)• high pressure in the vicinity of theseparatrix through strong gas puffing
A.J.H. Donné | NIFS | Toki, JA | 15 September 2023

Joint progress on plasma control on EU devices
Tokamak plasma control through deep reinforcement learning

Ex: recovery of discharge in Asdex-Upgrade based on MARFE
position monitoring, acting on gas & heating[Degrave Nature 602, 414 (2022)]

Supervisory control & dynamic pulse scheduling[Vu IEEE TNS 2021]

State observer implementations using RAPTOR / RAPDENS on ASDEXUpgrade and TCV[Bosman F.E.Des. 2021, Blanken F.E.Des. 2019, Felici IAEA 2016]

Real-time disruption proximity monitoring and control to avoid highdensity H-mode limit[Pau EPS 2022]‘Virtual actuators’ and optimization methods[Kudlacek Fus. Eng. Des 146 (2019), Maljaars Fus. Eng. Des 122, 2017][B. Sieglin, M. Maraschek, M. Bernert - ASDEX Upgrade]

A.J.H. Donné | NIFS | Toki, JA | 15 September 2023

Divertor detachment control
System identification approach applied to characterize dynamic
behaviour on Asdex-Upgrade, TCV, JET and MAST-U, using different
diagnostics
Ex. real-time feedback control of the C-III emission front in TCV
based on MANTIS 10-channel, 400Hz camera

W.A.J. Vijvers et al 2017 JINST 12 C12058
A. Perek et al. Rev. Sci. Instrum. 90 (12) 2019

A.J.H. Donné | NIFS | Toki, JA | 15 September 2023

The stellarator is the 8th missionof the European Roadmap

A.J.H. Donné | NIFS | Toki, JA| 15 September 2023

W7-X high energy-turnaround
1.3GJ in plasma on 15.02.2023
All upgrades are commissioned

A.J.H. Donné | NIFS | Toki, JA | 15 September 2023

Long detached plasmas(100s, almost no temperature increase
on divertor by series of Ne seeding
puffs)

https://youtu.be/GTmje2qsVgY

High-light: Progress in long-pulse operation

Progress in long-pulse operation

Waveforms of a 480s attached plasma discharge(4x1019m-3, 3MW, Te~ 2.3keV, Ti~1.5keV)
A.J.H. Donné | NIFS | Toki, JA | 15 September 2023

Large benefit from intnl collab: strong interaction with NIFS
• Dedicated actions for the preparation of W7-X experiments• Mutual participation in the experimental programs of LHD, W7-X,
Heliotron-J and TJ-II• Synergies within the cooperation framework: IEA TCP Stellaratorsand Heliotrons since 2003 (CWGM)• Benefits from joint actions and complementary capabilities• Examples: FILD detectors, TESPEL, cryogenic pellet injector,
pressure gauges, wall conditioning, plasma break-down, joint
experiments and contributions to the stellarator/heliotron physics
basis
A.J.H. Donné | NIFS | Toki, JA | 15 September 2023

Benefit from mutual program involvement: physics studies
employ different accessible magnetic configurations andcomplementary capabilities
Example: impurity studies
NIFS development
TESPEL laboratory @CIEMAT
Experiments: core impurity injectionof large amounts of tungsten-> inform metallic divertor developments-> conduct impurity transport experiments
Demonstration of high resilience of stellarators
against thermal quenches
Bouvain, Tamura et al., IAEA2023
A.J.H. Donné | NIFS | Toki, JA | 15 September 2023

Scenario preparation for W7-X: Plasma break-down studies

Ø Preparation of low-B operation in
W7-X
Ø ICRH break-down on W7-X achievedØ Next step: qualification of plasma
start-up schemes
Kovtun, Kasahara et.al.
A.J.H. Donné | NIFS | Toki, JA | 15 September 2023

Test of different neutral gas pressure gauges at LHD: ITER support
Planned activities for campaign 2024•

Operation of ITER test pressure gauge for a second campaign
to study long-term behaviour•

Installation of a new neutral gas pressure gauge using either
LaB6 or HfC as emitter material•

Visit to LHD for commissioning and calibration of the neutral
gas pressure gauges (Victoria Haak, March 2024)

ITER test pressure gauge using a ZrC-emitter (left) and neutral gas pressure gauge witha LaB6-emitter (right)

Activities at LHD•

Tests of neutral gas pressure gauges with respect to long term
stability during plasma operation since campaign 2019/2020•

Investigation of different emitter materials such as LaB6, W and
ZrC•

Development of different designs for neutral gas pressuregaugesTeam•••

Gen Motojima (LHD, motojima.gen@nifs.ac.jp)
Uwe Wenzel (uwe.wenzel@ipp.mpg.de)Victoria Haak (IPP, victoria.haak@ipp.mpg.de)

A.J.H. Donné | NIFS | Toki, JA | 15 September 2023

Towards a new roadmap

A.J.H. Donné | NIFS | Toki, JA| 15 September 2023

Parallelization of ITER and DEMO

A.J.H. Donné | NIFS | Toki, JA | 15 September 2023

ITER vs. DEMO

A.J.H. Donné | NIFS | Toki, JA | 15 September 2023

Public-Private Partnerships• The key to a swift development of DEMO andFPP is combining industrial andentrepreneurial approaches with theextensive know-how, and the ambitious yet
realistic vision of the public-funded European
fusion program (including EUROfusion, F4E,
the EU Commission, member and associatedstates)• DEMO will be built within an industrial
framework, utilizing fully industrial practices• Industrial input is also crucial for a programon technological gaps prior to DEMO design
A.J.H. Donné | NIFS | Toki, JA | 15 September 2023

Conclusions
EUROfusion plays an increasingly important role••••

Assist ITER developments and have a crucial role in ITER operation
Feed increasing demand for education & training
Allow R&D and exploration of new technologies for ITER, DEMO and FPPs
Ensure cohesion in the European fusion programme

Strong support for ITER and the present re-baselining•

ITER continues to be an essential element of the European Roadmap

Fusion R&D programme in support of DEMO will be:•••

Focused on addressing the remaining technology gaps
Carried out in parallel to the ITER programme
Making maximum use of lessons learned from ITER

Public-private-partnerships need to be established to:••Address and accelerate the long-lead R&D issues (T breeding, materials)
Take ownership of the DEMO and FPP design
A.J.H. Donné | NIFS | Toki, JA | 15 September 2023

A.J.H. Donné | NIFS | Toki, JA | 15 September 2023