1. Preparing next JET full D-T Campaign
João Figueiredo
EUROfusion

2. Comparison of Power Systems
Why fusion?
Most exoenergetic reaction in the known universe
Highest power density per Kg
Lowest emission of greenhouse gases
Technically safe
J. Figueiredo | ESI – Hamburg | July 2017

3. The fusion process Light nuclei fuse into heavier nuclei
Fusion products; 14.1 MeV neutron and 3.5 MeV alpha particle
J. Figueiredo | ESI – Hamburg | July 2017

4. Principle of Energy Production with Magnetic Fusion
For the nuclei to get close enough to fuse they have to overcome the Coulomb barrier.
To achieve this an alternative are hot plasmas: a plasma is a ionised gas (ions and electrons are separated)
For fusion to be an energy source, a hot and dense fuel plasma must be confined in a tight volume for long times...
”Magnetic bottle”
J. Figueiredo | ESI – Hamburg | July 2017

5. Magnetic confinement
The magnetic field (in reality the magnetic pressure), represented by horizontal white lines, reduces the random motion of the particles and confines the plasma (in the direction perpendicular to the magnetic field lines).
J. Figueiredo | ESI – Hamburg | July 2017

6. Parameters of Fusion Plasmas
Magnetic fusion plasmas have temperature and pressure higher than the solar corona and temperature one order of magnitude higher than the Sun core
Region of Quantum plasmas
J. Figueiredo | ESI – Hamburg | July 2017

7. Tokamak overview Magnetic field configuration Heating schemes
Fusion products MeV neutrons to provide the energy output. 3.5 MeV alpha particles confined to keep the plasma hot
Plasma current: at present generated inductively
J. Figueiredo | ESI – Hamburg | July 2017

8. Tokamak Plasma Overview
Tokamak plasma topology
The plasma has an elongated cross section to improve confinement. The divertor is the part of the device explicitly designed to cope with energy and particle exhaust. The particles follow complicated orbits.

9. Challenges for continuous operation
Efficient reactor at high Q =Pfus/Padd relies on
the optimisation of bootstrap currents (currents generated by the pressure gradients)
J. Figueiredo | ESI – Hamburg | July 2017

10. JET ILW–Be main Wall, W in the divertor
JET main parameters
Major radius 3.1 m
Vacuum vessel 3.96m x 2.4m
Plasma volume up to about 100 m3
Plasma current up to 5 MA
Toroidal field up to 4 Tesla
Pulses of tens of seconds
JET has some unique technical and scientific capabilities:
Tritium Operation
Plasma Volume and Magnetic Field to confine the alphas
The same wall materials as ITER (W and Be)
Mission: Mitigate ITER risks and help qualifying ITER scenarios, technologies and procedures.
A scan in isotopic composition and a DT campaign are unique opportunities

11. Fusion power has been produced on JET
16 MW fusion power produced on JET with 25 MW external power to heat the plasma
First demonstration of alpha heating
Tritium technologies tested
Illustrates main research thrusts
J. Figueiredo | ESI – Hamburg | July 2017

12. JET is the best performing magnetic fusion experiment
≈30 years
Measured confinement time (s)
Predicted confinement time (s)
Size
This approach has allowed the full qualification of the baseline regime of operation of ITER: the H-mode
TCV
Fusion research profits from a step ladder approach based on devices of different size but similar magnetic configuration
JET provides the point closest to ITER for the extrapolation of H-mode confinement
J. Figueiredo | ESI – Hamburg | July 2017

13. Strategic Context for JET
J. Paméla, Fusion Engineering Design, 2007
Coherent approach in a multi-annual “JET programme in support of ITER” based on the full exploitation of the ILW
J. Figueiredo | ESI – Hamburg | July 2017

14. JET ITER-Like Wall
New JET Capability for EP2 NBI: ~ 35MW Pellets for ELM control: 50Hz Enhanced spectroscopic coverage

15. New wall completely installed mainly with remote handling!
Beryllium
Saddle coil protection
W-coated CFC
Restraint Ring Protections
Inconel
Upper Dump Plate
Mushrooms
Bulk W
Inner Wall Cladding
Normal NBI Inner Wall GL’s
Poloidal Limiters
New wall completely installed mainly with remote handling!
About tile assemblies
More than 2 tons of Be
Inner Wall Guard Limiters
Re-ionisation Protections
Normal NBI IW Cladding
LH + ICRH Protection
Saddle Coil Protections
B&C tiles
Saddle Coil Protections
Divertor
Bulk W
J. Figueiredo | ESI – Hamburg | July 2017

16. Installation via Remote Handling Systems
J. Figueiredo | ESI – Hamburg | July 2017

17. Reduction in Fuel Retention with the ILW in Comparison with the CFC Wall
Robust and reproducible result from gas balance studies
Reduction of fuel retention by at least one order of magnitude
J. Figueiredo | ESI – Hamburg | July 2017

18. Reduction of C content by at least one order of magnitude
Reduction in impurity content with the ILW in Comparison with the CFC Wall
Evolution of carbon in the plasma edge (CIII at 97.7nm) during the last campaigns with CFC walls and the ILW
Reduction of C in the plasma edge: CFC vs ILW D He H D
JET with ILW
min. factor 10
JET with CFC
Reduction of C content by at least one order of magnitude
J. Figueiredo | ESI – Hamburg | July 2017

19. Neutral Beam Enhancement
IAEA TCM 2011, San Francisco, June 20-24
Neutral Beam Enhancement
NB Operating
Space (D2)
24 MW limit
10 s pulse length limit
35 MW limit
20s pulse length limit
New power supplies
Major reconfiguration
New PLC controllers
Reactive Power Compensation
J. Figueiredo | ESI – Hamburg | July 2017

20. Next DT Campaign on JET: DTE2 overview
Reference DTE2: 50/50 D-T for a neutron budget of 1.7x1021 about a factor of 7 higher than DTE1 (previous main DT campaign in JET which took place in 1997)
Neutron flux on the first wall up to 1013 n/s·cm2 as in ITER between the blanket and the vacuum vessel
Neutron fluence on first wall up to ≈ 1015n/cm2 (≈10-6 dpa). At this fluence level, degradation of physical properties of functional materials of diagnostic relevance can be observed (although not relevant for structural materials)
Unique TT campaign to complete the isotope scan (which was not granted time during DTE1)
J. Figueiredo | ESI – Hamburg | July 2017

21. Fusion performance Ambitious Target : Pfusion ~ 15MW for 5s DTE-2
ELMY-H
& Hybrid scenarios
ITER scenarios – Performance projections:
ELMy H-modes at 4.5 MA/3.6 T: H98~0.85-1, Zeff~2 at Q~
Hybrid plasmas at 3.5 MA/(3.45 T): H98~1.2, Zeff~2 at Q~
Advanced scenarios at MA/ T and q0~2 for a range of plasma parameters, e.g. and Zeff~2, projecting to Q~
J. Figueiredo | ESI – Hamburg | July 2017

22. Last DD Campaign on JET: Performance
In terms of performance of the heating systems, JET managed to achieve its target for the last campaigns.
3MA ILW
(2016)
(2014)
We are back on the IPB98y scaling
These discharges preserve the positive properties of the ILW
Peak neutron rate of about was achieved
J. Figueiredo | ESI – Hamburg | July 2017

23. Tritium Retention with ITER materials Be, W
~0.3% retention fraction
reduction by more than one order of magnitude
gas-balance & post-mortem analyses
Co-deposition in W-Be layers (2/3) dominates over implantation (1/3)
Fuel analysis in narrow gaps
Sectioning of beryllium limiters
JET–ILW:
castellations
L~ 7325 m, S~ 88m2 !
Fuel retention at the very entrance (<1mm) of grooves
no transport deeper into gaps
in agreement with modelling
Narrow gaps (0.4 mm) minimise retention
ITER predictions on basis of JET-ILW plasmas (C30C): 3000 – discharges

24. Comprehensive Dust Particles Survey
Mobilisable Dust two orders of magnitude less than JET C-Wall
1.82g Dust collected:
vacuum cleaning
sticky pad
Source
Predominantly from W-coated tiles
Be melting from disruptions
Only 50-70mg from Be co-deposit
Unique and reassuring data set for ITER safety
Safety issue

25. DT technical rehearsal
Additional technical and safety requirements in tritium operation:
Tritium is stored in uranium beds and will be supplied by the tritium plant to one or two neutral beam boxes and five new tritium introduction modules.
The torus hall atmosphere will be under depression (to limit the spread of tritium in case of accidental tritium release) and is depleted to 15% oxygen level (fire suppression).
Restricted access to key operational areas of the JET building (neutron activation)
Tightened access restrictions will be applied to computer networks.
All cryo-pumps will be regenerated daily (tritium inventory, flammable gas limit)
Additional tritium operational procedures are used in the JET and the tritium plant control rooms.
Fuel cycle at JET
J. Figueiredo | ESI – Hamburg | July 2017

26. JET Diagnostic Enhancement Projects
Operation support diagnostics
DT compatible camera views project (Itziar Balboa CCFE)
Upgrade Charge Exchange for Ti (Nick Hawkes CCFE)
Instabilities Diagnostics
Correlation and Doppler Reflectometer project (Antonio Silva IST)
Upgrade of the JET TAE system (Patrick Blanchard CRPP)
Neutron Diagnostics
JET Neutron Camera Upgrade project (Daniele Marocco ENEA)
Vertical Neutron Spectrometer project (Francesco Belli ENEA)
Gamma Diagnostics
Upgrade of the JET Gamma Ray Camera (Marco Tardocchi CNR)
JET Horizontal Gamma-Ray Spectrometer Upgrade for the alpha-Particle Diagnostic during the DT Campaign (Teddy Craciunescu IAP)
Fast Ion Diagnostic
Upgrade of the scintillator based Fast-Ion Loss Detector (FILD) at JET (Manuel García-Muñoz CIEMAT)
J. Figueiredo | ESI – Hamburg | July 2017

27. All invited to participate!!!
Summary
On the route to DTE2
There is a coherent scientific and technologic development programme
The recent results support the ambitious but realistic goals
Diagnostics are adequate to support the ambitious scientific programme
Many more activities will be carried out during DTE2
All invited to participate!!! 27