Overview of the JET preparation forDeuterium-Tritium Operation with
the ITER Like-Wall
E. Joffrin, on behalf of EUROfusion JET contributors
Acknowledgments: to the JET Task Force and Project Leaders, JET secondees,
EUROfusion Programme Management Unit, JET Exploitation Unit and JET operator

JET is designed for fusion power studies
in support of ITER
1975 JET design proposal: “…describes a large Tokamak experiment, which aims to study plasma
behaviour in conditions and dimensions approaching those required in a fusion reactor”.

JET-ILW:PNBI=32MWPICRH=8MW

JET is capable of confining 90% ofalpha particle for Ip above 2.5MA

E. Joffrin et al. | 27th IAEA Fusion Energy Conference | Gandhinagar, India| 22-27 Oct. 2018 | Page 2

Objectives and outline
EUROfusion research roadmap: Secure the success of future ITER operationvia specific preparation and experiments, including D-T operation of JET.
Fusionpower
15(MW)

15MW/5s target

DTE1
JET-C
(1997)

10

1. Develop D-T scenario andfusion power prediction

92436: PFUS-EQ
JET-ILW (2016)5

2. Understand isotope physics

0

3. Prepare the operation in D-T012345678Time (s)DTE1 in 1997-98: M. Keilhacker Nuc Fus 39 (1999) 209 & J. Jacquinot Nuc Fus 39 (1999) 235EUROfusion MST1 task Force: H. Meyer, OV2-1
E. Joffrin et al. | 27th IAEA Fusion Energy Conference | Gandhinagar, India| 22-27 Oct. 2018 | Page 3

Stationary Scenarios for the DT phase achieved~7-8MW of equivalent PFUS
“Hybrid” scenario 2.2MA/2.8T
q95~4, βN~2-3 H98(y,2)=1.3“Baseline” scenario 3.0MA/2.8T
q95~3, βN~1.8 H98(y,2)=1.1
PNBI (MW)PNBI (MW)PICRH (MW)PFUS (MW)30-35% thermo-nuclear

PICRH (MW)PFUS (MW)~60% thermo-nuclear

βNLine integrated density (1019m-2)Time (s)βNLine integrated density (1019m-2)Time (s)Fusion equivalent power for a 50/50 D/T mix:
7-8MW of fusion power for both scenarios
L. Garzotti, EX/3-6
E. De la Luna, EX/2-1 E. Joffrin et al. | 27th IAEA Fusion Energy Conference | Gandhinagar, India| 22-27 Oct. 2018 | Page 4

“After-glow” ITB scenario shows promisingroute for alpha-driven mode studiesAfter-glow

50/50 D-T
Prediction(TRANSP)

TAEs

Stabilitycalculation(MISHKA)

n=4
R. Dumont, Nuc. Fus. 2018
S. Sharapov, EX/P1-28
E. Joffrin et al. | 28th FEC conference | Ghandinaghar | 22-26 Oct. 2018 | Page 5

Prospects for 10 to 15MW of fusion
power in stationary scenarios in JET-ILW
16

PFUS [MW]14

D-T equivalent fusion power

D-T Equivalent fusion
power with 40MW

50/50 D/T mix for identicalplasma parameters

Hot-ionH-modes12

q No credit for isotope effects
q No credit for α-power

10BaselineHybridITB86q Equivalent fusion power
reaching similar level thanin the 1998 D-T campaign(DTE1) with two stationaryscenarios: baseline andhybrid.

DTE1Actual PFUS

4q Transient ITB scenario for
D-T equivalent fusion power α-particle driven modefor 2014-2016 discharges
studies

2005W [MJ]

10152025E. Joffrin et al. | 27th IAEA Fusion Energy Conference | Gandhinagar, India| 22-27 Oct. 2018 | Page 6

10-16MW of fusion power also predictedin D-T by first principle based modelling
19 CRONOS-TGFL & JINTRAC-QUALIKIZ: filled symbols
JINTRAC-BGB-EUROped: open symbols
CRONOS-CDBM: Stars

q Isotope effect from ExB shear
stabilisation or energy exchange.

15PFUS (MW)Taking into account additional effect:

Hybridq Alpha power contribution

117ITBq Auto-consistent modelling with core(BGB)-pedestal (EUROped) with noisotope effects.

Baseline

Uncertainty in PFUS accounts for different
plasma current and bootstrap models
32030

PIN (MW)40

J. Garcia, TH/3-1
F. Casson, TH/3-2
S. Saarelma, PPCF 2017

50E. Joffrin et al. | 28th FEC conference | Ghandinaghar | 22-26 Oct. 2018 | Page 7

ICRH power can efficiently control W
accumulation in D-T scenario
Central Te (keV)

ICRH schemes developed for D-T
Demonstrated experimentallyq n=1 H minority
è electron heating

E. Lerche, Nucl. Fus. 2016
M. Goniche, PPCF 2017

q n=1 He3 minority
è ion heatingFirst principle predictionof D-T scenario with40MW & Ti>TePICRH (MW)P. Jacquet, Nucl. Fus. 2016
D. van Eester, IAEA 2016

PRAD inside ρ=0.2 (MW)Central Ti (keV)q Combination ofboth

Ion heating predicted to provide
resilience to high-Z
4accumulation
Tio=10.7 [keV]

3Tio=12.7 [keV]

21Tio=14.2 [keV]0Time (s)1011789F. Casson, TH/3-2
E. Joffrin et al. | 28th FEC conference | Ghandinaghar | 22-26 Oct. 2018 | Page 8

3 ion schemes H-(DNBI)-D:a new development in support of D-T
Efficient acceleration of NBI ions to higher energies with n = 1 ICRH in mixed plasmas

T-NBI +
n=1 ICRH
T-NBIq H-D plasmas: increase in neutron rate due toaccelerating D-NBI ions to ED ≈ 1-2MeV,

D-T plasmas: optimize Q and fusion
power using NBI+ICRH synergies:

q Confirmed with TOFOR, γ-ray measurements
and ICRH modeling

ET-NBI = 118keV, à <ET> ≈ 200keV(off-axis n = 1 ICRH)

Y. Kazakov, EX/8-1 & Nat. Phys. 2017
J. Ongena, RF Conf. 2017
E. Joffrin et al. | 28th FEC conference | Ghandinaghar | 22-26 Oct. 2018 | Page 9

Understandisotope physics

E. Joffrin et al. | 28th FEC conference | Ghandinaghar | 22-26 Oct. 2018 | Page 10

L-mode: weak positive isotope
dependence on confinement & transport
Match of ρ*, β, ν* H/D pair satisfies
scale invariance (same ωciτEth )L-mode confinement scaling with mass
(PIN scan at ne=cst, Ti~Te; BT=2.9 T, Ip=2.5 MA)-0.5

Hydrogen
Deuterium

Hydrogen
Deuterium

TGLF

TGLF

-1.5thlog( τ ) [regression]

-1.0

-2.0

-2.5
-2.5

τth ~ A0.15±0.02-2.0-1.5-1.0log( τ ) [experiment]

3.0

3.4

R (m)

-0.5

thq Small positive isotope dependence of τthq Consistent with the H97L scaling τ ~ A0.2
H. Weisen, EX/P1-4
P. Strand, TH/P6-14
C. Maggi, PPCF 2018

3.2

3.6

3.8

3.0

3.2

3.4

3.6

3.8

R (m)

q No additional isotope dependence neededq Agreement achieved with modelling for theidentity pairq Difference with 0D scaling being examined

E. Joffrin et al. | 28th FEC conference | Ghandinaghar | 22-26 Oct. 2018 | Page 11

L-H power threshold likely to be lower in Tritium
for D-T scenario
x2

HD-T
x2/3

T

PL-H threshold ~ 1/APrediction with non-linear
fluid turbulence code(HESEL) reproduces strong
dependence: ~ 1/A1.4

J. Hillesheim, EX/4-1

2008 scalingq PL-H threshold likely to be reduced by 2/3 in tritium and 1/3 in D-T.
q Consistent with past DTE1 results (Righi et al. 1999).
C. Maggi, PPCF 2017
E. Joffrin et al. | 27th IAEA Fusion Energy Conference | Gandhinagar, India| 22-27 Oct. 2018 | Page 12

Type I ELMy H-mode: strong positive isotope
dependence on thermal confinement
H-mode confinement scaling with mass
H: 1.0MA/1.0T and 1.4MA/1.7T
D: 1.0MA/1.0T, 1.4MA/1.7T, 1.7MA/
1.7T

Deuteriumq Stronger isotope dependence than in JET-C
and IPB98(y,2) (~A0.2)
q Global momentum ~ A0.5±0.15
q Global particle ~ A0.5±0.06
All scalings robust against the set of variables
chosen for the regression.

Hydrogenτth ~ A0.4±0.1

Note: Density systematically lower in H at same
external fuelling
H. Weisen, EX/P1-4
C. Maggi, PPCF 2018

The pedestal is an important player in the observed isotope dependence
E. Joffrin et al. | 27th IAEA Fusion Energy Conference | Gandhinagar, India| 22-27 Oct. 2018 | Page 13

Larger pedestal pressure in D than H atsame power and gas fuelling rate
IP=1.4MA; BT=1.7T; PIN=10MW ELMs; same fuelling rate: 19Hz in D and 31Hz in H

Lower density observed in H for equivalent external gas injection rate
q Isotope effect peeling-ballooning is weak for same separatrix Te.
q Different separatrix temperature in H and D could change pedestal stability.
q Inter-ELM particle loss different in H and D.
L. Horwarth, Nuc. Fusion in preparation
E. Joffrin et al. | 27th IAEA Fusion Energy Conference | Gandhinagar, India| 22-27 Oct. 2018 | Page 14

Isotope mixing: key particle transporteffect for D-T scenario
91232 (1.4MA/1.7T), H/D=0.9.

.
.

èDi/DeR/LTIn typical JET scenario:è Di/De>1 and Vi/Ve>1

nD and nH R/Ln similar andindependent of the source.

Important for isotope fuelling &control in JET and ITER.

C. Bourdelle Nuc Fus 2018
M. Maslov Nuc Fusion 2018
C. Angioni, Phys. Plasmas 2018

E. Joffrin et al. | 28th FEC conference | Ghandinaghar | 22-26 Oct. 2018 | Page 15Be and W physical sputtering will
increase with Tritium
From binary collision approximation (SDTtrimSP code)

Physical sputtering yields

Be à W

Increase of Be sputtering bytritium in inter-ELM phaseT à Be

D à BeDetachment

H à BeTàW
DàW
HàW

L-modeD. Borodin, EX/P1-14
S. Brezinsek, EX/9-4

Inter-ELM

Intra-ELM

Increase of W sputtering
yields and thresholdenergy by tritium inintra-ELM phase.

The increase of Be physical sputtering by tritium
can lead to an increase of W sputtering by Be
E. Joffrin et al. | 27th IAEA Fusion Energy Conference | Gandhinagar, India| 22-27 Oct. 2018 | Page 16

Intra-ELM sputtering will dominate W
sputtering in tritium
Be erosion

Tungsten erosion with isotopeTDH(Analytical model)(Deuterium)

Synthetic
image ERO2.0

Intra-ELM: ~70% of the gross-erosion
Borodkina, Nuc. Mater. Energy
2017

J. Romazanov, PSI 2018

From post-mortem analysis in D:Ø W gross erosion: 40-60 g
Ø W net erosion: 2.4-4.8 g
Ø 90% of prompt redeposition

A. Kirschner
PPCF 2018

E. Joffrin et al. | 27th IAEA Fusion Energy Conference | Gandhinagar, India| 22-27 Oct. 2018 | Page 17

Decrease of material deposition rate byx4-9 compared to JET-C
Since 2011, operation with JET-ILW: 60h of plasma and 600MJ of input energy
q Deuterium retention decreased by afactor of 10 to 20 wrt to JET-C.

Be: 7 1019 atoms/cm2
D: 4 1018 atoms/cm2
C: 3 1018 atoms/cm2
O: 1019 atoms/cm2
N: 5 1018 atoms/cm2

q The retention of tritium in deposits is
not expected to be significantly
different than deuterium.
Dominant
strike pointposition

Be: 2 1019 atoms/cm2
D: 2 1018 atoms/cm2
C: 2 1018 atoms/cm2
O: 1019 atoms/cm2

Be: 4 1019 atoms/cm2
D: 2 1018 atoms/cm2
C: 5 1018 atoms/cm2
O: 5 1018 atoms/cm2
N: 5 1018 atoms/cm2Cryopump

546

A. Widdowson, Phys. Script. 2018
M. Mayer, EX/P1/15

E. Joffrin et al. | 27th IAEA Fusion Energy Conference | Gandhinagar, India| 22-27 Oct. 2018 | Page 18

Prepare theoperation in D-T

E. Joffrin et al. | 27th IAEA Fusion Energy Conference | Gandhinagar, India| 22-27 Oct. 2018 | Page 19

Upgrades for D-T: NBI and T injectionMaximum NBI power so far limited by one ofion dumps component cooling capabilities.

5 new tritium gas injection modules,(Only one existing in DTE1)
DBeam injectors

DDT
DDT
D

New plates with optimised cooling removing
the limits to beam voltage and pulse lengthè 34MW in D-T (21MW in DTE1)

DT

DT

T

I. Carvalho, 29th SOFT 2016

A. Shepherd, 29th SOFT 2016
E. Joffrin et al. | 27th IAEA Fusion Energy Conference | Gandhinagar, India| 22-27 Oct. 2018 | Page 20

Unique set of new diagnostics in place for alphaphysics and burning plasma studies in DTE2
Several burning plasma diagnostics
ready for the D-T phase.
Charge Exchange (Ti)TAE antenna
Neutron Camera
Vertical Neutron Spectrometer
γ-Ray Camera
Horizontal γ-Ray Spectrometer for alphaParticle Diagnostic
Upgrade of the scintillator based Fast-Ion Loss
Detector (FILD)

Visualization of fast
particle orbits withγ-ray tomography

Most diagnostics included syntheticallyin modelling suites for code validation
J. Figueiredo, EX/P7-42
S. Sharapov, EX/P1-28
E. Joffrin et al. | 27th IAEA Fusion Energy Conference | Gandhinagar, India| 22-27 Oct. 2018 | Page 21

New tools developed for burning plasma
Isotope ratio controlled
at 50% in H-mode

Infra-red protection camera moved
outside the biological shield

Pulse 91234 (1.4MA, 1.7T)

40m

New
mirrors

PNBI (MW)Isotopic ratio(vis. Spec.)

CameraDHTime (s)M. Lennholm & D. Valcarcel, FED 2017

V. Huber,
EX/P1-31

Both techniques will be essential for ITER D-T operations
E. Joffrin et al. | 27th IAEA Fusion Energy Conference | Gandhinagar, India| 22-27 Oct. 2018 | Page 22

14MeV neutron detector for the D-T phase calibrated
with an accuracy of ±6%.
3 Fission (235U) chambers and 1
Activation system

q 14MeV neutron generator deployedinside JET vessel by remotehandling§ 76h of irradiation in 73 different
poloidal and toroidal positions§ Calibration within ±6%
q Neutronic modelling carried out andcodes validated for ITER.
è Procedure transferable to ITER.

P. Batistoni, Nuc Fus 2018,
E. Laszynska, SOFT 2018 ,T. Vasilopoulou, SOFT 2018,
S. R. Villari, SOFT 2018

E. Joffrin et al. | 28th FEC conference | Ghandinaghar | 22-26 Oct. 2018 | Page 23

Tritium operation with JET-ILW:
x5 more neutron budget than in DTE1
DTE1TTDTE2

Neutron

3. 1020

0.1 1021

1.55 1021

Tritium injected

35g

~300g

~150g

T: 60gforDTE2

Strict accounting of tritiumused <11g in cryo panels
regenerated every day

Restricted access toarea where neutron
activation and γ
radiation can be high.

E. Belonohy, SOFT 2016

Plasma operation rehearsal planned during the D campaign
E. Joffrin et al. | 28th FEC conference | Ghandinaghar | 22-26 Oct. 2018 | Page 24

Highlights of the preparation for D-T
q Existing D-T scenarios have reached 7-8MW/2.5s equivalent fusion
power and can attain 10 to 16MW of fusion power with 40MW of input
power in the JET ITER-like wallq After-glow ITB scenario is a credible route for alpha particle driven
instabilities study and code validation for ITER
q Confinement and particle transport show strong positive isotope
dependences and is also investigated for ITER conditions
q Tritium will modify the SOL conditions and plasma surface
interactions significantly but retention is expected to stay low
q JET has developed a comprehensive set of diagnostics, tools andprocedures in support of ITER burning plasma operation

E. Joffrin et al. | 28th FEC conference | Ghandinaghar | 22-26 Oct. 2018 | Page 25

Next JET timeline and Prospects

D campaign
Ø D-T scenario preparation
Ø Disruption/RE studies
Shattered Pellet Iinjector

H&TØ Isotopecampaigns
D-T campaign
Ø 15 MW of fusion power for 5sin stationary conditions
Ø Study of alpha physics

E. Joffrin et al. | 27th IAEA Fusion Energy Conference | Gandhinagar, India| 22-27 Oct. 2018 | Page 26

Thank you for your attention on behalfof the EUROfusion JET contributors

E. Joffrin et al. | 27th IAEA Fusion Energy Conference | Gandhinagar, India| 22-27 Oct. 2018 | Page 27