JT-60SA divertor research strategy and radiative scenario modelling

with improving SONIC integrated code

2nd IAEA Technical Meeting on Divertor Concepts, 13-16 November 2017, Suzhou, China

K. Hoshino1, T. Nakano1, M. Wischmeier 2, M. Sakamoto 3 and the JT-60SA team 1 National Institutes for Quantum and Radiological Science and Technology, Japan 2 Max-Planck-Institut fur Plasmaphysik, Germany 3 University of tsukuba, Japan

lv-11

JT-60SA HP:

http://www.jt60sa.org/b/index.htm

Support ITER using break-even-equivalent class high-temperature deuterium plasmas lasting for a duration (~100 s).

Supplement ITER toward DEMO with long sustainment (~100 s) of high pressure steady state plasmas necessary in DEMO.

JT-60SA (superconducting tokamak)

ITER (France)

DEMO Foster next

generation

Contribute to early realization of fusion energy by addressing key

physics and engineering issues for ITER and DEMO.

Foster next generation of scientists and technicians

playing leading roles in R&D of ITER and DEMO

demonstration of power generation

DT burning

JT-60SA (super advanced) project 2

the Satellite Tokamak Program in the JA-EU Broader Approach Activity and

the Japanese national programme

Highly Shaped Large Superconducting Tokamak

JT-60SA:

Large superconducting tokamak

High plasma current (max. IP=5.5 MA)

Long pulse (typically 100 s)

High heating power (41 MW × 100 s)

Highly shaped (S=q95Ip/(aBT) ~7, A~2.5)

Full-monoblock carbon DIV, first wall

(Metallic wall in later phase)

Non-circular superconducting tokamaks

3

Plasma current, IP (MA) 5.5

Toroidal magnetic field, BT (T) 2.25

Major radius, Rp (m) 2.96

Aspect ratio, A 2.5

Elongation, kx 1.95

Triangularity, dx 0.53

Safety factor, q95 3.0

Injection power, Pin (MW) 41

Normalized beta, bN 3.1

Bootstrap current ftacution, fBS 0.28

Full IP, 41 MW operation

Construction of JT-60SA is progressing smoothly by the EU

and JA Integrated Project Team towards the first plasma in

Sep. 2020.

4

Disassembly of JT-60U

Vacuum vessel & Thermal shield

Cryostat base

Lower poloidal field coil

Vacuum vessel

Toroidal field coil

Construction ~ First plasma

First plasma

2011 2012

Construction

Operation

Year 2021 2008 2009 2010 2013 2014 2015 2016 2017

Disassembly Assembly

Commissioning

Preparation

2018 2019 2020

Experiment

Integrated

Commissioning

Changeover to Full Metal Wall ~2030 (TBD)

Partially W

(or W-coated CFC)

divertor tiles. ITER

H / He Possibility of

W-coated full monoblock CFC divertor

+ full W-coated first wall

+ fully water-cooled ~2030

5

JT-60SA Research Phase

JT-60SA Research Plan 6

“JT-60SA Research Plan (SARP)” summarizes

“Research items and Strategy for JT-60SA”

to solve critical issues in ITER and DEMO.

Points of the JT-60SARP

Make a plan

Encourage collaborative studies on JT-60SA

Optimize hard ware: heating, fueling, pumping, diagnostics, etc.

Growing year by year toward fruitful experiments.

Chapter 2: Research Strategy

Chapter 3: Operation Regime Development

Chapter 4: MHD Stability and Control

Chapter 5: Transport and Confinement

Chapter 6: High Energy Particle Behavior

Chapter 7: Pedestal and Edge Physics

Chapter 8: Divertor, SOL and PWI

Chapter 9: Fusion Engineering

Chapter 10: Theoretical models and simulation codes

Ver. 3.3: Mar. 2016

365 colleagues

(13 countries, 42 inst.)

join activities led by

Technical Responsible

Officers (TROs) in the

research fields.

7

• 15 MW/m2x100 s for 3000 cycles

• 10 MW/m2x100 s for 10000 cycles

Target Plate

Divertor Cassette

Dome Plate

Cryopump

CFC mono-block

pumping speed of 0 -100m3/s by 8 steps

Heat & Particle Control with ITER-like-shaped Divertor

V-shaped corner

high neutral compression enhancement of detachment

Divertor to control heat & particle for the long-pulse, high-confinement and high-density operation

high radiative divertor plasma

Initial Research I

(1-2y)

Initial Research II

(2-3y) Integrated Research I

(2-3y)

H/He D D

Power: 23 MW 33 MW 37 MW

Divertor : CFC tile (10 MW/m2 x 5s ) C mono-block（15 MW/m2 x 100s）

Divertor research strategy (1/2)

Impurity seeding experiment ⇒ Multi-impurity simulation (C+Ne/Ar)

High power & radiation exp. ⇒ impurity-impurity collision

time-dependent SONIC + core transport model

Real time control of Ne/Ar seeding

H/D mixture exp. ⇒ integrated sim. with

SONIC and core transport model

simulation including radiation transport

Geometry effect red: experiment

blue: model development &

simulation study Neutral transport / compression

comparison with JT-60U, simulation

linkage with

code development

/ model validation

are progressed

from initial phase

8

Initial Research I

(1-2y)

Initial Research II

(2-3y) Integrated Research I

(2-3y)

He exhaust exp. ⇒ simulation including

elastic coll., HeH molecule,

meta-stable, radiation transport, etc.

multi-impurity sim. (He+C+Ne/Ar)

He exhaust exp. with Ne/Ar seeding

Full-W wall

experiment

Scenario development with full-W wall

multi-impurity sim. + core transport model

W transport (Monte-Carlo kinetic model)

PWI simulation (MC kinetic + BCA model)

red: experiment

blue: model development &

simulation study

Toward changeover to full metal wall,

code development & simulation study

will be progressed.

Divertor research strategy (1/2) 9

H/He D D

Power: 23 MW 33 MW 37 MW

Divertor : CFC tile (10 MW/m2 x 5s ) C mono-block（15 MW/m2 x 100s）

The SONIC simulation for prediction of the JT-60SA divertor plasma

10

integrated divertor code, SONIC H. Kawashima, Plasma Fus. Res. 2006, K.Shimizu NF2009

MC: Monte-Carlo

by execution of several models on the integrated-modeling

framework newly developed

Recently, the SONIC code has been extended to multi-impurity

simulation using MC kinetic model

Neutral

MC kinetic

Impurity(Ar)

MC kinetic

SONIC

Plasma

fluid

data exchange

A number of models

are attachable.

Impurity(Ne)

kinetic Impurity(W)

kinetic Impurity(C)

MC kinetic

on new integrated-modeling framework

Predictive studies for JT-60SA divertor plasma

JA: SONIC (H.Kawashima JNM2011 CPP2017, K.Hoshino CPP2014, etc.) EU: JINTRAC(M.Romaneli NF2017), COREDIV(R.Zagórski NF2016, K.Gałązka PPCF2017)

Prediction accuracy is improved by considering

the generation of a wall impurity and its transport

Previous SONIC

Present SONIC

Ar (MC kinetic)

0.17 Pam3/s

C (coronal model)

nC/ni = 0.01

Ar (MC kinetic) C (MC kineic)

Ychem = 3% 0.16 Pam3/s

Ar radiation

Ar radiation

C radiation

C radiation

Very different profile

Multi-impurities by MC kinetic model

including phys. & chem. sputtering

Only one impurity by MC

11

12

• Low SOL Density (ne,sep <1.7x1019 m-3)

from core plasma scenario nebar = 5.0x1019m-3 (ne

bar/nGW=0.85)

JT-60SA mission: steady-state (SS) and high-b (> 3.5) operation.

Steady-state high-b operation is challenging

for divertor power handling

Zeff=2 for intrinsic C is assumed

but no other impurities.

By using Pin=24MW,

a plasma with βN=3.9, HH=1.5

(Bt=1.7 T, Ip=2.3 MA) & nearly

full CD condition was obtained.

Example of scenario by 1.5D core transport simulation (N.Hayashi, IAEA FEC2016)

• High SOL density is preferable

for reduction of divertor heat load to desired level of < 10 MW/m2

To develop the divertor power handling scenario under the low SOL density condition,

multi-impurity SONIC simulation with Ar seeding is performed.

Radiative divertor scenario compatible with the SS high-b scenario is found.

13

D2 puff : 8.5 Pa m3 / s & Ar puff: 0.15 Pa m3 / s

Ar radiation

5.6 MW

C radiation

7.4 MW

SONIC simulation for parameter survey of gas puffing rate of D2 and Ar

mid-plane outer divertor

< 1.7 x 1019 m-3

< 10 MW/m2

characteristic profiles

for C and Ar.

the SONIC result

compatible with the

operation scenario

with Ar seeding

C generation consistent

with plasma and Ar

(phys. & chem. sputtering)

W/O Ar

W/ Ar

W/O Ar

W/ Ar

K.Hoshino, PET17

SONIC simulation for W-wall is progressing

W & Ar are treated by a coronal model

for Full-Ip(5.5MA), Full power(41MW) and High-density

( nW/ni=1e-5 )

• In W-wall case w/o Ar (red), qpk<10MW/m2 is difficult due to low Prad

• By increasing Γpuff and nAr /ni (blue), qpk<10MW/m2 can be achieved.

• Other seeding impurity

• Detailed analysis with

multi kinetic impurity model

H.Kawashima CPP2016

nAr/ni = 0%

0.01 %

0.1%

Power handling scenario for full W-wall was studied

Future work

14

Γpuff

15 Summary

• Construction of JT-60SA is progressing smoothly by the EU and JA

Integrated Project Team towards the first plasma in Sep. 2020.

• JT-60SA Research Plan (divetor/sol/pwi in chap.8) is evolving through

discussions between EU & JA.

• The divertor plasma performance for steady-state high-b scenario has

been analyzed by the SONIC code with kinetic impurity model.

The radiative divertor scenario for the heat load < 10MW/m2 under

SS high-b plasma condition (Pin=24MW, ne,sep<1.7x1019m-3) was obtained.

• Changeover to full metal wall is planed, and the SONIC simulation with a

coronal model for full W-wall has been performed.

The target heat load < 10MW/m2 was obtained by the Ar puff

(nAr/ni~0.001), under the condition of full Ip, full power and high density.

Research plan V.4 will be documented in Mar. 2018.

• The multi-impurity simulation using a MC kinetic impurity model for full

metal wall is in preparation.