PPP&T – Power Exhaust Studies - Teknologiasta tulosta · PEX-01: Power Exhaust Physics Plasma boundary modelling ... (TEKES, FZJ) Organization of PEX activities & TEKES Contribution

PPP&T – Power Exhaust Studies

Leena Aho-MantilaVTT Technical Research Centre of FinlandVisiting researcher at the Max-Planck-Institut für Plasmaphysik (IPP),Garching, Germany

Association

Euratom-Tekes Euratom-TEKES Annual Seminar 2012

2LEENA AHO-MANTILA, Annual Seminar, 29.5.2012

Association

Euratom-Tekes

Power Plant Physics and Technology (PPP&T)

GOALS:

� Begin a coordinated effort in EU to quantify key physics/technology

prerequisites for a demonstration fusion power plant, DEMO

� To define a set of technical characteristics for DEMO and, subsequently,

to carry out the design work necessary to establish its conceptual design

� To define future R&D needs and to carry out specific validating R&D

work supportive of the conceptual design activities

G. Federici, Annual TEKES Fusion Seminar, Helsinki, 7-8.06.2011

All these activities are coordinated by the EFDA PPP&T department (head: G. Federici)


Association

Euratom-Tekes

Organization of PPP&T Activities

PPP&T

SYS (8)system code activities

PEX (12)power exhaust physics

integration activities

DTM (6)design tools and methodologies

DAS (28)design assessment

studies

MAT (14)materials R&D and

engineering database

SERF (2)socio economic research

on fusion


Association

Euratom-Tekes

Organization of PPP&T Activities

PPP&T

SYS (8)system code activities

PEX (12)power exhaust physics

integration activities

DTM (6)design tools and methodologies

DAS (28)design assessment

studies

MAT (14)materials R&D and

engineering database

SERF (2)socio economic research

on fusion


Association

Euratom-Tekes

Power exhaust is among the most critical problems to be s olvedfor a DEMO reactor

ITER is the first tokamak that can regularly exceed the technological limits of actively cooled PFCs (~10 MW / m2)� Already the particle fluxes may be high enough to

heat the PFCs above the allowed limits=> radiative cooling and divertor detachment are mandatory� Significant uncertainties in extrapolating the

power decay length and divertor detachment

DEMO design: � Maximize the total tolerable divertor power

loading� Minimize the device size (operation in H-

mode)

PIN = 50 MWPFUS = 500 MWPα = 100 MWPRAD = 50 MW

QDT = 10Reference magnetic equilibrium

ITERdivertor

λq|| = ?

R. Pitts, seminar at VTT in 2011


Association

Euratom-Tekes

Two approaches in PPP&T studies

(A) Conventional divertor� X-point configuration� Metallic walls and impurity seeding� Edge radiation pushed to the limit

(B) Novel divertor designs� Enhanced spreading of power:

snowflake, super-X divertor� High power handling:

liquid metal walls

V. Soukhanovskii (LLNL) S. Lisgo et al, EPS 2009

ITER organization


Association

Euratom-Tekes

PEX-01: Power Exhaust Physics� Plasma boundary modelling

(TEKES, IPP, CEA)� Erosion estimates

(TEKES, FZJ)

Organization of PEX activities & TEKES Contribution

PEX-02: Novel Divertor MagneticConfigurations

PEX-03: Bare Steel Wall� Preparation and characterization

of tiles/ markers (TEKES, IPP)� Campaign-integrated erosion rate,

comparison with spectroscopicallymeasured fluxes, enrichment of high-Z elements (TEKES, IPP)

PEX-04: Novel PFC MaterialSolutions / Liquid Metals

11% of available PPY and 20% of total PEX-2012 budget allocated to TEKES


Association

Euratom-Tekes

PEX-01: Power Exhaust Physics� Plasma boundary modelling

(TEKES, IPP, CEA)� Erosion estimates

(TEKES, FZJ)

Organization of PEX activities & TEKES Contribution

PEX-02: Novel Divertor MagneticConfigurations

PEX-03: Bare Steel Wall� Preparation and characterization

of tiles/ markers (TEKES, IPP)� Campaign-integrated erosion rate,

comparison with spectroscopicallymeasured fluxes, enrichment of high-Z elements (TEKES, IPP)

PEX-04: Novel PFC MaterialSolutions / Liquid Metals

11% of available PPY and 20% of total PEX-2012 budget allocated to TEKES


Association

Euratom-Tekes

Numerical modelling to address power exhaust issues

� 2D fluid codes are most extensively used to model the edge, scrape-off layer and divertorplasmas

� Parallel transport calculated for multiple fluidspecies (fuel and impurities)� Calculation of cross-field drifts and kinetic

treatment of neutrals possible in some codepackages

� Require assumptions on anomalous transport and plasma-wall interaction⇒Validation against existing devices needed

edge

SOL

divertor

2D calculation gridfor ASDEX Upgrade


Association

Euratom-Tekes

PEX studies aim to validate impurity radiation models

Goal: provide simplified, validated incremental models for system codes (SYS)

Take into account the limited validity of non-seeded plasma solutions, namely:No agreement btw code and experimentfor detached divertor plasma conditions

SOLPSEXP

outer targetlow recycling

Begin with the best understood non-seeded plasmas and study incrementaleffects of seeded impurities:Low-density L-mode plasmas in reactor-relevant devices

Need dedicated experimentsfor model validation


Association

Euratom-Tekes

Experiments at ASDEX Upgrade and JET

AUG: several characterization discharges with no seeding , N2 seeding to be investigatedJET: N2 seeding effects characterized in horizontal target configuration (more planned)

AUG – full-W wall JET – Be + W (ILW)


Association

Euratom-Tekes

A lot of physics to be understood…

Saturation of radiatedpower fraction at 60 %

Reduction in D2 fuellingefficiency

Increasing N2 seeding rate leads to:

Asymmetric roll-over in particle fluxes at the twotargets


Association

Euratom-Tekes

…with some promising first results from modelling

• Converged SOLPS5.0 simulations with impurities (C+N) and calculation of drifts and currents activated

• In-out asymmetryobserved in simulations, similarto both ASDEX Upgrade and JET simulations


Association

Euratom-Tekes

Future steps

� Expand the investigated plasma regimes as soonas there is confidence in code calculations (highrecycling, detachment)

� First DEMO simulations to investigate devicescaling

� Use specialized PWI codes to estimate targeterosion

2D SOLPS

grid

3D EROvolume


Association

Euratom-Tekes

Concluding remarks

� PPP&T activities have been launched on several key DEMO design areas

� Significant contribution from TEKES in PEX, focusing in particularon experiments at ASDEX Upgrade and JET� Numerical simulations and post-mortem surface analyses

� Work done in close collaboration with other associations (IPP, FZJ, CEA) and with EFDA CSU

Documents

PPP&T – Power Exhaust Studies - Teknologiasta tulosta · PEX-01: Power Exhaust Physics Plasma boundary modelling ... (TEKES, FZJ) Organization of PEX activities & TEKES Contribution