Inside ITER

8/3/2019 Inside ITER

http://slidepdf.com/reader/full/inside-iter 1/45

ITER Tokamak – April 2, 2009 Page 1

ITER Tokamak

Gary JohnsonDeputy Director General - Tokamak

2 April 2009




What we want todiscuss!

• What is a Tokamak?

• Why is the ITER Tokamak so big?

• Why do we have so many big superconducting magnets?

• Why do we have both a VV and a cryostat?

• What do the blanket and divertor do?

• How can you assemble such a machine?

• Why is Remote Handling important?

• Why is the design of the ITER machine so challenging?






Tokamak Historyтороидальная камера с магнитными катушками

(toroidal'naya kamera s magnitnymi katushkami )(Toroidal chamber with magnetic coils)1956 - Experimental work starts in tokamaksystems by a group of Soviet scientists led by

Lev Artsimovich based on the work of Tamm ,

Sakharov and Lavryentev1958 - World-wide declassification ofmagnetically confined fusion research atGeneva on Peaceful Uses of Atomic Energy

1960s : Tokamak established as leadingcontender for a thermonuclear system – Firstto achieve 1 keV temperature

1970s : Oil crisis propels major investment infusion research facilities worldwide

1980s : Third generation of large tokamaksexperiments come into operation : EU-JET ;US-TFTR ; URSS-T10 ( all aimed at DT tests )

and Japan- JT-60 ( DD only )

1985 ; ITER proposed at super power summit




The Tokamak:

Magnetic Confinement in a Tokamak

• toroidal magnetic field isproduced by externalmagnetic field coils

• plasma current produces

poloidal magnetic field

• result is a set of nested

helical surfaces

⇒

plasma confinement




JET

Tokamak’s

ITER

JET – Internals & Plasma

ITER will allow us to produce plasmas with

temperatures of 100 - 200 million ºC

(10 times the temperature of the sun’s core)

⇒⇒⇒⇒ 500 Megawatts of fusion power




Why is the ITER Tokamak so big?




Tokamak – 29 m high x 28 m dia. & ~23000 t



Add the name of your meeting/conference, the location and date Page 9

Cryostat Size ComparisonCryostat Size Comparison

ITER Tokamak29 m Tall x 28 m Wide

Arc de Triomphe49 m Tall x 45 m Wide




ITER Tokamak – Mass Comparison

ITER Machine mass:~23000 t

28 m diameter x 29 m tall

Charles de Gaulle mass:~38000 t (empty)

856 ft (261 m) long(Commissioned 2001)




- Ignition margin (& thus fusion power) increases with

plasma current and toroidal radius. So you need alarge plasma (both toroidal radius and cross section)to get a lot of fusion power. In our case 500 MW.

Over Sixty Years of Research

in Tokamaks (1956-2008)

The ITER Tokamak is so big because…




Why do we have so many bigsuperconducting magnets?




ITER Magnet‘s

6 PF Coils (EU & RF)

CS Coils – Stack of 6 (US)

31 Feeders (CN)

9 Pairs of Correction Coils (CN)

18 TF Coils(EU & JP)




Facts

• 48 superconducting coils

- ~9800 tons- ~187 km of conductor

- 11.8 T (peak TF field)

- 68 kA (peak current)

- Stored energy – 51 GJ

Challenges

• QA / QC

• Tolerances

• Schedule

Magnet System Status




TF CoilTF Coil

– –

Mass ComparisonMass Comparison

Mass of (1) TF Coil:~360 t

16 m Tall x 9 m Wide

Boeing 747-300(Maximum Takeoff Weight)

~377 t




TF Coil & Roads (TF Coil & Roads (FosFos toto CadaracheCadarache))

Mass of (1) TF Coil:~360 t

16 m Tall x 9 m Wide

Heavy Component on Road

(TF Coils, VV Sectors, & PF1 Coil)




TF Winding Pack

TF Coil

TF Coil Winding PackTF Coil Winding Pack

Inner Leg Cross Section

Winding Pack Assembly




Conductor

China

South KoreaJapan

Russia

United States

Europe

TF Coil

JapanTF coil cases

Japan

Europe

TF Coils - A Worldwide Collaboration




ITER Magnet Field

ITER Field

~10 Tesla or 200,000 x HigherEarths Magnetic Field

~ 0.5 gauss or 0.5x10-4 Tesla






TF Conductor ProcurementTF Conductor Procurement

40 mm diameter

ITER TF Conductor

Facts

• ~90 km / 400 t of Nb3Sn conductor(The biggest Nb3Sn conductor procurement in history)

- ~150000 km of strand (15 x around Earth)- Operates at ~5 K- 11.8 T (peak TF field)

- 68 kA (peak TF current)

• Manufactured by EU, JA, RF, CN, KO, & US




TF & PF ConductorTF & PF Conductor Activities in Heifei, China

TF & PF Winding BuildingTF & PF Winding Building

Winding & Compaction MachinesWinding & Compaction MachinesJacketing LineJacketing Line

Jacketing LineJacketing Line




TF Conductor Winding FacilityTF Conductor Winding Facility -- VideoVideo




CS Coils Status

Facts

• Central Solenoid Stack – 6 independently powered modules- Nb3Sn conductor- 13 T (peak CS field)- 45 kA (peak CS current)

- ~1000 tons

• One of the big lifts during assembly!

12 m tall x 4 m dia




Terminals

Support clamps

He inlets

PoloidalPoloidal Field CoilsField Coils

Conductor

Winding

Facts• So big must be manufactured onsite!• Building is 250 m long x 45 m wide

and will be the first on site!




We need many magnets …- 18 TF coils to contain the plasma (toroidal field)

- 6 PF coils to shape plasma and control it’s position

- 6 CS coils to drive current in the plasma- 18 CC coils to correct small field perturbations

(confinement is sensitive to these perturbations)

We have big magnets to …- go around the plasma and first wall and provide high fieldover the large area of the plasma

We need superconducting magnets to …- maintain the field efficiently

We have so many big superconducting magnets because …




Why do we have both a VV and acryostat?




Vacuum Vessel & Cryostat

Cryostat

Vacuum Vessel




Vacuum Vessel Mass Comparison

VV & In-vessel components mass: ~8000 t

19.4 m outside diameter x 11.3 m tall Eiffel Tower mass: ~7300 t324 m tall

(Completed 1889)




Vacuum VesselVacuum Vessel

Facts- First safety barrier for ITER- SS 316 LN-IG

- ~5300 tons (VV, ports, shielding only)- 19.4 m (63 ft) torus outer diameter- 11.3 m (37 ft) torus height




We have both a VV and a cryostat because …

- The VV is required to …

- Provide the vacuum boundary for the plasma- Shield the magnets (4 K)

- First safety barrier

- The cryostat is required to …

- Provide thermal insulation for the magnets at 4K




What do the blanket and diverter do?

In vessel Components Blanket & Divertor




VacuumVessel

Blanket

Port Plug

Divertor

In-vessel Components – Blanket & Divertor




Blanket System

Facts• 440 blanket modules at ~4 ton each• ~40 different blanket modules

Issues

• Thermal and mechanical loads very high• Manufactured by 6 Parties• QA/QC of components (at 6 Parties)• Remote handling

Divertor System




Divertor SystemFacts

- 54 Divertor assemblies

- 4320 Heat flux elements

Issues

• Thermal and mechanical loads veryhigh• QA/QC of components (at 6 Parties)• Remote handling

In-Vessel Components Material Choice




In Vessel Components Material Choice




The blanket and diverter are needed to …

The blanket

- Provide shielding for the superconducting coils

- Provides high heat flux component to face the plasma(protect the VV)

The divertor

- Provide shielding for the superconducting coils

- Extract heat and helium ash form the plasma (allows ahigh performance plasma)






Machine Assembly

TF Coil / Sector AssemblyTF Coil / Sector Assembly

~1400 ton~1400 ton

TokamakTokamak and Assembly Buildingand Assembly Building




Machine Assembly-Video




Why is Remote Handling important?

Many Remote Handling SystemsMany Remote Handling Systems



Add the name of your meeting/conference, the location and date Page 42

Transfer CaskSystems (EU+CN)

Blanket RH System (JA)

Many Remote Handling SystemsMany Remote Handling Systems

1

2

456

7891

0

3θ

1θ

2θ

3θ

4

α

1α

2α

3

θ

5

+/- 90°+/-

100°

+/- 90°+/-

180°

0°

180°

+/-180°

+/- 90°+/- 90°0

6200mm

0

4500mm

limits

Pitch 5

10

Roll

3

9Pitch 4

8Roll

27

Pitc

h 3

6Roll

15

Pitch 2

4Pitch 1

3Translation 2

2Translation 1

1Nam

eDOF

In-Vessel

Viewing System

Multi Purpose Deployer

Cassette Toroidal MoverHot Cell RH Equipment




Remote Handling - Video

Why is the design of the ITER machine so challenging?




• Project Management – Tight schedule and budget

– Limited resources – New organization – 7 Party coordination

• Design and Procurement – Complex design, requirement,

& interfaces – Severe QA / QC requirements

– Complex procurement split – >90 procurement packages

• Superconducting magnets – Unprecedented size of the

superconducting magnets and

structures – High field performance ~12T

•Plasma facing components – >10 MW/m2 steady heat flux – >10000 cycles

•Remote maintenance (very complex)

•Vacuum and Tritium technology

– Active recycling of tritium – Test of lithium blankets

•Cryogenic technology

•Heating and current drives – ~ 100 MW continuous – Neutral particles accelerators up to 1 MeV

– Ion cyclotron, electron cyclotron

And others…




The Way to the Future…

Documents

Inside ITER