4 July 2008R. Laesser, F4E ITER Department 1 ISS and WDS facilities at FZK Looking up ISS column in vacuum jacket WDS column Water reservoirs ISS WDS ISS

4 July 2008 R. Laesser, F4E ITER Department 1

ISS and WDS facilities at FZK

Looking up ISS column Looking up ISS column in vacuum jacketin vacuum jacket

WDS column

Water reservoirs

ISSWDS

ISS refrigerator, cold boxISS refrigerator, cold box

Simplified schematic of


12

m L

PC

E

Emergency tanks

Electrolyser

Tanks for H (>100Ci/kg), M, L, LL (<1.6 µCi/kg) level water

O2 gas processing:

• MS dryers

• Wet strippers

Water Detritiation System (EU)

Purpose of Water Detritiation System: To use the CECE (Combined Electrolysis Catalytic Exchange) for detritiation of water (20 kg/h@10 Ci/kg) via

• cracking water into hydrogen and oxygen,

• stripping the residual tritium from the hydrogen before its release.

The tritium is returned to the FC via ISS.

Several potential sources of tritiated water exist in ITER. The largest routine contributors to the WDS feed streams are the Atmosphere and Vent Detritiation Systems.


A few topics addressed in Working Group 7 A few topics addressed in Working Group 7 (Tritium Plant) during the ITER Design Review(Tritium Plant) during the ITER Design Review

Tritium Building Layout

Modification of HVAC, ADS and VDS

Tritium Tracking Strategy


Tritium Building Layout

New building layout required due to French law for • Compartmentalization (segregation of tritium inventories),• Fire zoning,• Too long escape routes,• Missing air locks,• Etc.


Generic Site Tritium Plant Building Layout (ITER FDR 2001)Generic Site Tritium Plant Building Layout (ITER FDR 2001)

Dimensions

Length: 79 mWidth: 20 mHeight: 34 m

Outdated design:

New regulations: • Escape routes not clear

and too long. • Airlocks not included

consistently. • HVAC to be changed.

Increase of width and length.

Stairways: 2 3

Elevator: 0 1

12/29


New Tritium Plant Building Layout: French RulesNew Tritium Plant Building Layout: French Rules• Tritium inventory segregation requires

rearrangement and even splitting of primary systems (SDS SDS1+2).

• WDS and ISS now next to each other.• Vacuum pumps: B1 L1.• Confinement sector / fire sector

basically on floor by floor basis-700 g700 g in a “confinement / fire sector”

• Physical limitation wherever possible

-70 g70 g in a single “fire zone” (component)• Physical limitation wherever possible

– Storage and Delivery System (SDS) & Long Term Storage (LTS) getter beds

• Isotope Separation System (ISS, 250g > 70 g) impossible to subdivide, requires additional protection against loss of primary confinement (fire)

13/29

Dow

n

Up

Dow

n

Up

6m

Passage

233 sq m

Passage

27 sq m

Passage

27 sq m

Up

TA TB TC TD TE TF TG TH TI TJ

T12

T13

T14

T15

WDS & ISS

TEPSDS 1

SDS 2

Ele

ctri

cal

Ro

om

Local Monitoring&Control

Room

B1B1

VPS: Vacuum Pumping System, CPS: Coolant Purification System


Modification of HVAC, ADS and VDSModification of HVAC, ADS and VDS

Complexity of HVAC and confinement systems for ITER Tokamak Complex grew over years:

• Overall configuration became very complex,• Concept of 90% HVAC air recycle considered to be

unworkable: human access restricted due to limited fresh air throughput of HVAC systems),

• Danger of cross contamination


S-ADS

VacuumVessel

S-VDS

Tritium plantArea I

VacuumVessel

Tritium plantArea II

Tritium plantArea II

Tritium plantArea I

Back-upNVDS 1

Back-upNVDS 2

PortCell

N-VDS-2

Other

VacuumVessel(VV)

Vault

VV PressureSupression

System

N-VDS-1

TestBlanketModule

Glove boxDetritiation

System

TokamakExhaust

ProcessingOther

HVAC 2

HVAC I

HVAC II

Depression I

Depression II

Tokamak building Tritium plantRelease

Point

PortPlug

NeutralBeam

WaterDetritiation

System LocalAir Coolers

HVAC 1

Depression 1

Gallery

Gallery

15/29

Generic ITER HVAC, Depression and Detritiation Systems Configuration:


ITER Detritiation System Block Diagram

17/29

ITER Detritiation System Block Diagram


Wet Stripping Column for Tritiated Water Removal

Counter current removal by exchange oftritiated water in a wet stripping column– Diameter about 0.7 m, length about 5 m

• Throughput about 1500 m3h-1

– No regeneration cycles as formolecular sieve beds

• Less complicated configurationand number of valves

• No dryer system required• 1 column instead of 3 molecular sieve beds• Potential cost savings

– Capital costs / operational costs

– R&D ongoing at Mendeleyev University, Moscow

– Pilot plant tests scheduled later in Japan

18/29

fresh water(liquid)

detritiated air(saturated) to

releasepoint

air / tritiatedwater vapor

tritiated water

to ITERWDS

packing

HTOV + H2OL H2OV + HTOL

H2OL

Air+HTOV HTOL

Air+H2OV

15 kg H2OL


ITER Ventilation and Confinement Concept

Primary confinement can include more than one barrier

• Glove box (GB) for maintenance purposes.

• GB atmosphere detritiation.

Secondary confinement comprises sub-atmospheric pressure control and atmosphere detritiation

Surrounding Containment(Glove Box)

PrimarySystem

PrimarySystem

Surrounding Containment(Glove Box)

ISS

Glove BoxDetritiation System

(GDS)

Building sector Building sector/Tritium spill

VentDetritiation

AtmosphereDetritiation

HVAC supplyFresh Air

ISS cold box

HVAC exhaust

Release point

Secondary Confinement

Primary Confinement

16/29

TEPISS



• Tritium inventory in Mass Balance Areas (MBA-1 for FC, MBA-2 for LTS) must be known.

• Tritium transfer between MBAs must be measured.• Accountancy techniques:

o pVT-c (gas)o Calorimetry (gas and metal tritides)o Scintillation (gas and liquid)


Tritium Inventory at any Selected TimeTritium Inventory at any Selected Time

Assume monthly checking.

Tn = Tn-1 - TBu - TD - TL + TI + TBr

• Tn-1: total tritium inventory of previous month • TBu: tritium burned • TD: tritium lost by decay • TL: tritium leaving plant in effluent streams: negligible under normal

operation• TI: tritium imported • TBr: the tritium bred: negligible

Burnrate = 5.90 10-07 mole T/s per MWF. T burned/pulse = 0.35 g 7 g/day for 20 short pulse (450 s)In 10 years: external tritium supply: total of 6.7 kg. Total amount burnt: 4.3

kg



exexininn TMTMT The tritium inventory at ITER site in MBA-1 can be divided in four parts:

Min: tritium mobile in-vessel; Tin: tritium trapped in-vessel; Mex: tritium mobile ex-vessel; Tex: tritium trapped ex-vessel.

Global tritium inventory procedure will assess these categories• Mobile tritium external to Vacuum Vessel will be collected in SDS beds and measured.• Tritium trapped ex-vessel will be estimated/calculated. • After stop of plasma operation, mobile in-vessel tritium will be removed via wall

conditioning, baking, etc., transferred via TEP and ISS to SDS and measured by in-bed calorimetry.

Tritium Tin trapped in-vessel after cleaning is computed by difference using calculated Tn value.

Approximately 10 days were found to be needed for the global tritium inventory procedure.Tritium tracking accuracy will also depend on the accuracy of the tritium amounts

• Known to be in the in-vessel components moved to Hot cell.• Burnt in fusion reactions (to be determined by diagnostics)


Comments to Tritium Tracking

High uncertainty in daily tritium measurements will limit significantly the availability of ITER.

The most important error is related to the measurement of fusion power needed to calculate the amount of tritium burnt.

2 calorimeters in the LTS will reduce the error on the imported tritium with possibility of eliminating systematic errors in these measurement (theory of combining measurements).

The main factor that determines the errors in tritium inventories is the analytics employed:

– Integral measurements should always be preferred,– Calorimetry is by far the most accurate method for tritium inventory

measurements (0.5% accuracy).

Ex-situ measurements of the tritium trapped in removed in-vessel materials should help in the evaluation of the total tritium trapped in-vessel and reassessing this value.

Vacuum vessel in-situ sampling techniques might be even better, but will they be available?


Tritium in Plasma Facing Components

JET experience clearly demonstrated that high amounts of fuel (deuterium and tritium) are trapped in co-deposited layers with large ratios of D and T over C ((D+T)/C), especially in the shadowed areas of the machine.

Extrapolation to ITER conditions indicates that in ITER the administrative limits for recovery of tritium would be reached after a very limited number of shots.

In conclusion: Carbon during DT phases in ITER must be avoided.

Even in a Be/W environment the number of plasma shots will be limited, however far higher. Tritium inventories and dust production will remain critical issues.

An all metal first wall (no carbon) is also a very positive development for the ITER Tritium Plant as the hydrocarbons will become an impurity category of minor importance.


Updated projections of Canadian + Korean tritium supply and consumption using ITER current schedule. (from Scott Willms [March 2007]).

This slide was presented by Prof. M. Abdou in the presentation “Fusion Nuclear Technology Development and the Role of CTF (and ITER TBM)” at the Workshop on CTF, Culham, U.K., 22-23 May 2007.

Canadian + Korean Inventory with ITER

Canadian + Korean Inventory without supply to fusion

Tritium Tritium supply supply and and consumpconsump-tion -tion during during life of life of ITERITER


Test Blanket Modules (TBMs) in ITER

In the present European fusion program ITER is the only interim step to check the performance of future breeding blankets by means of

DEMO relevant Test Blanket Modules (TBMs) in a fusion environment prior to their use in DEMO.

ITER device is a test facility for the TBMs.


2 EU blanket concepts (HCLL and HCPB BBs) will be tested in ITER.

4 TBMs per concept, each dedicated to one of the major ITER operational phases (H-H, D-D, low D-T and high D-T), will be fabricated and tested during the first 10 years of ITER operation.

Auxiliary systems: He purge and tritium extraction systems, Helium Coolant System (HCS) and Coolant Purification System (CPS) are required.

EU TBMs shall be ready from first day of ITER operation.

Installation and Testing of TBMs in ITER

Coolant: Helium at 300-500°C, 8 MPa

Structural Material

Reduced Activation Ferritic-Martensitic steel: EUROFER

Breeder Material

i) Li4SiO4 / Li2TiO3 (pebble beds)

ii) Pb-15.7at% Li (liquid metal)

ITER Test Port (Equatorial

plane)

EU TBMsFZK FZK

CEA CEA


Tritium Processing in TBMsTritium Processing in TBMs

Although very small, the amount of tritium bred in TBMs needs to be extracted, recovered and transferred into the inner DT-fuel cycle, with the main aim of:

• validating the theoretical predictions on tritium breeding,

• qualifying technologies and components for tritium processing,

• validating the theoretical predictions on tritium recovery performance and tritium inventory in the functional/structural materials.


Integration of TBM in the ITER Fuel Cycle

TEP: Tokamak Exhaust ProcessingHCS: Helium Cooling SystemTES: Tritium Extraction SystemCPS: Coolant Purification SystemVDS: Vent Detritiation SystemWDS: Water Detritiation SystemISS: Isotope Separation System

* High duty DT phase; 1.16E-6 g/s of T produced in HCPB-TBM

TBMISS

CPS

TES

HCS

to T storage and delivery (SDS)

TEPQ2

WDSVDS

ac

count

ancy

Q2O

33 mg/d HT*257 g/d H2

1.3 mg/d HT1.9 g/d H2

Off-gas release

He: 1.4 kg/s

He: 0.4 g/s

He: 0.35 g/s

He: 0.4 g/s


Conceptual Design of TES for HCPB-TBM

mol. sievebeds (TSA)

U-getter

mol. sieve bed

Main components- Adsorption column for Q2O removal operates at RT in adsorption phase- Two bed TSA system for Q2 removal

- U metal getter as scavenger bed in a by-pass line to be used mainly in the low duty DT phase

HCPBTBM


Conceptual Design of CPS for HCPB-TBMThree Step Process

1) oxidation of Q2 to Q2O and of CO to CO2 by an oxidising reactor (Cu2O-CuO) operated at 280°C;

2) removal of Q2O by two bed PTSA operated at RT and 8 MPa and at 300°C and 0.1 MPa in regeneration;

3) removal of the impurities in HCS by a two-bed cryogenic PTSA

No Q2O is released from CPS to TEP (or VDS) because of the presence of metallic reducing beds in the PTSA regeneration loop

cryo-mol. sievebeds (PTSA), step 3

mol. sieve bed (PTSA), step 2

cat. ox., step 1


Tritium Processing in DEMOTritium Processing in DEMO

DEMO relies on enough tritium production in breeding blankets (Tritium Breeding Ratio

(TBR): >1.0)


The DEMO Fuel Cycle: A few Numbers

In ITER DT fuel flow rates: 120 Pam3/s (up to 200 Pam3/s.

In DEMO, despite the 7 times larger power than in ITER, only slightly higher feed flow rates are expected due to the better burn-up efficiency.

In DEMO: o ~35 kg tritium per day to

be supplied for plasma operation

o ~500 g of tritium burnt per day

o ~550 g of tritium bred in the BBs (TBR=1.1) per day

o 50 g of tritium can be added to the long-term storage each day

ITER DEMO

Fusion power 0.5 GW 3.7 GW

Electrical power -- 1.5 GWel

Tritium burn-up 72 g/d 500 g/d

Burn-up efficiency 0.5 % 1.5 %

Tritium throughput 3.5 kg/d ~35 kg/d

DT feed flow rate 120 Pam3/s ~300 Pam3/s

Tritium inventories in different

subsystems of ITER and DEMO

< 4 kg in FC

< 1 kg in inner loop

< 1 kg in SDS

< 1 kg in vessel

< 1 kg in HC

< 5 kg in FC

< 1 kg in inner loop

< 4 kg in SDS

< 1 kg in vessel

< < 1 kg in HC

Tritium bred in ITER TBMs and in

DEMO BBs25 mg/d ~550 g/d


Simplified block diagram of DEMO Fuel Cycle

Main changes with respect to ITER inner Fuel Cycle: main Q2 bypasses ISS and SDS. No WDS in inner FC (all HTO treated in BB Tritium collection loop. No cryopumps (with exception of NBI) shown (needs to be assessed). BB tritium recovery systems will be discussed later.

External T needed for start

D from external sources

Storage and Delivery System (SDS)

Protium

Release

Tritiated Water

Analytical System (ANS)

Isotope Separation System (ISS)

Tokamak Exhaust Processing (TEP)

Release of detritiated gas via VDSs, HTO of

VDSs to BB WDSTritium Plant

Fuelling Systems (FS): Pellet Injection, Gas Puf.

DEMO

Torus

Neutral Beam Injection (NBI), Cryo Pumps

Breeding Blanket Tritium Recovery Syst.

Roughing Pumps (RP)

Leak detection system

BB

WDSBB tritium recovery syst.

Q2

DT


Main Parts of Inner D/T DEMO Fuel Cycle

DEMO Cryopumps: If higher pressures in the DEMO divertor can be tolerated, the cryopumps could be replaced by mechanical (Roots) pumps with the benefits of continuous vacuum operation (lower inventories, smaller cryoplant). To be assessed.

DEMO Impurity Processing System: will be similar to ITER TEP, however smaller. o The Q2 permeated through the first stage of TEP will be transferred directly to

the Fuelling System bypassing ISS and SDS. o The Q2 gases from the second and third stages of TEP will be sent to ISS and

after isotope enrichment to SDS.

DEMO Isotope Separation System (ISS): o DEMO ISS of inner loop will be smaller than in ITER ISS as most of the recycled

Q2 will bypass ISS. o Due to the lower throughput and lower inventories it should be possible to

produce pure H2, D2 and T2 gases. In this way isotopic composition changes of gas mixtures during delivery from metal tritide storage beds will be avoided.

DEMO Storage and Delivery System: The tritium and deuterium storage beds could be very similar to the ones of ITER (designed for in-situ calorimetry and high supply rates).

DEMO Analytical System: will serve the inner and the BB loop.

DEMO Fuelling Systems: similar in design as in ITER (wait for ITER experience).

The inner DEMO fuel Cycle loop may not need a Water Detritiation System (WDS). All water created there can be treated in the WDS of the BB loops.


Simplified Block Diagram for the Blanket Tritium Processing in DEMOSimplified Block Diagram for the Blanket Tritium Processing in DEMO

BB WDS

DEMO BlanketPth= 3.0 GW

GT= 385 g/d

CPS η=0.9

TES η=0.9

HCS

He+(Q2+Q2O)2400 kg/s, 8 MPa Tin 300ºCTout 500ºC

He + (Q2 + Q2O)2.4 kg/s, 8 MPa, Q2 = 1000 Pa; HT = 0.8 Pa Q2O = 50 Pa

Q2O 122 kg/d

1100 Ci/kg

He + Q2 + Q2O2.4 kg/s, 8 MPa, H2 = 1000 Pa; HT = 0.08 PaH2O = 50 Pa

He + (Q2 + Q2O)0.4 kg/s, 0.11 MPaQ2 = 110 Pa; HT = 1.6 Pa Q2O = 1.6 Pa

He + (Q2 + Q2O)0.4 kg/s, 0.11 MPaQ2 = 110 Pa; HT = 016 Pa Q2O = 0.16 Pa

Tritiated impurities

Q2O 2 kg/d

49500 Ci/kg

Q2 17.1 kg/d

HT: 202000 Ci/kg

Tperm= 15 g/d

Main subsystems of Main subsystems of breeding blanket breeding blanket tritium recovery tritium recovery loops in DEMO:loops in DEMO:

• Collection of HTO

• Collection of HT

• Processing of highly tritiated HTO

• ISS, WDS and TEP

BB TEP

BB TEP

BB ISS


ENDEND

AcknowledgementsAcknowledgements

Many thanks to the colleagues and principal investigators in the Associations and Industry who contributed to the

development of the DT Fuel Cycle.

Thanks to the contributors to this presentation, in particular: M. Abdou, N. Bekris, I. Cristescu, I.R. Cristescu, Ch. Day, M.

Glugla, S. Grünhagen, D. Murdoch, G. Piazza, Y. Poitevin and I. Ricapito.

Documents

4 July 2008R. Laesser, F4E ITER Department 1 ISS and WDS facilities at FZK Looking up ISS column in vacuum jacket WDS column Water reservoirs ISS WDS ISS