EFDA EUROPEAN FUSION DEVELOPMENT AGREEMENT EFDA CSU Garching S.Ciattaglia, page 1/25 OVERVIEW OF...
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Transcript of EFDA EUROPEAN FUSION DEVELOPMENT AGREEMENT EFDA CSU Garching S.Ciattaglia, page 1/25 OVERVIEW OF...
EFDA CSU Garching S.Ciattaglia, page 1/25
EFDA EUROPEAN FUSION DEVELOPMENT AGREEMENT
OVERVIEW OF SAFETY OF EUROPEAN FUSION POWER PLANT DESIGNS
Annual Meeting on
Nuclear Technology
May 10 - 12, 2005
Nuremberg
S.Ciattaglia, aL.Di Pace, W.Gulden, P.Sardain, bN.Taylor
EFDA Close Support Unit, S&E Field, Garching GermanyaENEA Fusion Technologies, Frascati (Rome), Italy
bEuratom/UKAEA Fusion Association, Culham Science Centre, Abingdon, UK
EFDA CSU Garching S.Ciattaglia, page 2/25
EFDA EUROPEAN FUSION DEVELOPMENT AGREEMENT
Outline
•Introduction
•Power Plant Conceptual Studies
•Safety analysis
•Environmental impact
•Radioactive wastes
•Achievements and open points
•Conclusions
EFDA CSU Garching S.Ciattaglia, page 3/25
EFDA EUROPEAN FUSION DEVELOPMENT AGREEMENT
Introduction
From 1990 to 2000 a series of studies on safety, environmental and economic potential of fusion power
• potential to provide inherent safety and favourable environmental features, to address global climate change and gain public acceptance
• the cost of fusion electricity likely to be comparable with that from other environmentally responsible sources of electricity generation
Further progress on experiments and R&D• Substantial advances in the understanding of fusion plasma physics
and in the development of more favourable plasma operating regimes, • Progress in the development of materials and technology.
EFDA CSU Garching S.Ciattaglia, page 4/25
EFDA EUROPEAN FUSION DEVELOPMENT AGREEMENT
Introduction (2)
PPCS (Power Plant Conceptual Studies)• A comprehensive design study for commercial fusion power plants
performed from mid 2001 to mid 2004, to serve as a better guide for the further evolution of the fusion development programme.
• Focussed on four (+1) power plant models, named PPCS A to PPCS D plus model AB, spanning a range from relatively near-term concepts, based on limited technology and plasma physics extrapolations, to a more advanced conception.
• They differ from one another in their size, fusion power and materials compositions, and these differences lead to differences in economic performance and in the details of safety and environmental impacts.
• The study was carried out with the help of a large number of experts from both the European fusion research community and its industrial partners.
EFDA CSU Garching S.Ciattaglia, page 5/25
EFDA EUROPEAN FUSION DEVELOPMENT AGREEMENT
Power Plant Conceptual Studies
Objectives
• Demonstration of:• Credibility of fusion power plant design• Safety and environmental advantages of fusions power• Economic viability of fusion power
• Set of requirements issued by industry and utilities• Safety• Operational aspects• Economic aspects
• Economic safety and environmental analyses of these models were made
EFDA CSU Garching S.Ciattaglia, page 6/25
EFDA EUROPEAN FUSION DEVELOPMENT AGREEMENT
Schematic diagram of a tokamak fusion power plant
Breeding Blanket
Poloidal Field Coil
Toroidal Field Coil
Power Conversion System
Supply Electric Power to the Grid
Heating &Current drive
IsotopeSeparation
PumpingD+T+ashes
Breeding Blanket
Poloidal Field Coil
Toroidal Field Coil
Power Conversion System
Supply Electric Power to the Grid
Heating &Current drive
IsotopeSeparation
PumpingD+T+ashes
Vacuum
Vessel
EFDA CSU Garching S.Ciattaglia, page 7/25
EFDA EUROPEAN FUSION DEVELOPMENT AGREEMENT
General layout
EFDA CSU Garching S.Ciattaglia, page 8/25
EFDA EUROPEAN FUSION DEVELOPMENT AGREEMENT
Key parameters
• 1500 MWe
• Fusion power is determined by efficiency, energy multiplication and current drive power
• Given the fusion power, plasma size mainly driven by divertor considerations
EFDA CSU Garching S.Ciattaglia, page 9/25
EFDA EUROPEAN FUSION DEVELOPMENT AGREEMENT
PPCS main elements
• All the models PPCS A to D are based on the tokamak concept as the main line of fusion development proceeding through JET, the world’s largest and most advanced operating machine, that is provides the basis for the plasma physics of ITER, under design finalisation.
• Two main elements:
• Blanket:
• Takes the energy of the energetic neutrons produced by the fusion process
• Neutrons absorbed by Li atoms to produce the fuel, tritium.
• Divertor
• for exhausting from the plasma chamber the fusion reaction products, mainly helium, and the associated heat power
EFDA CSU Garching S.Ciattaglia, page 10/25
EFDA EUROPEAN FUSION DEVELOPMENT AGREEMENT
Plants main features
Model A Model B Model C Model D
Fusion Power (GW) 5.0 3.6 3.4 2.5
Blanket Gain 1.18 1.39 1.17 1.17
Plant Efficiency 0.31 0.36 0.44 0.6
Bootstrap Fraction 0.45 0.43 0.63 0.76
Padd (MW) 246 270 112 71
H&CD Efficiency 0.6 0.6 0.7 0.7
DV Peak load (MW.m-2) 15 10 10 5
Average neutron wall load 2.2 2.0 2.2 2.4
Major Radius (m) 9.55 8.6 7.5 6.1
Structural material Eurofer Eurofer Eurofer SiC/SiC
Coolant Water Helium LiPb/Helium LiPb
Breeder LiPb Li4SiO4 LiPb LiPb
TBR 1.06 1.12 1.15 1.12
Structural material CuCrZr W alloy W alloy SiC/SiC
Armour material W alloy W alloy W alloy W alloy
Coolant Water Helium Helium LiPb
Conversion Cycle Rankine Rankine Brayton Brayton
Bla
nke
tD
V
EFDA CSU Garching S.Ciattaglia, page 11/25
EFDA EUROPEAN FUSION DEVELOPMENT AGREEMENT
PPCS A and PPCS B
• Limited extrapolations in plasma physics performance compared to the design basis of ITER.
• Blankets• based, respectively, on the “water-cooled lithium-lead” and the “helium-cooled
pebble bed” concepts, using of a low-activation martensitic steel
• Divertors• water-cooled divertor is an extrapolation of the ITER design and uses the
same materials. • helium-cooled divertor, operating at much higher temperature, requires the
development of a tungsten alloy as structural material. • Balance of plant
• model A based on PWR technology, which is fully qualified• model B relies on the technology of helium cooling, the industrial development
of which is starting now, in order to achieve a higher coolant temperature and a higher thermodynamic efficiency of the power conversion system
EFDA CSU Garching S.Ciattaglia, page 12/25
EFDA EUROPEAN FUSION DEVELOPMENT AGREEMENT
Model A
BlanketEurofer as structural materialWater as coolant LiPb as breeder and neutron multiplier
OutboardModulea 20˚ sector
EFDA CSU Garching S.Ciattaglia, page 13/25
EFDA EUROPEAN FUSION DEVELOPMENT AGREEMENT
Model A: Water-cooled Divertor
High temperature Dv Low temperature Dv
EFDA CSU Garching S.Ciattaglia, page 14/25
EFDA EUROPEAN FUSION DEVELOPMENT AGREEMENT
Model B: He-cooled divertor
Divertor concept using helium as coolant and W as structural material Peak load of 10 MW/m2 necessity to optimize the heat exchange
EFDA CSU Garching S.Ciattaglia, page 15/25
EFDA EUROPEAN FUSION DEVELOPMENT AGREEMENT
PPCS Models C and D
• PPCS C and D are based on successively more advanced concepts in plasma configuration and in materials technology
• The objective is to achieve even higher operating temperatures and efficiencies
• Their technology stems, respectively, from a “dual-coolant” blanket concept (helium and lithium-lead coolants with steel structures and silicon carbide insulators) and a “self-cooled” blanket concept (lithium-lead coolant with a silicon carbide structure)
• In PPCS C the divertor is the same concept as for model B• In PPCS D, the divertor is cooled with lithium-lead like the blanket. This
allows the pumping power for the coolant to be minimised and the balance of plant to be simplified.
EFDA CSU Garching S.Ciattaglia, page 16/25
EFDA EUROPEAN FUSION DEVELOPMENT AGREEMENT
Model C : DC Blanket Scheme and main Features
EFDA CSU Garching S.Ciattaglia, page 17/25
EFDA EUROPEAN FUSION DEVELOPMENT AGREEMENT
EU Fusion Programme development needs
• ITER operation• optimisation of low activation martensitic steels, • development of tungsten alloys, and their testing in IFMIF, as armour
material• development of the more advanced materials envisaged in the PPCS• development of blanket modules, to be tested in ITER• development of divertor systems, capable of combining high heat flux
tolerance and high temperature operation with sufficient lifetime in power plant conditions
• development and qualification of maintenance procedures by remote handling
• A DEMO power plant study has been lunched: a study to give guidance to the ITER-accompanying programme in plasma physics and technology
EFDA CSU Garching S.Ciattaglia, page 18/25
EFDA EUROPEAN FUSION DEVELOPMENT AGREEMENT
PPCS Safety analysis
• Aim• Critical design review and relevant recommendations in order to• Demonstrate that no design-basis accident and no internally
generated accident will constitute a major hazard to the population
outside the plant perimeter, e.g. requiring evacuation.
• Technique adopted
• Functional Failure Mode and Effects Analysis methodology to find out
representative accident initiators• a plant functional breakdown for the main systems. • a FFMEA for each lower level function
• Two design-basis accidents and two beyond design basis accidents
chosen and analysed in detailed for both Plant Model A and B
EFDA CSU Garching S.Ciattaglia, page 19/25
EFDA EUROPEAN FUSION DEVELOPMENT AGREEMENT
Safety analysis (2)
• Fusion Reactors will produce and contain radioactive materials that require careful management both during the operation (avoiding release in normal and accident conditions) and after decommissioning
• Main radioactive mobilisable inventories• tritium in the in-vessel components and in the fuel cycle• activated materials (dust originating from plasma-PFC interaction and
corrosion products)
• Energies that can mobilise the above inventories during accident conditions• decay heat• electromagnetic energy• chemical energy
EFDA CSU Garching S.Ciattaglia, page 20/25
EFDA EUROPEAN FUSION DEVELOPMENT AGREEMENT
SOURCE TERMS
ASSESSMENT
Normal working conditions Occupational dose
PIERASBAS
Thermodynamic transients Aerosols and H3 transport
Containments Release from the plant DCF
Overall Plant AnalysisFMEA
Radioactive waste Identification&classificationOperational&Decomm waste
Management•On-site•Recycling•Final disosal
Effluents
PST
PST EST
DCF
man*Sv/y
dose/sequence to MEI
frequency*dose
Quantity and waste categories
mSv/y
General fusion safety analysis approach
EFDA CSU Garching S.Ciattaglia, page 21/25
EFDA EUROPEAN FUSION DEVELOPMENT AGREEMENT
PPCS safety analysis has benefited by the main conclusions of ITER safety analysis
• A comprehensive analysis of off-normal events and failures and combination of failures
postulated to critically verify the design • Source Terms: 1 Kg of tritium, 100 Kg of Be and W dust, 200 Kg of carbon dust• ORE design target: < 0.5 person Sv/y• Energies definition: magnetic, • Protection/Mitigation systems definition (VV suppression tank, plasma shutdown, HVAC
systems and capability of dust and tritium filtering• Low decay heat at shutdown (360 ºC is PFC Tmax after 9hr from the plasma shutdown in case
of LOCA in-vessel)• Radioactive releases for all accident events below the project release guidelines (relevant doses
~ average annual natural background dose) • Hypothetical events (all cooling systems or common cause failure damaging both vacuum vessel
and cryostat): no evacuation, (<50 mSv). PFC Tmax ~ 650 ºC
Safety analysis (4)
EFDA CSU Garching S.Ciattaglia, page 22/25
EFDA EUROPEAN FUSION DEVELOPMENT AGREEMENT
• PPCS source terms
• Energies• Decay heat• Magnetic
• Activation
• ORE
• ?• Sarebbe dadare di dati/assunzinifate
Safety analysis (4)
EFDA CSU Garching S.Ciattaglia, page 23/25
EFDA EUROPEAN FUSION DEVELOPMENT AGREEMENT
• Bounding accident sequences: complete unmitigated loss of cooling; no safety systems operation; conservative modelling.
• Temperature transients: example opposite - Model A after ten days.
• Maximum temperatures never approach structural degradation.
Safety Analysis (5)
EFDA CSU Garching S.Ciattaglia, page 24/25
EFDA EUROPEAN FUSION DEVELOPMENT AGREEMENT
Bounding Temperature Accident Analysis
Plant Model A
Plant Model B
T
T
EFDA CSU Garching S.Ciattaglia, page 25/25
EFDA EUROPEAN FUSION DEVELOPMENT AGREEMENT
Specific activity of the mid-plane outboard
first wall in four Plant Models
Activation of tokamak structures and components
EFDA CSU Garching S.Ciattaglia, page 26/25
EFDA EUROPEAN FUSION DEVELOPMENT AGREEMENT
Safety Analysis (7)
The most challenging scenario in terms of environmental release:
“Loss of flow in one primary cooling loop with consequential in-vessel LOCA (Model B)”.
• Parametric analyses on the building leakage rate from Expansion Volume;
• Possibility to operate an Emergency Detritiation System to reduce environmental releases
EFDA CSU Garching S.Ciattaglia, page 27/25
EFDA EUROPEAN FUSION DEVELOPMENT AGREEMENT
Safety Analysis - Model B Loss of flow in one primary cooling loop with consequential in-vessel
LOCA
Reference building leakage rates Pressure inside VV, EV and PS
Complete mobilisation of 10 kg of dust &1 kg-T in the VV.
Elevated environmental releases due to building leakage rate considered: (75%/d); 58 g-T, 109 g of W, 346 g of SS dusts.
Parametric analyses• Lower leakage rates: 1%, 10%; • One cylindrical (H= 40.0 m; D= 46.0 m) concrete structure surrounding the
EV, and having a thickness of 0.4 m, externally insulated.
ECART results
EFDA CSU Garching S.Ciattaglia, page 28/25
EFDA EUROPEAN FUSION DEVELOPMENT AGREEMENT
Environmental Impact (1)
• Environmental source terms• activated dust/ corrosion products• tritium
• During normal operation• negligible release (doses to the most exposed individual less than 1%
of the natural background level),• ALARA principle is applied for public and workers
• No emission of any of the greenhouse gases
• Conservatively assumed
• a mobilisation fraction of 100 % for the dust at the beginning of the
accident sequence,
• 90% as HTO for T
• worst atmosphere conditions
EFDA CSU Garching S.Ciattaglia, page 29/25
EFDA EUROPEAN FUSION DEVELOPMENT AGREEMENT
Model B• Ex-vessel LOCA + in-vessel LOCA (Containment response and environm. release)
Total dust deposited
Total dust airborne
VV
TCHS
Dust in compart. T in the compart.Dust to the Env.
0.2 g
0.6 g
24 h
24 h
For 7-day T release assume a linear release with the slope of 1•10-8 kg/s. At 7 days T released = 5.4 g.
T to the Env.
EFDA CSU Garching S.Ciattaglia, page 30/25
EFDA EUROPEAN FUSION DEVELOPMENT AGREEMENT
Model A ex-vessel LOCA results
Pressure in TCWS vault, ST and DT
TCWSST
DT
7-day ACP release <1 mg
7-day T release <3 mg
ACP
T
EFDA CSU Garching S.Ciattaglia, page 31/25
EFDA EUROPEAN FUSION DEVELOPMENT AGREEMENT
Bounding accident sequences for Models A and B: complete unmitigated loss of cooling; no safety systems operation; conservative modelling
Mobilisation; transport within the plant; release and transport in environment; leading to:
Conservatively calculated worst case doses to the MEI from worst case accident:
MODEL A: 1.2 mSv MODEL B: 18.1 mSv
Comparable with typical annual doses from natural background.
Model C and Model D worst case doses (analyses undergoing) expected to be lower (abbiamo dei risultati???)
Environmental Impact (4)
EFDA CSU Garching S.Ciattaglia, page 32/25
EFDA EUROPEAN FUSION DEVELOPMENT AGREEMENT
Radioactive Wastes (1)
The fusion radioactive waste is characterised by low heat generation density and low radiotoxicity compared to fission plant waste. Therefore recycling may be a viable option.
Storing the fusion radioactive materials for 50-100 years on the plant allows reduction of radioactivity level waste masses
Table 2 – Classification of fusion radioactive waste.
Activated material classifications Contact dose
rate after 50 y
(mSvh-1)
Decay heat per
unit volume after
50 y (Wm-3)
Clearance
index after 50 y
[5]
PDW, Permanent Disposal Waste (Not
recyclable)
>20 >10 >1
CRM, Complex Recycle Material 2-20 1-10 >1
SRM, Simple Recycle Material <2 <1 >1
NAW, Non Active Waste (to be cleared) <1
EFDA CSU Garching S.Ciattaglia, page 33/25
EFDA EUROPEAN FUSION DEVELOPMENT AGREEMENT
For ALL the Models:
Activation falls rapidly: by a factor 10,000 after a hundred years
Significant contribution to SRM and CRM from operational wastes
Potentiality to have no waste for permanent repository disposal
Also tritiated + activated wastes
Wastes from model B
Radioactive Wastes (2)
EFDA CSU Garching S.Ciattaglia, page 34/25
EFDA EUROPEAN FUSION DEVELOPMENT AGREEMENT
NAWSMR
CMRPDW
D
C
BA
0
10,000
20,000
30,000
40,000
50,000
60,000
70,000
80,000
90,000
Tonnes
Radioactive material category
Power Plant model
Figure 2 - Masses of the material after 100 years decay
D
C
B
A
Radioactive Wastes (3)
EFDA CSU Garching S.Ciattaglia, page 35/25
EFDA EUROPEAN FUSION DEVELOPMENT AGREEMENT
NAWSMR
CMRPDW
D
C
BA
0
10,000
20,000
30,000
40,000
50,000
60,000
70,000
80,000
90,000
Tonnes
Radioactive material category
Power Plant model
Figure 1 - Masses of material after 50 years decay
D
C
B
A
Radioactive Wastes (4)
EFDA CSU Garching S.Ciattaglia, page 36/25
EFDA EUROPEAN FUSION DEVELOPMENT AGREEMENT
Radioactive Wastes (5)
If no recycling is planned
• the amount of waste to be disposed after 100 years, is equal to the CRM+SRM amounts. They don’t require a deep geological repository.
• Suitability and capability analyses of the final waste repositories in a few EU countries to store the PPCS wastes are undergoing (Konrad and Gorleben in Germany, SFR and SFL 3-5 in Sweden, CSA in France, El Cabril and DGR in Spain).
• First results, limited to Model B and German conditions, indicate that the fusion reactor waste can be al disposed in Konrad. For a few ones, detritiation is necessary to meet the relevant limits
EFDA CSU Garching S.Ciattaglia, page 37/25
EFDA EUROPEAN FUSION DEVELOPMENT AGREEMENT
Achievements and open points
Comprehensive safety analysis of PPCS has showed• “No evacuation” criteria met with margin also in case of severe
accidents (bounding accidents analysis and consequences)• Intrinsic-passive safety features of nuclear fusion plants confirmed
• Lack of operating experience• Reliability of prototypes • PFCs erosion/deposition and transport in SOL• Tritium retention and distribution in the tokamak • Detritiation techniques• ORE minimisation
• Quantity of operational waste• Tritiated + waste disposal
EFDA CSU Garching S.Ciattaglia, page 38/25
EFDA EUROPEAN FUSION DEVELOPMENT AGREEMENT
Conclusions (1)
• The four PPCS conceptual design for commercial fusion power plants
differ in their dimensions, gross power, and power density
• All models meet the overall objectives of the PPCS (design, safety,
economics)
• Plasma performance only marginally better than the design basis
of ITER is sufficient for economic viability of fusion reactors
• Conceptual design of a helium-cooled divertor capable of
tolerating a peak heat load of 10 MW/m2
• Definition of a maintenance concept capable of delivering high
availability (75%)
• A first commercial fusion power plant - accessible by a “fast track”
route of fusion development - will be economically acceptable,
with major safety and environmental advantages
EFDA CSU Garching S.Ciattaglia, page 39/25
EFDA EUROPEAN FUSION DEVELOPMENT AGREEMENT
Conclusions (2)
• R&D is needed• Materials
• Validation of Eurofer• Use of ODS
• Temperature• Welding
• Tungsten as structural material• SiC/SiC
• He cooled divertor• Integration and technology issues
• Attachment system and access to collectors
EFDA CSU Garching S.Ciattaglia, page 40/25
EFDA EUROPEAN FUSION DEVELOPMENT AGREEMENT
Conclusions (3)
The safety and environmental attractiveness of fusion power has been confirmed
Bounding accident sequence analyses driven by internal events have revealed no surprise: “no evacuation criteria” is met
• Bounding accident sequence analyses driven by external events have to be completed
• Model B LOFA + in-vessel LOCA i provides the largest environmental source terms
• Wastes amount are significant
• There is the potentiality to have no need of permanent disposal waste after 100 years from shutdown if recycling is applied