8th IAEA Technical Meeting on "Fusion Power Plant Safety1
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Safety Methodology Safety Methodology Implementation in the Conceptual Implementation in the Conceptual Design Phase of a Fusion ReactorDesign Phase of a Fusion Reactor
Lina Rodríguez-RodrigoJoëlle Uzan-Elbez
8th IAEA Technical Meeting on "Fusion Power Plant Safety2
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Safety Methodology Implementation in the Safety Methodology Implementation in the Conceptual Design Phase of a Fusion ReactorConceptual Design Phase of a Fusion Reactor
• For “an experimental reactor” could have beenthe question that the “fathers” of the ITER safetyapproach asked themselves.
• Answers are in a 1995 FED publication, NSSR and GSSR
8th IAEA Technical Meeting on "Fusion Power Plant Safety3
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Safety Methodology Implementation in the Safety Methodology Implementation in the Conceptual Design Phase of a Fusion ReactorConceptual Design Phase of a Fusion Reactor
• Why coming back to the same question for futurefusion reactor?– ITER will be a reference– Today environment:
• Non safety educated fusion community• Non fusion educated safety community
– Safety-fusion educated community should integrateimprove, organise safety in the design of future reactors
• introducing an appropiate quality assurance framework to be applied in the whole existing fusion community
• Provide scientific and technicat elements for informing thesociety?
• How? A conclusion for this meeting
8th IAEA Technical Meeting on "Fusion Power Plant Safety4
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Safety background in the Fusion CommunitySafety background in the Fusion CommunityFusion Machines
• JET 1991 1.7 MW fusion power1997 DTE1 16 MW fusion power
Safety case UK requirements and standards followedDismantling included in UKAEA
decommissoning
• TFTR 1993 + 3years DT campaign 11.5 MW Fusionpower
PSAR approved in 1978 USDOEFSAR approved in 1992 for DT operation
Dismantling and safe disposal 2002(in time and cost)
8th IAEA Technical Meeting on "Fusion Power Plant Safety5
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Safety background in the Fusion CommunitySafety background in the Fusion CommunityFusion Machines
8th IAEA Technical Meeting on "Fusion Power Plant Safety6
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Safety background in the Fusion CommunitySafety background in the Fusion Community
•Active Gas Handling System at JET •Tritium Laboratory Karlsruhe•Tritium Process Laboratory at Naka •Tritium Systems Test Assembly at Los Alamos (TSTA)•Tritium Laboratory at Valduc
Tritium laboratories
Inertial fusion
Methodology for IFE safety and environment assessment•HYLIFE-II•SOMBRERO
2005 INTERNATIONAL FUSION RESEARCH COUNCIL report7% of the article tackles safety for future fusion reactors
•Normal operation <1% of the naturally occurring dose rate•Most severe internal accident about annual natural radiation 1µSv•Waste
8th IAEA Technical Meeting on "Fusion Power Plant Safety7
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FissionFission background background forfor fusionfusion reactor conceptual reactor conceptual designdesign
Already implemented in previous mentioned installationsand in ITER
Slight differences• Definition of safety functions
•Control of the nuclear process in the reactor core
•Removal of heat from the core
•Confinement of the radioactive materials.
•Up to now limited potential of a fusion power increase
•Removal of the heat from the FW and VV activated material
•Confinement of the radioactive materials
fission fusion
8th IAEA Technical Meeting on "Fusion Power Plant Safety8
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Safety objectives
Risk
Source term
Energies
Safety functions
Confinement of radioactive products
Limitation of exposure for workers and environment
Residual power evacuation
Tritium
1st barrier
2nd barrier
Dynamic confinement
RadioprotectionWorker’s Doses evaluation
ALARAzoning
Safety objectives
MassActivityPhysical stateLocation
APDoses to the workers
EffluentReleases
ACP
Means for satisfying Safety functions
Passive means Maximum values
Safety objectives
Safety objectives
+ Illustration on the representative situations: operation, maintenance, incidents, design basis accidents
8th IAEA Technical Meeting on "Fusion Power Plant Safety9
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RISK RISK evaluationevaluation
Damage
Freq
uenc
y
0
1
RISK RISK evaluationevaluation
Curve of damage limit
Curve of characteristic risk
Safety margin
8th IAEA Technical Meeting on "Fusion Power Plant Safety10
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CompensatingCompensating meansmeans forfor riskrisk
• Principals of Damage mitigation– Protection by barriers– Defence in Depth– Lines of defence– Passive safety– Use of system…
Reduction of consequences to the Public, workers environement in normal, incidental en accidental situations
8th IAEA Technical Meeting on "Fusion Power Plant Safety11
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CompensatingCompensating meansmeans forfor riskrisk
• Reduction of the frequency of the damage– Redundancy– Diversity– Geographical separation– Unique failure criteria– Avoid common mode failure
Lowering probability of occurence ofevents
8th IAEA Technical Meeting on "Fusion Power Plant Safety12
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CompensatingCompensating meansmeans forfor riskrisk
• Ensure reliable, stable and easily manageable operation. • Prime goal the prevention of accidents.• Appropriate application of the Defence-In-Depth principle: several levels of
protection and multiple barriers to prevent releases of radioactive materialsto ensure that failures or combinations of failures that might lead to
significant radiological consequences are of very low probability.• Incorporated Technologies
proven orqualified by experience or testing or both
• The systematic consideration of the man–machine interface and human factors shall be included in all stages of design and in the associated development of operational requirements.
• The exposure to radiation of site personnel and releases of radioactive materials to the environment shall be made by design As Low As Reasonably Achievable (ALARA).
• A comprehensive safety assessment and independent verification shall be carried out to confirm that the design will fulfil the safety objectives and requirements before the operating organization completes its submission to the regulatory body.
DesignDesign PrincipalsPrincipals
IAEA Safety series nº 110
8th IAEA Technical Meeting on "Fusion Power Plant Safety13
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Scenarios•Transients•Accidents
Analysis of the eventsModels, codes, experiments,
(Damage, frequency)
DesignSystems
EquipmentsBuildings
...
OK?
Safety functionsSafety Objectives
ModificationNO
Prime goal the prevention of accidents
Implementation in the Design
YES
8th IAEA Technical Meeting on "Fusion Power Plant Safety14
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Scenarios•Transients•Accidents
Analysis of the eventsModels, codes, experiments,
(Damage, frequency)
DesignSystems
EquipmentsBuildings
...
OK?
Safety functionsSafety Objectives
Modification
Optimisation
Cost/Benefit
OK?
Implementation in the Design
NO
YES
YES
NO
Prime goal the prevention of accidents
8th IAEA Technical Meeting on "Fusion Power Plant Safety15
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Safety function confinement
•several levels of protection and multiple barriers
8th IAEA Technical Meeting on "Fusion Power Plant Safety16
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Safety function Decay heat removal
Approaches to safety, environment and regulatory approval for ITERFusion Engineering and Design 27 (1995) 83-95
8th IAEA Technical Meeting on "Fusion Power Plant Safety17
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Maintenance
Effective Doses calculationCollective doses
DesignSystems
RH-EquipmentsBuildingsSheldings
OK?
Safety functionsSafety Objectives
Modification
Optimisation
Cost/Benefit
OK?
Implementation in the Design
NO
YES
YES
NO
ORE and releases of radioactive materials to the environment by design As Low As Reasonably Achievable (ALARA).
ALARA
8th IAEA Technical Meeting on "Fusion Power Plant Safety18
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Normal operation
Ventilation-fire risk
DesignSystemsFlow-rateBuildings
OK?
Safety functionsSafety Objectives
Modification
Optimisation
Cost/Benefit
OK?
Implementation in the Design
NO
YES
YES
NO
ORE and releases of radioactive materials to the environment by design As Low As Reasonably Achievable (ALARA).
Reduction of releases
ALARA
8th IAEA Technical Meeting on "Fusion Power Plant Safety19
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ToolsTools forfor safetysafety in in thethe conceptual conceptual designdesign phasephase forfor futurefuture reactorsreactors
Classical methods would be complementedby probabilistic assessment using supportof forthcoming improved FMEA databasesand associated computer tools
8th IAEA Technical Meeting on "Fusion Power Plant Safety20
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Application to future power plantsApplication to future power plants
Reactor containement
Not only a fusion device•Nuclear buildings•Interfaces•Integration in the design
8th IAEA Technical Meeting on "Fusion Power Plant Safety21
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Auxilliary systemsControl system
Stack
Hot cells-Radwaste
Power supply
Reactor building
Ventilationdetritiation
System
Fuellingfacility
T
Fuellingfacility
Sch
em
ati
cS
chem
ati
co
f a f
usi
on
po
wer
pla
nt
of
a f
usi
on
po
wer
pla
nt
8th IAEA Technical Meeting on "Fusion Power Plant Safety22
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Auxilliary systemsControl system
Stack
Hot cells-Radwaste
Power supply
Reactor building
Ventilationdetritiation
System
Fuellingfacility
T
Fuellingfacility
Sch
em
ati
cS
chem
ati
co
f a f
usi
on
po
wer
pla
nt
of
a f
usi
on
po
wer
pla
nt
8th IAEA Technical Meeting on "Fusion Power Plant Safety23
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IMPACT IMPACT onon thethe DESIGNDESIGNAs already done for ITER or IFMIF
generic approach+
consideration of internal hazards that are not regulation depending– Fire– Explosion– Flooding
