Thorium-Plutonium LWR FuelThorium-Plutonium LWR Fuel Irradiation Testing Imminent

October 2012Julian F. Kelly, Chief Technology OfficerOctober 2012Julian F. Kelly, Chief Technology Officer

­ What­ Why­ How

OverviewOverviewTesting ceramic (Th,Pu)O2 fuel with prototypical LWR

composition & microstructure

Experiment primed to produce new and valuable data

― high Pu content for high burnup― high density― including some Th-U material― flexibly designed― support to other Th development projects

(HTGR, ADTR...)

StatusStatusTesting ceramic (Th,Pu)O2 fuel with prototypical LWR

composition & microstructure Status

― planning complete― pellet / material procurement finalized― Consortium assembled & in place― transport underway

Imminent Irradiation in the Halden HBWR― loading Jan 2013― highly instrumented test-pins― 3 different 'phases' involving different samples of (Th,Pu)O2

Experiment ObjectiveExperiment Objective

…. to yield data that can be used to demonstrate the

safe, long term performance of ceramic thorium-

plutonium oxide fuels, and that this information can

directly support the planning and approval of a

commercial irradiation for such a fuel…..

Regulator & Operator Audience:

& not purely academic

LWR Th-MOXLWR Th-MOX fuel is both a fuel is both a catalystcatalyst and a and atechnology technology springboardspringboard for further Th-deployment for further Th-deployment

Hi-BURNUPThorium Fuels

using matrix properties of ThO2

eg, deep burn Th fuels with SiC clad, actinide transmutation focus

(2ndgen MOX Pu, WG-Pu, MAs)

Thorium-PlutoniumLWR Oxide Fuel

• Power from stockpile Pu

• Thorium energy share

• ‘Familiar’ fuel material

• Reactor-operable

• Safety margin benefit

• Optimizable (BU, CR)

• Achievable in forseeable future

• Existing infrastructure

HI-CONVERSIONThorium Fuels

using breeding potential of Th(eg, RBWRs, PHWRs)

Technology development option

Technology development option

- Not a zero-sum Th game

- Possible to get commercial buy-in

LWR Th-MOXLWR Th-MOX fuel is both a fuel is both a catalystcatalyst and a and atechnology technology springboardspringboard for further Th-deployment for further Th-deployment

Hi-BURNUPThorium Fuels

using matrix properties of ThO2

eg, deep burn Th fuels with SiC clad, actinide transmutation focus

(2ndgen MOX Pu, WG-Pu, MAs)

Thorium-PlutoniumLWR Oxide Fuel

• Power from stockpile Pu

• Thorium energy share

• ‘Familiar’ fuel material

• Reactor-operable

• Safety margin benefit

• Optimizable (BU, CR)

• Achievable in forseeable future

• Existing infrastructure

HI-CONVERSIONThorium Fuels

using breeding potential of Th(eg, RBWRs, PHWRs)

Technology development option

Technology development option

- Not a zero-sum Th game

- Possible to get commercial buy-in

Viable thorium fuel technologies for the near term will be those of thehigh burn-up type & not those aiming for breeding ratios.

In-situ conversion and use of 233U is vastly more attractive than proposalsinvolving radio-chemical processing.

LWR thorium technologies can address Pu management issues

LWR thorium fuel technologies can integrate well with futurefast reactor use

LWR thorium fuel technologies can integrate very well with futureaccident-tolerant fuels & claddings

LWR Th-MOXLWR Th-MOX fuel must adapt to fuel must adapt tocurrent fuel cycle imperativescurrent fuel cycle imperatives

ThThee How HowA fuel testing campaign requires a lot of preparatory

work – and carries risk

Programmatic― $$¥£€― Consortium building― Material procurement (including transport)

Technical― Rig design― Pellet specifications & manufacture― Instrumentation ― PIE - Post-Irrad Examination

Behaviours to CharacterizeBehaviours to Characterize

• Temperature & Thermal Property Changes―temperature, conductivity decrease, expansion, heat capacity

• Fission Gas Release―amount, onset and composition

• Mechanical Interactions―densification, swelling

• Chemical Interactions―SCC, oxygen movement

Pellet properties evolve as fuel burns – the most important changes to know about are:

expect later onset for ThO2, more I?

may be less creep but more swelling for ThO2

O stoichiometry different in ThO2 I yield higher (released?)

ultimately, will cladding integrity be challenged?

To Be MeasuredTo Be Measured

• On-Line Measurables― temperature: centerline & coolant― pellet stack elongation― clad elongation― rod internal pressure

Experiment design involves compromises & risk assessment

PCMIFGR

swellingdensification

microstructureFP behaviour

fuel matrix properties

• Post-Irradiation Examination― fission gas analysis ― microscopy: optical, SEM, TEM, EPMA― conductivity― radiography― microhardness― γ scanning

Calibration valve for power calibration of test assembly

Inlet turbine assembly for power calibration of test assembly

Fuel rod thermocouple Test fuel rod, active section (Orange)

Neutron detectors vanadiumFuel stack elongation detector for measuring densification / swelling of fuel Fuel rod thermocouple

Fuel rod pressure transducer

Outlet turbine for power calibration of test assembly outlet steam holes for coolant Extension tube

Stainless steel shield plug

Top seal assembly, sealing against the reactor top lid

- Phase “1b” rig schematic

- Jan 2013

ITU- May 2013

R ba

cd

Shoulder width aChamfer width bChamfer depth Chamfer angle cDishing depth dDishing radius R

Pellet PropertiesPellet Properties

• Microstructure― density / porosity & pore size distribution ― grain size & grain distribution― Pu homogeneity

• Composition― impurities: metals, non-metals― stoichiometry

• Shaping― dishing, L/D

Test-fuel ceramic must represent that which can be deployed commercially. Pu content effects things cf U

Thorium Fuel Ceramic Studies• Thoria-Ceria Pellets: as analogs for thorium-MOX• Microstructure: different phases, significant 20-

100μm porosity, carbon…. next = binderless• Will Serve Model Development: thermal

conductivity & dependence on O/M, grainsize, etc

Experiment ExecutionExperiment Execution

• Rod Design― pellet-clad gap, fill gas

• Power ’Roadmap’― starting LHGR

Just a few more things to cover...

Conclusion: Thorium Fuel Testing ….Conclusion: Thorium Fuel Testing …. Ready to GoReady to GoStill welcoming new Consortium partners

The nuclear industry is not set up for attracting ’innovation’ financingUranium IS cheap, and could stay that way

Thanks to current Members: STL, NNL, IFE, Westinghouse, NFR, Fortum, ITU

Conclusion: Thorium Fuel Testing ….Conclusion: Thorium Fuel Testing …. Ready to GoReady to GoStill welcoming new Consortium partners

FINAL THOUGHTS:The nuclear industry is not set up for attracting ’innovation’ financingUranium IS cheap, and could stay that way

Thanks to current Members: STL, NNL, IFE, Westinghouse, NFR, Fortum, ITU