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European experience with Thorium fuels. Didier Haas. Didier.haas@hotmail.be ++32 491648840. NC2 Nuclear Consulting Company. Some references. T. Lung: EURATOM report 1777 (1997) THOR Energy Thorium Fuel Conference , Paris (2010)
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Europeanexperiencewith Thorium fuels Didier Haas Didier.haas@hotmail.be ++32 491648840 NC2 Nuclear Consulting Company Thorium Conference, CERN
Somereferences • T. Lung: EURATOM report 1777 (1997) • THOR Energy Thorium Fuel Conference, Paris (2010) • IAEA No NF-T-2.4 (2012): The role of Thorium to supplement Fuel Cycles of Future NuclearEnergySystems • GIF position paper on the use of Thorium in the Nuclear Fuel Cycle (2010) • SNETP StrategicResearch and Innovation Agenda (2013) and SRA Annex on Thorium (2011) • Published EURATOM Framework Programmes results and personal communications Thorium Conference, CERN
Content • EuropeanResearch on Thorium • Thorium in HTRs • Thorium oxide fuel behaviour • Moltensaltreactorsfueledwith Thorium • Conclusion Thorium Conference, CERN
3 main pillars + key cross-cutting issues SustainableNuclearEnergyTechnology Platform Launched in 2007 117members fromresearch, industry, academia, technical safetyorganizations Recent application of Weinberg Foudation (UK) and ThorEA (UK) bothpromoting Thorium research Produced a Research Agenda (2009, revised in 2013) and a DeploymentStrategy (2010)
EuropeanR&D Roadmapon Thorium • SNETP has produced an Annex (2011) on Thorium in the StrategicResearch Area. Highlights are: • LWRs: evolutionarydevelopmentfavoured, with use of Pu as seed (natural U savings); breedingwouldneed new reactortechnology • HWRs: high conversion ratio achievable • HTR: pastGerman HTR development programme aimedatreaching a breeding cycle with Thorium • FastReactors: breeding possible but with long doubling times; improvedvoidreactivity coefficient in sodium FR; advantage of ADS subcriticalreactor (high neutron energies, Th 232 fission + captures) • MSR: breedingmightbeachieved over a wide range of neutron energies; long-trermdevelopment option • Pu-burning: Thorium matrices for the purpose of incinerating Pu in LWRs • Challenges for solid fuels: reprocessing, remote fuel fabrication Thorium Conference, CERN
Thorium Projects in Europe • 1960-1980: limitedexperimentalwork on Thorium use in HTRs (DRAGON, ATR, THTR, Th-Ucarbide and oxide fuels) and in the Lingen BWR by SIEMENS (Th-MOX) • 1990-2002: Assessmentstudiesincluding the « Lung report » and the EURATOM projects « Thorium Cycle as a nuclearwaste management option » and « Red Impact » • 1998-2008: Thorium fuel experiments(Projects THORIUM CYCLE, OMICO, LWR-DEPUTY with irradiations in KWO-Obrigheim, HFR and BR2) • FP7 (2011-13): Performance assessment of Thorium in geologicaldisposal (SKIN Project) • FP5-FP7 (1998-now): Thorium fuel studies and characterization for a Molten Salt Reactor (Projects MOST, ALISIA, EVOL…) Thorium Conference, CERN
Thorium use in High TemperatureReactors • HTR thermal neutron spectrumisverywellsuited for Thorium breeding • Very high burnupcapability in HTRs in a once-through cycle; very high stability in geologicaldisposal of the Thorium matrix • This explains the (successful) use of Thorium in early HTR projects (DRAGON, AVR Jülich, PeachBottom, Fort St-Vrain, THTR); fresh fuel kernelswere mixed with Pu or U235 fissile material • Potential limitations are the high initial U235 content needed in the once-throughstrategy and the reprocessingdifficulty in case of closed cycle strategy • Today, (V)HTR is one of the six GIF R&D systems; Europeaninterest in HTR exists, but difficulty in gettingindustrycommitments Thorium Conference, CERN
Thorium fuels in HTRs:Abstractfrom the « Lung » report Thorium Conference, CERN
Thorium Oxide as a «Quasi »-Inert Matrix • ThO2 is a very stable ceramic: in-core applications, direct disposalwaste management (seeleaching tests resultsfrom JRC-ITU Karlsruhe) • Th-MOX (Th,PuO2) has been contemplated to incinerateseparated Pu in LWRs in a fertile matrix, and also as possible « quasi »-inert matrix for MA burning in « targets » • The Th matrix produce no new Pu and is fertile as required to keep the reactivity in LWRs • In-reactorproperties are equivalent (evenbetter if one considers the thermal behaviour and the stability) to U-MOX • Thermal diffusivitymeasurements on unirradiated Th-MOX at JRC-ITU: higherthan U-MOX Thorium Conference, CERN
FP5: THORIUM Cycle for P&T and ADS FP5 ADOPT Coordination Network EUROTRANS FP6 Project FP5 (1998-2002) Projects on Advanced Options for Partitioning and Transmutation
FP6 EUROTRANS Project and THORIUM as P&T fuel Associated Project on Advanced P&T Fuels: LWR-DEPUTY Project with Thorium fuels Inert Matrices fuels Thorium Conference, CERN
(Th,Pu)O2 in-reactor experience (2000-2012) • Experiments • (Th,Pu)O2 fuels were irradiated in three reactors • HFR-Petten (Na-capsule) • KWOObrigheim (non-instrumented, commercial PWR) • BR-2 Mol (instrumented & non-instrumented in PWR loop) • Post-irradiation examinations & radiochemistry by different labs (ITU, NRG, PSI, SCK•CEN)
Th-MOX pellet irradiated in Obrigheim within the FP5 THORIUM CYCLE and LWR-DEPUTY projects Safety assessment of Plutonium Mixed Oxide Fuel irradiated up to 37.7 GWd/tonne (JNM 2013) J. Somers1,*, D. Papaioannou1, J. McGinley1, D. Sommer2 1. Joint Research Centre – Institute for Transuranium Elements, Postfach 2340, D76125 Karlsruhe, Germany 2. EnBWKernkraftGmbH*, Postfach 1161, 74843 Obrigheim and Böhmerwaldstraße 15, 74821 Mosbach, Germany Thorium Conference, CERN
Thermal Behaviour • From: C. Cozzo et al., J. Nucl. Mater. (2011), doi:10.10C. Cozzo et al., J. Nucl. Mater. (2011), Thorium Conference, CERN
Th-MOX Thermal Conductivity as compared to U-MOX C. Cozzo et al., J. Nucl. Mater. (2011), doi:10.10C. Cozzo et al., J. Nucl. Mater. (2011), At 1000K TC of U-MOX: 3.0-3.5 of Th-MOX: >4.0 !! Importance of the fabrication process D. Staicu, M. Barker, J. Nucl. Mater. (2013), http://dx.doi.org/10.1016/j.jnucmat.2013.08.024 Thorium Conference, CERN
BR-2 experiments on (Th,Pu)O2: Model predictions versus experiment Personal communication By courtesy of SCK-CEN
Leaching test on Th-MOX Source: Rondinella & Al (JRC-ITU) Paris Thorium technical meeting 2010 Thorium Conference, CERN
SKIN Euratom Project (2011-2013)Comparison of solubility values of elements of interest Reference case: SKB spent fuel repository Bx, Gx: compartments of Bentonite, Granite Thorium Conference, CERN
SCK-CEN (BE) key findings from theEuratom (Th, Pu)O2 research programs • No showstoppers identified for Thorium-based MOX (Th,Pu)O2to its implementation as a possible LWR-fuel. • (Th,Pu)O2 has several advantages over Uranium-based MOX (U,Pu)O2 • Better thermal conductivity (unirradiated data only) • Improved chemical stability • Indications for improved reactivity margins for full-core PWR (Th,Pu)O2 compared to (U,Pu)O2 • Next steps: • Improving the fuel manufacturing technology, since the scoping studies used non-industrial (& non-industrialisable) manufacturing routes; tests on representative fabrications needed • Larger-scale demonstration programs with lead-rod and lead-assembly irradiations are needed before licensing Personal communication By courtesy of SCK-CEN
Use of Thorium in Molten Fuel Reactors • In MSRs thorium cycle can achieve a higher conversion ratio than the uranium/plutonium cycle. • MSR avoids some of the loss of conversion efficiency that occurs due to neutron capture events in Pa-233 (Pa-233 has a relatively long half-life of 27 days). The nuclear fuel in MSR is unique in that it circulates through the entire primary circuit and spends only a fraction of its time in the active core. This reduces the time-averaged neutron flux that the Pa-233 sees and significantly reduces the proportion of Pa-233 atoms that are lost to neutron captures • MSR continually reprocesses the nuclear fuel as it re-circulates in the primary circuit, removing fission products as they are generated. MSR therefore completely avoids the difficulties in conventional reactors with fabricating U-233 fuels (which have high gamma activities from U-232 daughters). • Since the nuclear fuel is a molten salt, there are no fuel mechanical performance issues to consider. Thorium Conference, CERN
MSR R&D in Europe and elsewhere A continuous and coordinated activity (European network) since 2001 MOST 6 countries + Euratom LICORN 7 countries + Euratom + Russia ALISIA EVOL 7 countries + Euratom + Russia 8 countries + Euratom + Russia 7 countries + Euratom (+ Russia) SUMO From MOST to EVOL 2001-2003 Confirmation of MSR potential Identification of key issues (vs MSBR) from MSBR 2004-2006 Strenghthening of European network Follow-up of R&D progress 2007-2008 Review of liquid salts for various applications Preparation of European MSR roadmap • 2009 • Feasibility demonstration of MSFR 2009-2012 Optimization of MSFR (remaining weakpoints) … to MSFR Thorium Conference, CERN
Strategic impact of EVOL A commonEuropeanMolten Salt Reactor concept for GENIV (major European contribution to the MSR GENIV initiative) Thorium as a nuclear fuel (closed MSR fuel cycle, sustainableenergy system) Partitioning& Transmutation (alternative route for P&T compared to solid fuel) Improvedunderstanding of liquidsaltproperties (MSR technology, but alsootherindustrialprocesses) Thorium Conference, CERN
MSFR concept MSFR reactor concept (French concept) (Molten Salt Fast Reactor) Initial MSFR fuel composition: X(LiF) = 77.45 mol% X(ThF4) = 20 mol% (LiF-ThF4 eutectic) X(UF4) = 2.55 mol% Operating temperature: Tinlet = 620 °C MSFR pre-conceptual design, GIF Annual Report 2009: (MSR)
JRC ITU MoltenSaltsDatabase MoltenSalt Database developedat JRC (ITU) (2002-2010): 38 assessedbinarysystems Thorium Conference, CERN
Conclusion • Several EC Projects on Th-MOX fuels mainly for LWRs as « Quasi »-Inert matrix to burn Pu and MAs • Thorium salts as fuel for the MSR • The SRIA published in 2013 recognises the « significant long-termpotentialities and the significant challenges to makeindustrialimplementation » of Thorium systems Thorium Conference, CERN
Thankyou for your attention ! With particularthank to Michel Hugon and Roger Garbil (EC DG RTD, Brussels), Vincenzo Rondinella, DragosStaicu, Joe Somers (EC JRC, ITU, Karlsruhe) and Marc Verwerft (SCK-CEN) for their assistance in providing all relevant information and comments. Thorium Conference, CERN