1. European experience with Thorium fuels
Didier Haas
NC2
Nuclear Consulting Company
Thorium Conference, CERN

2. Thorium Conference, CERN
Some references
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 Nuclear Energy Systems
GIF position paper on the use of Thorium in the Nuclear Fuel Cycle (2010)
SNETP Strategic Research and Innovation Agenda (2013) and SRA Annex on Thorium (2011)
Published EURATOM Framework Programmes results and personal communications
Thorium Conference, CERN

3. Thorium Conference, CERN
Content
European Research on Thorium
Thorium in HTRs
Thorium oxide fuel behaviour
Molten salt reactors fueled with Thorium
Conclusion
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4. 3 main pillars + key cross-cutting issues
Sustainable Nuclear Energy Technology Platform
Launched in 2007
117members from research,
industry, academia, technical
safety organizations
Recent application of
Weinberg Foudation (UK) and
ThorEA (UK) both promoting
Thorium research
Produced a Research Agenda
(2009, revised in 2013) and a
Deployment Strategy (2010)
3 main pillars + key cross-cutting issues 4

5. European R&D Roadmap on Thorium
SNETP has produced an Annex (2011) on Thorium in the Strategic Research Area. Highlights are:
LWRs: evolutionary development favoured, with use of Pu as seed (natural U savings); breeding would need new reactor technology
HWRs: high conversion ratio achievable
HTR: past German HTR development programme aimed at reaching a breeding cycle with Thorium
Fast Reactors: breeding possible but with long doubling times; improved void reactivity coefficient in sodium FR; advantage of ADS subcritical reactor (high neutron energies, Th 232 fission + captures)
MSR: breeding might be achieved over a wide range of neutron energies; long-trerm development option
Pu-burning: Thorium matrices for the purpose of incinerating Pu in LWRs
Challenges for solid fuels: reprocessing, remote fuel fabrication
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6. Thorium Projects in Europe
: limited experimental work on Thorium use in HTRs (DRAGON, ATR, THTR, Th-U carbide and oxide fuels) and in the Lingen BWR by SIEMENS (Th-MOX)
: Assessment studies including the « Lung report » and the EURATOM projects « Thorium Cycle as a nuclear waste management option » and « Red Impact »
: Thorium fuel experiments (Projects THORIUM CYCLE, OMICO, LWR-DEPUTY with irradiations in KWO-Obrigheim, HFR and BR2)
FP7 ( ): Performance assessment of Thorium in geological disposal (SKIN Project)
FP5-FP7 (1998-now): Thorium fuel studies and characterization for a Molten Salt Reactor (Projects MOST, ALISIA, EVOL…)
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7. Thorium use in High Temperature Reactors
HTR thermal neutron spectrum is very well suited for Thorium breeding
Very high burnup capability in HTRs in a once-through cycle; very high stability in geological disposal of the Thorium matrix
This explains the (successful) use of Thorium in early HTR projects (DRAGON, AVR Jülich, Peach Bottom, Fort St-Vrain, THTR); fresh fuel kernels were mixed with Pu or U235 fissile material
Potential limitations are the high initial U235 content needed in the once-through strategy and the reprocessing difficulty in case of closed cycle strategy
Today, (V)HTR is one of the six GIF R&D systems; European interest in HTR exists, but difficulty in getting industry commitments
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8. Thorium fuels in HTRs:Abstract from the « Lung » report
Thorium Conference, CERN

9. Thorium Oxide as a «Quasi »-Inert Matrix
ThO2 is a very stable ceramic: in-core applications, direct disposal waste management (see leaching tests results from JRC-ITU Karlsruhe)
Th-MOX (Th,PuO2) has been contemplated to incinerate separated 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-reactor properties are equivalent (even better if one considers the thermal behaviour and the stability) to U-MOX
Thermal diffusivity measurements on unirradiated Th-MOX at JRC-ITU: higher than U-MOX
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10. FP5: THORIUM Cycle for P&T and ADS
FP5 ADOPT
Coordination Network
EUROTRANS FP6 Project
FP5 ( ) Projects on Advanced Options
for Partitioning and Transmutation

11. 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
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12. (Th,Pu)O2 in-reactor experience (2000-2012)
Experiments
(Th,Pu)O2 fuels were irradiated in three reactors
HFR-Petten (Na-capsule)
KWO Obrigheim (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)

13. Thorium Conference, CERN
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. EnBW Kernkraft GmbH*, Postfach 1161, Obrigheim and Böhmerwaldstraße 15, Mosbach, Germany
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14. 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

15. 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:
of Th-MOX: >4.0
!! Importance of the
fabrication process
D. Staicu, M. Barker, J. Nucl. Mater. (2013),
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16. BR-2 experiments on (Th,Pu)O2: Model predictions versus experiment
5 cycli in 2006
Copernic = AREVA code; Transuranus = ITU code
Personal communication
By courtesy of SCK-CEN

17. Leaching test on Th-MOX
Source: Rondinella & Al (JRC-ITU)
Paris Thorium technical meeting 2010
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18. Thorium Conference, CERN
SKIN Euratom Project ( ) Comparison of solubility values of elements of interest
Reference case: SKB spent fuel repository
Bx, Gx: compartments of Bentonite, Granite
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19. SCK-CEN (BE) key findings from the Euratom (Th, Pu)O2 research programs
No showstoppers identified for Thorium-based MOX (Th,Pu)O2 to 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

20. 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.
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21. MSR R&D in Europe and elsewhere
From MOST to EVOL
A continuous and coordinated activity (European network) since 2001
Confirmation of MSR potential
Identification of key issues (vs MSBR)
MOST
from MSBR
6 countries + Euratom
Strenghthening of European network
Follow-up of R&D progress
LICORN
7 countries + Euratom
+ Russia
ALISIA
Review of liquid salts for various applications
Preparation of European MSR roadmap
7 countries + Euratom
+ Russia
SUMO
 2009
Feasibility demonstration of MSFR
8 countries + Euratom
+ Russia
EVOL
Optimization of MSFR
(remaining weakpoints)
7 countries + Euratom
(+ Russia)
… to MSFR
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22. Thorium Conference, CERN
Strategic impact of EVOL
A common European Molten Salt Reactor concept for GENIV
(major European contribution to the MSR GENIV initiative)
Thorium as a nuclear fuel
(closed MSR fuel cycle, sustainable energy system)
Partitioning & Transmutation
(alternative route for P&T compared to solid fuel)
Improved understanding of liquid salt properties
(MSR technology, but also other industrial processes)
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23. MSFR concept MSFR reactor concept (French concept)
(Molten Salt Fast Reactor)
Initial MSFR fuel composition:
X(LiF) = 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)

24. Thorium Conference, CERN
JRC ITU Molten Salts Database
Molten Salt Database developed at JRC (ITU)
( ): 38 assessed binary systems
Thorium Conference, CERN

25. 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-term potentialities and the significant challenges to make industrial implementation » of Thorium systems
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26. Thank you for your attention !
With particular thank to Michel Hugon and Roger Garbil (EC DG RTD, Brussels), Vincenzo Rondinella, Dragos Staicu, Joe Somers (EC JRC, ITU, Karlsruhe) and Marc Verwerft (SCK-CEN) for their assistance in providing all relevant information and comments.
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