ADSR08 Thorium Fuel Rods Bob Cywinski School of Applied Sciences University of Huddersfield ThorEA ADSR Workshop Cambridge 13 January 2009

ADSR08 ThorEA ADSR Workshop January 2009 Annual energy resources ~5x10 9 tonnes of coal 27x10 9 barrels of oil 65x10 3 tonnes of uranium 2.5x10 12 m 3 of natural gas Thorium equivalent 5x10 3 tonnes of thorium After Sorenson

ADSR08 ThorEA ADSR Workshop January 2009 Thorium in power reactors Shippingport LWBR –Fuelled with U-233 and Th- 232 –Produced 1.4% more fuel than it burned eg:

ADSR08 ThorEA ADSR Workshop January 2009 Advantages Thorium supplies plentiful Robust fuel and waste form Generates no Pu and fewer higher actinides 233 U has superior fissile properties Proliferation resistant Thorium as fuel It is generally considered that the neutrons necessary to produce 233 U from 232 Th must be introduced by seeding the Th fuel with 235 U or Pu Disadvantages No fission until 233 U is produced 233 U is weapon grade unless denatured Parasitic 232 U production results in high gamma activity Thorex processing of waste needs substantial development

ADSR08 ThorEA ADSR Workshop January 2009 Possibility 1 : The Indian approach The thermal Thorium Breeder Reactor (ATBR) Calculations suggest PuO 2 seeded thoria fuel gives excellent core characteristics, such as: two years cycle length high seed output to input ratio intrinsically safe reactivity coefficients Jagannathan, Pal Energy Conversion and Management 47 (2006) 2781

ADSR08 ThorEA ADSR Workshop January 2009 Possibility 1 : The Indian approach Seedless thorium cluster Jagannathan, Pal Energy Conversion and Management 47 (2006) 2781 Seeded fuel cluster ATBR core

ADSR08 ThorEA ADSR Workshop January 2009 Possibility 1 : The Indian approach Jagannathan, Pal Energy Conversion and Management 47 (2006) 2781 Seeded fuel cluster

ADSR08 ThorEA ADSR Workshop January 2009 Possibility 1 : The Indian approach Jagannathan, Pal Energy Conversion and Management 47 (2006) 2781

ADSR08 ThorEA ADSR Workshop January 2009 Possibility I1 : The Indian approach Jagannathan, Pal Energy Conversion and Management 47 (2006) 2781

ADSR08 ThorEA ADSR Workshop January 2009 Possibility 1 : The Indian approach Jagannathan, Pal Energy Conversion and Management 47 (2006) 2781 Epithermal flux distribution Thermal flux distribution 0 FPD 720 FPD

ADSR08 ThorEA ADSR Workshop January 2009 Possibility I : The Indian approach Jagannathan, Pal Energy Conversion and Management 47 (2006) 2781

ADSR08 ThorEA ADSR Workshop January 2009 Possibility II : The ‘pure’ Thorium-ADSR

ADSR08 ThorEA ADSR Workshop January 2009 Possibility II : The ‘pure’ Thorium-ADSR C Bungau RJ Barlow R Cywinski S Tygier Accelerator driven systems for energy production and waste transmutation EPAC08, 1854 Genoa, Italy, 2008

ADSR08 ThorEA ADSR Workshop January 2009 Possibility III: Transitional technology 232 Th to 233 U conversion can be better optimised, with mitigation against detrimental neutron absorption by 233 Th and 233 Pa Modifications to existing reactors are not necessary Wider global exploitation of nuclear technology is possible Fuel preparation and burn cycles are decoupled Production of ready-engineered Th fuel rods for direct deployment in conventional nuclear reactors, with fertile to fissile conversion achieved through dedicated spallation charging Why?

ADSR08 ThorEA ADSR Workshop January 2009 Possibility III: Transitional technology The Challenges Optimisation of proton beam characteristics; spallation target/fuel rod geometries; moderator and reflector geometries Optimisation of irradiation cycles; consideration of the neutron energy spectrum and related absorption characteristics of 232 Th, 233 Th, 233 Pa Characterisation of the 233 U fission during and after irradiation Selection of optimal fuel form; characterisation of material (physical, chemical and engineering properties under extreme conditions

ADSR08 ThorEA ADSR Workshop January 2009 Possibility III: Transitional technology A: Miniature spallation target in central bore of fuel element assembly High power (MW) proton beam B: ADS assembly Th fuel pins Spallation target

ADSR08 ThorEA ADSR Workshop January 2009 Fuel types ? Thorium Metal Ductile, can be shaped. High conductivity. Thoria -ThO 2 High melting point, most stable oxide known. Thorium Nitrides and Carbides Carbides ((ThU)C 2 ) have already been successfully used. The use of nitrides is also possible Cermet Fine oxide partilcles embedded in a metallic host. Cermet fuel element TRISO fuel (ORNL ) pyCSiC C MOX fuel pellet

ADSR08 ThorEA ADSR Workshop January 2009 Materials Properties LWR fuel rod element  Crack formation  Substantial grain growth in centre (ie in hotter region)  Small gap at pellet-cladding interface Effects of irradiation and thermal cycling on thorium fuel assemblies must be studied and characterised These fuel rods may be in the reactor for several years !

ADSR08 ThorEA ADSR Workshop January 2009 A hybrid scheme (U/Th) UraniumEnrichment Depleted Uranium Fuel Fabrication Burner Reactors Reprocessing High level waste ADS (converter) Fuel tailoring Thorium ore J.M. Martınez-Val, M. Piera / Energy Conversion and Management 48 (2007) 1480

ADSR08 ThorEA ADSR Workshop January 2009 A hybrid scheme (U/Th) J.M. Martınez-Val, M. Piera Energy Conversion and Management 48 (2007) 1480 “...the separation of energy production (to be done in LWR) and nuclear breeding (to be done in subcritical hybrids) presents a scenario with very appealing safety features and a high potential for efficient utilization of all natural resources of uranium and thorium that, in total, account for ,000 times the annual production of nuclear energy nowadays and about 2500 times as large as the total annual energy consumption all over the globe” ‘Pure’ thorium scheme

ADSR08 ThorEA ADSR Workshop January 2009 The next step.... STFC appear keen to fund a two year scoping study of the thorium fuel rod concept through PNPAS scheme (Barlow and Cywinski) The programme may progress as far as experimental tests, eg at TRIUMF, where FERFICON experiments were carried out in the 70s (these would allow irradiation by protons at up to 20nA at 450MeV). The programme will support two PDRAs for GEANT4/MCNPX simulations Materials studies