1. 1 MCNP simulation of salt channel in LR-0 reactor 12th session of the AER Working Group F - "Spent Fuel Transmutations" and 3rd meeting of INPRO Project RMI - "Meeting energy needs in the period of raw materials insufficiency during the 21st century" Liblice, Czech Republic, April 6 – 9, 2010 Martin Suchopár Nuclear Physics Institute Academy of Sciences of Czech Republic

2. AHTR and MSBR Demands on molten salts concerning their composition and properties differ in the way of their application Demands on molten salts concerning their composition and properties differ in the way of their application MSBR (Molten Salt Breeder Reactor) uses in the primary circuit molten salts containing fissile and fertile material, which serve as fuel and coolant at the same time MSBR (Molten Salt Breeder Reactor) uses in the primary circuit molten salts containing fissile and fertile material, which serve as fuel and coolant at the same time AHTR (Advanced High-Temperature Reactor) uses graphite- matrix high-temperature fuel like in helium-cooled reactors, but provides cooling with high-temperature fluoride salt (~900 °C) without fissionable material AHTR (Advanced High-Temperature Reactor) uses graphite- matrix high-temperature fuel like in helium-cooled reactors, but provides cooling with high-temperature fluoride salt (~900 °C) without fissionable material 2

3. 3 Project SPHINX SPHINX = SPent Hot fuel Incinerator by Neutron fluX SPHINX = SPent Hot fuel Incinerator by Neutron fluX Demonstration nuclear transmutor with liquid fuel based on molten fluoride salts Demonstration nuclear transmutor with liquid fuel based on molten fluoride salts Incineration of transuranic elements and long-lived fission products Incineration of transuranic elements and long-lived fission products Elementary module designed as subcritical fuel channel surrounded by graphite blocks equipped with tubes in which flow molten fluorides of long-lived radionuclides Elementary module designed as subcritical fuel channel surrounded by graphite blocks equipped with tubes in which flow molten fluorides of long-lived radionuclides System can be either critical or subcritical which is kept in stationary state and whos power is driven by an external neutron source or by driving zone surrounding the subcritical assembly System can be either critical or subcritical which is kept in stationary state and whos power is driven by an external neutron source or by driving zone surrounding the subcritical assembly

4. 4 Project SPHINX Elementary module of the SPHINX concept

5. 5 Program EROS EROS = Experimental zeRO power Salt reactor SR-0 EROS = Experimental zeRO power Salt reactor SR-0 Program serves for experimental verification of insertion zones of MSR type demonstration unit in reactor LR-0 Program serves for experimental verification of insertion zones of MSR type demonstration unit in reactor LR-0 Within the frame of the project SPHINX 5 experiments were carried out with modules denoted EROS 1 to EROS 5 inserted into the core of reactor LR-0 Within the frame of the project SPHINX 5 experiments were carried out with modules denoted EROS 1 to EROS 5 inserted into the core of reactor LR-0 Modules differed in number and configuration of various blocks, in amount of salt and graphite contained in the core and in number and enrichment of fuel assemblies Modules differed in number and configuration of various blocks, in amount of salt and graphite contained in the core and in number and enrichment of fuel assemblies Distribution of flux density and neutron spectrum in the driving zone and in salt channels were examined by 3 methods: neutron activation analysis, gama scanning method of fuel rods and thermoluminiscence detectors Distribution of flux density and neutron spectrum in the driving zone and in salt channels were examined by 3 methods: neutron activation analysis, gama scanning method of fuel rods and thermoluminiscence detectors

6. 6 Simulation of salt channel in MCNPX Simulated arrangement of salt channel surrounded by 6 fuel assemblies

7. MCNPX simulations of the salt channel Salt channel 600 mm high surrounded with 6 shortened WWER-1000 fuel assemblies enriched with 4.4 % 235 U Salt channel 600 mm high surrounded with 6 shortened WWER-1000 fuel assemblies enriched with 4.4 % 235 U Salt channel consists of 7 sections made of aluminum Salt channel consists of 7 sections made of aluminum The sections are filled with mixture of LiF-NaF salt with the composition 60-40 molar % and the density of 1.7 g/cm 3 The sections are filled with mixture of LiF-NaF salt with the composition 60-40 molar % and the density of 1.7 g/cm 3 LiF salt first with natural composition 92.5 % 7 Li, 7.5 % 6 Li, then changed to enriched 7 LiF salt with 99.995 % 7 Li LiF salt first with natural composition 92.5 % 7 Li, 7.5 % 6 Li, then changed to enriched 7 LiF salt with 99.995 % 7 Li 25 experimental channels with diameter of 10 mm 25 experimental channels with diameter of 10 mm Experimental aluminium probes with diameter of 8 mm and 3 positions for activation foils (bottom, middle, top) at height of 150, 300 and 450 mm above the bottom of the salt channel Experimental aluminium probes with diameter of 8 mm and 3 positions for activation foils (bottom, middle, top) at height of 150, 300 and 450 mm above the bottom of the salt channel Activation foils made of various activation materials with diameter of 6 mm and 50 µm thin Activation foils made of various activation materials with diameter of 6 mm and 50 µm thin 7

8. 8 Simulation of salt channel in MCNPX Salt channel with fuel assemblies – horizontal and vertical section of the arrangement

9. MCNPX simulations of the salt channel The simulations were made in MCNPX version 2.6 The simulations were made in MCNPX version 2.6 The source neutrons were generated by kcode routine with 4.10 9 source particles The source neutrons were generated by kcode routine with 4.10 9 source particles The cross-sections for kcode were taken from standard libraries for neutrons ENDF/B-VII.0 and JEFF 3.1.1 The cross-sections for kcode were taken from standard libraries for neutrons ENDF/B-VII.0 and JEFF 3.1.1 Maximum energy of neutrons was limited to 20 MeV (sufficient for reactor spectrum) Maximum energy of neutrons was limited to 20 MeV (sufficient for reactor spectrum) The energy range 0 – 20 MeV was divided into: The energy range 0 – 20 MeV was divided into: 6 logarithmic intervals for mesh tallies in salt channel 6 logarithmic intervals for mesh tallies in salt channel 50 logarithmic intervals for spectra in activation foils 50 logarithmic intervals for spectra in activation foils 9

10. 10 Simulation results mesh tallies salt channel filled with LiF-NaF – horizontal section 10 keV – 100 keV 100 keV – 1 MeV 1 MeV – 20 MeV 0 – 0.5 eV0.5 eV – 0.5 keV0.5 keV – 10 keV

11. 11 Simulation results mesh tallies salt channel filled with 7 LiF-NaF – horizontal section 0 – 0.5 eV0.5 eV – 0.5 keV0.5 keV – 10 keV 10 keV – 100 keV 100 keV – 1 MeV 1 MeV – 20 MeV

12. 12 Simulation results mesh tallies salt channel filled with LiF-NaF – vertical section 10 keV – 100 keV 100 keV – 1 MeV 1 MeV – 20 MeV 0 – 0.5 eV0.5 eV – 0.5 keV0.5 keV – 10 keV

13. 13 Simulation results mesh tallies salt channel filled with 7 LiF-NaF – vertical section 0 – 0.5 eV0.5 eV – 0.5 keV0.5 keV – 10 keV 10 keV – 100 keV 100 keV – 1 MeV 1 MeV – 20 MeV

14. 14 Simulation results neutron spectra salt channel filled with LiF-NaF – activation foils in middle positions of aluminium probes in experimental channels channel 1 channel 3 channel 2 channel 4

15. 15 channel 5 channel 7 channel 6 channel 8 Simulation results neutron spectra salt channel filled with LiF-NaF – activation foils in middle positions of aluminium probes in experimental channels

16. 16 Aktivační detektory Activation material Reaction Relative abundance in natural mixture [%] Half-life of product T 1/2 Energy of main gama line Eγ [keV] Relative intensity of main gama line Iγ [%] Reaction treshold [MeV] 197 Au 197 Au(n,γ) 198 Au1002,69517 d411,896– 115 In 115 In(n,γ) 116m In95,754,29 min1293,684,4– 115 In 115 In(n,n‘) 115m In95,74,486 h336,245,80,5 55 Mn 55 Mn(n,γ) 56 Mn1002,5785 h846,898,9– 58 Ni 58 Ni(n,p) 58 Co68,170,86 d810,8991,0 27 Al 27 Al(n,α) 24 Na10014,9590 h1368,61005,5 27 Al 27 Al(n,p) 27 Mg1009,458 min843,771,81,9 63 Cu 63 Cu(n,γ) 64 Cu69,212,700 h1345,80,47– 98 Mo 98 Mo(n,γ) 99 Mo24,165,94 h140,589,4– 186 W 186 W(n,γ) 187 W28,623,72 h685,827,3– 56 Fe 56 Fe(n,p) 56 Mn91,72,5785 h846,898,95,0 164 Dy 164 Dy(n,γ) 165 Dy28,22,334 h94,73,58– 175 Lu 175 Lu(n,γ) 176m Lu97,43,635 h88,38,9– 139 La 139 La(n,γ) 140 La99,91,6781 d1596,295,4– 89 Y 89 Y(n,γ) 90m Y1003,19 h202,597,3– 51 V 51 V(n,γ) 52 V99,83,743 min1434,1100– 45 Sc 45 Sc(n,γ) 46 Sc10083,79 d1120,599,99– 37 Cl 37 Cl(n,γ) 38 Cl24,237,24 min2167,442,4–

17. 17 Simulation results reaction yields of activation materials – (n,g) reactions upper positionlower position middle position

18. 18 Simulation results reaction yields of activation materials – (n,p) reactions upper positionlower position middle position

19. Thank you for your attention 19