Joint ICTP/IAEA School on Physics and Technology of Fast Reactors Systems November 2009

Transcription

1 Joint ICTP/IAEA School on Physics and Technology of Fast Reactors Systems 9-20 November 2009 Experimental checking and justification of pyrochemical origin plutonium dioxide application for pellet MOX-fuel fabrication Alexander Bychkov State Scientific Centre Research Institute of Atomic Reactors Dimitrovgrad Russia

2 Experimental checking and justification of pyrochemical origin plutonium dioxide application for pellet MOX-fuel fabrication A.G. Osipenko, R.S. Galiev, M.V. Kormilitsyn, V.A. Stupin, V.N. Suzev, A.D. Yurchenko, A.V.Bychkov Research Institute of Atomic Reactors, Dimitrovgrad, Russia

3 One of conceptions for on-site fast reactor closed fuel cycle Spent FAs Spent MOX-fuel Fast reactor Dismantling & Decladding 238 UO 2 powder Pyrochemical reprocessing in chloride melt #1 Precipitation Electrolysis/ Precipitation FP PuO 2 + MA + FP 238 UO 2 + MA + FP MA Conditioning in chloride melt #1 or #2 PuO 2 MA Fabrication of Vipac MA targets Fabrication of pellets and FAs Fabrication of Vipac FAs FP Waste conditioning Waste disposal

4 Request to powders for fabrication of pellet and Vipac MOX-fuel Characteristics Pellets* Vipac** Profile Vipac** O/Pu Particle size, μm <88 < Bulk density, g/cm 3 1,5-2.5 >2.3 >2.3 Specific surface, m 2 /g 5-30 no special request no special request Fluidity, g/s no special request no special request no special request *NE Standards NE E13-1T, Ceramic Grade Plutonium Dioxide, US DOE Nuclear Energy Programs, Washington, Standard Specification for Nuclear Grade Plutonium Dioxide Powder, Sinterable, ASTM, C Annual Book of ASTM Standards, V **Osipenko A.G., Poglyad S.S., Skiba O.V. et al. Influence of precipitation conditions on gralunometric composition of plutonium dioxide // Bulletin of USTU-UPI, 2004, p.132.

5 Reactions in chloride melt under bubbling of gas mixture In bulk melt Pu 3+ + ½ Cl 2 (gas) Pu 4+ + Cl - Pu 4+ + O 2 (gas) + 2Cl - PuO Cl 2 (gas) PuO Cl - PuO 2+ + ½ Cl 2 (gas) PuO 2+ + Cl - PuO 2 (s) + ½ Cl 2 (gas) PuO 2 (s) + Cl 2 (gas) PuO Cl - + ½ O 2 (gas) PuO 2 (s) Pu 4+ + O 2- ½O 2 (gas) + 2 Cl - O 2- + Cl 2 (gas) In surface of carbon containment and devices PuO C + Cl 2 (gas) Pu 4+ + CO 2 (gas) + 2 Cl - C + 2O Cl 2 (gas) CO 2 (gas) + 4 Cl -

6 Main factors effected to particle growth condition critical size of nucleus of crystal nucleus of crystal amount rate of feed supply (gas or other oxidant)

7 Influence of solvent a b c PuO 2 particle image: a) NaCl-2CsCl, T=550 o C; b) 3LiCl-2KCl, T=450 o C; c) 0,575LiCl-0,165KCl-0,26CsCl, T=450 o C Specific interphase surface 0.26 cm -1 P 1/2 (O 2 )/Р(Cl 2 ) 99

8 Conditions of powder production Powder properties Melt T, о C P 1/2 (O 2 )/Р(Cl 2 ) Specific interphase gas-liquid, cm -1 Lattice spacing, Å Size of coherent dispersion area, nm Fluidity, g/s Influence of solvent NaCl-2CsCl 550 5,3745 ± 0, ,2 ± 23,6 22 3LiCl- 2KCl 450 5,3804 ±0, ,9 ± 2,6 5,3745±0, ,7 ± 2,1 Specific surface, m 2 /g 3.8 ± ± ± 1.1 Bulk density, g/cm no 0,575LiCl- 0,165KCl- 0,26CsCl 450 no -20μm, wt% μm, wt%

9 Comparison with powder from oxalate a b Particle image : a) UO 2 from oxalate, T=750 o C; b) PuO 2 from 3LiCl-2KCl, T=450 o C;

10 Fabrication of MOX and PuO 2 pellets Composition of molding powder, wt% 100 UO 2 industrial (from oxalate) 97 UO 2 +3 PuO 2 (from 3LiCl-2KCl) Pellet density, g/cm UO PuO 2 (from LiCl-KCl-CsCl) UO PuO 2 (from 3LiCl-2KCl) PuO 2 (from LiCl-KCl-CsCl) 10.3

11 Microstructure of pickled pellet (80UO2+20PuO2) 100μm

12 Distribution of U and Pu on pellet Массовая доля U, Pu,% Content, wt% U Pu μm Расстояние, мкм

13 Influence of O 2 /Cl 2 ratio P 1/2 (O 2 )/P(Cl 2 )= 2.5 P 1/2 (O 2 )/P(Cl 2 )=99 Melt NaCl-2CsCl Temperature 550 о С Specific interphase surface 0.26

14 Influence of O 2 /Cl 2 ratio Conditions of powder production Melt T, о С Specific interphase gas-liquid, cm -1 P 1/2 (O 2 )/Р(Cl 2 ) NaCl-2CsCl Powder properties Fluidity, g/s Specific surface, m 2 /g ± ± Bulk density, g/cm /5.0-20μm, wt% μm, wt% 54 97

15 Influence of ratio O 2 /Cl 2 Dependence of the particles weight on their size 100 Size Size Weight, % O 2 /Cl 2 Specific interphase 0.26 cm -1 Temperature 550 о С

16 Effect of specific surphase on granulometric composition 100 Массовая Content in доля powder, фракции,% wt% фракция Size фракция Size Specific interphase surface, cm Межфазная удельная поверхность,1/см Temperature 550 о С P 1/2 (O 2 )/Р(Cl 2 ) 99

17 Conclusions Pyrochemical processes can be used for production of plutonium dioxide powders suitable for manufacturing of MOX or PuO 2 pellet The effect of solvent, ratio O 2 /Cl 2, specific interphase on morphology of plutonium dioxide precipitated from molten chloride was studied. Variation of these parameters makes it possible to widely vary properties of plutonium dioxide powder for MOX fuel (vibro or pellet)

18 Thank you for attention!