The European Commission s science and knowledge service

Transcription

1 The European Commission s science and knowledge service Joint Research Centre EU activities in the MSR project O. Beneš

2 JRC Karlsruhe ITU One of the 7 research institutes of the European Commission s Joint Research Centre ~ 300 staff members Location: EU, Germany, Karlsruhe 4 Scientific Units (actinides + irradiated fuel) (hot cells, γ-shielded GB, α-tight GB)

3 NUCLEAR SAFETY & NUCLEAR SECURITY Scientific Excellence: Fundamental properties & applications Safety of nuclear fuel cycle / waste management & decommissioning / environment Nuclear safeguards, non-proliferation & security Training & Education

4 Nuclear Fuels investigated - Oxides: UO 2 based MOX based MOX + MA - Halides: Fluorides (ThF 4, UF 4, PuF 3 ) Chlorides - Carbides: U-Pu-C system

5 JRC Karlsruhe Uniqueness: JRC Karlsruhe is one of the very few facilities being able to measure high temperature properties of actinide containing fluoride salts. This provides a significant support to other EU partners dealing with the design and safety assessments of MSR concepts. - WP leader of SAMOFAR (experimental data) Main concepts studied: MSFR (EU reference concept) MOSART (Russian concept) MSBR (TMSR) (traditional ORNL and Chinese concept)

6 MSR activities at JRC - MSR activities at JRC since permanent member of GIF MSR PSSC (EURATOM representative) (MoU signature in 2010) - JRC role is to: support member states (NL, FR, CZ, IT) Implementing body within GIF safety assessment of MSR No reactor development - Strongly supported by framework programmes of European Union Successful MSR EU projects of the past: MOST (3 years ) ALISIA (1 year 2007) EVOL (3 years ) SAMOFAR (4 years Aug Aug. 2019) (WP2 leader)

7 MS activities Synthesis of An-fluoride and chloride salts Pyrochemical reprocessing of the fuel Physico-chemical properties investigation Thermodynamic Database of F - and Cl - salts PIE of fuels

8 #1 - Synthesis PuF 3

9 #1 - Synthesis Synthesis of An halides from oxides/metals Ar, N 2 glove box (O 2, H 2 O < 2 ppm) Synthesis/Purification by Cl 2 /HCl and HF gases Fluorination: Furnaces with Inconel reactors (up to 1200 C) Chlorination: Furnace with quartz reactor HF gas installation Inconel fluorination reactor Quartz reactor for chlorination 9

10 #1 - Synthesis Purity must be checked XRD technique not enough!!! DSC technique for m.p. determination 10

11 #2 Electrochemistry/Pyrochemistry

12 #2a Electrochemistry (basic studies) Electrochemistry of An in molten chlorides and fluorides 2 glove boxes under purified Ar atmosphere Electrochemical properties of An in molten LiCl-KCl and LiF-CaF 2 Reaction mechanisms, diffusion coefficients, electrode potentials, activity coefficients, 12

13 #2b Pyrochemistry (irradiated) Lead-shielded cell under purified Ar atmosphere (< 20 ppm H 2 O, O 2 ) operated under CRIEPI- JRC collaboration agreement High temperature furnace and stainless steel electrolyser / reactor (100 gram scale) METAPHIX 1-3 fuels (U-Pu-Zr alloy with MA and RE) 13

14 #2b Pyrochemistry (irradiated) + i - Electrorefining using inert and reactive liquid electrodes 1 st step: Recovery of U as dendrites on an inert iron cathode 2 nd step: Recovery of Pu, minor actinides and the residual U on liquid Cd cathode An-Ln Fuel e - e - FP n+ Ln n+ An n+ Al-An alloy Al Al-An alloy Selective reduction Anodic dissolution Molten LiCl-KCl (450 C) Output: Very high separation factors of An vs. Ln (up to 10 4 ), transport properties (diffusion coefficient of An in Al),morphology, structure and chemical composition of the deposits 14

15 #3 Properties of MSR fuel

16 #3 Properties For the MSR design: - Neutronic properties - Melting temperature - Heat capacity - Vapour pressure - Actinide solubility Thermochemistry - Chemical stability to high T - Density and Viscosity - Thermal conductivity Under development (SAMOFAR) - Stability to radiation 16

17 #3 Properties Challenges for experimental studies Purity of of the materials Treatment with HF(g) How to contain the liquid? How to avoid corrosion? How to avoid vaporisation? 6 years to set-up the facility Ni-based, C, BN container materials Encapsulation

18 #3 Properties LiF-ThF 4 phase diagram revisited mixing enthalpy

19 #3 Properties Melting point and fuision H of Li 3 ThF 7 fusion enthalpy values DSC output T m = K our experiment fus H = 13.7 ± 2 kj/mol Gilbert 1962 fus H = 14.6 kj/mol our LiF-ThF 4 assessment fus H = 14.6 kj/mol melting of a Ag standard congruent melting of Li 3 ThF 7 19

20 #3 Properties LiF-ThF 4 phase diagram - our data - ORNL data - invariant eq. ORNL Other investigated systems: LiF - CeF 3 CeF 3 - ThF 4 ternary LiF-CeF 3 -ThF 4 CaF 2 ThF 4 LiF UF 3 NaF UF 3 CsF - ThF 4 PuF 3 to come in

21 #3 Properties High T C p determination of CsF Heat capacity: T m = 973 K solid phase: C p = ,981 J. K. mol -1 liquid phase: C p = J. K. mol -1 Fusion enthalpy: fus H = 21,550 J. mol -1 (DSC: fus H = 22,190 J. mol -1 ) 21

22 #3 Properties C p of binary mixtures Four LiF-CaF 2 compositions have been prepared: LiF-CaF 2 (50-50) ( ) (75-25) ( ) mol% C p measured by means of DSC using the step method. (50-50) by drop calorimetry. Other investigated systems: LiF NaF system LiF CaF 2 system LiF KF system LiF CeF 3 system LiF RbF system LiF ThF 4 system LiF CsF system 22

23 #3 Properties LiF-ThF 4 vapour pressure Cs and I release from MSR fuel CsF and CsI retention - Flinak solvent - LiF-ThF 4 solvent - LiF-ThF 4 -UF 4 solvent comparison to oxides

24 #4 Thermodynamic modelling

25 #4 Thermodynamic modelling For MSR design: - Neutronic properties - Melting temperature - Heat capacity - Vapour pressure - Actinide solubility Thermochemistry - Chemical stability to high T - Density and Viscosity - Thermal conductivity - Stability to radiation Thermodynamic modelling (all properties linked to Gibbs energy) 25

26 #4 Thermodynamic modelling LiF ThF 4 (78 22) composition at 1000K Boiling point 2026 K Phases present Liquid only First precipitate LiF + Li 3 ThF 7 Melting point 858 K F 2 potential corrosion driving force Activity coefficients γ(lif) = γ(thf 4 ) = Heat capacity 87.7 J K -1 mol -1 Solubility of ThF 4 in LiF TD quantities absolute entropy (S): J K -1 mol -1 enthalpy (H): J mol -1 Gibbs energy (G): J mol -1 Enthalpy of freezing Vapour pressure 0.07 Pa (total) Pa (LiF) 0.02 Pa (Li 2 F 2 ) Pa (Li 3 F 3 ) Pa (ThF 4 ) 26

27 #4 Thermodynamic modelling Ex.1 - solubility The LiF-BeF 2 -ThF 4 system

28 #4 Thermodynamic modelling ITU Salt Database: (46 binary systems) Fuel types one can fully describe: LiF BeF 2 NaF PuF 3 LiF-NaF-KF-RbF-CsF-LaF 3 -PuF 3 LiF-NaF-BeF 2 -UF 4 -ThF 4 LiF-NaF-UF 3 -UF 4 Database can be provided through bilateral contract LiF-ThF 4 -UF 4 -PuF 3 LiF-ThF 4 -CsF-CsI Properties of fuel concepts such as MSFR, MSBR/TMSR, MOSART can be optimized/predicted 28

29 #5 PIE of irradiated fuels 1. release 2. release 3. release matrix vaporization grain boudary diffusion through matrix

30 #5 - PIE SALIENT01 7 LiF-ThF 4 (78-22 mol%) NRG JRC collaboration SALIENT02 7 LiF-BeF 2 -UF 4 ( mol%) Corrosion-resistant graphite crucible Open container (through metallic filter) to accommodate FG release Crucible wall temperature maintained at ~T melt + 50 K Neutron fluence monitored through activation sets 30

31 #5 - PIE KEMS for FP release TEM for structure observation (FG bubbles, 5M particles) 31

32 Summary JRC Karlsruhe is an unique place to handle An-containing or irradiated fluoride/chloride salts Synthesis and purification of actinide fluoride/chlorides is established at ITU Physico-chemical properties to high T (up to 1800 K) are measured at ITU (including Heat capacity, Melting points, Equilibrium data, Heat of transition, Enthalpies, Vapour pressure) (Viscosity, Density, Thermal conductivity under development) Extensive thermodynamic Salt Database has been developed at ITU (Subject of availability through bilateral contracts) Open to 'any' kind of collaboration in the field of common ineterest 32

33 Stay in touch EU Science Hub: ec.europa.eu/jrc Facebook: EU Science Hub - Joint Research Centre LinkedIn: Joint Research Centre YouTube: EU Science Hub