RIAR Radiochemical Division

Status and Results of Research on PYROSMANI 

Coordinated ProjectResearch Institute of Atomic Reactors,  Dimitrovgrad

NRC “Kurchatov Institute”,  Moscow

Presented by Victor IgnatievIgnatev_VV@nrcki.ru

1

SACSESS International Workshop, Warsaw, Poland, April 22‐24, 2015

RIAR Radiochemical Division

PYROSMANIPYROchemical processes Study for Minor ActiNIdes

recycling in molten salts

Project objective –

to evaluate the feasibility of Minor Actinides recycling bypyro separation in molten salts

To prepare data base concerned the development ofpyropartitioning flow sheets, including ChemistryInstrumentation and Monitoring for Molten Salts Streams,for innovative types of fuel in order to improve thesustainability of nuclear power

RIAR Radiochemical Division

PYROSMANIPYROchemical processes Study for Minor ActiNIdes

recycling in molten salts

Project duration:  2014 ‐2016

Leading institution: JSC “SCC RIAR” (Dimitrovgrad)

Participating institutions: NRC “Kurchatov Institute” (Moscow), IHTE RAS and UFU‐UPI (Ekaterinburg)

EU partner:  FP7 SACSESS project  (DM 2)

CooA between CEA and RIAR signed in March 2014

RIAR Radiochemical Division

PYROSMANI: KI activity in 2014

Measurement of kinematic viscosity and

density for molten LiF-AlF3 and LiF-BeF2

salt mixtures

Liquid - liquid extraction of samarium and

europium fluorides for LiF-BeF2 / Bi system

Salt corrosion and chemistry control

5

73LiF‐27BeF2

NaF‐BeF2

LiF‐NaF‐BeF2

85LiF‐15 AlF3

‐‐‐‐ 73LiF‐27BeF2‐ ‐ ‐ (73LiF‐27BeF2)+1CeF3

Viscosity and Density

Temperature (C)

85LiF‐15 AlF3

Reductive Extraction with Liquid Bi-LiRelative extractabilities of elements are determined by measuring equilibrium distribution coefficients in the

two phase system : MFn(melt) + nLio(Bi) Mo(Bi) + nLiF(melt), Distribution coefficient for M is defined by: D=XM/XMFnRatio of distribution coefficients ( = D1 / D2) features the separation of the two components between phases

-4

-3,5

-3

-2,5

-2

-1,5

-1

-0,5

0-3,25 -2,75 -2,25

LgD(Li)

LgD

(Nd,

La,T

h)

I - Nd

II - La

III - Th

I

II

III

74LiF‐22BeF2‐4ThF4at 650C

73LiF‐27BeF2at 600C  

LgD(Nd)  = 3LgD(Li)+6.11 LgD(La)   = 3LgD(Li)+5.91 

LiCl at 650C

Impossible d’afficher l’image.

-16

-14

-12

-10

-8

-6

-4

-2

00.0005 0.001 0.0015 0.002 0.0025 0.003

1/Т, Кlg Cнас

lgC(K-O) lgC(K-Ni) lgC(K-Fe) lgC(K-Cr)lgC(Li-O) lgC(Li-Ni) lgC(Li-Fe) lgC(Li-Cr)lgC(Na-O) lgC(Na-Ni) lgC(Na-Fe1) lgC(Na-Cr)lgC(Na-Cr1) lgC(Pb-O) lgC(Pb-O1)lgC(Pb-Ni) lgC(Pb-Fe) lgC(Pb-Cr)

• For areas of processing unit where there is direct contact with the liquid metal(e.g. bismuth) traditional structural materials such as Ni‐ and Fe‐ based alloysare not suitable because of (1) increased solubility in the liquid metal or (2)subjecting the mass transfer at exposure system with a temperature gradient.

• Materials showed good compatibility with liquid metals in the limited numberof tests include graphite, and refractory metals such as tungsten, rhenium,molybdenum and tantalum. Except tantalum, these materials are difficult tomanufacture and compound. All rapidly oxidize in air at temperatures ofatmospheric processes and require protection.

Materials for processing unit

There are several methods to manage protective coatings:•The introduction of non‐metallic impurities into the structure of the containermaterials, including the introduction of liquid metal atoms into the steel (theformation of complex compounds MexLMyOz, where Me‐solid metal, LM‐liquidmetal, O–oxygen and x,y,z‐ stoichiometric ratios•Introducing metallic impurities into the structure of container material to forman intermetallic, followed by oxidation and without it•The precipitation of the compounds formed in the melt and others

Materials protection in liquid metals

-10,0

0,0

10,0

20,0

30,0

40,0

50,0

60,0

70,0

80,0

0,0 10,0 20,0 30,0 40,0 50,0 60,0 70,0 80,0 90,0

расстояние от поверхности, мкм

атом

ный

% эле

мен

тов

Al Si Cr Fe Ni

10Х15Н9С3Б1 steel after exposure in Al at 1073 К during 6 hrs

Al5FeNi or Al5Fe2.

Corrosion Systems for studiesU(IV)/U(III)

Solvent LiF-BeF2 LiF-AlF3

Fuel addition UF4, ThF4

Liquid metal Bi-Li Bi-Mg-Li Al-CuTemperature C 650 800

Exposure time, hrs

100 -1000

Container material

Graphite Mo, W, Ta, Re

-0.8 -0.6 -0.4 -0.2 0 0.2

E [ V ]

-500

-400

-300

-200

-100

0

100

200

300

Ecp [U(IV)→ U(I I I )]

=–0.32V

I [mA]

[U(IV)] /[U(III)]

HN80МT-VI,enlargement ×160

HN80МTY,enlargement ×160

500without loading at 735oC

K =3360pc×μm/cm; l =166μm K=1660pc×μm/cm; l=68μm

50025MPa 740oC

K =8300pc×μm/cm; l =180μm K = 1850pc×μm/cm ; l=80μm

10025MPa 740oC

no no

Corrosion in LiF-BeF2-ThF4-UF4

• In the short term, from an engineering point ofview the use of graphite block pyrochemicalprocessing will require the least amount ofresearch.

• Also, the use of graphite as the main structuralmaterial block pyrochemical reprocessing requirethe development of a class of compounds ofspecial graphite ‐ graphite and graphite ‐metal.

• Results for material compatibility and flowsheetdevelopment unit reprocessing received soon willdetermine the degree of follow‐up for each ofthese materials.

Materials for processing unit

RIAR Radiochemical Division

PYROSMANI: RIAR activity in 2014 PrF3 and AmFn solubility measurements in Li,Na,K/F

eutectics by three different methods: • Isothermicsaturation

• Reflectance spectroscopy

• Electrochemical method of limiting deposition current

АРГОН

9

2

3

4

6

7 8

11 12

10

1

5

The method of isothermal saturation

1– cell,2‐pellet’s supply tube3 ‐ crucible made of Nickel 4,8,11,12 ‐ Thermocouples 5,10 ‐ Argon supply; 6 – Furnac

RIAR Radiochemical Division

Reflectance spectroscopy

beam inlet ‐ 1, collimator – 2, mirror ‐3, divider (splitter) – 4, molten salt – 5, window ‐6, collimator‐ 7, channel optical fiber ‐8, shutter ‐9, reference – 10, catcher – 11, water‐cooled case – 12, heater ‐13, container ‐14, mirror ‐15, Pt‐Rh

RIAR Radiochemical Division15

Electrochemical methods

2 –carbon auxiliary electrode; 3–Mo working electrode; 

5 –Pt quazi reference electrode; 6–thermocouple; 

14 – glass graphite crucible; 15 ‐melt

LiF‐NaF‐KF+PrF3

LiF‐NaF‐KF+PrF3

LiF‐NaF‐KF+AmF3

Pulse‐differential voltammetry

LiF‐NaF‐KF+AmF3at 873 K

Cyclic voltammograms Cyclic voltammograms 

Normal‐differential voltammetry

Temperature,К

PrF3, mol. %

Isothermal saturation Electrochemical methods Reflectance spectroscopy

773 (8,87) 10,1±1,0 13,3±1,3823 (13,35) 13,7±1,0 17,7±1,7873 19,0±1,1 18,9±1,0 22,2±2,2923 26,6±1,4 (34,2) (26,7)973 36,2±1,8 (40,8) (31,2)1023 45,3±2,3 (48,3) (35,6)

Equation lgS=3,8731-2261,2/T lgS=3,43-1889/T lgS=2,87-1347/T

16

Temperature,К

AmF3, mol. %

Isothermal saturation Electrochemical methods Reflectance spectroscopy

773 (12,5) (8,3) 12,9±1,1823 18,0±1,8 12,8±1,0 17,9±1,8873 31,7±3,1 18,8±1,0 22,9±2,3923 34,0±3,4 (26,6) (27,9)973 43,4±4,3 (36,3) (33,0)

1023 (55,5) (48,0) (38,0)Equation lgS=3,75-2051,6/T lgS=4,04-2413/T lgS=3,03-1472/T

In brackets are the data obtained as a result of their calculation and the approximation by the equations

Individual Solubility in FLiNaK Eutectics

5

7

9

11

13

15

17

19

21

23

25

27

29

31

33

35

37

39

41

43

45

47

750 775 800 825 850 875 900 925 950 975 1000 1025 1050

Temperature, К

Solu

bilit

y, m

ol.%

Isothermalsaturation

Electrochemical

Reflectance spectroscopy

PrF3 Solubility in FLiNaK Eutectics

RIAR Radiochemical Division

579

11131517192123252729313335373941434547

750 775 800 825 850 875 900 925 950 975 1000 1025 1050

Temperature, К

Solu

bilit

y (A

mF 3

), m

ol.%

Electrochemical

Isothermalsaturation

Reflectance spectroscopy

AmF3 Solubility in FLiNaK Eutectics

RIAR Radiochemical Division

Individual Solubility in FLiNaK Eutectics

10

12

14

16

18

20

22

24

26

28

30

32

34

36

38

40

42

44

46

800 825 850 875 900 925 950 975 1000 1025 1050

Temperature, К

Solu

bilit

y, m

ol.%

UF4ThF4PuF3NdF3PrF3CeF3AmF3

Isothermal saturation

T,ºСIndividual Solubility, mol.% Joint Solubility, mol. %

PuF3 UF4 PuF3 UF4

550 6.1±0.6 15.3±0.8 1.16±0.06 1.75±0.09

600 11.1±1.1 24.6±1.2 2.9±0.1 3.5±0.2

650 21.3±2.1 34.8±1.7 13.2±0.6 11.0±0.6

700 32.8±3.3 44.7±2.2 19.1±1.0 17.3±0.9

750 - - 21.0±1.1 19.0±1.0

800 - - 22.5±1.2 20.0±1.1

Solubility and Viscosity in FLiNaK Eutectics

+30mol%UF4

+30mol%UF4 +10mol%CeF3

+30mol%UF4

+30mol%UF4 +10mol%CeF3

Isothermal saturation

RIAR Radiochemical Division

Key Papers’ 2014-2015 Feynberg O, Ignatiev V, Kormylitsin M, et al (2014) Molten salt actinide

recycler & transforming system without and with Th‐U support: fuelcycle flexibility and key material properties, Annals of Nuclear Energy,64: 408–420

Merzlyakov A, Ignatiev V, Abalin S (2014) Viscosity of LiF‐NaF‐KFeutectic and effect of cerium trifluoride and uranium tetrafluorideadditions, Nuclear Engineering and Design, 278: 268‐273

Lizin A, Tomilin S, Ignatiev V, et al (2015) Joint Solubility of PuF3 andCeF3 in Ternary Melts of Lithium, Thorium, and Uranium Fluorides,Radiokhimiya, 57 / 1: 32–37

Lizin A, Tomilin S, Ignatiev V, et al (2015) Joint Solubility of PuF3 and UF4in Ternary Melts of Lithium, Sodium and Potassium Fluorides,Radiokhimiya, to be published

Zagnit’ko A and Ignat’ev V (2015) The equilibrium distribution ofsamarium and europium between the molten fluoride salts and liquidbismuth, Russian Journal of Physical Chemistry, to be published