Oxide phase characterization in simulated high burn-up UO$_2$ fuels in the early stages of a nuclear severe accident

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Oxide phase characterization in simulated high burn-up

UO_2 fuels in the early stages of a nuclear severe

accident

C. Le Gall, E. Geiger, O. Proux, M. Rovezzi, P.L. Solari, M. Hunault, V.

Klosek, C. Riglet Martial, J. Léchelle, F. Audubert, et al.

To cite this version:

C. Le Gall, E. Geiger, O. Proux, M. Rovezzi, P.L. Solari, et al.. Oxide phase characterization in simulated high burn-up UO_2 fuels in the early stages of a nuclear severe accident. The 2018 MRS Spring Meeting & Exhibit, Apr 2018, Phoenix, United States. �cea-02338951�

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Oxide phase characterization in

simulated high burn-up UO

₂

fuels in

the early stages of a nuclear severe

accident

April 2-6, 2018 – Phoenix, Arizona

MRS Spring Meeting 2018

|

Claire Le Gall

CEA Cadarache

|

DEN

|

DEC

|

SA3E

|

LAMIR

C. Le Gall

1

_{, E. Geiger}

2

_{, O. Proux}

3

_{, M. Rovezzi}

3

_{, P.L. Solari}

4

_{, M. Hunault}

4

_{, V.}

Klosek

1

_{, C. Riglet-Martial}

1

_{, J. Léchelle}

1

_{, F. Audubert}

1

_{, Y. Pontillon}

1

_,

J.-L. Hazemann

5

1_{CEA / DEN / DEC,}2_{DCCE / RMC Canada,}3_OSUG-UGA,4_{MARS / SOLEIL Synchrotron,}5_{Institut Néel / CNRS UGA}

MRS Spring Meeting 2018, Phoenix, Arizona, April 2-6, 2018

(3)

NUCLEAR FUEL FISSION

Fission products

| PAGE 2 MRS Spring Meeting 2018, Phoenix, Arizona, April 2-6, 2018

D. Heinze Ph.D thesis (2010)

Mo _Ba

Fission yield: FP most probably producted

Fission occurs in nuclear fuel pellets

UO₂ or (U,Pu)O₂ fuel in its Zr alloyed cladding

Pressurized Water Reactor (PWR) Fuel assembly

(4)

SEVERE ACCIDENT PHENOMENA

Source term

Source Term

Nature and quantity of

released radioactive

materials

FP

FP release from the

fuel

J. P. Van Dorsselaere et al., NED 236 (2006) B. R. Sehgal, Nuclear safety in LWR (2012)

Corium formation

Loss of coolant

Cladding

oxidation

(5)

BaMoO

_4(s)

Oxide phase

STUDY OF FPs BEHAVIOR

Mechanism suggested in the literature

G. Nicaise, 8th International Conference on Candu Fuel (2003) G. Nicaise, NT DPAM/SEMIC 2004/37 (2004)

E. Geiger, PhD thesis (2016) H. Kleykamp, J. Nucl. Mater. (1985)

MoO

_2(g)

MoO

_2(s)

MoO

_2(g)

BaZrO

_3(s) Oxide phase

Zr

_(s)

ZrO

_2(s)

BaO

_(s)

BaZrO

_3(s)

BaO

_(g)

Ba

_(g)

Mo/Ru

_(s)

Mo

_(g)

Mo/Ru

_(s)

Oxidation

plateau

(1100-1500°C)

High temp.

plateau

(≥ 2300°C)

Temperature

ramp

(400-1100°C)

Temperature

ramp

(1500-2000°C)

Initial State

SIMFuels

(6)

SIMFuels SAMPLES

Fabrication data

Depleted UO

₂

+ 11 oxides

(FPs surrogates)

Sintering at 1650°C

during 2h under pure H

₂

Elements

Ba

Ce

La

Mo

Sr

Y

Zr

Rh

Pd

Ru

Nd

Concentration

(at%)

0,26

0,61

0,20

0,51

0,13

0,06

0,60

0,03

0,42

0,64

0,91

Concentrations representative of an irradiated fuel

(7)

SIMFuels SAMPLES

Thermal treatments

Mo (s ) + R u(s) + Pd(s) + Rh (s) + ZrO 2 (s) + BaZrO 3(s) + UO2(s) Ru(s) + Pd (s) + Rh(s) + ZrO 2(s) + Ba ZrO3 (s) + MoO2 (s) + UO2(s) Ru(s) + Pd(s) + Rh(s) + ZrO2(s) + BaMo O 4(s) + MoO2 (s) + U O 2(s) ZrO2(s) + BaM oO4(s) + MoO 2 (s) + U4 O9(s2 )

Pd(liq) + MoO2(s) + ZrO2(s)

Pd(liq) + UO2(s) + Ru(s) + Pd(s) + Rh(s ) + + Rh(s) + Ru(s) + UO2(s)

Ru(s) + Mo(s) + Rh3U(s)

H2O/ H2 = 50 H2O/H2 = 0.0 2 Pd (l iq ) + R h (s ) + R u (s ) + M o (s ) + Z rO 2 (s ) + B a Z rO 3 (s ) + U O2 (s ) BaZrO 3(s) BaMo O4(s) Ba - O₂ - Mo - Zr - Ru - Rh - Pd - U Temperature (°C) R T ln p (O 2 ) ( k J/ m ol O 2 ) 400 600 800 1000 1200 1400 1600 1800 2000 -500 -450 -400 -350 -300 -250 -200 -150 Mo (s ) + R u(s) + Pd(s) + Rh (s) + ZrO2(s) + Ba ZrO3 (s) + UO2(s) Ru(s) + Pd (s) + Rh(s) + ZrO 2(s) + Ba ZrO3(s) + Mo O2(s) + UO 2(s) Ru(s) + Pd(s) + Rh(s) + ZrO2(s) + BaMo O 4(s) + MoO2 (s) + U O 2(s) ZrO2(s) + BaMo O 4(s) + M oO 2(s) + U4O9(s2 )

Pd(liq) + MoO2(s) + ZrO2(s)

Pd(liq) + UO2(s) +

Ru(s) + Pd(s) + R

h(s) +

+ Rh(s) + Ru(s) + UO2(s)

Ru(s) + Mo(s) + Rh3U(s)

H2O/ H2 = 50 H2O/H2 = 0.0 2 Pd (l iq ) + R h (s ) + R u (s ) + M o (s ) + Z rO 2 (s ) + B a Z rO 3 (s ) + U O 2 (s ) BaZrO 3(s) BaMo O4(s) Ba - O₂ - Mo - Zr - Ru - Rh - Pd - U Temperature (°C) R T ln p (O 2 ) ( k J/ m ol O 2 ) 400 600 800 1000 1200 1400 1600 1800 2000 -500 -450 -400 -350 -300 -250 -200 -150 R1700 R1000 R900 R700 R400 O1000 O900 O700 O400

BaZrO

3(s)

+ MoO

2(s)

+ ½O

2(g)

BaMoO

4(s)

+ ZrO

2(s)

(8)

(Ba+Sr)/Mo ≈ 1

(Ba+Sr)/Zr ≈ 0.6

O/Zr ≈ 4

CHARACTERIZATIONS

SEM-EDX

C. Thouzellier internship (2017), H. Kleykamp, J. Nucl. Mater. (1985); E. Geiger et al. ERMSAR proceedings (2015); E Geiger et al. J. Nucl. Mater. (accepted)

Sample as sintered

1000°C, -292 kJ.mol

-1

_{1700°C, -426 kJ.mol}

-1

O/Zr ≈ 2

(Sr+Ba)/Zr ≈ 1

O/Zr ≈ 2.5

Ba

_0,8

Sr

_0,2

ZrO

₃

ZrO

₂

Ba

_0,9

Sr

_0,1

ZrO

₃

Mo

Oxide

phase

O/Mo ≈ 5

Ba

_0,8

Sr

_0,2

ZrO

₃

ZrO

2

(Ba, Sr)(Zr, Mo)O

_x

(9)

CHARACTERIZATIONS

SEM-EDX

C. Thouzellier internship (2017), H. Kleykamp, J. Nucl. Mater. (1985); E. Geiger et al. ERMSAR proceedings (2015); E Geiger et al. J. Nucl. Mater. (accepted)

Sample as sintered

1000°C, -292 kJ.mol

-1

_{1700°C, -426 kJ.mol}

-1

O/Mo ≈ 2

Oxide

phase

Metallic

phase

100% Mo

MoO

₂

(10)

0 1 2 3 4

5

6 7 8 9

10

11 19975 20025 20075

N

orm(

E)

Energy (eV)

0 1 2 3 4 5 6 7

8

9 10 11 12 19975 20025 20075 Norm( E ) Energy (eV) R1700 T₀ SrMoO₄ BaMoO₄ MoO3 O1000 O900 T₀ MoO2 Mo SrMoO4 BaMoO4 MoO3 MoO2 Mo 0 1 2 3 4

5

6 7 8 9

10

11 19975 20025 20075

N

orm(

E)

Energy (eV)

0 1 2 3 4 5 6 7

8

9 10 11 12 19975 20025 20075 Norm( E ) Energy (eV) R1700 T₀ SrMoO₄ BaMoO₄ MoO3 O1000 O900 T₀ MoO2 Mo SrMoO4 BaMoO4 MoO3 MoO2 Mo

CHARACTERIZATIONS

X-ray Absorption Spectroscopy at Mo K-edge

No strong evolution of Mo

XANES reducing conditions

Metallic Mo

0 1 2 3 4

5

6 7 8 9

10

11 19975 20025 20075

N

orm(

E)

Energy (eV)

0 1 2 3 4 5 6 7

8

9 10 11 12 19975 20025 20075 Norm( E ) Energy (eV) R1700 T₀ SrMoO₄ BaMoO₄ MoO3 O1000 O900 T₀ MoO2 Mo SrMoO4 BaMoO4 MoO3 MoO2 Mo

Evolution of Mo local

environment from 900°C in

oxidizing conditions

Consistent with Mo oxidation,

MoO

₂

formation and the oxide

(11)

0 1 2 3 4 5 6 7 8 9 10 17975 18025 18075 Norm( E ) Energy (eV) 0 1 2 3 4 5 6

7

8 9 17975 18025 18075 Norm (E) Energy (eV) BaZrO₃ ZrO₂ R1700 T0 Zr BaZrO₃ ZrO₂ Zr O1000 T₀ 0 1 2 3 4 5 6 7 8 9 10 17975 18025 18075 Norm( E ) Energy (eV) 0 1 2 3 4 5 6

7

8 9 17975 18025 18075 Norm (E) Energy (eV) BaZrO₃ ZrO₂ R1700 T0 BaZrO₃ ZrO₂ O1000 T₀ 0 1 2 3 4 5 6 7 8 9 10 17975 18025 18075 Norm( E ) Energy (eV) 0 1 2 3 4 5 6

7

8 9 17975 18025 18075 Norm (E) Energy (eV) BaZrO₃ ZrO2 R1700 T0 BaZrO3 ZrO₂ O1000 T₀ | PAGE 10 MRS Spring Meeting 2018, Phoenix, Arizona, April 2-6, 2018

Zr XANES evolution at 1700°C

in reducing conditions

Consistent with the

continuous BaZrO

₃

formation and stabilization

0 1 2 3 4 5 6 7 8 9 10 17975 18025 18075 Norm( E ) Energy (eV) 0 1 2 3 4 5 6

7

8 9 17975 18025 18075 Norm (E) Energy (eV) BaZrO₃ ZrO2 R1700 T0 Zr BaZrO3 ZrO₂ Zr O1000 T₀ 0 1 2 3 4 5 6 7 8 9 10 17975 18025 18075 Norm( E ) Energy (eV) 0 1 2 3 4 5 6

7

8 9 17975 18025 18075 Norm (E) Energy (eV) BaZrO₃ ZrO₂ R1700 T0 BaZrO₃ ZrO₂ O1000 T₀

Zr XANES evolution from

1000°C in oxidizing conditions

Destruction of part of the

BaZrO

₃

phase and formation of

ZrO

₂

?

Consistent with the oxide phase

evolution (Mo reacts with Ba)

CHARACTERIZATIONS

(12)

0 5 10 15 20 25 5 220 5 250 5 280 5 310 5 340 Norm (E ) Energy (eV) BaMoO4 BaZrO3 BaCO3 BaO 1700°C, 10-27 0 5 10 15 20 25 5 220 5 250 5 280 5 310 5 340 Norm (E ) Energy (eV) BaMoO4 BaZrO3 BaCO3 BaO 1700°C, 10-27 | PAGE 11 MRS Spring Meeting 2018, Phoenix, Arizona, April 2-6, 2018

No Ba XANES evolution at

1700°C in reducing conditions

BaZrO

₃

XANES analyses of the

O-samples scheduled in April

2018

CHARACTERIZATIONS

HERFD-XANES at Ba L

₃

-edge

BaZrO₃ BaMoO4 BaCO₃ BaO R1700 T₀

(13)

BaZrO

_3(s) Oxide phase

BaZrO

_3(s)

ZrO

_2(s)

Mo/Ru

_(s)

Mo/Ru

_(s)

BaMoO

_4(s) Oxide phase | PAGE 12 MRS Spring Meeting 2018, Phoenix, Arizona, April 2-6, 2018

MoO

_2(g)

ZrO

_2(s)

BaZrO

_3(s)

Mo/Ru

_(s)

1000°C

400°C – 900°C

1700°C

Initial State

CONCLUSIONS

Evolution of the oxide phase

Oxidizing atmosphere Reducing atmosphere

ZrO

_2(s)

To be confirmed

(14)

ESRF:

P. Colomp, O. Proux, M. Rovezzi, J. L. Hazemann

MARS/SOLEIL:

M. Hunault, P. L. Solari

CEA/LLCC:

C. Riglet Martial, D. Drouan, C. Tanguy, V. Klosek, J. Léchelle, G. Jomard

CEA/LCU:

F. Garel, P. Matheron, N. Tarisien, X. Itlis, H. Rouquette, J. Raynal,

J. Lamontagne

CEA/LAMIR:

C. Thouzellier, J.C. Richaud, M. Pontillon, G. Volle, A. Gallais During, Y.

Pontillon, F. Audubert, I. Moysan

Commissariat à l’énergie atomique et aux énergies alternatives Centre de Cadarache| 13108 Saint Paul lez Durance T. +33 (0)4 42 25 70 00

Etablissement public à caractère industriel et commercial | R.C.S Paris B 775 685 019 MRS Spring Meeting 2018, Phoenix, Arizona,