A finite element method (FEM) is applied to investigate the thermal conductivity of polycrystalline UO2. The influences of microstructure are especially important for UO2 due to the severe structural changes under irradiation conditions. In this study, we have investigated the influences of microstructures on the thermal conductivity of polycrystalline UO2 using FEM. The temperature profile of fuel pellet with different microstructures during service is also investigated. The thermal conductivity increases with increasing grain size. The grain size distribution has obvious influence on the thermal conductivity especially when there are pores in the polycrystal. The influences of porosity and pore size are very sensitive to the position of the pores. The results obtained in this study are useful for the prediction of property changes of UO2 fuel in pile and important to gain some design guidance to tune the properties through the control of the microstructure.

References

References
1.
Albarhoum
,
M.
,
2011
, “
Performance of UO2 Ceramic Fuel in Low-Power Research Reactors
,”
Prog. Nucl. Energy
,
53
(
1
), pp.
73
75
.
2.
Lucuta
,
P. G.
,
Matzke
,
H.
, and
Hastings
,
I. J.
,
1996
, “
A Pragmatic Approach to Modelling Thermal Conductivity of Irradiated UO2 Fuel: Review and Recommendations
,”
J. Nucl. Mater.
,
232
(
2–3
), pp.
166
180
.
3.
An
,
C.
,
Moreira
,
F. C.
, and
Su
,
J.
,
2014
, “
Thermal Analysis of the Melting Process in a Nuclear Fuel Rod
,”
Appl. Therm. Eng.
,
68
(
1–2
), pp.
133
143
.
4.
Soba
,
A.
,
Lemes
,
M.
,
González
,
M. E.
,
Denis
,
M.
, and
Romero.
,
L.
,
2014
, “
Simulation of the Behaviour of Nuclear Fuel Under High Burnup Conditions
,”
Ann. Nucl. Energy
,
70
, pp.
147
156
.
5.
Hyland
,
G. J.
,
1983
, “
Thermal Conductivity of Solid UO2: Critique and Recommendation
,”
J. Nucl. Mater.
,
113
(2–3), pp.
125
132
.
6.
Higuch
,
S.
,
1998
, “
A Molecular Dynamics Study of Thermal Conductivity of UO2 with Imupurities
,”
J. Nucl. Sci. Technol.
,
35
(11), pp. 833–835.
7.
Millett
,
P. C.
,
Tonks
,
M. R.
,
Chockalingam
,
K.
,
Zhang
,
Y.
, and
Biner
,
S. B.
,
2013
, “
Three Dimensional Calculations of the Effective Kapitza Resistance of UO2 Grain Boundaries Containing Intergranular Bubbles
,”
J. Nucl. Mater.
,
439
(1–3), pp.
117
122
.
8.
Harding
,
J. H.
, and
Martin
,
D. G.
,
1989
, “
A Recommendation for the Thermal Conductivity of UO2
,”
J. Nucl. Mater.
,
166
(
3
), pp.
223
226
.
9.
Konings
,
R. G. M.
,
Wiss
,
T.
, and
Beneš
,
O.
,
2015
, “
Predicting Material Release During a Nuclear Reactor Accident
,”
Nat. Mater.
,
14
(
3
), pp.
247
252
.
10.
Yang
,
H. S.
,
Bai
,
G. R.
,
Thompson
,
L. J.
, and
Eastman
,
J. A.
,
2002
, “
Interfacial Thermal Resistance in Nanocrystalline Yttria-Stabilized Zirconia
,”
Acta Mater.
,
50
(
9
), pp.
2309
2317
.
11.
Nikolopoulos
,
P.
, and
Ondracek
,
G.
,
1983
, “
Conductivity Bounds for Porous Nuclear Fuels
,”
J. Nucl. Mater.
,
114
(2–3), pp.
231
233
.
12.
Albrecht
,
J. D.
,
Knipp
,
P. A.
, and,
Reinecke
,
T. L.
,
2001
, “
Thermal Conductivity of Opals and Related Composites
,”
Phys. Rev. B
,
63
(
13
), p.
134303
.
13.
Loeb
,
A. L.
,
1954
, “
Thermal Conductivity 8. A Theory of Thermal Conductivity of Porous Materials
,”
J. Am. Ceram. Soc.
,
37
(
2
), pp.
96
99
.
14.
Bakker
,
K.
,
Kwast
,
H.
, and
Cordfunke
,
E. H. P.
,
1995
, “
Determination of a Porosity Correction Factor for the Thermal Conductivity of Irradiated UO2 Fuel by Means of the Finite Element Method
,”
J. Nucl. Mater.
,
226
(
1–2
), pp.
128
143
.
15.
Nichenko
,
S.
, and
Staicu
,
D.
,
2014
, “
Thermal Conductivity of Porous UO2: Molecular Dynamics Study
,”
J. Nucl. Mater.
,
454
(1–3), pp.
315
322
.
16.
Millett
,
P. C.
, and
Tonks
,
M.
,
2011
, “
Meso-Scale Modeling of the Influence of Intergranular Gas Bubbles on Effective Thermal Conductivity
,”
J. Nucl. Mater.
,
412
(
3
), pp.
281
286
.
17.
Chockalingam
,
K.
,
Millett
,
P. C.
, and
Tonks
,
M.
,
2012
, “
Effects of Intergranular Gas Bubbles on Thermal Conductivity
,”
J. Nucl. Mater.
,
430
(
166–170
), pp.
166
170
.
18.
Kim
,
H.
,
Kim
,
M. H.
, and
Kaviany
,
M.
,
2014
, “
Lattice Thermal Conductivity of UO2 Using Ab-Initio and Classical Molecular Dynamics
,”
J. Appl. Phys.
,
115
(
12
), p.
123510
.
19.
Chen
,
T.
,
Chen
,
D.
,
Sencer
,
B. H.
, and
Shao
,
L.
,
2014
, “
Molecular Dynamics Simulations of Grain Boundary Thermal Resistance in UO2
,”
J. Nucl. Mater.
,
452
(
1–3
), pp.
364
369
.
20.
Williams
,
N. R.
,
Molinari
,
M.
,
Parker
,
S. C.
, and
Storr
,
M. T.
,
2015
, “
Atomistic Investigation of the Structure and Transport Properties of Tilt Grain Boundaries of UO2
,”
J. Nucl. Mater.
,
458
, pp.
45
55
.
21.
Kang
,
K. W.
,
Yang
,
J. H.
,
Kim
,
J. H.
,
Rhee
,
Y. W.
,
Kim
,
D. J.
,
Kim
,
K. S.
, and
Song
,
K. W.
,
2010
, “
Effects of MnO-Al2O3 on the Grain Growth and High-Temperature Deformation Strain of UO2 Fuel Pellets
,”
J. Nucl. Sci. Technol.
,
47
(
3
), pp.
304
307
.
22.
Schelling
,
P. K.
,
Phillpot
,
S. R.
, and
Keblinski
,
P.
,
2002
, “
Phonon Wave-Packet Dynamics at Semiconductor Interfaces by Molecular-Dynamics Simulation
,”
Appl. Phys. Lett.
,
80
(14), p.
2484
.
23.
Smith
,
D. S.
,
Fayette
,
S.
,
Grandjean
,
S.
,
Martin
,
C.
,
Telle
,
R.
, and
Tonnessen
,
T.
,
2003
, “
Thermal Resistance of Grain Boundaries in Alumina Ceramics and Refractories
,”
J. Am. Ceram. Soc.
,
86
(
1
), pp.
105
111
.
24.
Amrit
,
J.
,
2006
, “
Grain Boundary Kapitza Resistance and Grain-Arrangement Induced Anisotropy in the Thermal Conductivity of Polycrystalline Niobium at Low Temperatures
,”
J. Phys. D: Appl. Phys.
,
39
(
20
), pp.
4472
4477
.
25.
Manzel
,
R.
, and
Walker
,
C. T.
,
2002
, “
Epma and Sem of Fuel Samples From Pwr Rods With an Average Burn-up of Around 100 MWd/kgHM
,”
J. Nucl. Mater.
,
301
(2–3), pp.
170
182
.
26.
Sasahara
,
A.
, and
Matsumura
,
T.
,
2008
, “
Post-Irradiation Examinations Focused on Fuel Integrity of Spent Bwr-Mox and Pwr-UO2 Fuels Stored for 20 Years
,”
Nucl. Eng. Des.
,
238
(
5
), pp.
1250
1259
.
27.
Arborelius
,
J.
,
Backman
,
K.
,
Hallstadius
,
L.
,
Limbaeck
,
M.
,
Nilsson
,
J.
,
Rebensdorff
,
B.
,
Zhou
,
G.
,
Kitano
,
K.
,
Loefstroem
,
R.
, and
Roennberg
,
G.
,
2006
, “
Advanced Doped UO2 Pellets in LWR Applications
,”
J. Nucl. Sci. Technol.
,
43
(
9
), pp.
967
976
.
28.
Harada
,
Y.
,
1997
, “
UO2 Sintering in Controlled Oxygen Atmospheres of Three-Stage Process
,”
J. Nucl. Mater.
,
245
(
2
), pp.
217
223
.
29.
Song
,
K. W.
,
Kim
,
K. S.
,
Kang
,
K. W.
, and
Jung
,
Y. H.
,
2003
, “
Grain Size Control of UO2 Pellets by Adding Heat-Treated U3O8 Particles to UO2 Powder
,”
J. Nucl. Mater.
,
317
(2–3), pp.
204
211
.
30.
Une
,
K.
,
Hirai
,
M.
,
Nogita
,
K.
,
Hosokawa
,
T.
,
Suzawa
,
Y.
,
Shimizu
,
S.
, and
Etoh
,
Y.
,
2000
, “
Rim Structure Formation and High Burnup Fuel Behavior of Large-Grained UO2 Fuels
,”
J. Nucl. Mater.
,
278
(
1
), pp.
54
63
.
31.
Noirot
,
J.
,
Lamontagne
,
J.
,
Nakae
,
N.
,
Kitagawa
,
T.
,
Kosaka
,
Y.
, and
Tverberg
,
T.
,
2013
, “
Heterogeneous UO2 Fuel Irradiated up to a High Burn-Up: Investigation of the HBS and of Fission Product Releases
,”
J. Nucl. Mater.
,
442
(
1–3
), pp.
309
319
.
32.
Yi
,
J.
,
Argon
,
A. S.
, and
Sayir
,
A.
,
2005
, “
Creep Resistance of the Directionally Solidified Ceramic Eutectic of Al2O3/C-ZrO2(Y2O3): Experiments and Models
,”
J. Eur. Ceram. Soc.
,
25
(
8
), pp.
1201
1214
.
33.
Zhang
,
J.
,
Su
,
H.
,
Song
,
K.
,
Liu
,
L.
, and
Fu
,
H.
,
2011
, “
Microstructure, Growth Mechanism and Mechanical Property of Al2O3-Based Eutectic Ceramic in Situ Composites
,”
J. Eur. Ceram. Soc.
,
31
(
7
), pp.
1191
1198
.
34.
Spino
,
J.
,
Cruz.
,
H. S.
,
Jovani-Abril
,
R.
,
Birtcher
,
R.
, and
Ferrero
,
C.
,
2012
, “
Bulk-Nanocrystalline Oxide Nuclear Fuels—An Innovative Material Option for Increasing Fission Gas Retention, Plasticity and Radiation-Tolerance
,”
J. Nucl. Mater.
,
422
(1–3), pp.
27
44
.
35.
Lösönen
,
P.
,
2000
, “
On the Behaviour of Intragranular Fission Gas in UO2 Fuel
,”
J. Nucl. Mater.
,
280
(
1
), pp.
56
72
.
36.
Kashibe
,
S.
,
Une
,
K.
, and
Nogita
,
K.
,
1993
, “
Formation and Growth of Intragranular Fission Gas Bubbles in UO2 Fuels With Burnup of 6-83 GWd/T
,”
J. Nucl. Mater.
,
206
(
1
), pp.
22
34
.
37.
Song
,
K. W.
,
Young
,
W. L.
,
Myung
,
S. Y.
,
Sohn
,
D.
, and
Kang
,
Y. H.
,
1994
, “
Pore Growth in Sintered UO2
,”
J. Nucl. Mater.
,
209
(
3
), pp.
263
269
.
You do not currently have access to this content.