Journal of Nuclear Science, Engineering and Technology (JONSAT)
In cooperation with the Iranian Nuclear Society

Analysis of Thermal Conductivity Degradation in Irradiated UO2 Fuel Due to Porosity Formation at High Burnup

Document Type : Research Paper

Authors

B Roostaii 1
H Kazeminejad 2
S Khakshournia 3

1 Nuclear Reactor and Safety Research School, Nuclear Science and Technology Research Institute, AEOI

2 Radiation Application Research School, Nuclear Science and Technology Research Institute, AEOI

3 Physics and Accelerators Research School, Nuclear Science and Technology Research Institute, AEOI

https://doi.org/10.24200/nst.2018.218
Abstract
One of the factors that changes the UO2 fuel thermal conductivity is the generated porosity in the fuel due to increasing burnup. At high burnups, the structure known as rim region, is created. This is due to the Xe depletion process from the fuel matrix, porosity formation, and fuel grain recrystallization, which in turn change the fuel thermal conductivity. In this paper by the use of existing low temperature high burnup fission gaseous swelling model with the progressive recrystallization for UO2 fuel, the matrix swelling terms are calculated and the evolution of the total volume porosity up to burnup of 120 MWd/kgU is estimated. For the study the effect of porosity formation on the irradiated UO2 thermal conductivity, the HALDEN correlation of the thermal conductivity is selected. Then, a porosity correction factor is developed  based on an assumption that the fuel morphology is a three-phase type consisting of the pores, with no contribution to the matrix swelling and large pores due to intergranular bubbles with the contribution to matrix swelling dispersed in the fully dense material, composed of UO2 matrix and solid fission products. The predicted thermal conductivity, based on the present porosity correction factor, demonstrates an additional degradation of 25% due to porosity formation at the burnup levels around 120 MWd/kgU causing an increase in the fuel temperature.

Highlights

[1] J. Rest, An alternative explanation for evidence that xenon depletion, pore formation, and grain subdivision begin at different local burnups, J. Nucl. Mater., 277 (2000) 231-238.

 [2] J. Rest, A model for the effect of the progression of irradiation-induced recrystallization from initiation to completion on swelling of UO2 and U–10Mo nuclear fuels, J. Nucl. Mater., 346 (2005) 226–232.

 [3] J. Rest, Derivation of analytical expressions for the network dislocation density, change in lattice parameter, and for the recrystallized grain size in nuclear fuels, J. Nucl. Mater., 349 (2006) 150–159.

 [4] J. Rest, G. Kagana, A Physical description of fission product behavior in fuels for advanced power reactors, ANL-07/24, Argonne National Laboratory, ( 2007) 21-26.

 [5] J. Rest, editor: Rudy J.M. Konings, Comp. Nucl. Mater., Vol. 3, Elsevier (2012) 579-627.

 [6] A.L. Loeb, Thermal Conductivity: VIII, A theory of thermal conductivity of porous materials, J. Amer. Ceram. Soc, 37 (1954) 96-99.

 [7] H. Kampf, G. Karsten, Effects of different types of void volume on the radial temperature distribution of fuel pins, Nucl. Appl. Technol, 9 (1970) 288-300.

 [8] J. Rest, The DART Dispersion Analysis Research Tool: A Mechanistic Model for Predicting Fission-Product-Induced Swelling of Aluminum Dispersion Fuels, AN L-95/36, (1995).

 [9] M. Owaki, N. Ikatsu, K. Ohira, N. Itagaki, Development of a fuel rod thermal-mechanical analysis code for high burn up, IAEA-TECDOC-1233, Session 6 (2000) 375-385.

[10] B.H. LEE, Y.H. KOO, D.S. SOHN, Rim characteristics and their effects on the thermal conductivity in high burnup UO2 fuel, J. Nucl. Sci. Tech, 38 (2001) 45-52.

 

[11] M. Lemes, A. Soba, A. Denis, An empirical formulation to describe the evolution of the high burnup structure, J. Nucl. Engin. Tech, 456 (2015) 174-181.

 [12] J. Spino, A.D. Stalios, H. Santa Cruz, D. Baron, Stereological evolution of the rim structure in PWR-fuels at prolonged irradiation: Dependencies with burnup and temperature, J. Nucl. Mater., 354 (2006) 66-84.

 [13] J. Spino, J. Rest, W. Goll, C.T. Walker, Matrix swelling rate and cavity volume balance of UO2 fuels at high burnup, J. Nucl. Mater., 346 (2005) 131-144.

 [14] W. Wiesenack, Assessment of UO2 conductivity degradation based on in-pile temperature data, Proc. Int. Topi. Mtg. LWR fuel performance, Portland, Oregon, (1997) 507.

 [15] D.R. Olander, Fundamental aspects of nuclear fuel elements, Technical Information Center & Energy Research and Development Administration (publisher), USA, (1976) 193-194.

 [16] J. Rest, A model for the influence of microstructure, precipitate pinning and fission gas behavior on irradiation-induced recrystal-lization of nuclear fuels, J. Nucl. Mater., 346 (2004) 175-184.

 [17] Y. Cui, S. Ding, Z. Chen, Y. Huo, Modifications and applications of the mechanistic gaseous swelling model for UMo fuel, J. Nucl. Mater., 457 (2015) 157-164.

 [18] C. Ronchi, M. Sheindlin, D. Staicu, M. Kinoshita, Effect of burn-up on the thermal conductivity of uranium dioxide up to 100.000 MWd/t, J. Nucl. Mater., 327 (2004) 58-76.

 [19] DL. Hagrman, GA. Reymann, MATPRO version 11-A, Handbook of materials properties for use in the analysis of light water reactor fuel rod behavior, 3rd edn. TREENUREC-1280, Adv. Inorg. Chem, (1979).

 [20] J. Rest, A microstructurally-based model for the evolution of irradiation-induced recrystallization in U-Mo monolithic and Al-dispersion fuels, RERTR-2004 International Meeting on Reduced Enrichment for Research and Test Reactors, USA, Argonne National Laboratory, (2004) 17.

 [21] C.T. Walker, D. Staicu, M. Sheindlin, D. Papaioannou, W. Goll, F. Sontheimer, On the thermal conductivity of UO2 nuclear fuel at a high burnup of around 100 MWd/kgHM, J. Nucl. Mater., 350 (2006) 19-39.

 [22] M.L. Bleiberg, R.M. Berman, B. Lustman, Effects of high burn-up on oxide ceramic fuels, in symp. on radiation damage in solid and reactor materials, Proc. Series, IAEA, Venice, (1963) 319.

 [23] C.B. Lee, J.G. Bang, D.H. Kim, Y.H. Jung, Development of irradiated UO2 thermal conductivity model, IAEA-TECDOC-1233, (2000) 363-371.

 [24] R. Brandt, J. Neuer, Thermal conductivity and thermal radiation properties of UO2, J. Non-Equilib. Thermodyn., 1 (1976) 3-23.

 [25] B. Roostaii, H. Kazeminejad, S.Khakshournia, Influence of porosity formation on irradiated UO2 fuel thermal conductivity at high burnup,  J. Nucl. Mater., 479 (2016) 374-381.

Keywords

Thermal Conductivity Degradation
Irradiated Fuel
Porosity
Matrix Swelling
[1] J. Rest, An alternative explanation for evidence that xenon depletion, pore formation, and grain subdivision begin at different local burnups, J. Nucl. Mater., 277 (2000) 231-238.
 [2] J. Rest, A model for the effect of the progression of irradiation-induced recrystallization from initiation to completion on swelling of UO2 and U–10Mo nuclear fuels, J. Nucl. Mater., 346 (2005) 226–232.
 [3] J. Rest, Derivation of analytical expressions for the network dislocation density, change in lattice parameter, and for the recrystallized grain size in nuclear fuels, J. Nucl. Mater., 349 (2006) 150–159.
 [4] J. Rest, G. Kagana, A Physical description of fission product behavior in fuels for advanced power reactors, ANL-07/24, Argonne National Laboratory, ( 2007) 21-26.
 [5] J. Rest, editor: Rudy J.M. Konings, Comp. Nucl. Mater., Vol. 3, Elsevier (2012) 579-627.
 [6] A.L. Loeb, Thermal Conductivity: VIII, A theory of thermal conductivity of porous materials, J. Amer. Ceram. Soc, 37 (1954) 96-99.
 [7] H. Kampf, G. Karsten, Effects of different types of void volume on the radial temperature distribution of fuel pins, Nucl. Appl. Technol, 9 (1970) 288-300.
 [8] J. Rest, The DART Dispersion Analysis Research Tool: A Mechanistic Model for Predicting Fission-Product-Induced Swelling of Aluminum Dispersion Fuels, AN L-95/36, (1995).
 [9] M. Owaki, N. Ikatsu, K. Ohira, N. Itagaki, Development of a fuel rod thermal-mechanical analysis code for high burn up, IAEA-TECDOC-1233, Session 6 (2000) 375-385.
[10] B.H. LEE, Y.H. KOO, D.S. SOHN, Rim characteristics and their effects on the thermal conductivity in high burnup UO2 fuel, J. Nucl. Sci. Tech, 38 (2001) 45-52.
 
[11] M. Lemes, A. Soba, A. Denis, An empirical formulation to describe the evolution of the high burnup structure, J. Nucl. Engin. Tech, 456 (2015) 174-181.
 [12] J. Spino, A.D. Stalios, H. Santa Cruz, D. Baron, Stereological evolution of the rim structure in PWR-fuels at prolonged irradiation: Dependencies with burnup and temperature, J. Nucl. Mater., 354 (2006) 66-84.
 [13] J. Spino, J. Rest, W. Goll, C.T. Walker, Matrix swelling rate and cavity volume balance of UO2 fuels at high burnup, J. Nucl. Mater., 346 (2005) 131-144.
 [14] W. Wiesenack, Assessment of UO2 conductivity degradation based on in-pile temperature data, Proc. Int. Topi. Mtg. LWR fuel performance, Portland, Oregon, (1997) 507.
 [15] D.R. Olander, Fundamental aspects of nuclear fuel elements, Technical Information Center & Energy Research and Development Administration (publisher), USA, (1976) 193-194.
 [16] J. Rest, A model for the influence of microstructure, precipitate pinning and fission gas behavior on irradiation-induced recrystal-lization of nuclear fuels, J. Nucl. Mater., 346 (2004) 175-184.
 [17] Y. Cui, S. Ding, Z. Chen, Y. Huo, Modifications and applications of the mechanistic gaseous swelling model for UMo fuel, J. Nucl. Mater., 457 (2015) 157-164.
 [18] C. Ronchi, M. Sheindlin, D. Staicu, M. Kinoshita, Effect of burn-up on the thermal conductivity of uranium dioxide up to 100.000 MWd/t, J. Nucl. Mater., 327 (2004) 58-76.
 [19] DL. Hagrman, GA. Reymann, MATPRO version 11-A, Handbook of materials properties for use in the analysis of light water reactor fuel rod behavior, 3rd edn. TREENUREC-1280, Adv. Inorg. Chem, (1979).
 [20] J. Rest, A microstructurally-based model for the evolution of irradiation-induced recrystallization in U-Mo monolithic and Al-dispersion fuels, RERTR-2004 International Meeting on Reduced Enrichment for Research and Test Reactors, USA, Argonne National Laboratory, (2004) 17.
 [21] C.T. Walker, D. Staicu, M. Sheindlin, D. Papaioannou, W. Goll, F. Sontheimer, On the thermal conductivity of UO2 nuclear fuel at a high burnup of around 100 MWd/kgHM, J. Nucl. Mater., 350 (2006) 19-39.
 [22] M.L. Bleiberg, R.M. Berman, B. Lustman, Effects of high burn-up on oxide ceramic fuels, in symp. on radiation damage in solid and reactor materials, Proc. Series, IAEA, Venice, (1963) 319.
 [23] C.B. Lee, J.G. Bang, D.H. Kim, Y.H. Jung, Development of irradiated UO2 thermal conductivity model, IAEA-TECDOC-1233, (2000) 363-371.
 [24] R. Brandt, J. Neuer, Thermal conductivity and thermal radiation properties of UO2, J. Non-Equilib. Thermodyn., 1 (1976) 3-23.
 [25] B. Roostaii, H. Kazeminejad, S.Khakshournia, Influence of porosity formation on irradiated UO2 fuel thermal conductivity at high burnup,  J. Nucl. Mater., 479 (2016) 374-381.

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