Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT) (방사성폐기물학회지)

Korean Radioactive Waste Society (한국방사성폐기물학회)
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Thermodynamic Evaluations of Cesium Capturing Reaction in Ceramic Microcell UO2 Pellet for Accident-tolerant Fuel

사고저항성 핵연료용 세라믹 미소셀 UO2 소결체의 Cs 포집반응에 대한 열역학적 평가

  • Received : 2018.12.05
  • Accepted : 2019.01.22
  • Published : 2019.03.31
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Abstract

As candidates for accident-tolerant fuels, ceramic microcell fuels, which are distinguished by their peculiar microstructures, are being developed; these fuels have $UO_2$ grains surrounded by cell walls. They contribute to nuclear fuel safety by retention of fission products within the $UO_2$ pellet, reducing rod pressure and incidence of SCC failure. Cesium, a hazardous fission product in terms of amount and radioactivity, can be captured by chemical reactions with ceramic cell materials. The capture-ability of cesium therefore depends on the thermodynamics of the capturing reaction. Conversely, compositional design of cell materials should be based on thermodynamic predictions. This study proposes thermodynamic calculations to evaluate the cesium capture-ability of three ceramic microcell compositions: Si-Ti-O, Si-Cr-O and Si-Al-O. Prior to the calculations, the chemical and physical states of the cesium and the cell materials were defined. Then, the reactivity was evaluated by calculating the cesium potential (${\Delta}G_{Cs}$) and oxygen potential (${\Delta}G_{O_2}$) under simulated LWR circumstances of normal operation. Based on the results, cesium capture is expected to be spontaneous in all cell compositions, providing a basis for the compositional design of ceramic microcell fuels as well as a facile way for evaluating cesium capture.

사고저항성 핵연료의 일환으로 $UO_2$ 입자가 세라믹 셀 벽으로 둘러싸인 미세구조를 갖는 세라믹 미소셀 $UO_2$ 소결체를 개발 중이다. 이는 핵분열생성물들을 $UO_2$ 펠렛 내에 포집하여 펠렛 외부로의 방출을 저감함으로써 봉내압 상승을 완화하고 응력부식균열 발생률을 낮춘다. 생성량이나 방사능 측면에서 위험한 핵분열생성물 중 하나로 여겨지는 세슘은 세라믹 미소셀소결체 내에서 셀 물질과 화학반응 하여 포집될 수 있다. 따라서, 세슘 포집능은 해당 화학반응의 열역학적, 속도론적 특성에 의해 결정된다. 역으로, 미소셀 소결체의 조성설계 시 해당 반응에 대한 열역학적 예측이 필수적이다. 본 연구는 세라믹 현재 개발 중인 여러 미소셀 조성(Si-Ti-O, Si-Cr-O, Si-Al-O)에 대해 세슘의 포집능을 평가하는 열역학적 계산을 다룬다. 계산에 앞서 먼저 HSC Chemistry를 이용해 세슘과 셀 물질의 물리/화학적 상태를 정의한 후, LWR 정상운전 모사환경에서 계산된 세슘포텐셜(${\Delta}G_{Cs}$)과 산소포텐셜(${\Delta}G_{O_2}$)에 근거하여 세슘포집 반응성을 평가하였다. 계산 결과에 근거하면, 세슘 포집반응은 상기 모든 조성에서 자발적일 것으로 예상되며 이로써 조성설계의 근거를 제시함과 동시에 세슘의 포집능을 평가하는 효과적인 방법을 제공한다.

Keywords

References

  1. I. Younker and M. Fratoni, "Neutronic Evaluation of Coating and Cladding Materials for Accident Tolerant Fuels", Prog. Nucl. Energy, 88, 10-18 (2016). https://doi.org/10.1016/j.pnucene.2015.11.006
  2. M.Q. Awan, L. Cao, and H. Wu, "Neutronic Design and Evaluation of a PWR Fuel Assembly with Accident Tolerant-fully Ceramic Micro-encapsulated (AT-FCM) Fuel", Nucl. Eng. Des., 319, 126-139 (2017). https://doi.org/10.1016/j.nucengdes.2017.04.019
  3. K.D. Johnson, A.M. Raftery, D.A. Lopes, and J. Wallenius, "Fabrication and Microstructural Analysis of UN-$U_3Si_2$ Composites for Accident Tolerant Fuel Applications", J. Nucl. Mater., 477, 18-23 (2016). https://doi.org/10.1016/j.jnucmat.2016.05.004
  4. C.P. Deck, G.M. Jacobsen, J. Sheeder, O. Gutierrez, J. Zhang, J. Stone, H.E. Khalifa, and C.A. Back, "Characterization of SiC-SiC Composites for Accident Tolerant Fuel Cladding", J. Nucl. Mater., 466, 667-681 (2015). https://doi.org/10.1016/j.jnucmat.2015.08.020
  5. X. Wu, T. Kozlowski, and J.D. Hales, "Neutronics and Fuel Performance Evaluation of Accident Tolerant Fe-CrAl Cladding under Normal Operation Conditions", Ann. Nucl. Energy, 85, 763-775 (2015). https://doi.org/10.1016/j.anucene.2015.06.032
  6. J.H. Park, H.G. Kim, J.Y. Park, Y.I. Jung, D.J. Park, and Y.H. Koo, "High Temperature Steam-oxidation Behavior of Arc Ion Plated Cr Coatings for Accident Tolerant Fuel Claddings", Surf. Coat. Technol., 280, 256-259 (2015). https://doi.org/10.1016/j.surfcoat.2015.09.022
  7. J.G. Stone, R. Schleicher, C.P. Deck, G.M. Jacobsen, H.E. Khalifa, and C.A. Back, "Stress Analysis and Probabilistic Assessment of Multi-layer SiC-based Accident Tolerant Nuclear Fuel Cladding", J. Nucl. Mater., 466, 682-697 (2015). https://doi.org/10.1016/j.jnucmat.2015.08.001
  8. Y.H. Koo, J.H. Yang, J.Y. Park, K.S. Kim, H.G. Kim, D.J. Kim, Y.I. Jung, and K.W. Song, "KAERI's development of LWR accident-tolerant fuel", Nucl. Technol., 186(2), 295-304 (2014). https://doi.org/10.13182/NT13-89
  9. D.J. Kim, K.S. Kim, D.S. Kim, J.S. Oh, J.H. Kim, J.H. Yang, and Y.H. Koo, "Development Status of Microcell $UO_2$ Pellet for Accident-tolerant Fuel", Nucl. Eng. Technol., 50(2), 253-258 (2018). https://doi.org/10.1016/j.net.2017.12.008
  10. L.N. Grossman, "Interactions in the System Cs(g, l)-$SiO_2-Al_2O_3$", Rev. Int. Hautes Temp. Refract., 16(3), 255-261 (1979).
  11. J. Matsunaga, Y. Takagawa, K. Kusagaya, K. Une, R. Yuda, and M. Hirai, "Fundamentals of GNF Al-Si-O Additive Fuel", Proc. of Top Fuel 2009, September 6, 2009, Paris, France.
  12. J. Matsunaga, K. Une, and K. Kusagaya, "Chemical Trap Effect of Aluminosilicate Additive Fuel", Proc. of Top Fuel 2010, September 26, 2010, Orlando, USA.
  13. A. Roine, Outokumpu HSC Chemistry for Windows, Outokumpu Research Oy: Pori, Finland (2002).
  14. K. S. Lee, Introduction to Nuclear Fuels, 1st ed., 180, Hyoil Press, Seoul (2001).
  15. T.B. Lindemer, T.M. Besmann, and C.E. Johnson, "Thermodynamic Review and Calculations - alkali Metal Oxide Systems with Nuclear Fuels, Fission Products and Structural Materials", J. Nucl. Mater., 100(1-3), 178-226 (1981). https://doi.org/10.1016/0022-3115(81)90533-X
  16. C.T. Walker, C. Bagger, and M. Mogensen, "Observations on the Release of Cesium from $UO_2$ Fuel", J. Nucl. Mater., 240(1), 32-42 (1996). https://doi.org/10.1016/S0022-3115(96)00477-1
  17. J. Spino and P. Peerani, "Oxygen Stoichiometry Shift of Irradiated LWR-fuels at High Burn-ups: Review of Data and Alternative Interpretation of Recently Published Results", J. Nucl. Mater., 375(1), 8-25 (2008). https://doi.org/10.1016/j.jnucmat.2007.10.007
  18. Hj. Matzke, "Oxygen Potential in the Rim Region of High Burn up $UO_2$ Fuel", J. Nucl. Mater., 208(1-2), 18-26 (1994). https://doi.org/10.1016/0022-3115(94)90193-7
  19. Hj. Matzke, "Oxygen Potential Measurements in High Burn up LWR $UO_2$ Fuel", J. Nucl. Mater., 223(1), 1-5 (1995). https://doi.org/10.1016/0022-3115(95)00004-6

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