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Analysis of the thermal-mechanical behavior of SFR fuel pins during fast unprotected transient overpower accidents using the GERMINAL fuel performance code

  • Received : 2023.05.26
  • Accepted : 2023.12.01
  • Published : 2024.03.25

Abstract

In the framework of the Generation IV research and development project, in which the French Commission of Alternative and Atomic Energies (CEA) is involved, a main objective for the design of Sodium-cooled Fast Reactor (SFR) is to meet the safety goals for severe accidents. Among the severe ones, the Unprotected Transient OverPower (UTOP) accidents can lead very quickly to a global melting of the core. UTOP accidents can be considered either as slow during a Control Rod Withdrawal (CRW) or as fast. The paper focuses on fast UTOP accidents, which occur in a few milliseconds, and three different scenarios are considered: rupture of the core support plate, uncontrolled passage of a gas bubble inside the core and core mechanical distortion such as a core flowering/compaction during an earthquake. Several levels and rates of reactivity insertions are also considered and the thermal-mechanical behavior of an ASTRID fuel pin from the ASTRID CFV core is simulated with the GERMINAL code. Two types of fuel pins are simulated, inner and outer core pins, and three different burn-up are considered. Moreover, the feedback from the CABRI programs on these type of transients is used in order to evaluate the failure mechanism in terms of kinetics of energy injection and fuel melting. The CABRI experiments complete the analysis made with GERMINAL calculations and have shown that three dominant mechanisms can be considered as responsible for pin failure or onset of pin degradation during ULOF/UTOP accident: molten cavity pressure loading, fuel-cladding mechanical interaction (FCMI) and fuel break-up. The study is one of the first step in fast UTOP accidents modelling with GERMINAL and it has shown that the code can already succeed in modelling these type of scenarios up to the sodium boiling point. The modeling of the radial propagation of the melting front, validated by comparison with CABRI tests, is already very efficient.

Keywords

References

  1. M. Lainet, et al., GERMINAL, a fuel performance code of the PLEIADES platform to simulate the in-pile behaviour of mixed oxide fuel pins for sodium-cooled fast reactors, J. Nucl. Mater. 516 (2019) 30-53, https://doi.org/10.1016/j.jnucmat.2018.12.030.
  2. I. Sato, et al., Transient Fuel Behavior and failure condition in the CABRI-2 experiments, Nucl. Technol. 145 (2004) 115-137, https://doi.org/10.13182/NT04-A3464.
  3. Y. Fukano, et al., Fuel pin behavior under slow-ramp-type transient-overpower conditions in the CABRI-FAST experiments, J. Nucl. Sci. Technol. 46 (2009) 1049-1058, https://doi.org/10.1080/18811248.2009.9711615.
  4. J. Papin, Behavior of fast reactor fuel during transient and accident conditions, Comprehensive Nuclear Materials 2 (2012) 609-634, https://doi.org/10.1016/B978-0-08-056033-5.00047-1.
  5. B. Michel, et al., Two fuel performance codes of the PLEIADES platform: ALCYONE and GERMINAL, Nuclear Power Plant Design and Analysis Codes (2021) 207-233, https://doi.org/10.1016/B978-0-12-818190-4.00009-7.
  6. G. Golden, J. Tokar, "Thermophysical properties of sodium", ANL-7323 argonne national laboratory, 9700 south cass avenue, Argonne Illinois (August 1967), 60439, https://doi.org/10.2172/4511962.
  7. T. Beck, et al., Conceptual design of ASTRID fuel sub-assemblies, Nucl. Eng. Des. 315 (2017) 51-60, https://doi.org/10.1016/j.nucengdes.2017.02.027.
  8. P. Sciora, et al., The low void worth core design ('CFV') based on an axially heterogeneous geometry, Nucl. Eng. Des. 366 (2020), 110763, https://doi.org/10.1016/j.nucengdes.2020.110763.
  9. G. Rimpault, et al., "The ERANOS Code and Data System for Fast Reactor Neutronic Analyses", Physor, Seoul, Korea, 2002. October 7-10, 2002.
  10. S. Massara, et al., Dynamics of critical dedicated cores for minor actinide transmutation, Nucl. Technol. 149 (2005) 150-174, https://doi.org/10.13182/NT05-A3587.
  11. C. Venard, et al., "The ASTRID Core at the End of the Conceptual Design Phase", FR17, Yekaterinburg, Russia, June 2017.
  12. S. Kondo et al., "SIMMER-III: A Computer Program for LMFR Core Disruptive Accident Analysis. Version 2. H Model Summary and Program Description", Technical Report JNC-TN-9400-2001-002. Japan Nuclear Cycle Development Inst..
  13. K. Herbreteau, et al., Sodium-cooled fast reactor pin model for predicting pin failure during a power excursion, Nucl. Eng. Des. 335 (2018) 279-290, https://doi.org/10.1016/j.nucengdes.2018.05.023.
  14. A. Zaetta, et al., "CADOR "Core with Adding Doppler effect" concept application to sodium fast reactors", EPJ Nuclear Sciences & Technologies 5 (1) (2019) https://doi.org/10.1051/epjn/2018049.