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Modelling of a Passive Hydraulic Lock concept for the Mitigation Transfer Tubes in a SFR core

Abstract : In the context of the safety increase of the integrated sodium-cooled fast breeder reactor, we present an original safety complementary disposal to prevent or mitigate the consequences of a hypothetical severe accident due to the weakness of decay heat removal by natural convection in the vessel. This disposal is set by ad-hoc empty transfer tubes, in place of some fuel sub-assemblies present in the reactor core, using an innovative passive hydraulic lock. It is based on the concept of hydraulic diode controlled by the flowrate of primary pumps. In case of the loss of the primary pumps, it provides a direct flow path between the hot pool, equipped with decay heat removal exchangers, and the cold pool, leading to an easier passage of colder sodium towards the cold pool to promote core cooling by natural convection. In addition, it provides an easy way to discharge corium towards the core catcher in the hypothetical case of severe accident. In this paper, we focus on the assessment of the lock function and of the small magnitudes of the perturbations induced by our disposal on the thermal-hydraulic behaviour of the reactor during normal operations. Through an analytical analysis and a multi-scale numerical approach, ranging from the local scale (CFD) to the system one, we claim that the lock function is kept during the normal situations at various power regimes. The leak flow represents no more than 1% of the primary pump flow. In addition, no important reactor thermal-hydraulic perturbation is brought by adding transfer tubes in the core. This is true for normal steady states, whatever the power is, but also for a full-power loss of forced flow accidental transient leading to the natural convection cooling.
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Preprints, Working Papers, ...
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Contributor : Bibliothèque Cadarache <>
Submitted on : Tuesday, November 5, 2019 - 10:29:09 AM
Last modification on : Tuesday, April 28, 2020 - 11:28:13 AM
Long-term archiving on: : Thursday, February 6, 2020 - 10:11:33 PM


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  • HAL Id : cea-02340027, version 1




M. Belliard, T. Cadiou, S. Bajard. Modelling of a Passive Hydraulic Lock concept for the Mitigation Transfer Tubes in a SFR core. 2019. ⟨cea-02340027⟩



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