Laure Carénini

Institut de Radioprotection et de Sûreté Nucléaire (IRSN) | IRSN · LEPC - Corium Physics Laboratory

Molten corium stabilization following a severe accident is of crucial importance in order to ensure containment integrity on a long-term basis and minimizing radioactive elements releases outside the plant. Among the possible options, In-Vessel Retention (IVR) through external cooling appears as an attractive solution that would limit the dispersio...

In-Vessel Retention (IVR) strategy for nuclear reactors in case of a Severe Accident (SA) intends to stabilize and retain the corium in the vessel by using the vessel wall as a heat exchanger with an external water loop. This strategy relies on simple actions to be passively taken as soon as SA signal is raised: vessel depressurization and reactor...

Motivated by nuclear safety issues, we study the heat transfers in a thin cylindrical fluid layer with imposed fluxes at the bottom and top surfaces (not necessarily equal) and a fixed temperature on the sides. We combine direct numerical simulations and a theoretical approach to derive scaling laws for the mean temperature and for the temperature...

In-Vessel Retention (IVR) of corium is one of the possible strategies for Severe Accident (SA) mitigation. Its main advantage lies in the fact that, by maintaining the corium within the vessel, it preserves the last containment barrier from corium aggression. One of the issues for the demonstration of the success of this strategy is the evaluation...

The strategy for In-Vessel Retention (IVR) of corium is currently considered for several new reactor designs in various countries. One of the issues for the demonstration of the success of this strategy is that there are significant uncertainties in physical modelling of corium in the lower plenum and its transient chemical and thermal interactions...

Prototypic oxidic-metallic molten corium oxidation has been studied in the conditions applicable for a severe accident at the NPP with PWR. Suboxidized oxidic melt and different pool configurations have been examined – one-liquid oxidic, two-liquid oxidic-metallic with surface and bottom positions of metallic liquid, and three-liquid with one oxidi...

During a severe accident in a nuclear reactor, core damage occurs and may lead to the formation of cor-ium, followed by relocation to the vessel lower head. The decay heat released by the corium can threaten the integrity of the vessel, if no effective cooling mechanism is in place. In-Vessel Retention (IVR) is a severe accident mitigation strategy...

The In Vessel Retention (IVR) strategy for Light Water Reactors (LWR) is based on the external reactor vessel cooling (ERVC), by water flooding of the reactor cavity, aiming to avoid the lower head failure and maintain the corium in the reactor pressure vessel. In the frame of the In Vessel Melt Retention (IVMR) project, funded by Horizon 2020 Fram...

A 2 inch, cold-leg loss-of-coolant accident (LOCA) in a 900 MWe generic Western PWR was simulated using ASTEC 2.1.1 and MAAP 5.02. The progression of the accident predicted by the two codes up to the time of vessel failure is compared. It includes the primary system depressurization, accumulator discharge, core heat-up, hydrogen generation, core re...

The In-Vessel Retention (IVR) strategy for Light Water Reactors (LWR) intends to stabilize and isolate corium and fission products in the reactor pressure vessel and in the primary circuit. This type of Severe Accident Management (SAM) strategy has already been incorporated in the SAM guidance (SAMG) of several operating small size LWR (reactor bel...

The In-Vessel Retention (IVR) strategy for Light Water Reactors (LWR) intends to stabilize and retain the core melt in the reactor pressure vessel. This type of Severe Accident Management (SAM) strategy has already been incorporated in the SAM guidance (SAMG) of several operating small size LWR (reactors below 500MWe, like VVER440) and is part of t...

The In-Vessel Retention (IVR) strategy for Light Water Reactors (LWR) intends to stabilize and isolate corium and fission products in the reactor pressure vessel and in the primary circuit. This type of Severe Accident Management (SAM) strategy has already been incorporated in the design and SAM guidances (SAMGs) of several operating small and medi...

The In-Vessel Retention (IVR) strategy for Light Water Reactors (LWR) intends to stabilize and retain the core melt in the reactor pressure vessel. This type of Severe Accident Management (SAM) strategy has already been incorporated in the SAM guidance (SAMG) of several operating small size LWR (reactors below 500MWe, like VVER440) and is part of t...

The Accident Source Term Evaluation Code (ASTEC) is used to perform numerical simulations of the accidents at the Fukushima Daiichi nuclear power station in the frame of the Organisation for Economic Co-operation and Development/Nuclear Energy Agency Benchmark Study of the Accident at the Fukushima Daiichi Nuclear Power Station (BSAF) project. At p...

One of the main goals of severe accident management strategies is to mitigate radiological releases to people and environment. To choose the most appropriate strategy, one needs to know the probability of its success taking into account the associated uncertainties. In the field of corium and debris behavior and coolability, research programs are s...

The Fukushima accident in Japan highlighted that both the in-depth understanding of Severe Accident phenomenology and the development or improvement of adequate severe accident management measures are essential in order to further increase the safety of the nuclear power plants operated throughout the world. One of the Severe Accident Management st...

The paper is devoted to the presentation of validation cases carried out for the models describing the corium behaviour in the "lower plenum" of the reactor vessel implemented in the V2.0 version of the ASTEC integral code, jointly developed by IRSN (France) and GRS (Germany). In the ASTEC architecture, these models are grouped within the single IC...

The severe accident integral code ASTEC, jointly developed since almost 20 years by IRSN and GRS, simulates the behaviour of a whole nuclear power plant under severe accident conditions, including severe accident management by engineering systems and procedures. Since 2004, the ASTEC code is progressively becoming the reference European severe acci...

Transients in containment systems of different scales (Phebus.FP containment, KAEVER vessel, Battelle Model Containment, LACE vessel and VVER-1000 nuclear power plant containment) involving thermal-hydraulic phenomena and aerosol behaviour, were simulated with the computer integral code ASTEC. The results of the simulations in the first four facili...

The thermophysical behaviour of a corium pool in reactor pressure vessel of a pressurised water reactor is of principal importance for the prediction of core melt down accident development. This concerns, in general, the understanding of a severe accident with core melting, its course, major critical phases and timing, and the influence of these pr...

Three two-dimensional Molten Core–Concrete Interaction tests have been conducted in the VULCANO facility with prototypic oxidic corium. The major finding is that for the two tests with silica-rich concrete, the ablation was anisotropic while it was isotropic for limestone-rich concrete. The cause of this behaviour is not yet well understood.Post Te...

In the hypothetical case of a severe accident, the reactor core could melt and the formed mixture, called corium, could melt through the vessel and interact with the reactor pit concrete. Recent two-dimensional concrete-ablation experiments (CCI and VULCANO VB test series) have shown that the ablation is roughly isotropic for limestone-rich concret...

Le rapport lui-même est confidentiel, c'est donc un article signé par Laure Carenini, Jean-François Haquet et Christophe Journeau du CEA de Cadarache, issu d'une conférence qui est proposé : Crust Formation and Dissolution during Corium Concrete Interaction. Proceedings of ICAPP 2007. Nice, France, May 13-18, 2007. Paper 7312