The Development of Severe Accident Codes at IRSN and Their Application to Support the Safety Assessment of EPR
- IRSN, 31, avenue de la Division Leclerc, BP 17 - 92262 Fontenay-aux-Roses Cedex (France)
IRSN uses a two-tier approach for development of codes analysing the course of a hypothetical severe accident (SA) in a Pressurized Water Reactor (PWR): on one hand, the integral code ASTEC, jointly developed by IRSN and GRS, for fast-running and complete analysis of a sequence; on the other hand, detailed codes for best-estimate analysis of some phenomena such as ICARE/CATHARE, MC3D (for steam explosion), CROCO and TONUS. They have been extensively used to support the level 2 Probabilistic Safety Assessment of the 900 MWe PWR and, in general, for the safety analysis of the French PWR. In particular the codes ICARE/CATHARE, CROCO, MEDICIS (module of ASTEC) and TONUS are used to support the safety assessment of the European Pressurized Reactor (EPR). The ICARE/CATHARE code system has been developed for the detailed evaluation of SA consequences in a PWR primary system. It is composed of the coupling of the core degradation IRSN code ICARE2 and of the thermal-hydraulics French code CATHARE2. The CFD code CROCO describes the corium flow in the spreading compartment. Heat transfer to the surrounding atmosphere and to the basemat, leading to the possible formation of an upper and lower crust, basemat ablation and gas sparging through the flow are modelled. CROCO has been validated against a wide experimental basis, including the CORINE, KATS and VULCANO programs. MEDICIS simulates MCCI (Molten-Corium-Concrete-Interaction) using a lumped-parameter approach. Its models are being continuously improved through the interpretation of most MCCI experiments (OECD-CCI, ACE...). The TONUS code has been developed by IRSN in collaboration with CEA for the analysis of the hydrogen risk (both distribution and combustion) in the reactor containment. The analyses carried out to support the EPR safety assessment are based on a CFD formulation. At this purpose a low-Mach number multi-component Navier-Stokes solver is used to analyse the hydrogen distribution. Presence of air, steam and hydrogen is considered as well as turbulence, condensation and heat transfer in the containment walls. Passive auto-catalytic recombiners are also modelled. Hydrogen combustion is afterwards analysed solving the compressible Euler equations coupled with combustion models. Examples of on-going applications of these codes to the EPR safety analysis are presented to illustrate their potentialities. (authors)
- Research Organization:
- The ASME Foundation, Inc., Three Park Avenue, New York, NY 10016-5990 (United States)
- OSTI ID:
- 20997009
- Resource Relation:
- Conference: 14. International conference on nuclear engineering (ICONE 14), Miami - Florida (United States), 17-20 Jul 2006; Other Information: Country of input: France
- Country of Publication:
- United States
- Language:
- English
Similar Records
Preliminary Analysis of Phebus FPT3 Experiment with the Severe Accident ICARE2 Code
Status of ICARE2 and ICARE/CATHARE development
Related Subjects
ACCIDENTS
CONCRETES
CONTAINMENT
CORIUM
DISTRIBUTION
ELECTRON SPIN RESONANCE
GESELLSCHAFT FUER ANLAGEN- UND REAKTORSICHERHEIT
HEAT TRANSFER
HYDROGEN
MACH NUMBER
NAVIER-STOKES EQUATIONS
PROBABILISTIC ESTIMATION
PWR TYPE REACTORS
RISK ASSESSMENT
SAFETY ANALYSIS
STEAM
THERMAL HYDRAULICS