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ICHMT DIGITAL LIBRARY ONLINE

ISSN 961-91393-0-5

Individual price:

$246.00 (Must be sent to your home address)

You can order single issue or individual article. To purchase a single issue or an individual article as well as to view tables of contents and abstracts click on issue number.

Institutional price:

$518.00

Volumes per year:

various

For Online Access

Year 1995

• 1Heat and Mass Transfer in Severe Nuclear Reactor Accidents
Proceedings of International Symposium - 22 -26 May, 1995, Kusadasi, Turkey

708 pages

Volume price - $176.00

ICARE2 LATE PHASE DEGRADATION MODELS APPLICATION TO TMI-2 ACCIDENT

F. Fichot
Institut de Protection et de Surete Nucleaire (IPSN) Centre d'Etudes de Cadarache - 13108 St Paul lez Durance - France

R. Gonzalez
lnstitut de Protection et de Surete Nucleaire (IPSN), France

P. Chatelard
Institut de Protection et de Surete Nucleaire (IPSN) Centre d'Etudes de Cadarache - 13108 St Paul lez Durance - France

B. Lefevre
Institut de Protection et de Surete Nucleaire (IPSN) Centre d'Etudes de Cadarache - 13108 St Paul lez Durance - France

N. Garnier
Institut de Protection et de Surete Nucleaire (IPSN) Centre d'Etudes de Cadarache - 13108 St Paul lez Durance - France

ABSTRACT

The ICARE2 code is designed to calculate in a mechanistic way reactor core damage in LWRs. It is developed at the French Institute for Nuclear Protection and Safety (IPSN), as an analytical support of the in-pile experimental PHEBUS SFD and FP programs. Important progress has been made in developing numerical codes such as ICARE2 to model the early phase of severe accidents. The late stages of core degradation involve substantial melting and material relocation. Models have been developed in ICARE2 to describe the formation of solid debris as a result of cladding degradation. A mechanistic model, using classical porous media results, is implemented to calculate the heat and mass transfers within this debris bed. In case of a molten pool formation, free convection effects are modelled to estimate the heat transfers. A description of the main models for early and late phase degradation is provided, and a calculation of the phase 2 of TMI-2 accident is presented. After cladding oxidation and embrittlement, a large debris bed forms in the centre of the core. The rapid melting of solid particles in the debris bed leads to the formation of a large molten pool. This pool is supported by a stable lower crust but expands radially and finally liquid corium reaches the sides of the reactor core. The material relocation and thermal behaviour calculated in this simulation seem reasonable and confirm some of the assumed scenarios of the accident.