The KROTOS KFC and SERENA/KS1 tests : experimental results and MC3D calculations

• During a hypothetical severe accident in a Pressurized Light Water Reactor, the hot molten material mixture (corium) issuingfrom the degraded reactor core may generate a steam explosion if it comes in contact with water. Such an explosion maydamage the structures and threaten the reactor integrity. The SERENA program is an international OECD project which aims athelping the understanding of the interaction mechanisms between the different components of the system (the hot molten pool,the liquid water, the generated fragments and steam) by providing experimental data and calculation analysis.In the KROTOS facility, energetic steam explosions can be triggered and studied using prototypic corium. CEA takes part in theSERENA program by performing experimental tests in the KROTOS facility designed to allow direct visual observations ofmelt injection into a water tank and mixing conditions (Huhtiniemi 2001). Still in the SERENA frame, pre- and post-testanalysis are also carried out by CEA with the MC3D software. MC3D is developed by IRSN, it is a thermal-hydraulicmultiphase flow code mainly dedicated to ex-vessel and in-vessel Fuel Coolant Interactions (FCI) studies (Meignen 2005).The purpose of this paper is to present the KROTOS experimental setup and instrumentation, expose the experimental resultsand a MC3D analysis of the recent KROTOS tests. The experimental results are presented for the KFC scoping test of theKROTOS program for which the results are not restricted to the SERENA partners. On the contrary, the KROTOS KS1 resultsbeing only available to the SERENA partners, the pre-mixing and explosion MC3D post-KS1 test calculations are proposed butwithout any scale. The calculation hypothesis leading to a good agreement with the experimental results (in terms of jetprogression and void fraction in the system) are discussed.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Maskinteknik -- Energiteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Mechanical Engineering -- Energy Engineering (hsv//eng)

Nyckelord

severe accidents

nuclear reactors

steam explosion

KROTOS

MC3D

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