CONGA: Containment behavior in the event of core melt with large gaseous and aerosol releases

• Unité de recherche: PCRD EU
• Numéro de projet: 96.0238
• Titre du projet anglais: CONGA: Containment behavior in the event of core melt with large gaseous and aerosol releases

Mots-clé (Anglais)

Aerosol; Condensation; passive decay heat removal

Autre Numéro de projet (Anglais)

EU project number: FIS4-CT96-0039

Programme de recherche (Anglais)

EU-programme: 4. Frame Research Programme - 5.2 Nuclear fission safety

Description succincte (Anglais)

See abstract

Partenaires et organisations internationales (Anglais)

CIEMAT (S), ENEL (I), JRC-ISPRA (EU), SIEMENS-KWU (D)

Résumé des résultats (Abstract) (Anglais)

The main objectives of the PSI participation, Work Package 2.1, of the CONGA project are to study the aerosol deposition behaviour on the heat exchanger tubes and its interaction with the condensation heat transfer in a condensing environment using two different types of heat exchanger mock-ups. One mock-up is a model unit of a heat exchanger designed to remove the decay heat from a PWR containment. The second mock-up models the heat exchanger unit designed to remove the decay heat from the advanced BWR-1OOO design from KWU-Siemens Germany. Both exchanger units are envisaged to be attached directly to the containment and would require no operator action to be put in operation. The units are designed to remove the decay heat at the required decay power levels. However, stringent licensing rules require the advance plants also to cope with the severe conditions expected during the severe accidents. As a result the heat exchanger units must still remove the decay heat in an aerosol-non-condensable gas- steam environment. The lack of information necessitates an in-depth investigation of the heat exchanger behaviour under simulated severe accident conditions.
As a result of difficulties associated with the quality of the components delivered by the project partner ENEL (reported in the 1997 yearly report), additional efforts had to be spent to take corrective measures. In addition, more time was needed to perform tests to define the velocity profiles above the heat exchanges and also the coolant flow rates in each tube. Three aerosol tests were carried out between September 1998 and the end of 1998, two tests, using the BWR heat exchanger and one test with the PWR heat exchanger. The tests indicated that whenever aerosol flow was initiated the heat removed by the heat exchangers showed degradation which reached up to 37 % until the end of the tests.
Four more tests are planned until the end of March 1999. The first test of this series will be a repetition of one of the Work Package2.2 tests and the others will employ two components (CsOH+5n02) aerosol particles. The project will be terminated at the end of April 1999 by issuing a topical report providing all the test results.

Références bases de données (Anglais)

Swiss Database: Euro-DB of the
State Secretariat for Education and Research
Hallwylstrasse 4
CH-3003 Berne, Switzerland
Tel. [phone]
Swiss Project-Number: 96.0238