Annals of the Assembly for International Heat Transfer Conference 13

ISBN 1-56700-225-0 / CD 1-56700-226-9

Year 2006

Eugenijus Uspuras
Laboratory of Nuclear Installation Safety, Lithuanian Energy Institute, Breslaujos str. 3, LT-44403 Kaunas, Lithuania

Rolandas Urbonas
Laboratory of Nuclear Installation Safety, Lithuanian Energy Institute Breslaujos 3, LT-44403 Kaunas, Lithuania

Algirdas Kaliatka
Laboratory of Nuclear Installation Safety, Lithuanian Energy Institute, Breslaujos 3, LT-44403 Kaunas, Lithuania

The main challenge, which leads to the overheating of the fuel elements and other core components in case of reactor accidents, is an unbalance between heat generation in the fuel elements and other core structures and heat sink. The main phenomenon, occurring in this case is the transition from nucleate coolant boiling to film boiling − Critical Heat Flux. In this paper the issues related to the modelling of CHF and post-CHF heat transfer in RBMK-1500 reactor, using RELAP5 and ATHLET codes, are discussed. The validation process of CHF phenomenon for RBMK-1500 on available experimental investigations performed in Russian research and design organizations are presented. The comparison results show that the CHF values calculated with RELAP5 and ATHLET are slightly lower than the experimental ones, if coolant quality is low. It shows that RELAP5 and ATHLET calculations give a more conservative view. However, in the case of high coolant quality (x > 0.6) the standard approach for CHF calculation can be used since in this region the RELAP5 code gives a good agreement with the experimental data.

NCL-08 pages DOI: 10.1615/IHTC13.p7.80 Download article

Article price - $35.00

<< Previous article   Next article >>