Assessment of the MELCOR 1.8.6 condensation heat transfer model under the presence of noncondensable gases

중대사고 해석코드 MELCOR 1.8.6의 비응축성기체 존재 시 응축열전달 모델 평가

  • Received : 2016.04.07
  • Accepted : 2016.06.16
  • Published : 2016.06.30


A condensation heat transfer model is very important for the safety analysis of nuclear power plants. Especially, condensation under the presence of noncondensable gases (NCGs) is an important issue in nuclear safety because the presence of even a small quantity of NCGs in the vapor largely reduces the condensation rate. In this study, the condensation heat transfer model of the severe accident analysis code MELCOR 1.8.6 has been assessed using a set of condensation experiments performed under the thermal-hydraulic conditions similar to those inside a containment during design-basis accidents or severe accidents. Experiment conditions are categorized into 4 types according to the shape of the condensation surface: vertical flat plates, outer surface of vertical pipes, inner surface of vertical pipes, the inner surface of horizontal pipes. The results of the calculations show that the MELCOR code generally under-predicts the condensation heat transfer except the condensation on inner surface of vertical pipes.


Condensation heat transfer;Noncondensable gases;The MELCOR code;MELCOR 1.8.6


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