抄録
This paper deals with the heat removal performance of the BWR drywell local cooler (DWC) applied as a Japanese phase-II accident management. Separate effect tests were conducted using a single DWC unit of a typical BWR plant under severe accident (SA) condition. It was demonstrated that noncondensable gas mixture with nitrogen and helium was constantly vented from the DWC casing by natural circulation due to the density difference between DWC tube space and outside. Favorable steam condensation rate was maintained even under the highest assumed noncondensable gas condition and obtained condensation data sets were reduced to empirical correlations for the DWC heat removal model. The dependence of the DWC heat removal performance on the noncondensable species was discussed by analyzing the computational fluid dynamic code of STAR-CD. In conclusion, the DWC was found to be promising even under wide range of SA conditions.
