Analysis of diffusion flames on the IRWST vents of the Westinghouse AP600 during severe accidents

This paper evaluates (1) the potential existence of diffusion flames at the IRWST vents, (2) the size of diffusion flames, and (3) the thermal loading on the containment shell of the AP600 design. The evaluation utilizes MAAP4 to quantify accident sequences that generate up to 100% metal-water reactions at artificially high generation rates and release all hydrogen into the IRWST. Conservative thermal calculations were used to estimate the upper bound of the localized containment shell heating. It is found that even for the most bounding scenario the localized containment heating due to standing diffusion flames will not result in containment failure. 9 refs., 8 figs