CFD Study of Thermal Stratification in a Scaled-Down, Toroidal Suppression Pool of Fukushima Daiichi Type BWR

During the 2011 nuclear catastrophe at Fukushima Daiichi, Unit 3 had a sharper increase in containment pressure than 2, with thermal stratification of suppression pool cited as one contributing factors. In present work, buoyancy-induced circulation consequent to steam condensation large, toroidal water is studied using computational fluid dynamics (CFD) simulations view understanding role important design parameters system. The tunnelling phenomenon observed development process delineated terms establishment thermocline. effects number injection points and cross-section on characteristics have been investigated through case studies. all cases, surface temperature, which responsible for over-pressurization containment, found be significantly higher bulk temperature. Multiple same overall flow rate are lead temperatures due shortened path. For volume water, show that deeper narrower gives rise wider shallower pool. This attributed relatively penetration into