Containment cooling using natural convection and radiation is a key passive safety feature studied for a 600-MW(electric) advanced small pressurized water reactor. A free-standing cylindrical steel containment vessel is surrounded by a reinforced concrete shield building configured as a chimney. Various methods to enhance natural-convection cooling were evaluated. The evaluation and selection process considered effectiveness, constructibility and effect on schedule, cost, degree of passivity, inspection and maintenance requirements, operational problems, and simplicity. As a result of these evaluations, a combination of fins and convection from the dome in addition to the cylinder is selected.