Abstract: A plasma gasification reactor, and process for its operation, with one or both of, first, a quench zone within an upper part of a top section of the reactor and, second, feed ports through a lateral wall of a middle section of the reactor for supplying feed material to a feed bed within the middle section and the feed ports located proximate the feed bed. The quench zone is provided with nozzles for introducing a fluid to reduce the temperature of molten solid bits sufficiently to minimize their sticking within external ductwork. The middle section feed port arrangement assists in more thorough reaction of light particles in the feed material that may otherwise exit with gaseous products.