Abstract: An improved arrangement for feeding a cool liquid into a pressure vessel and mixing the fed liquid with hot vessel-contained liquid includes an ejector thermal sleeve within an inlet nozzle. An upstream portion of the sleeve sealed to the nozzle surrounds a supply line through which a main feed flow is conducted to a sparger outlet port in the vessel. Cool leakage liquid flow is confined within the sleeve and ejected from an ejector chamber formed around the port by a downstream portion of the sleeve. The leakage liquid is ejected by and with the main feed flow away from the nozzle whereby thermal cycling and cracking thereof are substantially reduced.