THOREX PILOT PLANT CORROSION STUDIES:II. CORROSION OF TYPES SOUL, 309SCb, AND 347 STAINLESS STEEL DURING DEVELOPMENT AND PRODUCTION-DEVELOPMENT PERIODS

摘要

Corrosion data for types 304L, 309SCb, and 347 stainless steel were obtained in a number of process vessels in the ORNL Thorex pilot plant during the development and the production-development periods of operation occurring between December 195^ and September 1956. Stressed corrosion-test specimens were exposed in the hatch dissolver tank, the feed adjustment tank, the BT vapor separator, the A-column feed tank, and the BTC catch tank. Generally, types 3C4L and 309SCb stainless steel exhibited comparable corrosion resistance in all environments examined. Most of the studies were conducted with these two alloys. Severe corrosion damage was encountered in the vapor phase of both the batch dissolver tank, operated at a maximum temperature of 115°C, and the feed adjustment tank, operated at a maximum temperature of 155 °C. Corrosion rates for types 304L tnd 309SCb stainless steel varied from approximately 30 to 55 mpy in the batch dissolver tank during the development and the production-development periods. Vapor-phase corrosion rates in the feed adjustment tank during the last half of the development period ranged from 85 to 100 mpy. Severe corrosion attack was-experienced also in the BT vapor separator, which operated at a maximum temperature of 115°C Rates were 30 to 55 mpy for type 30^L stainless steel, 25 mpy for type 309SCb stainless steel, and a maximum rate of 150 mpy for a composite specimen of types 309SCb and 3^7 stainless steel.