ENGINEERING EXPERIENCE AT BROOKHAVEN NATIONAL LABORATORY IN HANDLING FUSED CHLORIDE SALTS

Two fused chloride salt eutectics, binary LiCl-KCl and ternary NaCl- KCl- MgCl/sub 2/, were used in fuel processing studies as part of the Liquid Metal Fuel Reactor research and development program. Results of engineering work done at Brookhaven since 1950 are summarized. It was demonstrated that fused chloride salt technology is sufficiently developed so that loops and other experimental equipment can be designed and operated at 500 deg C with a high degree of confidence. The equipment, which was operated for many hours, included a large forced-circulation loop and many thermal-convection loops and tanks. The specifications used for the fabrication, cleaning, and testing of equipment for salt service are described. All welded systems, welded by the usual inert-arc procedures, are preferred, but ring type joint stainless-steel flanged connections were found satisfactory, mainly for connecting melt tanks to experimental equipment and for mounting orifice flowmeters. The surfaces of equipment to be used with fused salts were cleaned satisfactorily prior to assembly by several different methods, but sandblasting was found applicable to all types of equipment. Radiography was used to check all welds in contact with fused salt for flaws and, during operation, to locate and determine the cause of any malfunction. Components tested at the normal operating temperature of 500 deg C included pumps, valves, agitators, sightports, samplers, and filtens. Salt samples were usually taken by the thief method. Both stationary and movable resistance type, liquid-level probes were used and were reliable so long as the salt surface remained quiescent; otherwise, splashing and short-circuiting occurred. Nullmatic, pilot-operated pressure transmitters gave good service in conjunction with both orifice and Venturi flowmeters. A procedure is described for preparing pound quantities of pure eutectics, which, in the case of the ternary eutectic, differs from that used in preparing gram quantities. Both eutectics were pretreated with a Bi- Mg-U solution to remove oxidizing impurities before use in corrosion and processing experiments. The results of physical property measurements on the two eutectics are included. (auth