THERMAL STABILITY OF GADOLINIUM NITRATE SOLUTION AT HIGH TEMPERATURE

摘要

During a feasibility study of auxiliary shutdown systems for the Spert II and Spert III reactor facilities, salts possessing high neu-tron absorption cross sections were considered for use in water soluble poison injection systems. One of these salts, gadolinium nitrate, appeared to be very promising. However, very little information was available in the literature on the use of gadolinium salts in stainless steel systems at high temperatures.nTests were carried out in a high pressure static autoclave to determine the stability of gadolinium nitrate solution at elevated temperature. At temperatures of 300 F and above, the solution decomposed with formation of a white precipitate. Thus, gadolinium nitrate was found to be unacceptable for use as a soluble poison in high temperature water moderated reactor systems.