Tank characterization data report: Tank 241-C-112

Tank 241-C-112 is a Hanford Site Ferrocyanide Watch List tank that was most recently sampled in March 1992. Analyses of materials obtained from tank 241-C-112 were conducted to support the resolution of the Ferrocyanide Unreviewed Safety Question (USQ) and to support Hanford Federal Facility Agreement and Consent Order (Tri-Party Agreement) Milestone M-10-00. Analysis of core samples obtained from tank 241-C-112 strongly indicates that the fuel concentration in the tank waste will not support a propagating exothermic reaction. It is probable that tank 241-C-112 exceeds the 1,000 g-mol inventory criteria established for the Ferrocyanide USQ; however, extensive energetic analysis of the waste has determined a maximum exothermic value of -9 cal/g dry waste. This value is substantially below any levels of concern (-75 cal/g). In addition, an investigation of potential mechanisms to generate concentration levels of radionuclides high enough to be of concern was performed. No credible mechanism was postulated that could initiate the formation of such concentration levels in the tank. Tank 241-C-112 waste is a complex material made up primarily of water and inert salts. The insoluble solids are a mixture of phosphates, sulfates, and hydroxides in combination with aluminum, calcium, iron, nickel, and uranium. Disodium nickel ferrocyanide and sodium cesium nickel ferrocyanide probably exist in the tank; however, there appears to have been significant degradation of this material since the waste was initially settled in the tank