Gas generation from Tank 241-SY-103 waste

Abstract

This report summarizes progress made in evaluating mechanisms by which flammable gases are generated in Hanford double-shell tank wastes, based on the results of laboratory tests using actual waste from Tank 241-SY-103. The objective of this work is to establish the identity and stoichiometry of degradation products formed in actual tank wastes by thermal and radiolytic processes as a function of temperature. The focus of the gas generation tests on Tank 241-SY-103 samples is first the effect of temperature on gas generation (volume and composition). Secondly, gas generation from irradiation of Tank 241-SY-103 samples at the corresponding temperatures as the thermal-only treatments will be measured in the presence of an external radiation source (using a {sup 137}Cs capsule). The organic content will be measured on a representative sample prior to gas generation experiments and again at the termination of heating and irradiation. The gas generation will be related to the extent of organic species consumption during heating. Described in this report are experimental methods used for producing and measuring gases generated at various temperatures from highly radioactive actual tank waste, and results of gas generation from Tank 241-SY-103 waste taken from its convective layer. The accurate measurement of gas generation rates from actual waste from highly radioactive waste tanks is needed to assess the potential for producing and storing flammable gases within the waste tanks. This report addresses the gas generation capacity of the waste from the convective layer of Tank 241-SY-103, a waste tank listed on the Flammable Gas Watch List due to its potential for flammable gas accumulation above the flammability limit.