Dissolution experiments were performed to build on previous work and allow for modifications of the UNF dissolution flowsheet. The targeted UNF for dissolution at the Savannah River Site (SRS) are fuels similar to the University of Missouri Research Reactor (MURR) fuel. The UAlx-Al fuels are dissolved with HNO3 and Hg catalyst. The experiments initially performed used Al-1100 alloy coupons. The Al-1100 coupons were considered a representative surrogate (based on the fuel bundle and assembly material) that provided an upper bound on the generation of flammable gas during the dissolution process. Hydrogen generation profiles from Al-1100 dissolutions differed from previous work used for the technical basis for UNF dissolution performed with U-Al alloy. To resolve differences in the previous data, additional experiments were performed with U-Al alloys. Results from the initial phase of experimental work are presented including discussion of flammability calculations representative of H-Canyon fuel dissolutions.