Hydrogen generation rates in Savannah River Site high-level nuclear waste

High-level nuclear waste (HLW) is stored at the Savannah River Site (SRS) as alkaline, high-nitrate slurries in underground carbon steel tanks. Hydrogen is continuously generated in the waste tanks as a result of the radiolysis of water. Hydrogen generation rates have recently been measured in several waste tanks containing different types of waste. The measured rates ranged from 1.1 to 6.7 cubic feet per million Btu of decay heat. The measured rates are consistent with laboratory data which show that the hydrogen generation rate depends on the nitrate concentration and the decay heat content of the waste. Sampling at different locations indicated that the hydrogen is uniformly distributed radially within the tank