Alternate processing flowsheets for treating NCAW waste slurry with formic acid: Split acid addition to reduce H{sub 2} generation rate and total NH{sub 3} production

High-level radioactive waste stored in tanks at the US Department of Energy`s Hanford Site will be pretreated to concentrate radioactive constituents and fed to the vitrification plant. A flowsheet for feed preparation within the vitrification plant (based on Hanford Waste Vitrification Plan (HWVP)) design, called for HCOOH addition during the feed preparation step in order to adjust rheology and redox conditions. However, the potential for generating H{sub 2} and NH{sub 3} during treatment of high-level waste (HLW) with HCOOH was identified at Pacific Northwest Laboratory by Wiemers.