WM2008 Conference, February 24-28, 2008, Phoenix, AZ Fluidized Bed Steam Reforming (FBSR) Mineralization for High Organic and Nitrate Waste Streams for the Global Nuclear Energy Partnership (GNEP) - 8314 C.M. Jantzen and M.R. Williams Savannah River National Laboratory Aiken, SC 29808, USA ABSTRACT Waste streams that may be generated by the Global Nuclear Energy Partnership (GNEP) Advanced Energy Initiative may contain significant quantities of organics (0-53 wt%) and/or nitrates (0-56 wt%). ‡ Decomposition of high nitrate streams requires reducing conditions, e.g. organic additives such as sugar or coal, to reduce the NO x in the off-gas to N 2 to meet the Clean Air Act (CAA) standards during processing. Thus, organics will be present during waste form stabilization regardless of which GNEP processes are chosen, e.g. organics in the feed or organics for nitrate destruction. High organic containing wastes cannot be stabilized with the existing HLW Best Developed Available Technology (BDAT) which is HLW vitrification (HLVIT) unless the organics are removed by preprocessing. Alternative waste stabilization processes such as Fluidized Bed Steam Reforming (FBSR) operate at moderate temperatures (650-750°C) compared to vitrification (1150-1300°C). FBSR converts organics to CAA compliant gases, creates no secondary liquid waste streams, and creates a stable mineral waste form that is as durable as glass. For application to the high Cs-137 and Sr-90 containing GNEP waste streams a single phase mineralized Cs-mica phase was made by co-reacting illite clay and GNEP simulated waste. The Cs-mica accommodates up to 30% wt% Cs 2 O and all the GNEP waste species, Ba, Sr, Rb including the Cs-137 transmutation to Ba-137. For reference, the cesium mineral pollucite (CsAlSi 2 O 6 ), currently being studied for GNEP applications, can only be fabricated at ≥1000°C. Pollucite mineralization creates secondary aqueous waste streams and NO x . Pollucite is not tolerant of high concentrations of Ba, Sr or Rb and forces the divalent species into different mineral host phases. The pollucite can accommodate up to 33% wt% Cs 2 O. INTRODUCTION As part of the United States Advanced Energy Initiative, the Department of Energy (DOE) has launched the GNEP Technology Demonstration Program (TDP). The GNEP-TDP will demonstrate technologies needed to implement a closed fuel cycle that enables recycling and consumption of spent nuclear fuel in a proliferation-resistant manner. Several different flowsheets are being considered for the separation of the principal heat- generating isotopes Cs-137 and Sr-90 from the wastes generated from energy production. These isotopes will be separated and stabilized into a single waste form along with Rb and Ba ∗ and stored at a special facility where the isotopes will be allowed to decay for approximately 10 half lives. ξ This strategy would relieve the federal geologic repository of the anticipated short-term (300 year) heat load. The repository volume will be used less efficiently if heat-producing waste forms (such as those continuing Cs-137 and Sr-90) are geologically disposed. Therefore, removing Cs-137 and Sr-90 during the reprocessing stage is needed if repository space is to be conserved. ‡ on a dry weight percent basis at 60°C ∗ the Cs and Sr are stripped from the waste stream but the stripping agents carry along Ba and Rb in the waste stream as well. For brevity, the stream is referred to as Cs/Sr only. ξ The half life of 137 Cs is 30.2 years, and the half life of 90 Sr is 29.1 years.