Durability Testing of Fluidized Bed Steam Reforming (FBSR) Products

Abstract

Fluidized Bed Steam Reforming (FBSR) is being considered as a potential technology for the immobilization of a wide variety of high sodium aqueous radioactive wastes. The addition of clay and a catalyst as co-reactants converts high sodium aqueous low activity wastes (LAW) such as those existing at the Hanford and Idaho DOE sites to a granular "mineralized" waste form that may be made into a monolith form if necessary. Simulant Hanford and Idaho high sodium wastes were processed in a pilotscale FBSR at Science Applications International Corporation (SAIC) Science and Technology Applications Research (STAR) facility in Idaho Falls, ID. Granular mineral waste forms were made from (1) a basic Hanford Envelope A low-activity waste (LAW) simulant and (2) an acidic INL simulant commonly referred to as sodium-bearing waste (SBW). The FBSR waste forms were characterized and the durability tested via ASTM C1285 (Product Consistency Test, 10), the Environmental Protection Agency (EPA) Toxic Characteristic Leaching Procedure (TCLP), and the Single Pass Flow Through (SPFT) test. The durability of the FBSR waste form products was tested in order to compare the measured durability to previous FBSR waste form testing on Hanford Envelope C waste forms that were made by THOR sm Treatment Technologies (TTT) and to compare the FBSR durability to vitreous LAW waste forms, specifically the Hanford low activity waste (LAW) glass known as the Low-activity Reference Material (LRM). The durability of the FBSR waste form is comparable to that of the LRM glass for the test responses studied.

Radioactive Demonstrations of Fluidized Bed Steam Reforming (FBSR) with Hanford Low Activity Wastes

“…Based on the trend of alkali (Na) release being co-linear with Al release (Figure 1b) it was hypothesized that this was an aluminosilicate buffering mechanism. 17,18 The Na release is colinear with the Al release in the BSR and 2008 engineering scale data as well as in the historical 2001 and 2004 data as seen in Figure 1b. All the other cations appear to be released as a function of the solution pH (Figure 1c, d and e) and this includes Si, S, and Re.…”

Radioactive Demonstration Of Mineralized Waste Forms Made From Hanford Low Activity Waste (Tank SX-105, Tank AN-103, And AZ-101/102) By Fluidized Bed Steam Reformation (FBSR)

“…To prevent the chromium oxidation, often the IOC is added. [34,40,41] Thus, the REDOX values of the mineral products are determined to confirm that the conditions achieved during BSR processing were consistent with the target conditions from the FBSR ESTD campaigns.…”

“…Comparative studies have been performed at SRNL with methods 1-3 and the same compositions are achieved. [40,41] Comparative studies have been performed at PNNL of roasted and unroasted samples and the same compositions were also achieved. [98] Heating to remove the carbon was chosen as the preferential method of coal removal before analysis because it was a more thorough removal method and adaptable for the filter fines, i.e., hand removal of the carbon in the filter fines would be impossible.…”

“…Samples before and after this heating were examined by XRD to verify that the phase assemblages had not changed. [40,41] In order to remove the coal by roasting first the Loss-on-Drying (LOD) is measured as the weight loss at 110°C from adsorbed water. The LOI is then performed at 525°C in air by heating the samples to 525°C overnight.…”

“…It has been noted in earlier studies [40,41,50] that the IOC acts to form the FeCr 2 O 4 Chromite spinels, which keep the chromium in an oxidation state of +3 which is much less soluble than +6 chromium. The chromium was expected to be in the oxidized +6 state and leachable for the ferric nitrate campaign and it was.…”