Test Summary Report INEEL Sodium-Bearing Waste Vitrification Demonstration RSM-01-1

Abstract

SummaryOver several decades, site operations at what is now the U.S. Department of Energy's (DOE's) Idaho National Engineering and Environmental Laboratory have included nuclear reactor testing, reprocessing of spent nuclear fuel, and the storage, treatment, and disposal of the resultant radioactive and mixed wastes generated. Liquid, acidic, and radioactive high-level waste (HLW) and sodium bearing waste (SBW) from spent-fuel reprocessing operations have for the most part been calcined in the New Waste Calcining Facility (NWCF) and the earlier Waste Calcining Facility (WCF) to produce a dry granular waste form that is safer to store. However, about a million gallons of SBW remains uncalcined, and this liquid mixed waste, stored in tanks, does not meet current regulatory requirements for long-term storage and/or disposal. As a part of the Settlement Agreement between DOE and the State of Idaho, the tanks currently containing SBW are to be taken out of service by December 31, 2012, which requires the removal and treatment of the remaining SBW.Several potential options have been proposed for treating the SBW. Of those considered, vitrification received the highest weighted score against the criteria used. Beginning in fiscal year 2000, the INEEL HLW program embarked on a program for technology demonstration and development that would lead to conceptual design of a vitrification facility, based upon the liquid-fed melter technology, in the event that vitrification is the preferred alternative for SBW disposal. This program includes several separate activities that include, among others, waste-form development, process feed-stream design, and melter vitrification demonstration testing of the nonradioactive, surrogate SBW flowsheet. The first of the melter flowsheet tests conducted in support of INEEL's vitrification facility design is discussed below.The Pacific Northwest National Laboratory's (PNNL's) Research-Scale Melter (RSM) was used to conduct these initial melter-flowsheet evaluations. The RSM is a small (1/100-scale) joule-heated melter that is capable of processing melter feed on a continuous basis. This capability is key for:• developing/evaluating process flowsheets• characterizing relationships between feed composition and the properties of the final glass produced• establishing the fate and behavior of process effluent.This melter system's capability to produce glass in a continuous manner is also essential for estimating the behavior of a full-scale system. Moreover, the size of the RSM allows the impacts of process variables upon melter performance or glass quality to be quickly and efficiently evaluated without undue expense or waste generation.The experimental scope of this initial, 5-d, 120-h, SBW vitrification test was to evaluate the:• processing characteristics of the newly formulated SBW surrogate melter feed stream• acceptability of various SBW to glass-forming additive ratios• possible formation of a secondary sodium sulfate phase iv • effectiveness of sugar as a glass oxidation-state modifie...

Sulfur Partitioning During Vitrification of INEEL Sodium Bearing Waste: Status Report

“…Since only a small fraction of the sulfur fed to the melter was found in the molten salt after the test, the remaining sulfur was likely partitioned to the off gas, but escaped analyses. Details of this test are described by Goles et al (2001), with highlights discussed in Section 3.2.…”

“…Since only a small fraction of the sulfur fed to the melter was found in the molten salt after the test, the remaining sulfur was likely partitioned to the off gas, but escaped analyses. Details of this test are described by Goles et al (2001), with highlights discussed in Section 3.2.iv A third melter test (EV-16-2001-1) was performed using the EV-16 melter at Clemson University. The target glass composition used in this test was the same as that fabricated during the first two segments of the RSM-01-1 test-30 mass% waste loading (on a dry, non-volatile oxide basis), SBW-9 additive mix (see Section 1.0).…”

Preliminary Investigation of Sulfur Loading in Hanford LAW Glass

“…Studies of sulfur segregation during waste-glass melting have been performed in support of waste vitrification activities (for examples, see Perez et al 1983;Bates et al 1985;Fu et al 1996;Li et al 1996;Vienna et al 1999;Pegg et al 2000;Musick et al 2000;Darab et al 2001;Li et al 2001;Goles et al 2001;Muller et al 2001;Peeler et al 2001;Goles et al 2002;Vienna et al 2003;Hrma et al 2003;and Hrma et al 2004). The following subsections review a portion of that literature thought to be key to the understanding of sulfate-incorporation limits during Hanford LAW vitrification.…”

Worst-Case" Simulant for INTEC Soduim-Bearing Waste Vitrification Tests

“…WM-180 is the one waste composition that has been characterized and a simulant waste prepared for vitrification tests through pilot scale. 2,8 Actual WM-180 waste has been vitrified in crucibles, as well. 9 Since a single worst case recipe will be prepared, this will give a perspective of how much deviation from WM-180 occurs.…”

“…First, in order to detect and measure it in the glass during the RSM-01-1 test at PNNL, 8 cesium in WM-180 simulant was increased a factor of 209 over that of the actual waste concentration 2 to 1.65 10 -3 M. This was required to result in 0.05 wt% Cs 2 O in the glass (calculated at 25% waste oxide loading) that could be measured. 10 Secondly, when both are present at concentrations typical of commercial HLLW, technetium can potentially affect (increase) volatility of cesium (and cesium can decrease the volatility of technetium) by forming cesium pertechnetate.…”