Studies of the Fundamental Chemistry of Hanford Tank Sludges

2003 ◽  
Author(s):  
Gregg J. Lumetta ◽  
Brian M. Rapko ◽  
Herman M. Cho
Keyword(s):  
Complex Mixture ◽  
Chemical Species ◽  
Department Of Energy ◽  
High Level Waste ◽  
Resonance Spectroscopy ◽  
X Ray Diffraction ◽  
Hanford Site ◽  
Mineral Phases ◽  
Fe Oxyhydroxides ◽  
High Level

The U.S. Department of Energy has embarked on an effort to retrieve, immobilize, and dispose of the 2.1 × 105 m3 of radioactive tank wastes that were generated during weapons production and other operations at the Hanford Site in Washington State. One of the major challenges associated with this effort is the processing of the 4.2 × 104 m3 of high-level waste sludges. These sludges consist of a complex mixture of amorphous and crystalline mineral phases. The current plan for processing the sludge solids consists of leaching with aqueous NaOH, washing out the NaOH and dissolved components, then vitrifying the solids in borosilicate glass. The purpose of the NaOH leaching step is to remove components such as Al, Cr, and P that can lead to the production of an unacceptable quantity of high-level waste glass. In this paper, we will discuss the chemistry underlying the leaching and washing processes, focusing on the specific mineral phases present in the sludge solids and how these phases respond to the leaching process. The chemical phases present in the Hanford tank sludge solids have been identified through microscopy coupled with electron diffraction and through powder X-ray diffraction. We have also recently been applying nuclear magnetic resonance spectroscopy to characterize chemical species in tank sludge solids. Numerous chemical species have been identified including the aluminum oxy/hydroxides gibbsite and boehmite, aluminosilicates, iron oxy/hydroxides, and mixed Cr/Fe oxyhydroxides. Identification of these phases has led to a more fundamental understanding of the behavior of the various sludge components during leaching; in turn, this understanding will allow for improved process flow sheets. For example, we have shown that certain tank sludges are high in boehmite, Υ-AIOOH. This mineral phase is much more refractory than other AI phases such as gibbsite. Thus, more severe leaching conditions (e.g., increased temperature, NaOH concentration, and leaching duration) are required to remove AI from wastes high in boehmite.

Improved Third Generation Peristaltic Crawler for Removal of High-Level Waste Plugs in United States Department of Energy Hanford Site Pipelines

2013 ◽  
Author(s):  
Gabriela Vazquez ◽  
Tomas Pribanic
Keyword(s):  
Fatigue Testing ◽  
Experimental Tests ◽  
Department Of Energy ◽  
High Level Waste ◽  
Pipeline System ◽  
United States Department ◽  
Third Generation ◽  
Test Bed ◽  
Hanford Site ◽  
High Level

There are approximately 56 million gallons (212km3) of high level waste (HLW) at the U.S. Department of Energy (DOE) Hanford Site. It is scheduled that by the year 2040, the HLW is to be completely transferred to secure double-shell tanks (DST) from the leaking single-tanks (SST) via transfer pipeline system. Blockages have formed inside the pipes during transport because of the variety in composition and characteristics of the waste. These full and partial plugs delay waste transfers and require manual intervention to repair, therefore are extremely expensive, consuming millions of dollars and further threatening the environment. To successfully continue the transfer of waste through the pipelines, DOE site engineers are in need of a technology that can accurately locate the blockages and unplug the pipelines. In this study, the proposed solution to remediate blockages formed in pipelines is the use of a peristaltic crawler: a pneumatically/hydraulically operated device that propels itself in a worm-like motion through sequential fluctuations of pressure in its air cavities. The crawler is also equipped with a high-pressure water nozzle used to clear blockages inside the pipelines. The crawler is now in its third generation. Previous generations showed limitations in its durability, speed, and maneuverability. Latest improvements include an automation of sequence that prevents kickback, a front-mounted inspection camera for visual feedback, and a thinner wall outer bellow for improved maneuverability. Different experimental tests were conducted to evaluate the improvements of crawler relative to its predecessors using a pipeline test-bed assembly. Anchor force tests, unplugging tests, and fatigue testing for both the bellow and rubber rims have yet to be conducted and thus results are not presented in this research. Experiments tested bellow force and response, cornering maneuverability, and straight line navigational speed. The design concept and experimental test results are reported.

Liquidus Temperature of Spinel Precipitating High-Level Waste Glasses

1996 ◽  
Vol 465 ◽  
Author(s):  
M. Mika ◽  
M. J. Schweiger ◽  
J. D. Vienna ◽  
P. Hrma
Keyword(s):  
Mixture Models ◽  
Crystalline Phase ◽  
Liquidus Temperature ◽  
Glass Composition ◽  
High Level Waste ◽  
Hanford Site ◽  
High Iron ◽  
Negative Effect ◽  
High Level ◽  
Glass Viscosity

ABSTRACTThe liquidus temperature (TL) often limits the loading of high-level waste in glass through the constraint that TL must be at least 100°C below the temperature at which the glass viscosity is 5 Pa-s. In this study, values of TL for spinel primary crystalline phase were measured as a function of glass composition. The test glasses were based on high-iron Hanford Site tank wastes. All studied glasses precipitated spinel (Ni,Fe,Mn)(Cr,Fe)2O4 as the primary crystalline phase. TL was increased by additions of Cr2O3, NiO, Al2O3, Fe2O3, MgO, and MnO; while Li2O, Na2O, B2O3, and SiO2 had a negative effect. Empirical mixture models were fitted to data.

Materials Interface Interactions Test (MIIT); in-Situ Testing of Simulated Hlw Forms in Salt- Performance of Srs Simulated Waste Glass After up to 5 Years of Burial at the Waste Isolation Pilot Plant (WIPP)

1991 ◽  
Vol 257 ◽  
Author(s):  
G.G. Wicks ◽  
A.R. Lodding ◽  
P.B. Macedo ◽  
D.E. Clark
Keyword(s):  
United States ◽  
Pilot Plant ◽  
Field Tests ◽  
Field Testing ◽  
The United States ◽  
Waste Glass ◽  
Department Of Energy ◽  
High Level Waste ◽  
Waste Isolation Pilot Plant ◽  
High Level

ABSTRACTThe first field tests conducted in the United States involving burial of simulated high-level waste [HLW] forms and package components, were started in July of 1986. The program, called the Materials Interface Interactions Test or MIIT, is the largest cooperative field-testing venture in the international waste management community. Included in the study are over 900 waste form samples comprising 15 different systems supplied by 7 countries. Also included are approximately 300 potential canister or overpack metal samples along with more than 500 geologic and backfill specimens. There are almost 2000 relevant interactions that characterize this effort which is being conducted in the bedded salt site at the Waste Isolation Pilot Plant (WIPP), near Carlsbad, New Mexico. The MIIT program represents a joint endeavor managed by Sandia National Laboratories in Albuquerque, N.M., and Savannah River Laboratory in Aiken, S.C. and sponsored by the U.S. Department of Energy. Also involved in MIIT are participants from various laboratories and universities in France, Germany, Belgium, Canada, Japan, Sweden, the United Kingdom, and the United States. In July of 1991, the experimental portion of the 5-yr. MIIT program was completed. Although only about 5% of all MIIT samples have been assessed thus far, there are already interesting findings that have emerged. The present paper will discuss results obtained for SRS 165/TDS waste glass after burial of 6 mo., 1 yr. and 2 yrs., along with initial analyses of 5 yr. samples.

Lessons Learned Siting and Successfully Processing U.S. DOE Radioactive Wastes Using a High Throughput Vitrification Process

2003 ◽  
Author(s):  
Robert E. Prince ◽  
Bradley W. Bowan
Keyword(s):  
The United States ◽  
Lessons Learned ◽  
Volume Reduction ◽  
Waste Form ◽  
High Level Waste ◽  
Hanford Site ◽  
High Level ◽  
Low Activity ◽  
The U.S ◽  
Ceramic Melter

This paper describes actual experience applying a technology to achieve volume reduction while producing a stable waste form for low and intermediate level liquid (L/ILW) wastes, and the L/ILW fraction produced from pre-processing of high level wastes. The chief process addressed will be vitrification. The joule-heated ceramic melter vitrification process has been used successfully on a number of waste streams produced by the U.S. Department of Energy (DOE). This paper will address lessons learned in achieving dramatic improvements in process throughput, based on actual pilot and full-scale waste processing experience. Since 1991, Duratek, Inc., and its long-term research partner, the Vitreous State Laboratory of The Catholic University of America, have worked to continuously improve joule heated ceramic melter vitrification technology in support of waste stabilization and disposition in the United States. From 1993 to 1998, under contact to the DOE, the team designed, built, and operated a joule-heated melter (the DuraMelterTM) to process liquid mixed (hazardous/low activity) waste material at the Savannah River Site (SRS) in South Carolina. This melter produced 1,000,000 kilograms of vitrified waste, achieving a volume reduction of approximately 70 percent and ultimately producing a waste form that the U.S. Environmental Protection Agency (EPA) delisted for its hazardous classification. The team built upon its SRS M Area experience to produce state-of-the-art melter technology that will be used at the DOE’s Hanford site in Richland, Washington. Since 1998, the DuraMelterTM has been the reference vitrification technology for processing both the high level waste (HLW) and low activity waste (LAW) fractions of liquid HLW waste from the U.S. DOE’s Hanford site. Process innovations have doubled the throughput and enhanced the ability to handle problem constituents in LAW. This paper provides lessons learned from the operation and testing of two facilities that provide the technology for a vitrification system that will be used in the stabilization of the low level fraction of Hanford’s high level tank wastes.

Effect of Li, Fe, and B Addition on the Crystallization Behavior of Sodium Aluminosilicate Glasses as Analogues for Hanford High Level Waste Glasses

MRS Advances ◽  
2016 ◽  
Vol 2 (10) ◽  
pp. 549-555 ◽  
Author(s):  
José Marcial ◽  
Mostafa Ahmadzadeh ◽  
John S. McCloy
Keyword(s):  
Function Analysis ◽  
High Level Waste ◽  
X Ray Diffraction ◽  
X Ray ◽  
High Sodium ◽  
Chemical Ordering ◽  
Sodium Aluminosilicate ◽  
Aluminosilicate Glasses ◽  
Heat Treated ◽  
High Level

ABSTRACTCrystallization of aluminosilicates during the conversion of Hanford high-level waste (HLW) to glass is a function of the composition of the glass-forming melt. In high-sodium, high-aluminum waste streams, the crystallization of nepheline (NaAlSiO4) removes chemically durable glass-formers from the melt, leaving behind a residual melt that is enriched in less durable components, such as sodium and boron. We seek to further understand the effect of lithium, boron, and iron addition on the crystallization of model silicate glasses as analogues for the complex waste glass. Boron and iron behave as glass intermediates which allow for crystallization when present in low additions but frustrate crystallization in high additions. In this work, we seek to compare the average structures of quenched and heat treated glasses through Raman spectroscopy, X-ray diffraction, vibrating sample magnetometry, and X-ray pair distribution function analysis. The endmembers of this study are feldspathoid-like (LiAlSiO4, NaAlSiO4, NaBSiO4, and NaFeSiO4), pyroxene-like (LiAlSi2O6, NaAlSi2O6, NaBSi2O6, and NaFeSi2O6), and feldspar-like (LiAlSi3O8, NaAlSi3O8, NaBSi3O8, and NaFeSi3O8). Such a comparison will provide further insight on the complex relationship between the average chemical ordering and topology of glass on crystallization.

Simultaneous resolution of reactive radioactive decay, non-isothermal flow, and migration with application to the performance assessment for HLW repositories

2010 ◽  
Vol 98 (6) ◽  
Author(s):  
R. Juncosa ◽  
I. Font ◽  
J. Delgado
Keyword(s):  
Ion Exchange ◽  
Radioactive Decay ◽  
Chemical Species ◽  
High Level Waste ◽  
Chemical Components ◽  
Clay Material ◽  
Decay Series ◽  
And Migration ◽  
High Level ◽  
Radioactive Species

AbstractRadioactive decay is an important subject to take into account when studying the thermo-hydro-dynamic behavior of the buffer clay material used in the containment of radioactive waste. The modern concepts for the multibarrier design of a repository of high level waste in deep geologic formations consider that once canisters have failed, the buffer clay material must ensure the retention and/or delay of radionuclides within the time framework given in the assessment studies. Within the clay buffer, different chemical species are retarded/fixed according to several physicochemical processes (ion exchange, surface complexation, precipitation, matrix diffusion, ...) but typical approaches do not consider the eventuality that radioactive species change their chemical nature (The radioactive decay of an element takes place independently of the phase (aqueous, solid or gaseous) to which it belongs. This means that, in terms of radionuclide fixation, some geochemical processes will be effective scavengers (for instance mineral precipitation of crystal growth) while others will not (for instance ion exchange and/or sorption).In this contribution we present a reactive radioactive decay model of any number of chemical components including those that belong to decay series. The model, which is named FLOW-DECAY, also takes into account flow and isotopic migration and it has been applied considering a hypothetical model scenario provided by the project ENRESA 2000 and direct comparison with the results generated by the probabilistic code GoldSim. Results indicate that FLOW-DECAY may simulate the decay processes in a similar way that GoldSim, being the differences related to factors associated to code architecture.

Cold Crucible Vitrification of U-bearing SRS SB4 HLW Surrogate

2010 ◽  
Vol 1265 ◽  
Author(s):  
Sergey Stefanovsky ◽  
Alexander Ptashkin ◽  
Oleg Knyazev ◽  
Olga Stefanovsky ◽  
James C Marra
Keyword(s):  
High Level Waste ◽  
Cold Crucible ◽  
Savannah River ◽  
X Ray Diffraction ◽  
Alumina Crucible ◽  
X Ray ◽  
Xrd Study ◽  
Processing Facility ◽  
High Level ◽  
River Site

AbstractSavannah River Site Defense Waste Processing Facility (DWPF) Sludge Batch 4 (SB4) high level waste (HLW) simulant at 55 wt % waste loading was produced in the demountable cold crucible and cooled to room temperature in the cold crucible. Appreciable losses of Cs, S and Cl took place during the melting. A second glass sample was subjected to canister centerline cooling (CCC) regime in an alumina crucible in a resistive furnace. X-ray diffraction (XRD) study showed that the glass blocks were composed of vitreous and spinel structure phases. No separate U-bearing phases were found.

scholarly journals Glass Formulation Development in Support of Melter Testing to Demonstrate Enhanced High Level Waste Throughput

2008 ◽  
Vol 1107 ◽  
Author(s):  
James C. Marra ◽  
Kevin M. Fox ◽  
David K. Peeler ◽  
Thomas B. Edwards ◽  
Amanda L. Youchak ◽  
...  
Keyword(s):  
Product Quality ◽  
Department Of Energy ◽  
High Alumina ◽  
High Level Waste ◽  
Alumina Concentration ◽  
Formulation Development ◽  
Technology Innovations ◽  
Glass Formulation ◽  
Waste Loading ◽  
High Level

AbstractThe U.S. Department of Energy (DOE) is currently processing high-level waste (HLW) through a Joule-heated melter (JHM) at the Savannah River Site (SRS) and plans to vitrify HLW and Low activity waste (LAW) at the Hanford Site. Over the past few years at the Defense Waste Processing Facility (DWPF), work has concentrated on increasing waste throughput. These efforts are continuing with an emphasis on high alumina concentration feeds. High alumina feeds have presented specific challenges for the JHM technology regarding the ability to increase waste loading yet still maintain product quality and adequate throughput. Alternatively, vitrification technology innovations are also being investigated as a means to increase waste throughput. The Cold Crucible Induction Melter (CCIM) technology affords the opportunity for higher vitrification process temperatures as compared to the current reference JHM technology. Higher process temperatures may allow for higher waste loading and higher melt rate.Glass formulation testing to support melter demonstration testing was recently completed. This testing was specifically aimed at high alumina concentration wastes. Glass composition/property models developed for DWPF were utilized as a guide for formulation development. Both CCIM and JHM testing will be conducted so glass formulation testing was targeted at both technologies with a goal to significantly increase waste loading and maintain melt rate without compromising product quality.

Sign in / Sign up

Export Citation Format

Share Document