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Assessment of the Use of Nitrogen Trifluoride for Purifying Coolant and Heat Transfer Salts in the Fluoride Salt-Cooled High-Temperature Reactor

Description: This report provides an assessment of the use of nitrogen trifluoride for removing oxide and water-caused contaminants in the fluoride salts that will be used as coolants in a molten salt cooled reactor.
Date: September 28, 2010
Creator: Scheele, Randall D. & Casella, Andrew M.
Partner: UNT Libraries Government Documents Department

Scale-Up, Production, and Procurement of PEP Simulants

Description: Pacific Northwest National Laboratory has been tasked by Bechtel National Inc. on the River Protection Project-Hanford Tank Waste Treatment and Immobilization Plant (RPP-WTP) project to perform research and development activities to resolve technical issues identified for the Pretreatment Facility. The Pretreatment Engineering Platform (PEP) was designed, constructed, and operated as part of a plan to respond to issue M12, “Undemonstrated Leaching Processes.” The PEP is a 1/4.5-scale test platform designed to simulate the WTP pretreatment caustic leaching, oxidative leaching, ultrafiltration solids concentration, and slurry washing processes. The PEP replicates the WTP leaching processes using prototypic equipment and control strategies. This report provides the lessons learned regarding the manufacture and delivery of simulated feeds for PEP testing.
Date: October 29, 2009
Creator: Scheele, Randall D.; Brown, Garrett N. & Kurath, Dean E.
Partner: UNT Libraries Government Documents Department

Nitrogen Trifluoride-Based Fluoride- Volatility Separations Process: Initial Studies

Description: This document describes the results of our investigations on the potential use of nitrogen trifluoride as the fluorinating and oxidizing agent in fluoride volatility-based used nuclear fuel reprocessing. The conceptual process uses differences in reaction temperatures between nitrogen trifluoride and fuel constituents that produce volatile fluorides to achieve separations and recover valuable constituents. We provide results from our thermodynamic evaluations, thermo-analytical experiments, kinetic models, and provide a preliminary process flowsheet. The evaluations found that nitrogen trifluoride can effectively produce volatile fluorides at different temperatures dependent on the fuel constituent.
Date: September 28, 2011
Creator: McNamara, Bruce K.; Scheele, Randall D.; Casella, Andrew M. & Kozelisky, Anne E.
Partner: UNT Libraries Government Documents Department

Thermal Flammable Gas Production from Bulk Vitrification Feed

Description: The baseline bulk-vitrification (BV) process (also known as in-container vitrification ICV™) includes a mixer/dryer to convert liquid low-activity waste (LAW) into a dried, blended feed for vitrification. Feed preparation includes blending LAW with glass-forming minerals (GFMs) and cellulose and drying the mixture to a suitable dryness, consistency, and particle size for transport to the ICVTM container. The cellulose is to be added to the BV feed at a rate sufficient to destroy 75% of the nitrogen present as nitrate or nitrite. Concern exists that flammable gases may be produced during drying operations at levels that could pose a risk. The drying process is conducted under vacuum in the temperature range of 60 to 80°C. These flammable gases could be produced either through thermal decomposition of cellulose or waste organics or as a by-product of the reaction of cellulose and/or waste organics with nitrate or the postulated small amount of nitrite present in the waste. To help address the concern about flammable gas production during drying, the Pacific Northwest National Laboratory (PNNL) performed studies to identify the gases produced at dryer temperatures and at possible process upset conditions. Studies used a thermogravimetric analyzer (TGA) up to 525°C and isothermal testing up to 120°C to determine flammable gas production resulting from the cellulose and organic constituents in bulk vitrification feed. This report provides the results of those studies to determine the effects of cellulose and waste organics on flammable gas evolution
Date: May 21, 2008
Creator: Scheele, Randall D.; McNamara, Bruce K. & Bagaasen, Larry M.
Partner: UNT Libraries Government Documents Department

Evaluation of Exothermic Reactions from Bulk-Vitrification Melter Feeds Containing Cellulose

Description: PNNL has demonstrated that cellulose effectively reduces the amount of molten ionic salt during Bulk Vitrification of simulated Hanford Low Level Waste (LLW). To address concerns about the potential reactivity of cellulose-LLW, PNNL used thermogravimetric analysis, differential thermal analysis, and accelerating rate calorimetry to determine in these preliminary studies that these mixtures will support a self-sustaining reaction if heated to 110°C at adiabatic conditions. Additional testing is recommended.
Date: June 25, 2007
Creator: Scheele, Randall D.; McNamara, Bruce K.; Bagaasen, Larry M.; Bos, Stanley J.; Kozelisky, Anne E. & Berry, Pam
Partner: UNT Libraries Government Documents Department

Review of Potential Candidate Stabilization Technologies for Liquid and Solid Secondary Waste Streams

Description: Pacific Northwest National Laboratory has initiated a waste form testing program to support the long-term durability evaluation of a waste form for secondary wastes generated from the treatment and immobilization of Hanford radioactive tank wastes. The purpose of the work discussed in this report is to identify candidate stabilization technologies and getters that have the potential to successfully treat the secondary waste stream liquid effluent, mainly from off-gas scrubbers and spent solids, produced by the Hanford Tank Waste Treatment and Immobilization Plant (WTP). Down-selection to the most promising stabilization processes/waste forms is needed to support the design of a solidification treatment unit (STU) to be added to the Effluent Treatment Facility (ETF). To support key decision processes, an initial screening of the secondary liquid waste forms must be completed by February 2010.
Date: January 30, 2010
Creator: Pierce, Eric M.; Mattigod, Shas V.; Westsik, Joseph H.; Serne, R. Jeffrey; Icenhower, Jonathan P.; Scheele, Randall D. et al.
Partner: UNT Libraries Government Documents Department

Preparation and Characterization of {sup 238}Pu-Ceramics for Radiation Damage Experiments

Description: The results from this initial characterization of the {sup 238}Pu- and {sup 239}Pu-bearing ceramics showed that the target phase assemblage was achieved in all but one material, {sup 238}Pu-zirconolite baseline. This {sup 238}Pu-zirconolite baseline material appears to have been prepared incorrectly with a 14 mass% excess of Pu (9.6 mass% actual vs. 8.4 mass% target; 4.8 mole% actual vs. 4.1 mole% target). It is not surprising that PuO{sub 2} was found to be one of the dominant phases. The densities of these materials compared well with the theoretical densities given by Stewart, Vance, and Ball [14]. For all but three of the materials, the average density was >94% of theoretical. Of the three, one was {sup 238}Pu-zirconolite baseline (108%) that contained unreacted PuO{sub 2}. In our MCC leach testing, the normalized elemental mass losses from the various ceramic specimens depended on the elemental ceramic constituent, the Pu isotope, and the ceramic. Of the primary constituents, Al and Ca were the most easily released. Plutonium and U were the next most susceptible to release. In general, the Hf had the lowest releases during the tests. The Gd and Ti releases varied, depending on the ceramic and the Pu isotope in the ceramic. The Mo, which was added as a trace constituent to monitor the stability of the crystalline structure, exhibited consistently high-normalized elemental releases. The amount of Pu leached depended the most on the Pu isotope in the ceramic with more Pu released from the {sup 238}Pu specimens than from the {sup 239}Pu specimens, independent of ceramic type. Interestingly, the Mo releases were typically higher for the {sup 239}Pu specimens than for the {sup 238}Pu specimens. The higher Pu release from the {sup 238}Pu specimens is not yet understood; the consistency between the ICP/MS- and GEA-measured Pu releases from the {sup ...
Date: June 15, 2000
Creator: Strachan, Denis M; Scheele, Randall D; Buchmiller, William C; Vienna, John D; Sell, Richard L & Elovich, Robert J
Partner: UNT Libraries Government Documents Department

The Status of Radiation Damage Experiments

Description: Experiments have been on-going for about two years to determine the effects that radiation damage have on the physical and chemical properties of candidate titanate ceramics for the immobilization of plutonium. We summarize the results of these experiments in this document.
Date: November 20, 2001
Creator: Strachan, Denis M.; Scheele, Randall D.; Icenhower, Jonathan P.; Kozelisky, Anne E.; Sell, Richard L.; Legore, Virginia L. et al.
Partner: UNT Libraries Government Documents Department

Thermal Stability Studies of Candidate Decontamination Agents for Hanford’s Plutonium Finishing Plant Plutonium-Contaminated Gloveboxes

Description: This report provides the results of PNNL's and Fluor's studies of the thermal stabilities of potential wastes arising from decontamination of Hanford's Plutonium Finishing Plant's plutonium contaminated gloveboxes. The candidate wastes arising from the decontamination technologies ceric nitrate/nitric acid, RadPro, Glygel, and Aspigel.
Date: September 29, 2005
Creator: Scheele, Randall D.; Cooper, Thurman D.; Jones, Susan A.; Ewalt, John R.; Compton, James A.; Trent, Donald S. et al.
Partner: UNT Libraries Government Documents Department

Processes for Removal and Immobilization of 14C, 129I, and 85Kr

Description: This is a white paper covering the results of a literature search and preliminary experiments on materials and methods to remove and immobilize gaseous radionuclided that come from the reprocessing of spent nuclear fuel.
Date: October 5, 2009
Creator: Strachan, Denis M.; Bryan, Samuel A.; Henager, Charles H.; Levitskaia, Tatiana G.; Matyas, Josef; Thallapally, Praveen K. et al.
Partner: UNT Libraries Government Documents Department

The Status of Radiation Damage Experiments

Description: Experiments have been on-going for about two years to determine the effects that radiation damage have on the physical and chemical properties of candidate titanate ceramics for the immobilization of plutonium. We summarize the results of these experiments in this document.
Date: November 20, 2001
Creator: Strachan, Denis M; Scheele, Randall D; Icenhower, Jonathan P; Kozelisky, Anne E; Sell, Richard L; Legore, Virginia L et al.
Partner: UNT Libraries Government Documents Department

Uranium Oxide Aerosol Transport in Porous Graphite

Description: The objective of this paper is to investigate the transport of uranium oxide particles that may be present in carbon dioxide (CO2) gas coolant, into the graphite blocks of gas-cooled, graphite moderated reactors. The transport of uranium oxide in the coolant system, and subsequent deposition of this material in the graphite, of such reactors is of interest because it has the potential to influence the application of the Graphite Isotope Ratio Method (GIRM). The GIRM is a technology that has been developed to validate the declared operation of graphite moderated reactors. GIRM exploits isotopic ratio changes that occur in the impurity elements present in the graphite to infer cumulative exposure and hence the reactor’s lifetime cumulative plutonium production. Reference Gesh, et. al., for a more complete discussion on the GIRM technology.
Date: January 23, 2012
Creator: Blanchard, Jeremy; Gerlach, David C.; Scheele, Randall D.; Stewart, Mark L.; Reid, Bruce D.; Gauglitz, Phillip A. et al.
Partner: UNT Libraries Government Documents Department