scholarly journals Americium/Curium Extraction from a Lanthanide Borosilicate Glass

1996 ◽  
Vol 465 ◽  
Author(s):  
T. S. Rudisill ◽  
J. M. Pareizs ◽  
W. G. Ramsey
Keyword(s):  
National Laboratory ◽  
Fission Products ◽  
Glass Particle ◽  
Radioactive Isotopes ◽  
Dissolution Time ◽  
Savannah River ◽  
Oak Ridge ◽  
Glass Dissolution ◽  
Time Required ◽  
River Site

ABSTRACTA solution containing kilogram quantities of highly radioactive isotopes of amerícium and curium (Am/Cm) and lanthanide fission products is currently stored in a process tank at the Department of Energy's Savannah River Site (SRS). This tank and its vital support systems are old, subject to deterioration, and prone to possible leakage. For this reason, a program has been initiated to stabilize this material as a lanthanide borosilicate (LBS) glass.1 The Am/Cm has commercial value and is desired for use by the heavy isotope programs at the Oak Ridge National Laboratory (ORNL).A recovery flowsheet was demonstrated using a curium-containing glass to extract the Am/Cm from the glass matrix. The procedure involved grinding the glass to less than 200 mesh and dissolving in concentrated nitric acid at 110°C. Under these conditions, the dissolution was essentially 100% after 2 hours except for the insoluble silicon. Using a nonradioactive surrogate, the expected glass dissolution rate during Am/Cm recovery was bracketed by using both static and agitated conditions. The measured rates, 0.0082 and 0.040 g/hrcm2, were used to develop a predictive model for the time required to dissolve a spherical glass particle in terms of the glass density, particle size, and measured rate. The calculated dissolution time was in agreement with the experimental observation that the curium glass dissolution was complete in less than 2 hr.

CFD Modeling of Solid Fluidization in a Column

2005 ◽  
Author(s):  
Si Y. Lee
Keyword(s):  
National Laboratory ◽  
Primary Objective ◽  
Cfd Modeling ◽  
Savannah River ◽  
Hydraulic Behavior ◽  
Savannah River National Laboratory ◽  
Computational Fluid Dynamics Cfd ◽  
Pass Through ◽  
River Site ◽  
Sedimentation Processes

Primary objective of the work is to model resin particles within the column during the particle fluidization and sedimentation processes and to understand hydraulic behavior for particles within column during the resin fluidization and sedimentation processes. The modeling results will assist in interpreting experimental results, providing guidance on specific details of testing design, and establishing a basic understanding of resin particle’s hydraulic behavior within the column. The model was benchmarked against the literature data and the test data conducted by Savannah River National Laboratory at Savannah River Site (SRS). A scoping analysis effort has been undertaken to address the feasibility of simulating the basic fluidization and sedimentation aspects pertinent to the resin addition/removal process considered here. The existing computational fluid dynamics (CFD) code Fluent was chosen for this effort. Both fluidization and sedimentation of granular particles (i.e., of varying sizes) were based on an Eulerian model for granular flow. A two-dimensional axial symmetrical cylindrical geometry was chosen to perform the solid-fluid simulations. The column consisted of a fluid region of 48” in diameter by 94” in height where at both the top and bottom boundaries liquid fluid could pass through, but resin particle could not (i.e., assuming screens at both ends).

Proof-of-Concept Flowsheet Tests for Cesium Removal from Tank Waste by Caustic-Side Solvent Extraction

2002 ◽  
Vol 713 ◽  
Author(s):  
David B. Chamberlain ◽  
Scott Aase ◽  
Hassan A. Arafat ◽  
Cliff Conner ◽  
Ralph A. Leonard ◽  
...  
Keyword(s):  
Solvent Extraction ◽  
National Laboratory ◽  
Argonne National Laboratory ◽  
Decontamination Factor ◽  
High Level Waste ◽  
Savannah River ◽  
Alkyl Aryl ◽  
Oak Ridge ◽  
Cesium Removal ◽  
Tank Waste

ABSTRACTA caustic-side solvent extraction (CSSX) process to remove cesium from Savannah River Site (SRS) high-level waste has been developed through a joint program with Oak Ridge National Laboratory (ORNL), the Savannah River Technical Center (SRTC), and Argonne National Laboratory (ANL). The CSSX solvent consists of four components: (1) an extractant, a calixarene crown, calix[4]arene-bis(tert-octylbenzo-crown-6) designated BOBCalixC6, (2) a modifier, an alkyl aryl polyether, 1-(2,2,3,3,-tetrafluoropropoxy)-3-(4-sec-butylphenoxy)-2-propanol, also called Cs-7SB, (3) a suppressant, an alkyl amine, trioctylamine (TOA), and (4) a diluent, Isopar®L. The solvent composition is 0.01 M BOBCalixC6, 0.50 M Cs-7SB, and 0.001 M TOA in Isopar®L. In this program we have developed and demonstrated a flowsheet that can be used to process SRS tank waste. To this end, a series of flowsheet tests were completed using simulated waste in a 2-cm centrifugal contactor at ANL. Three short-term (3-4 hours) tests were completed to demonstrate various aspects of the flowsheet. These tests were followed by a 71-h test where the solvent was recycled 42 times. In each case, we met or exceeded the key process goals: (1) cesium removal from the waste with a decontamination factor greater than 40,000, (2) concentration of cesium in the aqueous strip effluent by a factor of 15 using dilute nitric acid, and (3) stripping the solvent sufficiently to allow it to be recycled many times. The results from the 71-h test are discussed.

scholarly journals Product Consistency Leach Tests of Savannah River Site Radioactive Waste Glasses

1989 ◽  
Vol 176 ◽  
Author(s):  
Ned E. Bibler ◽  
John K. Bates
Keyword(s):  
National Laboratory ◽  
Argonne National Laboratory ◽  
Savannah River Site ◽  
Good Precision ◽  
Savannah River ◽  
Consistency Test ◽  
Leach Test ◽  
Processing Facility ◽  
General Order ◽  
River Site

ABSTRACTThe Product Consistency Test (PCT) is a glass leach test developed at the Savannah River Site (SRS) to confirm the durability of radioactive nuclear waste glasses that will be produced in the Defense Waste Processing Facility. The PCT is a seven day, crushed glass leach test in deionized water at 90°C. Final leachates are filtered and acidified prior to analysis. To demonstrate the reproducibility of the PCT when performed remotely, SRS and Argonne National Laboratory have performed the PCT on samples of two radioactive glasses. The tests were also performed to compare the releases of the radionuclides with the major nonradioactive glass components and to determine if radiation from the glass was affecting the results of the PCT.The test was performed in triplicate at each laboratory. For the major soluble elements, B, Li, Na, and Si, in the glass, each investigator obtained relative precisions in the range 2–5% in the triplicate tests. This range indicates good precision for the PCT when performed remotely with master slave manipulators in a shielded cell environment. When the results of the two laboratories were compared to each other, the agreement was within 20%. Normalized concentrations for the nonradioactive and radioactive elements in the PCT leachates measured at both facilities indicated that the radionuclides were released from the glass slower than the major soluble elements in the glass. For both laboratories, the normalized releases for both glasses were in the general order Li∼B∼Na>Si>Cs-137>Sb-125>Sr-90. The normalized releases for the major soluble elements and the final pH values in the tests with radioactive glass are consistent with those for nonradioactive glasses with similar compositions. This indicates that there was no significant effect of radiation on the results of the PCT.

scholarly journals A Model for a National Low Level Waste Program

2009 ◽  
Author(s):  
James A. Blankenhorn
Keyword(s):  
National Laboratory ◽  
National Program ◽  
Savannah River ◽  
Alamos National Laboratory ◽  
Los Alamos ◽  
Waste Hierarchy ◽  
Los Alamos National Laboratory ◽  
Low Level ◽  
River Site ◽  
Transuranic Waste

A national program for the management of low level waste is essential to the success of environmental clean-up, decontamination and decommissioning, current operations and future missions. The value of a national program is recognized through procedural consistency and a shared set of resources. A national program requires a clear waste definition and an understanding of waste characteristics matched against available and proposed disposal options. A national program requires the development and implementation of standards and procedures for implementing the waste hierarchy, with a specific emphasis on waste avoidance, minimization and recycling. It requires a common set of objectives for waste characterization based on the disposal facility’s waste acceptance criteria, regulatory and license requirements and performance assessments. Finally, a national waste certification program is required to ensure compliance. To facilitate and enhance the national program, a centralized generator services organization, tasked with providing technical services to the generators on behalf of the national program, is necessary. These subject matter experts are the interface between the generating sites and the disposal facility(s). They provide an invaluable service to the generating organizations through their involvement in waste planning prior to waste generation and through championing implementation of the waste hierarchy. Through their interface, national treatment and transportation services are optimized and new business opportunities are identified. This national model is based on extensive experience in the development and on-going management of a national transuranic waste program and management of the national repository, the Waste Isolation Pilot Plant. The Low Level Program at the Savannah River Site also successfully developed and implemented the waste hierarchy, waste certification and waste generator services concepts presented below. The Savannah River Site services over forty generators and has historically managed over 12,000 cubic meters of low level waste annually. The results of the waste minimization program at the site resulted in over 900 initiatives, avoiding over 220,000 cubic meters of waste for a life cycle cost savings of $275 million. At the Los Alamos National Laboratory, the low level waste program services over 20 major generators and several hundred smaller generators that produce over 4,000 cubic meters of low level waste annually. The Los Alamos National Laboratory low level waste program utilizes both on-site and off-site disposal capabilities. Off-site disposal requires the implementation of certification requirements to utilize both federal and commercial options. The Waste Isolation Pilot Plant is the US Department of Energy’s first deep geological repository for the permanent disposal of Transuanic waste. Transuranic waste was generated and retrievably stored at 39 sites across the US. Transuranic waste is defined as waste with a radionuclide concentration equal to or greater than 100 nCi/g consisting of radionuclides with half-lives greater than 20 years and with an atomic mass greater than uranium. Combining the lessons learned from the national transuranic waste program, the successful low level waste program at Savannah River Site and the experience of off-site disposal options at Los Alamos National Laboratory provides the framework and basis for developing a viable national strategy for managing low level waste.

scholarly journals Hydrogen Concentrations During Storage of 3013 Oxide Samples

2011 ◽  
Author(s):  
N. M. Askew ◽  
J. E. Laurinat ◽  
S. J. Hensel
Keyword(s):  
National Laboratory ◽  
Hydrogen Gas ◽  
Surveillance Program ◽  
Nuclear Materials ◽  
Savannah River ◽  
Shipping Containers ◽  
Savannah River National Laboratory ◽  
Hydrogen Accumulation ◽  
Lower Flammability Limit ◽  
River Site

As part of a surveillance program intended to ensure the safe storage of plutonium bearing nuclear materials in the Savannah River Site (SRS) K-Area Materials Storage, samples of these materials are shipped to Savannah River National Laboratory (SRNL) for analysis. These samples are in the form of solids or powders which will have absorbed moisture. Potentially flammable hydrogen gas is generated due to radiolysis of the moisture. The samples are shipped for processing after chemical analysis. To preclude the possibility of a hydrogen deflagration or detonation inside the shipping containers, the shipping times are limited to ensure that hydrogen concentration in the vapor space of every layer of confinement is below the lower flammability limit of 4 volume percent (vol%) [1]. This study presents an analysis of the rate of hydrogen accumulation due to radiolysis and calculation of allowable shipping times for typical K-Area materials.

Sign in / Sign up

Export Citation Format

Share Document