Alternative Igneous Source Term Model for Tephra Dispersal at the Yucca Mountain Repository

2004 ◽  
Vol 148 (2) ◽  
pp. 205-212 ◽  
Author(s):  
Richard Blake Codell
Keyword(s):  
Source Term ◽  
Yucca Mountain ◽  
Tephra Dispersal ◽  
Term Model ◽  
Source Term Model

Vegetation-Derived Insights on the Mobilization and Potential:Transport of Radionuclides from the Nopal I Natural Analog Site, Mexico

1999 ◽  
Vol 556 ◽  
Author(s):  
Bret W. Leslie ◽  
David A. Pickett ◽  
English C. Pearcy
Keyword(s):  
Source Term ◽  
Activity Ratio ◽  
Decay Chain ◽  
Yucca Mountain ◽  
Nuclear Waste Repository ◽  
Natural Analog ◽  
Ore Body ◽  
Term Model ◽  
High Level ◽  
Source Term Model

AbstractThe Nopal I uranium (U) deposit, Peñia Blanca, Mexico is a source term and contaminant transport natural analog to the proposed high-level nuclear waste repository at Yucca Mountain, Nevada. In an attempt to characterize the mobilization and potential transport of adionuclides in the unsaturated zone at the Nopal I deposit, vegetation growing on ore piles was analyzed for 238U, 235U, and 232Th decay-series isotopes. Specimens of Phacelia robusta growing on highgrade piles of U ore were collected and analyzed by alpha autoradiography, and by alpha and gamma spectrometry. Activities for U, thorium (Th), and radium (Ra) isotopes (Bq/kg dried plant) were 300, 1000, and 7000 for 238U, 230Th, and 226Ra, respectively. The 226Ra activities in these specimens are among the highest ever measured for plants; furthermore, the plant-to-soil 226Ra concentration ratio is higher than expected. These results demonstrate the large mobility and bio-availability of Ra in the Nopal I environment, and support previous indications of recent loss of 226Ra from the ore body. Comparison between the activities of 238U and 232Th decay-chain Th isotopes in the plants and in the ore substrate indicate that relative mobilization into pore solutions of 228Th > 230Th > 232Th, in a ratio of about 50 – 25:4:1, respectively. The similarity of the plant's 234U/238U activity ratio (˜1.2) to that of a caliche deposit that formed adjacent to the Nopal ore body around 54 ka suggests the 234U/238U activity ratio of U released from the ore is approximately 1.2. The U and 236Ra isotope activities of the plants and ore substrate, and solubility considerations, are used to assess a source term model of the potential Yucca Mountain repository. These results suggest the use of a natural analog source term model in performance assessments may be non-conservative.

scholarly journals Source term model of radioactive liquid spills for actual decision support systems

2021 ◽  
Vol 280 ◽  
pp. 09001
Author(s):  
Yurii Kyrylenko ◽  
Iryna Kameneva ◽  
Oleksandr Popov ◽  
Andrii Iatsyshyn ◽  
Iryna Matvieieva ◽  
...  
Keyword(s):  
Decision Support ◽  
Initial Data ◽  
Source Term ◽  
Radioactive Material ◽  
Atmospheric Models ◽  
The Public ◽  
Term Model ◽  
Radiological Impact ◽  
Emergency Scenarios ◽  
Source Term Model

Spills of liquid radioactive material are reviewed as potential event that can be associated with release into the atmosphere. Existing approaches to radiological impact assessment for onsite as well as offsite of facility are presented. The example of using the actual Java version of the European RODOS system as prototype of the decision support system shows the general implementation of the analysis and preparation of initial data in order to model the radiological impact on the public, personnel and environment. Given the specifics of the occurrence of emergency scenarios of this type, features of atmospheric models application, description of the source term model, software integration features, ventilation task solving, completeness and format of the initial data required for radiological consequence modelling.

Source Term Model for Fine Particle Resuspension from Indoor Surfaces

2008 ◽  
Author(s):  
Yoojeong Kim ◽  
Ashok Gidwani ◽  
Mark Sippola ◽  
Chang W. Sohn
Keyword(s):  
Fine Particle ◽  
Source Term ◽  
Particle Resuspension ◽  
Term Model ◽  
Source Term Model

Endwall Cavity Flow Effects on Gaspath Aerodynamics in an Axial Flow Turbine: Part II — Source Term Model Development

2000 ◽  
Author(s):  
Scott D. Hunter ◽  
Paul O. Orkwis
Keyword(s):  
Secondary Flow ◽  
Source Term ◽  
Axial Flow ◽  
Cavity Flow ◽  
Cavity Flows ◽  
Low Pressure Turbine ◽  
Turbine Efficiency ◽  
Term Model ◽  
Cavity Effects ◽  
Source Term Model

Axial flow turbine designers are currently using Navier-Stokes flow solvers to reveal the details of the three dimensional flowfield inside individual bladerow passages. This new capability has allowed designers to focus on secondary flow reduction to improve turbine efficiency. These steady bladerow solvers include viscous and film cooling effects and show good agreement with test measurements in the midspan region. However, the difference between computational results and experimental data at the endwalls is significant due to the exclusion of endwall cavity effects. A clear understanding of how the cavity flow interacts with the gaspath aerodynamics, in conjunction with an accurate computational model, is needed to predict accurately the secondary flow patterns and endwall losses. In Part I, the experimental and computational results from an investigation of the endwall cavity and gaspath flow interaction in a low pressure turbine were presented. Steady and unsteady computational analyses were utilized to model different combinations of the cavity and bladerow geometries. The data and computations confirmed that endwall cavity flows have a significant influence on gaspath aerodynamics and that these flows need to be included in bladerow computations for accurate results. However, the level of effort required to construct the computational grid and obtain a flow solution renders these computational models prohibitive. In Part II, the development of a source term model for a steady bladerow solver that simulates endwall cavity flows in a low pressure turbine is reviewed. Different levels of model complexity were evaluated to determine the impact of endwall geometry and source term distributions on analysis accuracy. The source term model adequately captured endwall cavity effects and accurately predicted secondary flow in the adjacent bladerow. This source term model gives designers the capability to investigate new ideas of reducing secondary flow in a timely manner, leading to improvements in overall turbine efficiency.

scholarly journals DRINK: a biogeochemical source term model for low level radioactive waste disposal sites

1997 ◽  
Vol 20 (3-4) ◽  
pp. 557-571 ◽  
Author(s):  
Paul Humphreys ◽  
Ray McGarry ◽  
Alex Hoffmann ◽  
Peter Binks
Keyword(s):  
Radioactive Waste ◽  
Waste Disposal ◽  
Source Term ◽  
Radioactive Waste Disposal ◽  
Low Level ◽  
Term Model ◽  
Source Term Model ◽  
Low Level Radioactive Waste
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