Development of a New Mechanistic Low-Level Waste Source Term Model

1996 ◽  
Vol 465 ◽  
Author(s):  
Man-Sung Yim
Keyword(s):  
Source Term ◽  
Transport Model ◽  
Near Field ◽  
Cumulative Probability ◽  
Gas Generation ◽  
Low Level ◽  
Waste Forms ◽  
Term Model ◽  
Radionuclide Release ◽  
Source Term Model

ABSTRACTA new mechanistic low-level waste source term model was developed. Key features of this effort are: use of cumulative probability functions to describe the failures of waste containers; capability to describe diffusion controlled release which is dependent on the conditions of the waste package surroundings; consideration of the effects of gas generation on the source term, and; use of a source inventory characterization routine to provide a built-in capability for defining the distributions of radionuclides in various waste forms and streams. The model is capable of describing the diffusion of radionuclides in waste forms with the use of concentration and flux continuity boundary conditions. Release of radionuclides from various waste streams is modeled by the combination of diffusion, dissolution, and surface release. Failures of waste containers are portrayed by the use of probabilistic failure functions based on Weibull and lognormal distributions. The model for radionuclide release from waste packages is coupled with the near-field transport model to describe the effects of migration and dispersion within the disposal unit. Characteristics of the new model were evaluated through sensitivity analysis and compared with existing source term codes.

BNFL Lysimeter Proaramme to Investigate the Leachina of Radlonuclides from Low-Level Radioactive Waste

1992 ◽  
Vol 294 ◽  
Author(s):  
K. Clayton ◽  
R. Clegg ◽  
R.G.G. Holmes ◽  
G.W.A. Newton
Keyword(s):  
Radioactive Waste ◽  
Near Field ◽  
Analytical Data ◽  
Nuclear Fuels ◽  
Gas Generation ◽  
Effective Technique ◽  
Low Level ◽  
Leaching Behaviour ◽  
Radionuclide Release ◽  
Low Level Radioactive Waste

ABSTRACTBritish Nuclear Fuels ple has initiated an experimental programme to measure the leaching behaviour of radionuclides from various low level radioactive waste (LLW) mareials using Lysimeters. The programme commenced in 1986 and to date 10 lysimeters have been commissioned. These have concentrated on simulating shallow trench conditions but a further programme is now planned to study concrete vault environments. The aim of the study is to provide information on leaching processes as part of the ongoing Drigg Near Field Programme, and also to yield input data for radiological assessment purposes. Towards this end, data have been gained from the lysimeters on basic chemistry, gas generation and radionuclide Release Coefficients. This paper concentrates on one of the lysimeters which has recently been decommissioned and for which interim analytical data are available. Some general comments are given on BNFL's experience using lysimeters and their applicability as a rapid and effective technique for studying near field degradation processes.

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.

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