Brief Analysis of the Simulative Plutonium Aerosol Source-Term in the Circumstance of High Explosive Detonation

2012 ◽  
Vol 518-523 ◽  
pp. 946-950
Author(s):  
Wen Jie Liu ◽  
Peng Lai Wang ◽  
Zhi Qiang Xiao
Keyword(s):  
Original Work ◽  
Source Term ◽  
High Explosive ◽  
Source Terms ◽  
Respirable Fraction ◽  
Mass Fractions ◽  
Cumulative Mass ◽  
Aerosol Source ◽  
Explosive Detonation ◽  
Human Death

The plutonium material in weapons grade nuclear device would be aerosolized and dispersed into the atmosphere if the device was involved in a high explosive detonation. It is significant to investigate the environmental and public hazard caused by the possible dispersion of plutonium. The original work is to determine the source terms of plutonium aerosol in certain nuclear accident scenario. In such scenario the inhalation of plutonium aerosols is the main human hazard source. Only the plutonium aerosols with aerodynamic diameter less than 10 μm are respirable and may ultimately lead to fatal human death. The field detonation test with plutonium by U.S. government is reviewed and the results indicate that for expected high explosive detonation scenario the plutonium source terms are 100 % aerosolization and 20 % respirable fraction. In order to find the aerosolized similarity of plutonium and several conventional metals, two detonation experiments in which the stannum foil and the vanadium powder are used as the replacement of plutonium respectively have been conducted by our group. After the detonation the metal aerosols are collected and analyzed. It has been found that the metallic powder is much easier to be aerosolized than the foil while the integrated aerosol source terms (respirable mass fractions) of stannum and vanadium are quite different with plutonium. Unlike the integrated aerosol data, the differential source terms (cumulative mass fractions via particle size) of the simulative samples are partially similar with plutonium.

scholarly journals CP-violating transport theory for electroweak baryogenesis with thermal corrections

2021 ◽  
Vol 2021 (11) ◽  
pp. 042
Author(s):  
Kimmo Kainulainen
Keyword(s):  
Source Term ◽  
Transport Theory ◽  
Finite Width ◽  
Source Terms ◽  
Boltzmann Equations ◽  
Current Divergence ◽  
The One ◽  
Infrared Divergences ◽  
Correct Implementation ◽  
Divergence Equations

Abstract We derive CP-violating transport equations for fermions for electroweak baryogenesis from the CTP-formalism including thermal corrections at the one-loop level. We consider both the VEV-insertion approximation (VIA) and the semiclassical (SC) formalism. We show that the VIA-method is based on an assumption that leads to an ill-defined source term containing a pinch singularity, whose regularisation by thermal effects leads to ambiguities including spurious ultraviolet and infrared divergences. We then carefully review the derivation of the semiclassical formalism and extend it to include thermal corrections. We present the semiclassical Boltzmann equations for thermal WKB-quasiparticles with source terms up to the second order in gradients that contain both dispersive and finite width corrections. We also show that the SC-method reproduces the current divergence equations and that a correct implementation of the Fick's law captures the semiclassical source term even with conserved total current ∂μ j μ = 0. Our results show that the VIA-source term is not just ambiguous, but that it does not exist. Finally, we show that the collisional source terms reported earlier in the semiclassical literature are also spurious, and vanish in a consistent calculation.

scholarly journals Verification of SpacePy's radial diffusion radiation belt model

2011 ◽  
Vol 4 (3) ◽  
pp. 2165-2197 ◽  
Author(s):  
D. T. Welling ◽  
J. Koller ◽  
E. Camporeale
Keyword(s):  
Radiation Belt ◽  
Source Term ◽  
Model Verification ◽  
Radiation Environment ◽  
Source Terms ◽  
Time Step ◽  
Manufactured Solutions ◽  
Quantitative Verification ◽  
Numerical Solver ◽  
Selection Of

Abstract. Model verification, or the process of ensuring that the prescribed equations are properly solved, is a necessary step in code development. Careful, quantitative verification guides users when selecting grid resolution and time step and gives confidence to code developers that existing code is properly instituted. This work introduces the RadBelt radiation belt model, a new, open-source version of the Dynamic Radiation Environment Assimilation Model (DREAM) and uses the Method of Manufactured Solutions (MMS) to quantitatively verify it. Order of convergence is investigated for a plethora of code configurations and source terms. The ability to apply many different diffusion coefficients, including time constant and time varying, is thoroughly investigated. The model passes all of the tests, demonstrating correct implementation of the numerical solver. The importance of DLL and source term dynamics on the selection of time step and grid size is also explored. Finally, an alternative method to apply the source term is examined to illustrate additional considerations required when non-linear source terms are used.

scholarly journals Higher-order dissipation in the theory of homogeneous isotropic turbulence

2016 ◽  
Vol 803 ◽  
pp. 250-274 ◽  
Author(s):  
Norbert Peters ◽  
Jonas Boschung ◽  
Michael Gauding ◽  
Jens Henrik Goebbert ◽  
Reginald J. Hill ◽  
...  
Keyword(s):  
Source Term ◽  
Isotropic Turbulence ◽  
Stokes Equations ◽  
Higher Order ◽  
Distribution Functions ◽  
Order Structure ◽  
Source Terms ◽  
Homogeneous Isotropic Turbulence ◽  
Higher Order Moments ◽  
Even Order

The two-point theory of homogeneous isotropic turbulence is extended to source terms appearing in the equations for higher-order structure functions. For this, transport equations for these source terms are derived. We focus on the trace of the resulting equations, which is of particular interest because it is invariant and therefore independent of the coordinate system. In the trace of the even-order source term equation, we discover the higher-order moments of the dissipation distribution, and the individual even-order source term equations contain the higher-order moments of the longitudinal, transverse and mixed dissipation distribution functions. This shows for the first time that dissipation fluctuations, on which most of the phenomenological intermittency models are based, are contained in the Navier–Stokes equations. Noticeably, we also find the volume-averaged dissipation $\unicode[STIX]{x1D700}_{r}$ used by Kolmogorov (J. Fluid Mech., vol. 13, 1962, pp. 82–85) in the resulting system of equations, because it is related to dissipation correlations.

scholarly journals High Speed, Localized Multi-Point Strain Measurements on a Containment Vessel at 1.7 MHz Using Swept-Wavelength Laser-Interrogated Fiber Bragg Gratings

Sensors ◽  
2020 ◽  
Vol 20 (20) ◽  
pp. 5935
Author(s):  
Steve Gilbertson ◽  
Mark Pickrell ◽  
Dario Castano ◽  
Gary Salazar ◽  
Tom Beery ◽  
...  
Keyword(s):  
Strain Measurement ◽  
High Speed ◽  
High Explosive ◽  
Fiber Bragg Gratings ◽  
Bragg Gratings ◽  
Laser Source ◽  
Global Changes ◽  
Element Analysis ◽  
All Optical ◽  
Explosive Detonation

Dynamic elastic strain in ~1.8 and 1.0 m diameter containment vessels containing a high explosive detonation was measured using an array of fiber Bragg gratings. The all-optical method, called real-time localized strain measurement, recorded the strain for 10 ms after detonation with additional measurements being sequentially made at a rate of 1.7 MHz. A swept wavelength laser source provided the repetition rate necessary for such high-speed measurements while also providing enough signal strength and bandwidth to simultaneously measure 8 or more unique points on the vessel’s surface. The data presented here arethen compared with additional diagnostics consisting of a fast spectral interferometer and an optical backscatter reflectometer to show a comparison between the local and global changes in the vessel strain, both dynamically and statically to further characterize the performance of the localized strain measurement. The results are also compared with electrical resistive strain gauges and finite element analysis simulations.

Aerosol Source Term in High Pressure Melt Ejection

1984 ◽  
Vol 88 (3) ◽  
pp. 342-356 ◽  
Author(s):  
J. E. Brockmann ◽  
W. W. Tarbell
Keyword(s):  
High Pressure ◽  
Source Term ◽  
Aerosol Source ◽  
Melt Ejection

Assessing Sensitivity of Observations in Source Term Estimation for Nuclear Accidents

2012 ◽  
Author(s):  
Yuanwei Ma ◽  
Dezhong Wang ◽  
Wenji Tan ◽  
Zhilong Ji ◽  
Kuo Zhang
Keyword(s):  
Data Assimilation ◽  
Source Term ◽  
Dynamic Models ◽  
Source Parameters ◽  
Nuclear Accident ◽  
Fukushima Nuclear Accident ◽  
Observation Data ◽  
Source Terms ◽  
Highly Nonlinear ◽  
Assimilation System

In the Fukushima nuclear accident, due to the lack of field observations and the complexity of source terms, researchers failed to estimate the source term accurately immediately. Data assimilation methods to estimate source terms have many good features: they works well with highly nonlinear dynamic models, no linearization in the evolution of error statistics, etc. This study built a data assimilation system using the ensemble Kalman Filter for real-time estimates of source parameters. The assimilation system uses a Gaussian puff model as the atmospheric dispersion model, assimilating forward with the observation data. Considering measurement error, numerical experiments were carried on to verify the stability and accuracy of the scheme. Then the sensitivity of observation configration is tested by the twin experiments. First, the single parameter release rate of the source term is estimated by different sensor grid configurations. In a sparse sensors grid, the error of estimation is about 10%, and in a 11*11 grid configuration, the error is less than 1%. Under the analysis of the Fukushima nuclear accident, ahead for the actual situation, four parameters are estimated at the same time, by 2*2 to 11*11 grid configurations. The studies showed that the radionuclides plume should cover as many sensors as possible, which will lead a to successful estimation.

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