scholarly journals Reactor Kinetics

2021 ◽  
pp. 51-81
Author(s):  
Cheol Ho Pyeon
Keyword(s):  
Kinetic Equation ◽  
Kinetic Method ◽  
Fast Neutrons ◽  
Neutron Guide ◽  
Kinetics Parameters ◽  
Reactor Kinetics ◽  
Hard Spectrum ◽  
The One ◽  
Spallation Neutrons ◽  
Core Characteristics

AbstractIn static and kinetic experimental analyses, the reactivity effect of introducing a neutron guide has been examined with various materials and adjustments of the beam window. With the objective of improving the KUCA core characteristics, the implementation of the neutron guide is predicted to increase the fast neutrons in directing the fuel region. With regard to the kinetic characteristics, the subcriticality and the prompt neutron decay constant are monitored for several core configurations and detector positions. The KUCA core is equipped to make locally a hard spectrum core region with the combined use of 235U fuel, a polyethylene moderator, and a Pb–Bi reflector for criticality. In this study, the first attempt is made to examine experimentally the characteristics of kinetics parameters in ADS comprised of 235U-fueled and Pb–Bi-zoned core, and spallation neutrons generated by an injection of 100 MeV protons onto the solid Pb–Bi target. Online monitoring of reactivity has been deduced in real time by the inverse kinetic method on the basis of the one-point kinetic equation with measured neutron signals in the core. Here, measurements by the one-point kinetic equation are validated through the subcriticality evaluation with the PNS histogram and the methodology by the inhour equation.

Calculation of adjoint-weighted reactor kinetics parameters in OpenMC

2019 ◽  
Vol 128 ◽  
pp. 231-235 ◽  
Author(s):  
Xingjie Peng ◽  
Jingang Liang ◽  
Benoit Forget ◽  
Kord Smith
Keyword(s):  
Kinetics Parameters ◽  
Reactor Kinetics

scholarly journals High sensitive depleted MOSFET-based neutron dosimetry

2019 ◽  
Vol 18 ◽  
pp. 145
Author(s):  
M. Fragopoulou ◽  
V. Konstantakos ◽  
M. Zamani ◽  
S. Siskos ◽  
T. Laopoulos ◽  
...  
Keyword(s):  
Lithium Fluoride ◽  
Field Effect ◽  
Field Effect Transistor ◽  
Metal Oxide Semiconductor ◽  
Oxide Semiconductor ◽  
Fast Neutrons ◽  
Thermal Neutrons ◽  
Neutron Dosimetry ◽  
Effect Transistor ◽  
The One

A new dosemeter based on a depleted Metal-Oxide-Semiconductor field effect transistor, sensitive to both neutrons and gamma radiation was manufactured at LAAS-CNRS Laboratory, Toulouse France. In order to be used for neutron dosimetry a thin film of lithium fluoride was deposited on the surface of the gate of the device. The characteristics of the dosemeter such as its response to neutron dose were investigated. The response in thermal neutrons was found to be high. In fast neutrons the response was lower than that of thermal neutrons but higher than the one presented in literature.

Kinetics on the Ultrasonic-Assisted Extraction of Polysaccharides from Limonium bicolor kunze (Bge.)

2014 ◽  
Vol 1003 ◽  
pp. 3-6
Author(s):  
Xiao Song ◽  
Peng Zhao ◽  
Qing Hua Meng ◽  
Zhi Shu Tang ◽  
Chang Li Wang
Keyword(s):  
Kinetic Equation ◽  
Extraction Process ◽  
Ultrasonic Extraction ◽  
Second Law ◽  
Technical Design ◽  
Kinetics Parameters ◽  
Limonium Bicolor ◽  
Assisted Extraction ◽  
Ultrasonic Assisted ◽  
Ultrasonic Assisted Extraction

To explore the kinetics parameters in the ultrasonic-assisted extraction from Limonium bicolor Kunze (Bge.) , the kinetic equation for polysaccharide ultrasonic extraction process was established with ball model. According to Fick’s second law of diffusion, extraction process was analysed. The results can provide the valuable theory basis for the technical design and further research of polysaccharide extraction process.

Design of Engineering Diffractometer at J-PARC

2006 ◽  
Vol 524-525 ◽  
pp. 199-204 ◽  
Author(s):  
Stefanus Harjo ◽  
Atsushi Moriai ◽  
Shuki Torii ◽  
Hiroshi Suzuki ◽  
Kentaro Suzuya ◽  
...  
Keyword(s):  
Materials Science ◽  
Flight Path ◽  
Fast Neutrons ◽  
Neutron Guide ◽  
Energy Agency ◽  
Neutron Diffractometer ◽  
Materials Science And Engineering ◽  
Crystallographic Structures ◽  
Intensity Loss ◽  
Good Agreement

An engineering diffractometer designed to solve many problems in materials science and engineering including investigations of stresses and crystallographic structures within engineering components is now being developed at J-PARC project. This instrument views a decoupled-poisoned liquid H2 moderator providing neutrons with good symmetrical diffraction profiles in the acceptable wavelength range. The primary flight path and the secondary flight path are 40 m and 2.0 m, respectively, for 90 degree scattering detector banks. A curved supermirror neutron guide will be installed to avoid intensity loss due to the long flight path and to reduce backgrounds from fast neutrons and gamma rays. Therefore, stress measurements with sufficient accuracies in many engineering studies are quite promising. The optimization of this instrument has been performed with a Monte Carlo simulation, and an appropriate resolution of less than 0.2 % in d/d has been confirmed. A prototyped radial collimator to define a gauge width of 1 mm has been designed and manufactured. From performance tests conducted at the neutron diffractometer for residual stress analysis RESA in JRR-3 of Japan Atomic Energy Agency, the normal distribution with a full width at half maximum of 1 mm was obtained in a good agreement with the simulation.

Lactams in sulfuric acid. The mechanism of amide hydrolysis in weak to moderately strong aqueous mineral acid media

1998 ◽  
Vol 76 (6) ◽  
pp. 649-656 ◽  
Author(s):  
Robin A Cox
Keyword(s):  
Sulfuric Acid ◽  
Water Molecule ◽  
Kinetic Method ◽  
Activation Parameters ◽  
Mineral Acid ◽  
Medium Effect ◽  
Acid Media ◽  
Unknown Mechanism ◽  
Reaction Rate Constants ◽  
The One

Reaction rate constants obtained in moderately concentrated sulfuric acid for the hydrolysis of simple lactams of ring sizes five, six, seven, and eight as a function of acidity and temperature have been analyzed using the excess acidity kinetic method. The basicity constants for these substrates have been recalculated; the 13C NMR spectra used to obtain these values are very sensitive to medium effects. It was found that the basicities of the lactams at 0.003-0.1 M lactam concentration were over half a pK unit more basic than they were at 0.5 M lactam, presumably because of the medium effect. Apart from this, the rate constant results obtained at different times by different groups using different techniques for monitoring the kinetics are in adequate agreement. The excess acidity analysis showed that the kinetics could be fitted according to the "three-water-molecule followed by one-water-molecule" mechanistic scenario previously found, or could just as well be fitted by a "one-water-molecule followed by unknown mechanism" scenario, with the mechanistic change taking place at 50 wt.% sulfuric acid for all the substrates. Other evidence makes the latter seem the more likely possibility of the two, and activation parameters based upon the "one-water-molecule" process were determined. Sufficient data points to enable the unknown mechanism to be established were not present; possible mechanisms applicable in media more concentrated than 50 wt.% sulfuric acid are discussed. Previously obtained values of the parameter r, the number of water molecules involved with the substrate in A2 processes, are now questionable.Key words: amides, lactams, excess acidity, hydrolysis, mechanism.

Solution of Generalized Jaynes-Cummings Model for many Particle Systems

2013 ◽  
Vol 481 ◽  
pp. 272-277
Author(s):  
N.N. Jr. Bogolubov ◽  
M.Yu. Rasulova ◽  
I.A. Tishabaev
Keyword(s):  
Kinetic Equation ◽  
Linear Equation ◽  
Schrodinger Equation ◽  
Particle Systems ◽  
Cavity Field ◽  
One Dimensional ◽  
Generalized Kinetic Equation ◽  
The One ◽  
The Given ◽  
Multi Mode

We consider the dynamics of a system consisting of N two-level atoms interacting with a multi-mode cavity field. For the given system, the generalized kinetic equation is obtained and conditions are given under which its solution is reduced to solution of a linear equation, and of the one-dimensional nonlinear Schrodinger equation, respectively.

Conclusions: the technocratic logics of contemporary planning

2019 ◽  
pp. 255-268
Author(s):  
Federico Savini ◽  
Mike Raco
Keyword(s):  
Financial Crisis ◽  
Urban Environments ◽  
The Other ◽  
The Core ◽  
Dialectical Tension ◽  
Planning Processes ◽  
The One ◽  
And Control ◽  
Core Characteristics ◽  
Modes Of Governance

This concluding chapter re-assesses the core propositions set out in the first chapter. Succeeding chapters have drawn on these core characteristics to examine and assess the emergence of technocratic logics in contemporary urban environments and the interweaving of new modes of technocracy with political projects and agendas following the financial crisis. While the term ‘technocracy’ is associated with particular, and very specific, historical conjunctures, this chapter argues that by focusing on technocratic logics and conceptions of technocracy it is possible to develop more powerful insights into contemporary planning processes and governance dynamics. At the heart of this discussion lies a dialectical tension between political projects that seek to implement technocratic modes of governance in the pursuit of broader aims, on the one hand, and the complexities of places and place-politics that often lie beyond the limits of technocratic calculation and control on the other. The tensions between these dialectical perspectives are on-going, subject to multiple influences, and prone to forms of incompleteness and contestation at various scales.

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