Neutronics and Thermal Hydraulics Coupled 3-D Calculation of Pressure-Tube Deformation

2020 ◽  
Author(s):  
Eunhyun Ryu ◽  
Hangyu Joo ◽  
Seungyul Yoo ◽  
Jongyub Jung
Keyword(s):  
Dimensional Space ◽  
Three Dimensional ◽  
Safety Margin ◽  
Pressure Tube ◽  
Coolant Temperature ◽  
Main Concern ◽  
Thermal Hydraulics ◽  
Pressure Tubes ◽  
Fuel Pin ◽  
Heavy Water Reactor

Abstract Among the various parts in a pressurized heavy-water reactor (PHWR), pressure tubes are of tremendous importance. This is because they withstand extreme both pressure and temperature differences that exist between the Primary Heat Transport System (PHTS) and the moderator. The pressure tubes also contribute to prevention of fission product release from the PHTS to the PHWR plant (together with end fittings and nearby parts including plugs). When a PHWR is given a 1% derating, half is due to the aging of the pressure tubes. The main concern with pressure tubes is decrease of the safety margin. Most of the reduction comes from the effects caused by radial expansion and axial sagging, which are belong to four major phenomena including the thinning and the elongation. More specifically, the fuel-pin temperature distribution changes for the worse if deformation of the pressure tube occurs. Because there is extreme irradiation inside the core, the tube content is exposed to high temperature and high pressure. Thus, the shape of the pressure tube is deformed as times goes on. In this paper, using modeling of a deformed pressure tube in three-dimensional space, the effects on the fuel, coolant temperature, and coolant density, were studied quantitatively. This included a neutronics effect explored using coupled neutronics and thermal hydraulics (T/H) calculations. Among the results, only marginal changes of the neutronics effects were observed. The T/H results, which included temperature and density of the fuel and the coolant, were not critical. Through this study, we are now able to determine in new ways, conventional derating values from a pressure tube.

Safety Analysis of the Control Rod Drop Event Applying 3-D Neutronics/Thermal-Hydraulics Coupling Code SPARKLE

2009 ◽  
Author(s):  
Yuta Maruyama ◽  
Satoshi Imura ◽  
Junto Ogawa ◽  
Shuhei Miyake
Keyword(s):  
Power Distribution ◽  
Transient Analysis ◽  
Three Dimensional ◽  
Safety Margin ◽  
Safety Analysis ◽  
Thermal Hydraulics ◽  
Analysis Method ◽  
Dynamic Changes ◽  
Control Rod ◽  
Ejection Event

Mitsubishi Heavy Industries (MHI) has developed the SPARKLE code, which is a PWR plant system transient analysis code that includes a three-dimensional (3D) neutronics module coupled with a thermal-hydraulics module. MHI has performed a study of the applicability of the SPARKLE code to the events which are associated with dynamic changes in power distribution, such as the rod ejection event or the steam line break event. In this paper, MHI has applied the SPARKLE code to the control rod drop event (drop of multiple rods), which features such a power distribution change. In addition, the neutron flux detection is dependent on the location of the dropped rods in this event, which can be dynamically calculated in the SPARKLE code. By applying the SPARKLE code to the control rod drop event, it was confirmed that the safety margin for this event is sufficiently larger than the margin calculated using the current safety analysis method, even if the appropriate conservative assumptions are made.

Axial Power and Coolant-Temperature Profiles for a Non-Re-Entrant Pressure-Tube Supercritical Water-Cooled Reactor Fuel Channel

2015 ◽  
Vol 2 (1) ◽  
Author(s):  
Vitali Kovaltchouk ◽  
Eleodor Nichita ◽  
Eugene Saltanov
Keyword(s):  
Cross Sections ◽  
Power Distribution ◽  
Pressure Tube ◽  
Coolant Temperature ◽  
Outlet Temperature ◽  
Thermal Hydraulics ◽  
Fuel Temperature ◽  
Fuel Channel ◽  
Technical Specifications ◽  
Institute Of Technology

The axial power and coolant-temperature distributions in a fuel channel of the Generation IV pressure-tube super-critical water-cooled reactor (PT-SCWR) are found using coupled neutronics-thermal-hydraulics calculations. The simulations are performed for a channel loaded with a fresh, 78-element Th-Pu fuel assembly. Neutronics calculations are performed using the DONJON diffusion code using two-group homogenized cross sections produced using the lattice code DRAGON. The axial coolant temperature profile corresponding to a certain axial linear heat generation rate is found using a code developed in-house at University of Ontario Institute of Technology (UOIT). The effect of coolant density, coolant temperature, and fuel temperature variation along the channel is accounted for by generating macroscopic cross sections at several axial positions. Fixed-point iterations are performed between neutronics and thermal-hydraulics calculations. Neutronics calculations include the generation of two-group macroscopic cross sections at several axial positions, taking into account local parameters such as coolant temperature and density and average fuel temperature. The coolant flow rate is adjusted so that the outlet temperature of the coolant corresponds to the SCWR technical specifications. The converged axial power distribution is found to be asymmetric, resembling a cosine shape skewed toward the inlet (reactor top).

Fracture Protection of CANDU Zr-2.5Nb Pressure Tubes With High Hydrogen Equivalent Concentration

2015 ◽  
Author(s):  
Preeti Doddihal ◽  
Douglas Scarth ◽  
Paula Mosbrucker ◽  
Steven Xu
Keyword(s):  
Fracture Toughness ◽  
Heavy Water ◽  
Pressure Tube ◽  
Normal Operation ◽  
Tube Material ◽  
High Hydrogen ◽  
Equivalent Concentration ◽  
Corrosion Reaction ◽  
Pressure Tubes ◽  
Heavy Water Reactor

The core of a CANDU®1 (CANada Deuterium Uranium) pressurized heavy water reactor includes horizontal Zr-2.5Nb alloy pressure tubes that contain the fuel. Pressure-temperature limits are used in CANDU® reactors for normal operation heat-up and cool-down conditions to maintain margins against fracture. The pressure-temperature limits are determined by postulating a 20 mm long axial through-wall crack in the pressure tube and using a fracture toughness-based calculation procedure. Due to a corrosion reaction with the heavy water coolant, pressure tubes absorb deuterium isotope in service, resulting in an increase in hydrogen equivalent concentration. Experiments have shown that high hydrogen equivalent concentration reduces the fracture toughness of pressure tube material at low temperatures during reactor heat-up and cool-down from normal operating temperatures. New fracture toughness curves that are applicable to material with high hydrogen equivalent concentration have been developed to address this issue. These curves are being used to develop new pressure-temperature limits for fracture protection of CANDU® pressure tubes. The methodology for deriving the pressure-temperature limits for a CANDU® Zr-2.5Nb pressure tube using the new fracture toughness curves is presented in this paper. Preliminary results of pressure-temperature limits for a CANDU® reactor are also provided.

Coupled Neutron Dynamic and Thermal Hydraulic Models of the HTR Simulator

2013 ◽  
Author(s):  
Zhe Sui ◽  
Jun Sun ◽  
Chunlin Wei ◽  
Yuanle Ma ◽  
Wenzhi Shan
Keyword(s):  
Nuclear Power ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Reactor Core ◽  
Hydraulic Modeling ◽  
Thermal Hydraulics ◽  
Dynamic Simulations ◽  
Hydraulic Models ◽  
Coupling Techniques ◽  
Dimensional Space Time

Along with the design and construction of the high temperature reactor pebble bed module (HTR-PM), the engineering simulator system (ESS) has been accomplished to deal with the key techniques of the HTR simulator. In our previous papers, the three dimensional space-time neutron dynamics and the thermal hydraulic modeling of the HTR reactor core were introduced. In this paper, we concentrated on the detailed coupling techniques of the neutron dynamic and thermal hydraulic models, which was one of the most important assurances to the dynamic simulations of the HTR-PM. The mechanism of minus temperature feedback effect of the HTR was introduced by the materials participated in the coupling calculations, as well as those parameters being transferred. In parallel calculations, the neutron dynamics and thermal hydraulics were coupled by exchanging the power density and the temperature in fuels, moderates, reflectors and so on. With complete reactor core model, the coupling calculations of the neutron dynamics and thermal hydraulics were tested in many static and dynamic cases to show good performances. Based on that model ability, the ESS can simulate the start-up, shut-down and several accidents for the whole nuclear power plant.

Three Dimensional structure and organization of diploid chromosomes by optical section microscopy

1987 ◽  
Vol 45 ◽  
pp. 633-635
Author(s):  
David A. Agard ◽  
Yasushi Hiraoka ◽  
John W. Sedat
Keyword(s):  
Dimensional Space ◽  
Three Dimensional ◽  
Developmental State ◽  
Mitotic Cell ◽  
Biological Properties ◽  
Dimensional Structure ◽  
Specific Gene ◽  
Three Dimensional Structure ◽  
Complementary Techniques ◽  
Dynamic Structures

In an effort to understand the complex relationship between structure and biological function within the nucleus, we have embarked on a program to examine the three-dimensional structure and organization of Drosophila melanogaster embryonic chromosomes. Our overall goal is to determine how DNA and proteins are organized into complex and highly dynamic structures (chromosomes) and how these chromosomes are arranged in three dimensional space within the cell nucleus. Futher, we hope to be able to correlate structual data with such fundamental biological properties as stage in the mitotic cell cycle, developmental state and transcription at specific gene loci.Towards this end, we have been developing methodologies for the three-dimensional analysis of non-crystalline biological specimens using optical and electron microscopy. We feel that the combination of these two complementary techniques allows an unprecedented look at the structural organization of cellular components ranging in size from 100A to 100 microns.

Diffraction contrast of dislocations in icosahedral quasicrystals

1990 ◽  
Vol 48 (4) ◽  
pp. 454-455
Author(s):  
K. Urban ◽  
Z. Zhang ◽  
M. Wollgarten ◽  
D. Gratias
Keyword(s):  
Dimensional Space ◽  
Three Dimensional ◽  
Complete Characterization ◽  
Extinction Condition ◽  
Burgers Vector ◽  
Diffraction Contrast ◽  
Lattice Geometry ◽  
Reference Space ◽  
Icosahedral Quasicrystals ◽  
The One

Recently dislocations have been observed by electron microscopy in the icosahedral quasicrystalline (IQ) phase of Al65Cu20Fe15. These dislocations exhibit diffraction contrast similar to that known for dislocations in conventional crystals. The contrast becomes extinct for certain diffraction vectors g. In the following the basis of electron diffraction contrast of dislocations in the IQ phase is described. Taking account of the six-dimensional nature of the Burgers vector a “strong” and a “weak” extinction condition are found.Dislocations in quasicrystals canot be described on the basis of simple shear or insertion of a lattice plane only. In order to achieve a complete characterization of these dislocations it is advantageous to make use of the one to one correspondence of the lattice geometry in our three-dimensional space (R3) and that in the six-dimensional reference space (R6) where full periodicity is recovered . Therefore the contrast extinction condition has to be written as gpbp + gobo = 0 (1). The diffraction vector g and the Burgers vector b decompose into two vectors gp, bp and go, bo in, respectively, the physical and the orthogonal three-dimensional sub-spaces of R6.

Flavin radicals, conformational sampling and robust design principles in interprotein electron transfer: the trimethylamine dehydrogenase-electron-transferring flavoprotein complex

2004 ◽  
Vol 71 ◽  
pp. 1-14
Author(s):  
David Leys ◽  
Jaswir Basran ◽  
François Talfournier ◽  
Kamaldeep K. Chohan ◽  
Andrew W. Munro ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Kinetic Studies ◽  
Molecular Assembly ◽  
Conformational Sampling ◽  
Trimethylamine Dehydrogenase ◽  
Key Residues ◽  
Electron Transferring Flavoprotein ◽  
Electron Transfer Complex

TMADH (trimethylamine dehydrogenase) is a complex iron-sulphur flavoprotein that forms a soluble electron-transfer complex with ETF (electron-transferring flavoprotein). The mechanism of electron transfer between TMADH and ETF has been studied using stopped-flow kinetic and mutagenesis methods, and more recently by X-ray crystallography. Potentiometric methods have also been used to identify key residues involved in the stabilization of the flavin radical semiquinone species in ETF. These studies have demonstrated a key role for 'conformational sampling' in the electron-transfer complex, facilitated by two-site contact of ETF with TMADH. Exploration of three-dimensional space in the complex allows the FAD of ETF to find conformations compatible with enhanced electronic coupling with the 4Fe-4S centre of TMADH. This mechanism of electron transfer provides for a more robust and accessible design principle for interprotein electron transfer compared with simpler models that invoke the collision of redox partners followed by electron transfer. The structure of the TMADH-ETF complex confirms the role of key residues in electron transfer and molecular assembly, originally suggested from detailed kinetic studies in wild-type and mutant complexes, and from molecular modelling.

Topics in Quaternion Linear Algebra

2014 ◽  
Author(s):  
Leiba Rodman
Keyword(s):  
Linear Algebra ◽  
Complex Analysis ◽  
Dimensional Space ◽  
Applied Mathematics ◽  
Three Dimensional ◽  
Number System ◽  
Graduate Course ◽  
Open Problems ◽  
Unpublished Research ◽  
Reference Tool

Quaternions are a number system that has become increasingly useful for representing the rotations of objects in three-dimensional space and has important applications in theoretical and applied mathematics, physics, computer science, and engineering. This is the first book to provide a systematic, accessible, and self-contained exposition of quaternion linear algebra. It features previously unpublished research results with complete proofs and many open problems at various levels, as well as more than 200 exercises to facilitate use by students and instructors. Applications presented in the book include numerical ranges, invariant semidefinite subspaces, differential equations with symmetries, and matrix equations. Designed for researchers and students across a variety of disciplines, the book can be read by anyone with a background in linear algebra, rudimentary complex analysis, and some multivariable calculus. Instructors will find it useful as a complementary text for undergraduate linear algebra courses or as a basis for a graduate course in linear algebra. The open problems can serve as research projects for undergraduates, topics for graduate students, or problems to be tackled by professional research mathematicians. The book is also an invaluable reference tool for researchers in fields where techniques based on quaternion analysis are used.

Extension of the Spatial PDI Model to Three Dimensions

1997 ◽  
Vol 84 (1) ◽  
pp. 176-178
Author(s):  
Frank O'Brien
Keyword(s):  
Population Density ◽  
Dimensional Space ◽  
Finite Lattice ◽  
Three Dimensional ◽  
Upper Bounds ◽  
Three Dimensions ◽  
Lower And Upper Bounds ◽  
Density Index ◽  
Three Dimensional Space

The author's population density index ( PDI) model is extended to three-dimensional distributions. A derived formula is presented that allows for the calculation of the lower and upper bounds of density in three-dimensional space for any finite lattice.

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