bluuebunny/crossref_metadata_2025_split huggingface dataset:
Defect Particles in an Irradiated RPV Steel Studied by a Systematic Variation of Irradiation and Annealing Conditions: Preliminary Results by Small Angle Neutron Scattering
Authors: Solt G , Frisius F , Waeber WB 
Published: December 2008

Defect particles with typical mean radii of 7 to 9 Å were detected by SANS in neutron-irradiated (E &gt; 1 MeV) steel specimens cut out of the same block and subjected to four various fluences in the range (0.5 to 5.0) × 1019 n/cm2. In addition to the as-irradiated condition, the effect of a heat treatment after irradiation and, in another series of experiments, the consequences of an anneal in between the two halves of the irradiation period were studied.
The forged RPV material contains 0.173 wt% Cu and 1.47 wt% Mn; the irradiations at the given fluences were performed at 290°C in a research reactor. The SANS results show that: 1. In the as-irradiated condition themean particle radius is ˜9 Å and the size distribution functions are reasonably sharp (ΔR/¯R = 0.25). For the smaller doses the mean radius is somewhat smaller (6 to 8 Å). The average copper content of the particles is c = 50 to 70 at% calculated on the base of a copper-vacancy agglomerate model, and it varies but slightly with the fluence. For the volume fraction we obtain f= 0.15 to 0.18% except for the lowest fluence. 2. Post irradiation annealing (420°C/24 h) decreases the particle volume fraction as expected, and it also broadens the size distribution. The scattering contrasts show the significantly higher copper content in the damage particles (c = 85 to 90 at%) than in the as-irradiated material. 3. The irradiated-annealed (450°C/168 h)-reirradiated samples show a qualitatively different scattering pattern. One-peaked size distributions, even if very broad (ΔR/¯R ˜ 0.45), give at best a moderately good fit only to the small fluence data, and two characteristic particle sizes could be determined for the higher fluence samples (¯R1 = 7 to 9 Å and ¯R2 = 20 to 30 Å)with f= 0,07 to 0.14%.
Utilization of Energy Code Compliance Procedures for the Prediction of Commercial Building Annual Fuel Consumption
Authors: Worbs HE 
Published: December 2008

Many state model energy codes provide, as an optional alternative to building design by performance standards, a numerical computational procedure to predict a commercial building's annual energy fuel consumption. This annual energy fuel consumption value determines if the building complies with the code energy efficiency. The physical constraints of the building are considered in the calculation—that is, the building envelope and internal heat gains involving people, lighting, equipment, and ventilation. In addition, the efficiency of the building's heating and cooling mechanical plant are also considered.
This paper will first describe the computational procedures, together with the imposed assumptions and limitations, and then describe how this procedure can be adapted to a computer. It is then suggested that this computer program would be valuable in determining the changes one could expect in annual fuel usage by varying certain building design parameters.
An actual representative commercial office building was then selected using the actual building design parameters as the reference building. Variation in building orientation, wall and roof U values, changes in shading and glazing values, changes in allowable ventilation levels, and changes in the efficiency of the heating and cooling mechanical heating, ventilating, and air-conditioning system are all presented to show which ones exhibited a large sensitivity to overall building energy usage. The results will allow the design engineer to make some general conclusions as to which factors are most intensive from an energy conservation point of view.
Design Criteria for Underground Insulated Piping Systems
Authors: Govan FA , Demetroulis NM 
Published: December 2008

The U.S. Government encountered a series of major failures of underground heat distribution systems in the early 1950s. A task force of engineers from nine federal construction agencies was formed, under the auspices of the National Academy of Sciences, to determine the cause of the failures, to develop design criteria for new systems, and to recommend their implementation.
This paper details the results of those investigations and discusses the specific design criteria for each system included in the study.
Heat Transfer Through a Still Air Layer
Authors: Jaouen J-L , Klarsfeld S 
Published: December 2008

One question is at the origin of this study—Could a still air layer be used as a reference material in interlaboratory measurements by the guarded hot plate or heat flow meter method? Such a “material,” which is easy to get, has indeed been recommended by the International Organization for Standardization (ISO) Technical Committee 163 in a round-robin test, but very few measurement results have been reported from the participating laboratories.
The authors have investigated this configuration of particular interest using a one-specimen guarded hot plate apparatus with a thermal gradient directed downwards. By studying the variation of thermal conductance as a function of air layer thickness, we have been able to determine the thermal conductivity of still air, λg, and the total hemispherical emissivity, ε, of the measurement surfaces and to compare the experimental data with the numerical results derived from a simple model, taking into account simultaneous radiative and conductive heat transfers and giving the values of λg and ε.
This study allows us to answer the initial question positively and to show the possible sources of misunderstanding in comparing and analyzing the thermal conductivity measurements from different laboratories.
Experiences in Identification of Thermal Bridging and Elimination of the Thermal Short
Authors: McCaa DJ , Pentz ED , Carre J , Infante LJ 
Published: December 2008

Our experiences encompass basic laboratory studies using the guarded hot box, field identification of the building envelope defect, and correction of the problem based on proven techniques and products.
In the laboratory, a total of 24 wall configurations were tested using ASTM Test for Steady-State Thermal Performance of Building Assemblies by Means of a Guarded Hot Box (C 236-80). Comparing theoretical R versus actual R values enabled us to identify several causes of thermal shorts along with techniques to correct the defects.
This work was related to the field as we observed:
(a) thermal bridging due to construction design,
(b) insulation gaps due to workmanship defects, and
(c) inability of certain construction systems to recover from high humidity and condensation conditions.
Considerable attention was given to these factors during our introduction of two new fiberglass products. In both the retrofit and new construction field, examples illustrate how the insulation was used to correct the envelope defects as well as how to avoid the defects.
Design Considerations on Guarded and Calibrated Hot Box Apparatus
Authors: De Ponte F 
Published: December 2008

The precision and accuracy of guarded and calibrated hot box apparatus have seldom been evaluated, either during the design process or at the performance check stage. Even round robins can supply little information on errors if no theory of the apparatus is available. The purpose of this paper is to consider heat transfer in the apparatus, to supply some rough practical tips to aid in understanding the apparatus performance, even though much more has to be done to reach the same level of knowledge achieved for the guarded hot plate apparatus.
Convection heat transfer is considered first. Theoretical relationships are recalled to predict local surface coefficients in natural convection. These change along specimen surfaces, inducing temperature nonuniformities along the border of the metering box. Transitions from laminar to turbulent flow are also considered, which add hardly predictable temperature fluctuations. The problem of the position of the sensors that detect air temperatures in forced convection is then analyzed.
The analysis of coupled radiation and convection heat transfer allows a definition of the maximum expected sensitivity of the apparatus to imbalance conditions.
From the theoretical description of some sources of error, guidelines may be obtained for an apparatus performance check.
Risk of Blistering of Built-Up Roofing Membranes Applied to Polyurethane Foam Insulation
Authors: Rossiter WJ , Mathey RG 
Published: December 2008

The use of polyurethane foam insulation boards in low-sloped roof constructions has increased in recent years to upgrade their thermal efficiency. Built-up membranes applied directly over polyurethane foam insulation may experience greater incidence of blistering than membranes applied on other roofing insulation boards. The bubbling of hot asphalt during its application to the polyurethane insulation board can cause voids in the asphalt layer, which eventually can grow into blisters. This paper presents the results of a study to investigate the effect of application of hot asphalt directly onto polyurethane insulation boards. In addition, it discusses causes of blistering and methods for using polyurethane foam insulation boards in built-up roofing systems so as to reduce the risk of blistering.
Polyurethane foam insulation specimens, typical of those used in the late 1970s in the United States for built-up roofing construction, were included in the study. Most of the insulations contained a facing material. Hot asphalt was applied to the insulations with facings to determine the extent of off-gassing. Hot asphalt was also applied to insulations without facings, to facings removed from insulation, and to oven-dried insulations and facings to investigate the effect of the moisture content of the insulations and facings on the off-gassing.
In other tests, oven-dried and moist (“room dry”) felts were used in the preparation of built-up membranes over polyurethane boards. Delamination of the roofing specimens indicated many large voids in the asphalt layer between the polyurethane insulation and the first ply of felt. These voids were considered to increase the risk of blistering in built-up membranes applied directly on the polyurethane foam insulation. The data support previous suggestions to apply a thin layer of rigid insulation to the polyurethane foam before the membrane is applied.
Thermal Conductivity of Insulants at High Temperature: Reference Materials and Standards
Authors: Klarsfeld S , Boulant J , Langlais C 
Published: December 2008

Extensive work has been done on insulants at ambient temperature: standards, reference materials, and national and international interlaboratory measurements (ISO/TC 163 round robin test). The situation is more complex at high temperatures, and this paper in an attempt to clarify this complexity, taking into account the new International Organization for Standardization (ISO) draft proposal on guarded hot plate apparatus.
Using a simple model describing heat transfer through fibrous insulants, and introducing the notion of optical thickness or opacity, the study proposes a quantitative criterion to minimize the radiative transfer, in order to obtain measurement results independent of the experimental conditions (the thickness of the specimen and emissivities of the limiting surfaces).
This criterion shows the importance of optical parameters and should, from a practical point of view, help in choosing the reference materials used for checking and in making interlaboratory comparisons of guarded hot plate apparatuses.
A Comparison of Crack-Tip Opening Displacement Ductile Instability Analyses
Authors: Gordon JR , Garwood SJ 
Published: December 2008

This paper presents the results of a large test program undertaken to study ductile fracture in aluminum weldments. The main body of the experimental program consisted of a series of wide-plate tests on 10-mm-thick parent material and welded aluminum alloy center-cracked panels. In addition to the wide-plate tests, tension, and single-specimen unloading compliance, R-curve tests were conducted on specimens extracted from the various parent materials and weld metals.
The wide-plate tests were analyzed using a crack-tip opening displacement (CTOD) strip yield model, a CTOD reference stress model, and the CTOD equivalent of the J estimation scheme published by the Electric Power Research Institute. It was found that all three models provided reasonably accurate predictions of maximum far-field stress if a representative CTOD R-curve was incorporated in the analysis.
Correlation Between 400°C Steam Corrosion Behavior, Heat Treatment, and Microstructure of Zircaloy-4 Tubing
Authors: Thorvaldsson T , Andersson T , Wilson A , Wardle A 
Published: December 2008

The uniform general corrosion behavior of Zircaloy-4 has been determined in long-term autoclave tests at 400°C and modelled using the annealing parameter A concept. The cumulative effect of subsequent heat treatments in the alpha phase field after beta quenching can be given by A = ∑i ti exp (Q/RTi) where ti is annealing time, Ti is the temperature (degrees Kelvin), Q is the activation energy, and R is the gas constant.
The corrosion weight gains at prolonged corrosion testing were determined and plotted as a function of the annealing parameter. The resulting curves can be used to predict the corrosion behavior. It was found that a minimum A value, that is, heat treatment combination, has to be exceeded in order to obtain good corrosion properties since a sharp transition from bad to good corrosion behavior occurred.
Detailed microstructural investigations using mainly electron microscopy techniques were performed on material with known corrosion behavior both before and after corrosion tests. The microstructures were characterized, and intermetallic particle size distributions were measured. Special care was taken in order to measure the particle size distributions on the tube outer surfaces, that is, where waterside corrosion actually occurs. No correlation was found between intermetallic particle sizes and the corrosion behavior: It is postulated that the matrix solute concentration is more important for the corrosion properties and that silicon and perhaps iron have the largest beneficial effects.
Corrosion Performance of Zircaloy-2 and Zircaloy-4 PWR Fuel Cladding
Authors: Rudling P , Pettersson H , Andersson T , Thorvaldsson T 
Published: December 2008

A variety of Zircaloy-2 and Zircaloy-4 cladding tubes with different microstructures has been manufactured. Test rods have been included in two fuel assemblies, and the assemblies have been inserted into the Ringhals 3 pressurized water reactor. Samples from the same cladding tube variants have been subjected to steam autoclave testing in the range 400 to 500°C for different exposure times and have been characterized with respect to their microstructure.
After one cycle of in-reactor exposure, the oxide thickness was thinner on stress relief annealed Zircaloy-2 rods than on Zircaloy-4 rods with the same heat treatment. Replacing the last stress relief anneal with a recrystallization anneal increased the out-of-pile corrosion resistance of the Zircaloy-4 cladding, whereas no statistical difference was seen in-pile after the first cycle. Scanning electron microscopy (SEM) measurements of the particle size distribution revealed only small differences in sizes between the cladding types.
The results from the autoclave tests done at 400°C/200 days, 410°C/28 days, 430°C/30 days, and 500°C/24 h indicated that the long-term 400°C test is capable of predicting the in-reactor behavior, whereas the 500°C as expected was found to be related to the nodular corrosion mechanism. The 430°C test seemed to be in a transition range from the uniform to the nodular corrosion mechanism. Short-term testing at 410°C resulted in the same ranking of materials as the long-term 400°C test indicating that a 410°C test could be used to predict the in-reactor behavior in a relatively short time.
Corrosion Performance Ranking of Zircaloy-2 for BWR Applications
Authors: Rudling P , Machiels AJ 
Published: December 2008

The waterside nodular corrosion of Zircaloy cladding in boiling water reactors (BWRs) remains a primary concern in fuel performance because of (1) recurring fuel failures in several BWRs and (2) the current trend in the nuclear industry towards higher fuel burnups. The failures might be avoided if there were a reliable way of sorting claddings, so that only cladding that is highly resistant to corrosion would be used. In-reactor corrosion testing of cladding tubes is expensive and time-consuming, and consequently, there exists a strong incentive to develop a short-term, out-of-pile corrosion test that is able to predict cladding corrosion behavior for BWR applications.
It is shown in this paper that a high-pressure steam autoclave test performed at 520°C for 24 h is capable of classifying the in-reactor nodular corrosion properties of the fuel cladding. The effects of test temperature, sample surface treatment, and oxygen and hydrogen content in the steam on corrosion performance are documented.
Heterogeneous Scale Growth During Steam Corrosion of Zircaloy-4 and 500°C
Authors: Charquet D , Tricot R , Wadier J-F 
Published: December 2008

Various Zircaloy-4 materials have been exposed in steam at 500°C for times between 2 and 72 h. The observations indicate that two major factors govern scale growth: crystal orientation and precipitate density. Furthermore, the study of coarse grained materials shows that when two adjacent grains corrode at very different rates, the catastrophic oxidation of one of them has little tendency to propagate into its more highly resistant neighbor. This “barrier” effect to the lateral extension of local regions of thick scale is particularly efficient when the individual grains have markedly dissimilar characteristics. This is especially true for acicular and alpha-beta structures.
In equiaxed structures, the corrosion rate depends on both structure and texture. Structures with very fine precipitates (ϕ &gt; 0.1 μm) show excellent nodular corrosion resistance. On the contrary, when the precipitates are coarse (ϕ &lt; 0.2 μm), the nodular corrosion resistance is very poor. In both of these cases, the texture has little influence. However, for intermediate precipitate dimensions (0.1 μm &lt; ϕ &lt; 0.2 μm), the effect of orientation becomes preponderant. If a grain whose orientation favors rapid corrosion is surrounded by more resistant neighbors, then the localized corrosion will not develop. On the contrary, if the adjacent grains are also propitiously oriented for enhanced oxidation, a critical nucleus size is attained and the resulting corrosion nodule can continue to grow. This mechanism assumes that the initiation site includes a minimum number of grains.
Intermetallic Precipitates in Zirconium-Niobium Alloys
Authors: Meng X , Northwood DO 
Published: December 2008

Transmission electron microscopy (TEM), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS) have Seen used to study the composition and structure of intermetallic precipitates, principally those containing iron and chromium, in Zr-2.5wt%Nb pressure tubing and Zr-lwt%Nb fuel sheathing. The Zr-lwt%Nb fuel sheathing contained Zr(FeCr)2 Laves phase precipitates with either the C-14 hexagonal or C-15 cubic structure. Orthorhombic Zr3Fe precipitates were also tentatively identified. Tetragonal Zr2Fe precipitates were found in Zr-2.5wt%Nb pressure tubing containing 700-ppm iron. The volume fraction of Zr2Fe was very small (&lt;0.1% on an area basis) and was much smaller than the volume fraction of Zr(FeCr)2 precipitates in Zr-1wt%Nb.
The difference in type and volume fraction of iron-containing precipitates in Zr-lwt%Nb and Zr-2.5wt%Nb despite similar iron and chromium contents is tentatively attributed to the different volume fractions of the β-phase. Iron is a β-stabilizer and concentrates in the β-phase. The Zr-2.5wt%Nb alloy, which contains the higher volume fraction of β-phase, takes in more iron in solution in the β-phase thus leaving less to precipitate out as an intermetallic.
The Effect of Temperature on the Irradiation Growth of Cold-Worked Zr-2.5 Nb
Authors: Holt RA , Fleck RG 
Published: December 2008

Specimens of cold-worked Zr-2.5% Nb pressure tube material fabricated by several different routes have been irradiated unstressed in the Dido reactor at Atomic Energy Research Establishment (AERE) Harwell to fluences up to 7.5 × 1025 n/m2, E & 1 MeV (about 18 dpa). Their irradiation growth behavior has been investigated as a function of temperature in the range 553 to 623 K.
The growth strains and strain rates in the axial direction are found to decrease with increased irradiation temperature even though the long-term growth rate in the axial direction may be either negative or positive. The effect of temperature on the transverse growth is the reverse of the effect on axial growth. Increasing the irradiation temperature incrementally from 553 K by 30 or 70 K produces a transient negative growth strain in the axial direction which increases in magnitude with the magnitude of the temperature increment. Decreasing the temperature from 623 or 583 K produces a transient which is approximately the reverse of that observed with a temperature increment.
These results are discussed in terms of a model in which growth is driven by the size interaction (SI) between point defects and dislocations and by the difference in diffusional anisotropy (DAD) between vacancies and self interstitial atoms (SIAs). Several microstructural features compete as sinks for the vacancies and SIAs produced by the fast neutron flux. It appears that changing the temperature in this range may change the balance in the net point defect fluxes to the sinks because of different temperature dependencies of the SI and the DAD.
A Low-Volume Microtube In-Furrow Sprayer
Authors: McCracken A 
Published: December 2008

This paper describes a new application system that uses specific lengths of microtubes to deliver low volumes of insecticide into open seed furrows at the time of planting. The system was developed as an alternative for specific product/crop pest combinations and offers greater accuracy and safety than conventional methods such as seed treatment, band spraying, or granular application.
The microtube applicator uses small-bore plastic tubing with a 0.75 to 2.00-mm (0.03 to 0.08-in.) internal diameter to meter the chemical solution directly into the soil. Specific lengths of microtube of specific bore sizes are selected to permit the use of low volumes of water, as low as 10 L/ha on wheat.
The tubes are attached to the seed coulters of the planter, and the chemical solution is pumped using a 12-V pump with a pressure regulator system or a ground-driven metering pump. Depending on the chemical concentration and the rate required, tests have confirmed that the product may be applied undiluted or mixed with water, using a mixing valve, prior to its discharge through the microtubes.
Effective tests have been conducted in Australia and the United States, and current developments include closed-system handling of the chemical.