bluuebunny/crossref_metadata_2025 huggingface dataset:
The Toughness of Irradiated Pressure Water Reactor (PWR) Vessel Shell Rings and the Effect of Segregation Zones
Authors: Bethmont M , Frund J-M , Housin B , Soulat P
Published: March 2009

To establish the integrity of pressure water reactor (PWR) vessels it is necessary to determine the toughness of A508C1.3 steel at the end of its life, that is after thermal ageing and irradiation embrittlement. In safety analyses the toughness can be deduced from a reference curve set forth in the code (ASME or RCC-M). The validity of the reference curve has been verified for several years for unirradiated French reactor vessels. Tests were performed on specimens taken from materials having heterogeneities in chemical composition. For most of the test results the reference curve is a lower bound. To solve the problem of determining the toughness of SA 508 C1.3 steel after irradiation and in the presence of possible heterogeneities, the toughness results were gathered. The synthesis shows that the RCC-M code curve is conservative.
Low Temperature Embrittlement of RPV Support Structure Steel
Authors: Boydon FMD , McElroy RJ , Gage G , Phythian WJ
Published: March 2009

In recent years concerns have arisen regarding low temperature irradiation damage processes following the observation of an apparent tenfold increase in embrittlement in the HFIR reactor surveillance programme at Oak Ridge compared with accelerated material irradiation's in MTR's. The possible importance of this phenomenon to the integrity of LWR Support Structures was recognised by USNRC and it was formally designated Generic Safety Issue 15. This topic has also become an important UK regulatory issue in the context of the Sizewell PWR. Here the concern was that the high copper material used in the RPV Supports, when taken in light of the HFIR results of that time, highlighted the possibility that irradiation induced copper precipitation could occur at the low temperatures (50–600°C) and peak end-of-life dose of 2mdpa, ~1×1018 n.cm−2 (E>1MeV), encountered in RPV Supports, which contain significant levels (>0.20%) of copper.

This paper describes the results of an experiment set up to establish whether copper precipitation could occur at low temperatures in the Sizewell “B” RPV Support Structure steel. The irradiation was set up to achieve a target dose consistent with the full precipitation of copper, based on modelling data from conventional tests, at the lowest possible damage rate compatible with an irradiation of less than 1 year. The irradiation achieved a high dose of 49.6mdpa, 3.74×1019 n.cm−2 (E>1MeV), at an average temperature of 71°C.

Mechanical properties measured by conventional hardness and Charpy test were performed. The data interpretation was aided by a combination of micro structural and post irradiation annealing experiments. In addition to the Support Structure material, two series of reference alloys with varying copper and nickel content were also irradiated. These alloys have been used in other programmes and offer the ability to cross check the effect of irradiation temperature.

The series of model steels previously studied after irradiation at 288°C in the IAEA CRP-3, under which conditions they exhibited a dependence of hardening on copper and nickel content, showed no clear evidence of copper precipitation under the low temperature irradiation conditions employed. Post irradiation annealing studies demonstrated that the irradiation embrittlement in the A588 support structure steel at low temperatures is due to matrix damage. Although the exact nature of the matrix defect/defects responsible for the embrittlement was not identified, the copper content is believed to be unimportant. There is, therefore, no reason to believe that the relatively high copper specification of A588 support structure steel will be detrimental to the steels toughness after low temperature/high dose irradiation as expected in the Sizewell B support structure.
Effects of Neutron Flux and Irradiation Temperature on Irradiation Embrittlement of A533B Steels
Authors: Suzuki M , Onizawa K , Kizaki M
Published: March 2009

Irradiation embrittlement of A533B steels with low copper contents were investigated from the point of dose rate and irradiation temperature effects. Change of neutron flux in the range from -1012 to -1013 n/cm2/s (E> 1MeV) did not have a significant effect on the embrittlement. Irradiation temperature change of 1°C resulted in the transition temperature shift (ΔT41J) of about 1°C and yield stress change (Δoy) of about 0.8MPa. Factors that might affect the embrittlement of low copper steels are also discussed.
On Impact Testing of Subsize Charpy V-Notch Type Specimens
Authors: Sokolov MA , Nanstad RK
Published: March 2009

The potential for using subsize specimens to determine the actual properties of reactor pressure vessel steels is receiving increasing attention for improved vessel condition monitoring that could be beneficial for light-water reactor plant-life extension. This potential is made conditional upon, on the one hand, by the possibility of cutting samples of small volume from the internal surface of the pressure vessel for determination of actual properties of the operating pressure vessel. On the other hand, the plant-life extension will require supplemental surveillance data that cannot be provided by the existing surveillance programs. Testing of subsize specimens manufactured from broken halves of previously tested surveillance Charpy V-notch (CVN) specimens offers an attractive means of extending existing surveillance programs. Using subsize CVN type specimens requires the establishment of a specimen geometry that is adequate to obtain a ductile-to-brittle transition curve similar to that obtained from full-size specimens. This requires the development of a correlation of transition temperature and upper-shelf toughness between subsize and full-size specimens. The present study was conducted under the Heavy-Section Steel Irradiation Program. Different published approaches to the use of subsize specimens were analyzed and five different geometries of subsize specimens were selected for testing and evaluation. The specimens were made from several types of pressure vessel steels with a wide range of yield strengths, transition temperatures, and upper-shelf energies (USEs). The effects of specimen dimensions, including depth, angle, and radius of notch have been studied. The correlation of transition temperature determined from different types of subsize specimens and the full-size specimen is presented. A new procedure for transforming data from subsize specimens was developed and is presented. The transformed data are in good agreement with data from full-size specimens for materials that have USE levels < 200 J.
Application of Micromechanical Models of Ductile Fracture Initiation to Reactor Pressure Vessel Materials
Authors: Chaouadi R , De Meester P , van Walle E , Fabry A , Van de Velde J
Published: March 2009

The aim of the current study is the application of local micromechanical models to predict crack initiation in ductile materials. Two reactor pressure vessel materials have been selected for this study: JRQ IAEA monitor base metal (A533B C1.1) and Doel-IV weld material. Charpy impact tests have been performed in both un-irradiated and irradiated conditions. In addition to standard tensile tests, notched tensile specimens have been tested.

The upper shelf energy of the weld material remains almost un-affected by irradiation, whereas a decrease of 20% is detected for the base metal. Accordingly, the tensile properties of the weld material do not reveal a clear irradiation effect on the yield and ultimate stresses, this in contrast to the base material flow properties. The tensile tests have been analyzed in terms of micromechanical models. A good correlation is found between the standard tests and the micromechanical models, that are able to predict the ductile damage evolution in these materials. Additional information on the ductility behaviour of these materials is revealed by this micromechanical analysis.
Effects of Proton Irradiation on Positron Annihilation and Micro-Vickers Hardness of Fe-C-Cu Model Alloys
Authors: Shibamoto H , Koyama K , Yuya H , Hasegawa M , Kimura A , Matsui H , Yamaguchi S
Published: March 2009

Positron lifetime and micro-Vickers hardness were measured on well annealed model alloys, Fe-C(0%, 0.2%, 0.35%)-Cu(0%, 0.15%, 0.3%), after 1MeV proton irradiation with a dose of 3×1017 /cm2 below 80°C. Longer lifetime, ranging from 310 to 360 ps, component appears and gives evidence of formation of microvoids containing about 10 vacancies. The longer lifetime decreases with increasing copper content and suggests smaller microvoids for Fe-Cu alloys. The longer lifetime increases with annealing temperature up to 400°C in pure Fe, but exhibits decrease around 300°C in Fe-C-Cu alloys. This decrease indicates reduction in effective size of microvoid around 350°C. Irradiation hardening is accelerated by copper but retarded by carbon. Post-irradiation anneal hardening is revealed at about 150°C and 350°C in Fe-C and Fe-C-Cu alloys. In Fe-Cu alloys, however, a single narrow hardening peak is observed around 350°C. The irradiation hardening in Fe-C alloy anneals out around 550°C, while that in alloys containing Cu makes complete recovery at about 650°C.
Evaluation of Embrittlement in a Pressure Vessel Steel by Fracture Reconstruction
Authors: Wirth B , Edsinger K , Odette GR , Lucas GE
Published: March 2009

Confocal microscopy (CM) and fracture reconstruction (FR), along with mechanical tests and scanning electron microscopy, were used to characterize irradiation embrittlement of a reference A533B pressure vessel steel. Toughness-temperature [K(T)] curves from tests on one-third size, pre-cracked Charpy specimens resemble the results from full sized specimens; however, the small specimen curves are shifted down in temperature and have steeper transition slopes. Cleavage fracture generally occurred by load-shedding pop-ins, arresting at distances which decreased with increasing temperature. The CM/FR measurements showed nucleation of multiple cleavage facets in high-stress regions in front of the crack tip, followed by coalescence into unstable fracture over a small increment of crack opening. At higher temperature and toughness values the damage was confined to the region around the blunting zone due to the limited specimen capacity. In this regime microvoids were also nucleated on inclusion particles. Irradiation shifted the K(T) curve about 95°C at 75 MPa.m1/2. However, no major differences in the basic cleavage fracture mechanisms were observed. Indeed at low toughness, shifts in the K(T) curve closely reflected temperature differences at a common yield stress in the irradiated versus unirradiated material. Finally, the toughness values estimated from CM/FR measurements of the critical crack tip opening displacement were in good agreement with the results of the mechanical tests.
Effects of Helium/DPA Ratio, Alloy Composition and Cold Work on Microstructural Evolution and Hardening of 59Ni-Doped Fe-Cr-Ni Alloys Neutron-Irradiated at 465°C
Authors: Kawanishi H , Hamilton ML , Garner FA
Published: March 2009

Three ternary austenitic alloys(Fe-15Cr-25Ni, Fe-15Cr-25Ni-0.04P, Fe-15Cr-45Ni in both annealed and cold worked conditions) were irradiated at 465°C to 0.15, 0.28, and 0.42 dpa at above core position in the Fast Flux Test Facility utilizing the Materials Open Test Assembly to study the separate and synergistic effects of He/dpa ratio, phosphorus addition, nickel content and cold work level on microstructural evolution and hardening. The helium/dpa ratio was varied by isotopic doping with 59Ni to enhance the production rate of helium. The helium production rate was evaluated to be 62 appm He/dpa in the 59Ni-doped specimens and 0.26 appm He/dpa in the undoped specimens.

Transmission electron microscopic examinations revealed that alloy composition affected significantly the evolution of microstructure during irradiation. Phosphorus addition prevented the formation of Frank loops through the precipitation of phosphide. Nickel content influenced the nucleation of cavities. Helium production rate influenced the densities of dot-typed clusters in 25Ni alloys and cavities in 45Ni alloys.
Swelling, Mechanical Properties and Structure of Austenitic High-Nickel Alloy Irradiated in a Fast Reactor
Authors: Shamardin VK , Neustroev VS , Povstyanko AV , Bulanova TM , Ostrovsky ZE , Kuznetzov AA , Kursevitch IP , Nikolaev VA
Published: March 2009

Specimens from fuel assembly wrappers and control rod cases of 0.07C-15Cr-35Ni-3Mo-B-Zr-Y alloy were investigated after irradiation in the BOR-60 and BN-600 reactors up to a maximum damage dose of about 110 dpa at temperatures between 340 to 550°C.

Maximum swelling occurs at 420 to 430°C with 6% at a dose of about 80 dpa and 13.5% at a dose of 108 dpa. The maximum change in strength properties and corresponding decrease of ductility occur at an irradiation temperature of 385°C. With increasing testing temperature the ductility increases from 3–6% up to 22% at 450°C for the material irradiated at 60–80 dpa.

Frank dislocation loops with an average diameter of 25 nm (concentration is 2×1016 cm−3), voids having diameter between 20 to 23 nm (concentration is (6–7)×1014 cm−3) and semicoherent needle-like precipitates with an average length of 21 nm, oriented to several directions, were observed in the alloy structure irradiated to 60 dpa at 430°C.

Analysis of the experimental data was performed and the service life time of the investigated alloy was estimated for use as a material for control rod cases of the BOR-60 reactor.
On the Fundamentals of Radiation Damage in FCC Materials, A Review
Authors: Schüle W
Published: March 2009

A short historical report is given on the formation of the one-interstitial model (OIM) which was introduced by F. Seitz and H. B. Huntington in the late fifties. In the early sixties J. F. Brinkman and A. Seeger suggested the two-interstitial model (TIM) after many new experimental and theoretical results became available and raised a continous discussion on the validity of the two models.

A few of the many experimental results obtained on radiation damage in fcc metals and alloys over the last thirty-five years are discussed and it is shown that all these results only support the TIM. It could further be shown that the migration activation energies of point defects decrease with increasing high energy particle flux, that dynamic crowdions can change lattice sites 50,000 times before their energy is dissipated to the lattice, that the recombination volume α between self-interstitials and vacancies is one order of magnitude larger than assumed so far etc.. These and many other features of point defects are discussed and the extended version of the TIM, namely the modified two interstitial model (MTIM), is presented.

It is further shown that the rate equations to calculate point defect concentrations built up during irradiation with high energy particles are powerful ways to understand and explain radiation damage. However, the advocates of the OIM in the past used only the steady state solutions of the rate equations which are only mathematical solutions and do not reflect physical reality.

Correlated self-interstitial-vacancy pairs annihilate in recovery stages I and II and correlated crowdion-vacancy pairs annihilate in the broad recovery sub-stage ID in such materials in which crowdions are stable. Crowdions migrate in the tiny sub-recovery stage IE, self-interstitials in recovery stage III, and vacancies in recovery stage IV.

The implications and importance of the application of the MTIM for the development of radiation resistant materials are outlined.
Irradiation Behavior of Weldments of Austenitic Stainless Steel Made by Various Welding Techniques
Authors: Shiba K , Sawai T , Jitsukawa S , Hishinuma A , Pawel JE
Published: March 2009

An austenitic stainless steel, 316F, irradiated in the High Flux Isotope Reactor to doses of about 8 to 33 dpa at 400° and 500°C was investigated. Electron beam (EB) welding and metal inert gas (MIG) welding techniques were used to make weldment specimens. Weldment specimens were made from their weld metal or weld joint (including heat affected zone) regions of the weldments. Base metal was also studied for comparison. Microstructures of these specimens were observed by TEM.

Tensile tests were carried out at the nominal irradiation temperature in vacuum. Solution annealed 316F showed the large irradiation hardening at 400°C, while the change in yield stress observed at 500°C was not so large. Weldments specimens had the same temperature and dose dependence as the base metal. The differences between EB and MIG after irradiation were small, compared to the differences before irradiation, except for the slight less ductility of MIG weldments. The defect microstructures of weldments were the same as base metal.
The Development of Structural Materials for Reduced Long-Term Activation
Authors: Ehrlich K , Cierjacks SW , Kelzenberg S , Möslang A
Published: March 2009

A reliable calculation of neutron-induced activation of materials requires the inclusion of all kinematically allowed reactions and subsequent reaction chains. While neutron-induced reactions have been sufficiently covered in the past, sequential (x,n) reactions with charged particles x, produced in a first-step reaction, were neglected. To include this type of reaction three new libraries and a preparatory code were developed to produce pseudo cross sections for the European reference code FISPACT. Inventory calculations with the updated FISPACT code, done for all stable elements, showed for 30 elements an increase of at least one of the radiological quantities activity, dose rate and decay heat. Two types of candidate structural materials were investigated: Ferritic-martensitic steels and vanadium-based alloys. While V-Cr-Ti alloys without impurities are known to have far superior long-term activation properties, a realistic assumption of technically achievable amounts of tramp elements leads nearly to the same level of activation as for the optimized ferritic-martensitic steels.
Effects of Physical Aging at Elevated Temperatures on the Viscoelastic Creep of IM7/K3B
Authors: Gates TS , Feldman M
Published: March 2009

Physical aging at elevated temperatures of the advanced composite IM7/K3B was investigated through the use of creep compliance tests. Testing consisted of short-term isothermal, creep/recovery with the creep segments performed at constant load. The matrix-dominated transverse tensile and in-plane shear behavior were measured at temperatures ranging from 200 to 230°C. Through the use of time-based shifting procedures, the aging shift factors, shift rates, and momentary master curve parameters were found at each temperature. These material parameters were used as input to a predictive methodology that was based upon effective time theory and linear viscoelasticity combined with classical lamination theory. Long-term creep compliance test data was compared to predictions to verify the method. The model was then used to predict the long-term creep behavior for several general laminates.
Mechanical Performance of Composite Sandwich Beams with Syntactic Foam Cores
Authors: Jize NN , Hiel C , Ishai O
Published: March 2009

A design concept for composite wind tunnel compressor blades at NASA Ames Research Center was based on a sandwich construction composed of carbon fiber-reinforced polymer (CFRP) skins bonded to a syntactic foam core. The detailed design and analysis of this blade required the input of the elastic and strength properties of the sandwich constituents. Available standards that apply to regular foams and honeycomb cores were found to be partly inadequate for this purpose. An improved testing procedure and its analysis that provided the basic elastic and strength properties are reported in this paper. Tensile, compressive, and shear properties of the foam and skin are identified using beam deflection and failure mode analysis.

Constituent properties derived from beam flexure tests culminate in a general strategy of comparing analytical parameters to results found experimentally. The beam failure modes are found to be either in compressive failure of the skin or in shear failure of the core. This matched the analytical predictions. The deflection of the beam in a three-point flexure test was also found to correlate well with the analytical model.

The study concludes that the correlation between experimental results and the analytical predictions will enable the designer to predict the mechanical behavior and strength of a sandwich beam design. Furthermore, it allows for the experimental analysis of a sandwich beam without having to separate its constituent materials.
Through-the-Thickness Tensile Strength of Textile Composites
Authors: Jackson WC , Ifju PG
Published: March 2009

A series of tests was run to characterize the through-the-thickness tensile strength of a variety of composites that included two-dimensional (2D) braids, 2D and three-dimensional (3D) weaves, and prepreg tapes. A new test method based on a curved beam was evaluated. The through-the-thickness deformations were characterized using moire interferometry. Failures were significantly different between the 2D materials and the 3D weaves. The 2D materials delaminated between layers due to out-of-plane tensile stresses. The strength of the 2D textile composites did not increase relative to the tapes. The 3D weaves failed due to radial cracks that initiated between the surface yarns because of the circumferential stresses along the inner radius. A circumferential crack similar to the 2D materials produced the final failure. Final failure in the 3D weaves occurred at a lower bending moment than in the other materials. The early failures were caused by radial crack formation rather than a low through-the-thickness strength.
Using a Mixed-Mode Fatigue Delamination Criterion
Authors: Martin RH , Sriram P , Hooper SJ
Published: March 2009

This paper applies a mixed-mode delamination onset criterion to predict edge delamination in quasi-isotropic laminates of IM7/8320 and IM7/5260. The laminates were tested statically and in fatigue at 23 and 175°C. The three stages involved in this process were: (1) determination of the mixed-mode ratio, (2) determination of the mixed-mode delamination onset criterion using the mixed-mode bending apparatus, and (3) comparison with experimental data. To determine the mixed-mode ratio, several finite element analysis (FEA) models were created with different element sizes at the delamination front and with resin layers also modeled. The β = 0 approach was employed to converge the FEA results. Surface fits were made to the mixed-mode data to allow for prediction of the flat laminate experimental data. The influence of the Mode II component in the predictions resulted in the predictions being less conservative than using a Mode I failure criterion, although the predictions were still conservative.
Detailed Characterization of a Technical Impracticability Zone Using Drive Point Profiling
Authors: Soloyanis SC , McKenzie MA , Pitkin SE , Ingleton RA
Published: March 2009

A team of geologists and engineers conducted an investigation in a dense, non-aqueous phase liquid contaminant (DNAPL) source area at Pease Air Force Base (AFB) Installation Restoration Program Site 32. The investigation was designed to (1) demonstrate that vertical drive point profiling using techniques and equipment developed by the Waterloo Centre for Groundwater Research would work at this hydrogeologically complex site and (2) locate solute concentrations indicative of DNAPL.

The original contaminant source at Site 32 was a 1,200-gallon (≅ 4500 L) underground storage tank with an overflow discharge pipe. The tank held waste solvents from aircraft maintenance in Building 113 at the former Pease AFB. The tank was removed in 1988. The overflow discharge pipe and contaminated soil under and along the pipe were removed in 1990. The results of the Site 32 Source Area Remedial Investigation/Feasibility Study indicate that solvent-related contaminants are present in soil and overburden and in bedrock groundwater and that there is a residual DNAPL source resulting in dissolved-phase groundwater contamination. Efforts to locate DNAPL using monitor wells have been unsuccessful. A limited action remedial alternative based on technical impracticability is proposed for this site.

A drive point profiler was used to obtain 40 discrete interval groundwater samples from a total of five locations in nine days of field work. The drive point profiler enabled sampling of fine-grained, low permeability units in which monitor wells would not usually be installed. Samples were analyzed in a mobile laboratory for volatile organic compounds: trichloroethene, 1,2-dichloroethene, and vinyl chloride. The investigation produced useful information about the highly variable distribution of these compounds in the overburden units.
Monitoring Biofouling in Source and Treated Waters: Status of Available Methods and Recommendation for Standard Guide
Authors: Smith SA
Published: March 2009

Biofouling control in ground-water systems depends upon early detection as part of a maintenance program. However, standard methods of analysis for biofouling components have not provided reliable detection in operational use. Improved methods have been useful in evaluating and predicting biofouling in ground water systems. Filtration and flowcell methods improve sample quality collection, enhancing the usefulness of microscopy. Time-series sampling improves the usefulness of culture analysis of biofouling waters. Prepackaged cultural methods provide practical on-site culture analysis. Used together, such methods provide early warning of biofouling, permitting timely judgments on relative severity, type, and location of the problem. These improvements in methods are being incorporated into standard practices. Although fully quantitative methods of assessing biofouling are not currently available, present methods can be useful to monitor ground water systems for operational purposes. Method development is at the point where a standard guide for biofouling monitoring in operational practice is possible.
Methods for the Collection of Subsurface Samples During Environmental Site Assessments
Authors: Weinstock EA
Published: March 2009

With the market for Environmental Site Assessments growing in response to the requirements of lending institutions, the need to collect subsurface samples quickly and inexpensively is greater today than ever before. ASTM, through committee E-50, has developed standardized procedures for the performance of a Pre-Transaction Environmental Screening and for a Phase I Environmental Site Assessment. Standards for the performance of subsurface sample collection during a Phase II Environmental Site Assessment are currently being drafted by committee E-50.

This paper discusses numerous sample collection techniques that have been successfully employed during Phase II Assessments and presents case histories of their application.

The collection of shallow soil samples is described using commercially available hand augers and hand-driven core samplers. These devices are modified with extensions to collect deeper samples from storm drains and leaching pools.

The performance of soil gas surveys are described using both hand-driven sample probes and vehicle-mounted, hydraulically driven vapor probes. Once the soil vapor is collected at the ground surface, a sample of the media is either analyzed on-site using a field-operated detection device or delivered to a laboratory for analysis.

Application and case histories of the Geoprobe(™) sampling system, a form of “direct push” technology, are described. This device uses vehicle-mounted, hydraulically-driven sample probes. The probe can be advanced to depths as great as 100 feet below grade and can retrieve soil, soil gas and groundwater samples.

Use of standard truck-mounted drill rigs are also considered. Collection of soil samples are discussed using standard techniques such as a split-barrel core sampler (ASTM Method D 1586-84, Standard Method for Penetration Test and Split-Barrel Sampling of Soils) and installation of monitoring wells: Applications and case histories of the Hydropunch(™) in-situ groundwater sampler are also described. This device allows for the collection of a groundwater sample during the process of performing a soil boring without the installation of a monitoring well.

The method selected for a given project will vary depending on site-specific criteria such as the depth to groundwater and the subsurface geology. This paper discusses the advantages and disadvantages of each method. It also evaluates the criteria that should be considered in selecting in-situ sampling devices, such as a driven sampling probe, versus a permanent monitoring well.
U.S. Geological Survey Protocol for Measuring Low Levels of Inorganic Constituents, Including Trace Elements, in Surface-Water Samples
Authors: Fitzgerald KK , Miller TL , Horowitz AJ , Demas CR , Rickert DA
Published: March 2009

The U.S. Geological Survey (USGS) has sponsored a number of studies to evaluate its sampling, processing, and analytical procedures for filtered water samples. The major findings of these studies were that surface-water sampling and processing procedures and equipment used in USGS programs were inadequate to produce contaminant-free trace-element data on a consistent basis. This led to development of a new protocol for collecting, processing, and analyzing filtered water samples for the analysis of trace elements at the 1 microgram-per-liter (ug/L) level using “clean” procedures. The protocol specifies (1) supplies, (2) office and between-site cleaning procedures, (3) samplers, (4) sample splitters, (5) use of disposable capsule filters, (6) quality-assurance measures including use of disposable gloves and shelters for sample processing, and (7) quality-control requirements including blanks, replicates, and split samples.

The USGS is now implementing this protocol for all USGS efforts to produce trace-inorganic data at the microgram-per-liter level on filtered water samples. The protocol will also be used for collecting and processing samples for major ions and nutrients when trace-elements are also being determined.
Decontamination of Field Equipment: An Institutional Status Report
Authors: Bellandi R , Mickam JT , Burrows VC
Published: March 2009

Advances in hazardous waste remediation have forced the development and refinement of correlative activities such as the decontamination of field equipment. Specific decontamination procedures are routinely included in remediation requirements such as the quality assurance project plan (QAPP). The authors surveyed the decontamination practices of several states and major federal agencies in 1988 before ASTM promulgated D 5088-90, “Decontamination of field equipment used at nonradioactive sites. ” They found a diversity of practices with little consistency of detail or attention.

The authors revisited the practices of several states and the USEPA regions to assess the effect of D 5088-90. Their presumption was that the ASTM standard would make inroads on practices. They found that D 5088-90 has had less than the expected effect because too few practitioners are aware of it.
Application of Nitrogen-Alloyed Martensitic Stainless Steels in the Aviation Industry
Authors: Stein G , Kirschner W , Lueg J
Published: March 2009

Nitrogen in stainless martensitic steels has a beneficial influence on the mechanical as well as on the chemical properties. However the effect of nitrogen is limited due to the rather low solubility of this element. A special alloy development in combination with a pressurized melting technique lead to distinctly higher nitrogen contents. Stainless martensitic steels containing high nitrogen contents are manufactured by VSG today on an industrial scale using the PESR-process (Pressurized Electroslag Remelting). Depending on special applications these steels are available with different chemical analysis under the trade mark CRONIDUR.

The basic composition of all CRONIDUR-alloys consists of about 15% Chromium, 1% Molybdenum, 0.15 to 0.35% Carbon and 0.20 to 0.40% Nitrogen. The combination of Cr + Mo + N leads to a superior corrosion resistance of these HNS-steels (HNS: High Nitrogen Steels) in comparison to similar carbon based alloys. Focused on applications with a required minimum hardness of 58 HRC, like stainless bearings or screw shafts, the C+N-content is tuned between 0.60 to 0.80% (Brand: CRONIDUR 30). Additions of max. 0.3% Vanadium and 0.1% Niobium qualifies the brand CRONIDUR 20 for enhanced temperature applications like turbine disks or blades.
Process Model Development for Optimization of Forged Disk Manufacturing Processes
Authors: Fischer CE , Gunasekera JS , Malas JC
Published: March 2009

This paper addresses the development of a system which will enable the optimization of an entire processing sequence for a forged part. Typically such a sequence may involve several stages and alternative routes of manufacturing a given part. It is important that such a system be optimized globally, (rather than locally, as is the current practice) in order to achieve improvements in affordability, producibility, and performance. This paper demonstrates the development of a simplified forging model, discussion techniques for searching and reducing a very large design space, and an objective function to evaluate the cost of a design sequence.
Prediction and Control of Segregations in CrMoV Steel Ingot for Monoblock HLP Rotor Forgings Using Experimental Results Obtained from 8 Ton Sand Mold Ingots
Authors: Itoh A , Yamada H , Takenouchi T
Published: March 2009

Remarkable segregation was observed in the modified super clean CrMoV steel forgings for electric power generation applications. Therefore, to make the mechanism clear, effect of such elements as Mn, Ni, Cr and Mo on segregation was studied, using 8 ton sand mold ingots, the solidification time of which corresponds to that of 100 ton ingot.

As a result, we found that factors controlling the segregation are δ-solidification ratio, mean partition coefficient, density difference of molten steels between bulk and segregated liquid at the solidification front and so on. These factors can be calculated from chemical composition of steels.

Then, based on prediction model obtained from the experimental results, chemical composition and shape of ingot were tried to be changed. As for chemical composition, such elements as Mo which is heavy and δ-former were kept low in the specification range. And, as for ingot shape, height to diameter ratio H/D was kept high to shorten the solidification time. The carbon segregation along the axis of ingot was kept relatively low by this ingot design.

The eutectic Nb(C,N) inclusions which give bad effect on the toughness were also investigated. The conditions for the formation of such inclusions were made clear and then predicted and controlled by the calculation from chemical composition.

By this technical development, quality of ingot for HLP rotor forgings was extremely improved.
Predicting Times to Corrosion from Field and Laboratory Chloride Data
Authors: Berke NS , Hicks MC
Published: March 2009

Corrosion of steel in concrete is one of the major causes of the premature failure of steel reinforced concrete. In marine and deicing salt environments the ingress of chloride is the primary cause for the breakdown of passivity and the onset of severe corrosion. In this paper, we show how to develop effective diffusion coefficients for chloride ingress based on chloride profiles from several marine structures. Predictions of the times to reach chloride levels associated with initiation of severe corrosion are made.

Chloride profiles using effective diffusion coefficients determined in other studies are given for bridge decks and parking structures. There are significant benefits of increased concrete cover and the use of corrosion inhibitors in increasing the time to corrosion. Finally, comparisons of Standard Test Method for Electrical Indication of Concrete's Ability to Resist Chloride Ion Penetration (ASTM C 1202) coulomb values with effective diffusion coefficients, determined from field and laboratory studies, indicate that effective diffusion coefficients for low permeability concretes can be estimated using simple modifications of this test method. Thus, we demonstrate that knowledge of the chloride profile is useful to assess the future performance of existing structures that are not undergoing active corrosion, and in predicting the time to corrosion initiation of new structures.
Finite Element Modeling of Ground Level Potential Measurements of Galvanic Cells on Concrete Pipe
Authors: Carlson EJ , Stringfellow RG , Hall SC
Published: March 2009

Ground potential surveys are used to monitor for the presence of corrosion activity on buried pipe. Questions arise as to the relationship between the measured potentials and anode size, detectable anode size, and the parameters which influence the magnitude of the potential. In this study, surface center-line and side-drain potentials were calculated for galvanic cells in buried concrete pipe using a 3-D finite element model. The model was calibrated using the results from potential surveys conducted on buried pipe with implanted anodes. Soil cover, anode size, and anode location are the dominant variables affecting surface potential. The analyses reveal the detection limits of potential surveys for the given range of parameters studied.
Review of Information Obtained from Investigation of 20 Distressed Exterior Brickwork Walls Built in a Severe Weathering Region of the USA
Authors: Chin IR
Published: March 2009

The investigation of 20 distressed brickwork walls built in a severe weathering region of the USA revealed that the lack of expansion joints to accommodate movements of the wall and structure is the major cause of distress in brickwork walls as is documented in the literature of the masonry industry. Other significant findings found during the investigation that are not as well documented are as follows: 1. Deterioration of brick in walls due to exposure to severe weathering is rare even among brick that meets ASTM Grade SW by alternate considerations. 2. Deterioration of mortar in walls due to exposure to severe weathering is rare in non air-entrained portland cement lime (PCL), mortar, and in air-entrained masonry cement (MC) mortar. 3. Efflorescence occurred in 35 percent of the distressed brickwork walls investigated. 4. Water leakage into the interior of the building occurred in 20 percent of the distressed brickwork walls investigated. 5. There is no obvious correlation between the use of Type M, S, or N mortar, the use of PCL or MC mortar, or the air-entrainment content of mortar with the types of distress conditions that occurred in the brickwork walls investigated.

The information obtained from the 20 distressed brickwork walls investigated can be used to minimize the development of distressed conditions in new brickwork walls, and to study methods to improve the performance and durability of brickwork.
A Review of Masonry Tuckpointing Materials and Procedures
Authors: Kaskel BS , Chin IR , Kim KY
Published: March 2009

Tuckpointing is a time tested method for maintaining masonry walls. Tuckpointing has been proven effective in reducing water permeance and improving the appearance of masonry walls. ASTM C270, “Standard Specification for Mortar for Unit Masonry”, provides guidelines in the appendix section for tuckpointing mortar. The Brick Institute of America also provides guidelines for tuckpointing procedures. These two sources often provide sufficient information for the designer to specify successful tuckpointing and for the mason to install successful tuckpointing. This paper will examine by case studies, tuckpointing materials and procedures and than compare effects of tuckpointing and surface grouting on water permeance.
Improved Method for Testing Grout used as Masonry Cell Fill
Authors: O'Leary JS
Published: March 2009

Currently, ASTM C 1019 “Standard Method of Sampling and Testing Grout” governs the compression testing of grout used in masonry construction. This test method utilizes masonry units from the project as the mold to cast the grout specimens for compressive strength testing, thereby accounting for the absorption of the masonry units and its corresponding affect on compressive strength of the test specimens. However, due to the cost, time, materials, space and laboratory ability required for this test, many times the owner or contractor opts for standard concrete cylindrical specimens cast in nonabsorbent molds.

This research investigates the use of a low cost, efficient, single unit mold which produces compressive strength results within an acceptable range of that produced by the ASTM C 1019 specimens. With the current method, many physical defects are inherent with the specimens, such as a concave end, non-square cross-section, ends not perpendicular to axis, and sloped ends. The proposed method will eliminate these types of problems and yield more consistent results with much greater ease and lower cost.
A Capillary Suction Model for Concrete Masonry and Its Application to Integral Water-Repellent Masonry
Authors: Karkare MV , Walloch CT
Published: March 2009

Capillary suction plays a major role in water transport and redistribution after water comes in contact with the face of masonry structures. This paper proposes a new test method to characterize the capillary suction properties of concrete masonry units.

Water capillary suction data for both concrete block and Type S portland cement-lime mortar containing different amounts of integral water-repellent (IWR) admixtures are presented. An empirical two-parameter power law model is proposed to fit the test data. The effect of IWR admixture dosage rates on the model parameters and water repellent characteristics of the masonry components is discussed. The significance of the parameter values is also explained. The testing showed that as IWR dosage rate increases, capillary suction decreases. At commonly used IWR admixture dosages, the reduction in capillary suction of the masonry exceeded 80% at 24 h. It was also demonstrated how the model parameters can be used to determine the optimum admixture dosage range.
Uni-Directional Freezing and Thawing Durability Tests for Brick Masonry Panels
Authors: Kaskel BS
Published: March 2009

Current USA practice for predicting the durability of clay masonry units rely largely on physical properties for an indication of the masonry durability. As an alternative to physical properties, freezing and thawing tests provide a more reliable measure of the durability of clay masonry. In the USA, freezing and thawing testing of clay masonry is typically performed in accordance with ASTM C 67 procedures. However, the C 67 test method does not represent freezing and thawing conditions as occur on exterior clay brick masonry walls. In masonry walls the freezing and thawing environment occurs from one direction, from the exterior side of the wall. Test methods currently in use in Europe and Canada offer test conditions that represent the uni-directional freezing and thawing characteristics of clay masonry units placed in the wall. This paper reviews the uni-directional tests currently available, describe their advantages and disadvantages and makes specific recommendations as to uni-directional test methods for the USA.
Low-Cost Concrete Masonry Housing in Colombia
Authors: Madrid GG , Peláez LG
Published: March 2009

The use of Concrete Masonry (CM) for low-cost housing in Colombia is influenced by local physical, technical, economic and social conditions; some of which can exist in other places in different combinations. Even though it is difficult to talk about special national achievements in this technology, it has been possible to define guidelines for the physical characteristics of low-cost housing and for the construction with Concrete Blocks (CB). Additionally, a few alterations have been made to the CB used in several projects, like in the dimensions of the units and the on-site production of special blocks. Those changes modify the cost structure and allow great savings, especially in social-interest programs (where labor is provided as a part of the payment), giving CM a special social significance.
Crack-Bridging Effects in Notch Fatigue of SCS-6/TIMETAL 21S Composite Laminates
Authors: Larsen JM , Jira JR , John R , Ashbaugh NE
Published: March 2009

Fatigue tests of middle-hole tension specimens of SCS-6/TIMETAL 21S composite (silicon-carbide fibers reinforcing a matrix of Ti-15Mo-2.6Nb-3Al-0.2Si alloy) were performed on three laminate architectures: unidirectional, cross ply, and quasi-isotropic. Specimens were tested over a range of stress levels, and fatigue damage was documented in situ by macrophotography and direct-current electric potential drop measurements. Typically, failure evolved by the formation of a few dominant cracks at the notch that propagated into the composite matrix and, in many instances, were substantially affected by unbroken fibers bridging the cracks. Fractographic and failure mode characterization revealed key differences in the effectiveness of crack bridging in the three laminates. A shear-lag crack-bridging model was shown to correlate crack growth data in the laminates based on an empirical value of fiber/matrix interfacial shear stress. Crack-bridging stress distributions were predicted using the shear lag model and verified by comparing the predicted crack opening displacement profiles with measurements made using a laser interferometric displacement gage system. Implications of the results are discussed with respect to the potential use of these materials in practical structural applications.
Life Prediction of a [0/90] Metal Matrix Composite Under Isothermal and Thermomechanical Fatigue
Authors: Nicholas T , Russ SM , Neu RW , Schehl N
Published: March 2009

Experimental data on cycles to failure are reported for a SCS-6/TIMETAL 21S [0/90]s composite under isothermal fatigue at 650 and 815°C over a range of frequencies from 0.01 to 200 Hz as well as under in-phase and out-of-phase thermomechanical fatigue from 150 to 650°C. Several models are evaluated for correlating fatigue lives based on computed micromechanical stresses using a life fraction concept that considers both cycle-dependent and time-dependent terms. Fractography is used to illustrate the range of failure modes in this material system as well as to both guide and validate the modeling concepts. Over the range of conditions covered in this investigation, purely time-dependent, purely cycle-dependent, fiber-dominated, and matrix-dominated modes of failure, as well as combinations of these, are observed.