893 Matching Results

Search Results

Advanced search parameters have been applied.

Nondestructive Evaluation Techniques for Silicon Carbide Heat-Exchanger Tubes : Second Annual Report, October 1978-September 1979

Description: This report discusses the development of ultrasonic testing, acoustic microscopy, dye-enhanced radiography, holographic interferometry, and infrared scanning techniques for flaw detection in silicon carbide (SiC) heat-exchanger tubing. Both preservice and in-service testing requirements are discussed. An ultrasonic boreside probe and an acoustic microscope stage have been designed for continuous monitoring of SiC tubing. Preliminary results with these acoustic systems are presented. In addition, a novel technique for detecting small surface flaws using holographic interferometry is discussed. Fracture mechanics analysis suggests that detection of flaws on the order of 100 um is necessary to assure good reliability of ceramic heat exchangers. The acoustic and holographic techniques have been shown to be capable of detecting flaws of this size. However, the sensitivity of ultrasonic flaw detection in SiC is affected by the microstructure of the component. The practical considerations involved in the use of these techniques are discussed.
Date: November 1979
Creator: Kupperman, D. S.; Yuhas, D.; Deininger, W. & Sciammarella, Cesar A.
Partner: UNT Libraries Government Documents Department

Progress in Nondestructive Testing: A Summary of Hanford Achievements in These Programs Under General Electric, 1952 - 1964

Description: Report discussing the development of Hanford Laboratories' nondestructive testing programs and a summary of their results. Programs include AlSi fuel testing, N-Reactor fuel testing, and reactor research and development.
Date: August 1964
Creator: Walker, R. A. & Russell, J. T.
Partner: UNT Libraries Government Documents Department

Bulk defect analysis with a high-energy positron beam

Description: A program using a positron beam to probe defects in bulk materials has been developed at Lawrence Livermore National Laboratory. Positron annihilation lifetime spectroscopy (PALS) provides non-destructive analysis of average defect size and concentration. A 3 MeV positron beam is supplied by Sodium-22 at the terminal of a Pelletron accelerator. The high-energy beam allows large (greater than or equal to 1 cm<sup>2</sup>) engineering samples to be measured in air or even sealed in an independent environment. A description of the beam-PALS system will be presented along with a summary of recent measuremen
Date: September 23, 1998
Creator: Hartley, J. H.; Howell, R. H. & Sterne, P. A.
Partner: UNT Libraries Government Documents Department

Experimental Program for Development and Evaluation of Nondestructive Assay Techniques for Plutonium Holdup

Description: An outline is presented for an experimental program to develop and evaluate nondestructive assay techniques applicable to holdup measurement in plutonium-containing fuel fabrication facilities. The current state-of-the-art in holdup measurements is reviewed. Various aspects of the fuel fabrication process and the fabrication facility are considered for their potential impact on holdup measurements. The measurement techniques considered are those using gamma-ray counting, neutron counting, and temperature measurement. The advantages and disadvantages of each technique are discussed. Potential difficulties in applying the techniques to holdup measurement are identified. Experiments are proposed to determine the effects of such problems as variation in sample thickness, in sample distribution, and in background radiation. These experiments are also directed toward identification of techniques most appropriate to various applications. Also proposed are experiments to quantify the uncertainties expected for each measurement.
Date: May 1977
Creator: Brumbach, S. B.
Partner: UNT Libraries Government Documents Department

Materials analysis using positron beam lifetime spectroscopy

Description: We are using a defect analysis capabilities based on two positron beam lifetime spectrometers: the first is based on a 3 MeV electrostatic accelerator and the second on our high current linac beam. The high energy beam lifetime spectrometer is routinely used to perform positron lifetime analysis with a 3 MeV positron beam on thick sample specimens. It is being used for bulk sample analysis and analysis of samples encapsulated in controlled environments for in situ measurements. A second, low energy, microscopically focused, pulsed positron beam for defect analysis by positron lifetime spectroscopy is under development at the LLNL high current positron source. This beam will enable defect-specific, 3-dimensional maps of defect concentration with sub-micron location resolution. When coupled with first principles calculations of defect specific positron lifetimes it will enable new levels of defect concentration mapping and defect identification.
Date: November 12, 1998
Creator: Hartley, J.; Howell, R. H., Asoka-Kumar, P.; Sterne, P. & Stoeffl, W.
Partner: UNT Libraries Government Documents Department

Role of nondestructive evaluation in life cycle management

Description: This paper provides an overview of some common NDE methods and several examples for the use of different NDE techniques throughout the life cycle of a product. NDE techniques are being used to help determine material properties, design new implants, extend the service life of aircraft, and help dispose of radioactive waste in a safe manner. It is the opinion of this author and others that the NDE community needs to work more closely with end users in the life cycle of a product to better incorporate NDE techniques. The NDE community needs to highlight the importance of NDE in the entire life-cycle process of a product by showing real costs savings to the manufacturing community.
Date: December 18, 1997
Creator: Martz, H.
Partner: UNT Libraries Government Documents Department

Optimization of neutron tomography for rapid hydrogen concentration inspection of metal castings

Description: Hydrogen embrittlement describes a group of phenomena leading to the degradation of metal alloy properties. The hydrogen concentration in the alloy can be used as an indicator for the onset of embrittlement. A neutron tomography system has been optimized to perform nondestructive detection of hydrogen concentration in titanium aircraft engine compressor blades. Preprocessing of back projection images and postprocessing of tomographic reconstructions are used to achieve hydrogen concentration sensitivity below 200 ppm weight. This paper emphasizes the postprocessing techniques which allow automated reporting of hydrogen concentration.
Date: February 3, 1998
Creator: Gibbons, M. R., LLNL
Partner: UNT Libraries Government Documents Department

Three-Dimensional Thermal-Neutron Radiography

Description: Three-dimensional radiographic methods provide a means of determining the depth of defect indications and minimizing the confusion that results from overlapping images of structures at various depths in an object. One method of obtaining and displaying three-dimensional radiographic images is multiple-film laminagraphy, i.e., a series of radiographic films taken at different orientations can be viewed superimposed to present a sharply focused image of any desired object plane. Methods that use multiple-film laminagraphy for three-dimensional thermal-neutron images will be described.
Date: October 1976
Creator: Berger, H. & Reimann, K. I.
Partner: UNT Libraries Government Documents Department

Microstructural Effects and Signal-Enhancement Techniques in Ultrasonic Examination of Stainless Steel

Description: Ultrasonic inspection of large-grain stainless steel and stainless steel welds is difficult, and the results obtained are not easily interpreted. In the present study, the effects of stainless steel microstructure on ultrasonic test results are described, and several signal-processing techniques for enhancing ultrasonic flaw signals are discussed.
Date: September 1976
Creator: Kupperman, D. S. & Reimann, K. J.
Partner: UNT Libraries Government Documents Department

Fast Critical Assembly Safeguards. Summary Report, October 1978 - September 1979, Volume 2

Description: PART 1: The effectiveness of a neutron well correlation counter (NWCC) and a random driver (RD) for plutonium-containing item assay and loss detection has been studied. The items were 4 in. x 2 in. x 1/4 in. stainless steel-clad metal plates and 6 in. x 3/8 in. stainless steel-clad oxide rods, each in two types of containment. PART 2: A neutron-counting/fuel-weighting system has been developed to provide the capability to assay the ZPR-6 and -9 plutonium fuel canisters rapidly and accurately. This system makes feasible the inline monitoring of fuel transfer from the storage vault to the fuel loading hoods and vice-versa. To exploit fully the system's potential, the equipment is intended to be used in conjunction with an on-line computer having a fuel and fuel-canister data base.
Date: September 1980
Creator: Winslow, G. H.; Bellinger, F. O.; Scharping, R. A.; Rusch, G. K. & Groh, E. F.
Partner: UNT Libraries Government Documents Department

Nondestructive-Evaluation Needs for Coal Liquefaction

Description: Nondestructive-evaluation (NDE) needs for coal liquefaction have been identified by acquiring information from site visits, a literature review, and discussions with government personnel. Nondestructive evaluation has been highly rated in importance as a way to help alleviate problems in coal-conversion systems. The primary problems are associated with highly erosive and corrosive slurries being transferred throughout the coal-conversion process. Applicable NDE techniques for both pre-service and in-service inspection include high-temperature ultrasonics, acoustic emission, radiography, acoustic holography, and ultrasonic spectroscopy.
Date: 1977?
Creator: Kupperman, D. S.
Partner: UNT Libraries Government Documents Department

A Statistical Study of EBR-II Fuel Elements Manufactured by the Cold Line at Argonne-West and by Atomics International

Description: Nine elements from each batch of fuel elements manufactured for the EBR-II reactor have been analyzed for uranium-235 content by NDA methods. These values, together with those of the manufacturer, are used to estimate the product variance and the variances of the two measuring methods. These variances are compared with the variances computed from the stipulations of the contract. A method is derived for resolving the several variances into their within-batch and between-batch components. Some of these variance components have also been estimated by independent and more familiar conventional methods for comparison.
Date: September 1977
Creator: Harkness, A. L.
Partner: UNT Libraries Government Documents Department

Autoradiography as a Safeguards Inspection Technique for Unirradiated LWR Fuel Assemblies

Description: A nondestructive autoradiographic method is described which can provide a verification that rods in the interior of unirradiated LWR fuel assemblies contain low-enriched uranium. Sufficient absorber must be used to reduce contributions to image density by beta radiation from uranium-238 daughters. When appropriate absorbers are used, the density of the image of a uranium-containing fuel rod is proportional to the uranium-235 enrichment in that rod. Exposure times as short as 1.5 hours can be achieved by using fast film and intensifying screens. Methods are discussed for reducing contributions to the image density of any single rod from radiation produced by all other rods in the assembly. The technique is useful for detecting missing rods, dummy rods, and rods containing depleted uranium. These defects can be detected by visual inspection of the autoradiographs. In its present state of development, the technique is not sensitive enough to reliably detect the difference between the various uranium-235 enrichments encountered in current BWR fuel assemblies. Results are presented for field tests of the technique at BWR and PWR facilities.
Date: May 1978
Creator: Brumbach, S. B. & Perry, R. B.
Partner: UNT Libraries Government Documents Department

An Ultrasonic Scanner for Stainless Steel Weld Inspections

Description: The large grain size and anisotropic nature of stainless steel weld metal make conventional ultrasonic testing very difficult. This paper evaluates a technique for minimizing the coherent noise in stainless steel weld metal. The method involves digitizing conventional A-scan traces and averaging them with a minicomputer. Results are presented for an ultrasonic scanner which interrogates a small volume of the weld metal while averaging the coherent ultrasonic noise.
Date: September 1978
Creator: Kupperman, D. S. & Reimann, K. J.
Partner: UNT Libraries Government Documents Department

Second Mechanized In-Service Inspection of EBR-2 Steam Generator

Description: The second mechanized ultrasonic inspection of evaporation EV-702, part of the EBR-II steam-generator system, was completed in March 1978. The 2 1/2 Cr-1 Mo duplex tubes were inspected from the bore (water) side for flaws and changes in wall thickness and for evaluating the condition of the braze between the tubes. An addition to this second inspection was the use of an ultrasonic probe to search for circumferential flaws. The inspection equipment was thoroughly checked and routinely calibrated, using a reference standard containing electrical-discharge-machined notches. Notches as small as 1.6 mm long by 0.25 mm deep were readily detected.
Date: November 1978
Creator: Longua, K. J.; Whitham, G. K.; Allen, C. C. & Larson, H. A.
Partner: UNT Libraries Government Documents Department

The development of the shadow analysis team concept

Description: Part II, Section E, Paragraphs 52-55 of the {open_quotes}Verification Annex{close_quotes} (Annex 2) of the Chemical Weapons Convention (CWC) provides the general rights and obligations of both the Inspected State Party (ISP) and the Inspection Team (IT) as to the collection and analysis of samples. In summary, the inspection team has the right to request the collection of samples which will be collected by the ISP unless the decision is made by the ISP to allow the inspectors to collect them. Samples will, if possible, be analyzed at the inspection site, with the assistance of the ISP if requested by the IT. The ISP has the right to retain portions all collected samples. Samples may be sent off-site for independent analysis if deemed necessary. These rights are modified in the case of {open_quotes}Challenge Inspections{close_quotes} by the {open_quotes}Managed Access{close_quotes} Provisions of Part X, Section C, Paragraphs 4648 which specifies that sample collection is to be negotiated between the Inspection Team and the Inspected State Party. In order to assist the ISP in fulfilling its obligation to assist the IT in determining compliance, and in preserving its rights to protect sensitive information not relevant to the CWC, we propose to establish the Army Material Command Treaty Laboratory (AMCTL) Shadow Analysis Team.
Date: November 1, 1995
Creator: McGuire, R.R.
Partner: UNT Libraries Government Documents Department

Monitoring of Refractory Wall recession using high temperature impact echo instrumentation

Description: Regression of refractory linings of furnaces occurs due to a variety of mechanisms. The specific mechanism selected for investigation during this program is the regression of refractories which are in direct contact with a liquid corrodant. Examples include the melting of glass, the production of pig iron and steel, and the melting of aluminum. The rates of regression to a wall thickness which requires reline or extensive reconstruction vary widely, from less than a year to over ten years depending on the specific service environment. This program investigated the feasibility of measuring refractory wall thickness with an impact-echo method while at operating temperature (wall temperatures exceeding 500 C). The impact-echo method uses the impact of a small sphere with the surface of the test object to send a stress wave into the object. In a plate-like structure, the stress wave reflects back to the front surface, reverberating in the structure and causing a periodic surface displacement whose frequency is inversely proportional to the thickness of the test object. Impact-echo testing was chosen because it requires access to only one side of the test object and could be performed during the operation of a refractory structure. Commercially-available impact-echo instrumentation is available for room temperature use for a variety of tests on concrete. The enabling technology for this work was to use a high-temperature piezoelectric material, aluminum nitride, as the receiving sensor for the stress waves, allowing its use on refractories during furnace operation.
Date: April 30, 2004
Creator: Dayton, University of
Partner: UNT Libraries Government Documents Department

Noncontacting thermoelectric detection of material imperfections in metals

Description: This project was aimed at developing a new noncontacting thermoelectric method for nondestructive detection of material imperfections in metals. The method is based on magnetic sensing of local thermoelectric currents around imperfections when a temperature gradient is established throughout a conducting specimen by external heating and cooling. The surrounding intact material serves as the reference electrode therefore the detection sensitivity could be very high if a sufficiently sensitive magnetometer is used in the measurements. This self-referencing, noncontacting, nondestructive inspection technique offers the following distinct advantages over conventional methods: high sensitivity to subtle variations in material properties, unique insensitivity to the size, shape, and other geometrical features of the specimen, noncontacting nature with a substantial stand-off distance, and the ability to probe relatively deep into the material. The potential applications of this method cover a very wide range from detection metallic inclusions and segregations, inhomogeneities, and tight cracks to characterization of hardening, embrittlement, fatigue, texture, and residual stresses.
Date: June 17, 2005
Creator: Nagy, Peter B.; Nayfeh, Adnan H.; Faidi, Waseem I.; Carreon, Hector; Lakshminaraya, Balachander; Yu, Feng et al.
Partner: UNT Libraries Government Documents Department