scholarly journals The thermal-mechanical analysis of targets for the high volume production of molybdenum-99 using a low-enriched uranium metal foil

2012 ◽  
Author(s):  
Kyler K. Turner
Keyword(s):  
High Volume ◽  
Mechanical Analysis ◽  
Metal Foil ◽  
Uranium Metal ◽  
High Volume Production ◽  
Volume Production ◽  
Enriched Uranium ◽  
Thermal Mechanical Analysis

Experimental Testing of Annular Target Surrogates for the Production of Molybdenum-99

2012 ◽  
Author(s):  
Philip F. Makarewicz ◽  
Srisharan Garg Govindarajan ◽  
Gary L. Solbrekken
Keyword(s):  
Experimental Testing ◽  
Thermal Contact ◽  
Cooling Water ◽  
High Volume ◽  
Metal Foil ◽  
High Volume Production ◽  
Volume Production ◽  
Enriched Uranium ◽  
Global Threat ◽  
Target Design

Technetium-99m (Tc-99m) is a diagnostic radiopharmaceutical that is currently used about 100,000 times daily for diagnostic imaging procedures globally [1]. The parent isotope for Tc-99m is molybdenum-99 (Mo-99), most commonly obtained through the irradiation of high enriched uranium (HEU). In accordance with the Department of Energy’s Global Threat Reduction Initiative (GTRI), an effort is underway to develop a process to produce Mo-99 using low enriched uranium (LEU). One method utilizes LEU cast in the form of a metal foil as opposed to current powder based dispersion designs for HEU. New high-volume production LEU target concepts need to be analyzed to assure safe, reliable operation during all stages of production as use of a foil requires a significant modification to the current target design. Analytic and numeric models have been built to simulate the thermal-mechanical behavior of LEU-foil based targets under irradiation conditions. Experimental testing is being used to validate the models. Heating conditions are controlled by heater placement and cooling water circulation to place the target interfaces into controlled states of compression and tension. Thermocouples are used to measure the temperature at key locations so that the thermal contact resistance can be evaluated and compared with the predictions.

Thermal-Mechanical Analysis of Varying Boundary Conditions on a LEU Foil Based Molybdenum-99 Plate Processing Target

2010 ◽  
Author(s):  
Kyler K. Turner ◽  
Gary L. Solbrekken ◽  
Charlie W. Allen
Keyword(s):  
United States ◽  
Boundary Conditions ◽  
Nuclear Reactor ◽  
The United States ◽  
Mechanical Analysis ◽  
Metal Foil ◽  
Enriched Uranium ◽  
Aluminum Plates ◽  
Thermal Mechanical Analysis ◽  
The Impact

Technetium-99m is a diagnostic radio-pharmaceutical that is currently used in 85% of the United States diagnostic imaging procedures [1]. All supplies of technetium-99m’s parent isotope molybdenum-99 currently originate from the irradiation of high enriched uranium (HEU) in nuclear reactor facilities located outside the United States. In accordance with the Global Threat Reduction Initiative all uranium used in future molybdenum-99 production will use low enriched uranium (LEU). Conversion to LEU material effectively mandates using LEU in the form of a metal foil as opposed to current powder based dispersion designs for HEU. Using a foil requires a significant modification to the current target design. One design approach uses an LEU foil sandwiched between two nominally flat aluminum plates. The LEU is enclosed in the sandwiched structure by welding the aluminum plates together about their edges. The plate design is inspired by LEU fuel plates with the exception that the LEU is not bonded to the aluminum plates nor is it necessary to clamp the plate edges to prevent lateral translation. This paper will review the thermal-mechanical analysis of an LEU based molybdenum-99 target with plate geometry. This study describes the impact of boundary conditions on the thermally-induced stress and strain in the aluminum plates.

scholarly journals Congener-specific partition properties of chlorinated paraffins evaluated with COSMOtherm and gas chromatographic retention indices

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jort Hammer ◽  
Hidenori Matsukami ◽  
Satoshi Endo
Keyword(s):  
Chemical Properties ◽  
High Volume ◽  
Retention Indices ◽  
Chromatographic Retention ◽  
Linear Free Energy Relationship ◽  
Linear Free Energy ◽  
Chlorinated Paraffins ◽  
Gas Chromatographic Retention Indices ◽  
High Volume Production ◽  
Volume Production

AbstractChlorinated Paraffins (CPs) are high volume production chemicals and have been found in various organisms including humans and in environmental samples from remote regions. It is thus of great importance to understand the physical–chemical properties of CPs. In this study, gas chromatographic (GC) retention indexes (RIs) of 25 CP congeners were measured on various polar and nonpolar columns to investigate the relationships between the molecular structure and the partition properties. Retention measurements show that analytical standards of individual CPs often contain several stereoisomers. RI values show that chlorination pattern have a large influence on the polarity of CPs. Single Cl substitutions (–CHCl–, –CH2Cl) generally increase polarity of CPs. However, many consecutive –CHCl– units (e.g., 1,2,3,4,5,6-C11Cl6) increase polarity less than expected from the total number of –CHCl– units. Polyparameter linear free energy relationship descriptors show that polarity difference between CP congeners can be explained by the H-bond donating properties of CPs. RI values of CP congeners were predicted using the quantum chemically based prediction tool COSMOthermX. Predicted RI values correlate well with the experimental data (R2, 0.975–0.995), indicating that COSMOthermX can be used to accurately predict the retention of CP congeners on GC columns.

High Volume Production Growth of GaAs on Silicon Substrates

1986 ◽  
Vol 67 ◽  
Author(s):  
Chris R. Ito ◽  
M. Feng ◽  
V. K. Eu ◽  
H. B. Kim
Keyword(s):  
Schottky Diodes ◽  
High Volume ◽  
Wafer Surface ◽  
Silicon Substrates ◽  
Growth Technique ◽  
Wafer Thickness ◽  
Production Growth ◽  
High Volume Production ◽  
Volume Production ◽  
P Type

ABSTRACTA high-volume epitaxial reactor has been used to investigate the feasibility for the production growth of GaAs on silicon substrates. The reactor is a customized system which has a maximum capacity of 39 three-inch diameter wafers and can accommodate substrates as large as eight inches in diameter. The MOCVD material growth technique was used to grow GaAs directly on p-type, (100) silicon substrates, three and five inches in diameter. The GaAs surfaces were textured with antiphase boundaries. Double-cyrstal rocking curve measurements showed single-cyrstal GaAs with an average FWHMof 520 arc seconds measured at four points over the wafer surface. Within-wafer thickness uniformity was ± 4% with a wafer-to-wafer uniformity of ± 2%. Photoluminescence spectra showed Tour peaks at 1.500, 1.483, 1.464, and 1.440 ev. Schottky diodes were fabricated on the GaAs on silicon material.

Determination of transverse flexural and shear moduli of chopped carbon fiber tape-reinforced thermoplastic by vibration

2017 ◽  
Vol 52 (3) ◽  
pp. 395-404
Author(s):  
Xiuqi Lyu ◽  
Jun Takahashi ◽  
Yi Wan ◽  
Isamu Ohsawa
Keyword(s):  
Carbon Fiber ◽  
Beam Theory ◽  
Transversely Isotropic ◽  
High Volume ◽  
Bending Test ◽  
Thermoplastic Material ◽  
Shear Moduli ◽  
High Volume Production ◽  
Volume Production

Chopped carbon fiber tape-reinforced thermoplastic material is specifically developed for the high-volume production of lightweight automobiles. With excellent design processability and flexibility, the carbon fiber tape-reinforced thermoplastic material is manufactured by compressing large amounts of randomly oriented, pre-impregnated unidirectional tapes in a plane. Therefore, the carbon fiber tape-reinforced thermoplastic material presents transversely isotropic properties. Transverse shear effect along the thickness direction of carbon fiber tape-reinforced thermoplastic beam has a distinct influence on its flexural deformation. Accordingly, the Timoshenko beam theory combined with vibration frequencies was proposed to determine the set of transverse flexural and shear moduli. Meanwhile, the transverse flexural and shear moduli of carbon fiber tape-reinforced thermoplastic beam were finally determined by fitting all the first seven measured and calculated eigenfrequencies with the least squares criterion. In addition, the suggested thickness to length ratio for the 3-point bending test and Euler–Bernoulli model was given.

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