Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 22
Book Description
Effect of Thermal Cycling on the Alpha-beta Transformation Temperature of Plutonium
Author: Studies on the Alpha-to-beta and Beta-to-alpha Phase Transformations of Plutonium
Author: J. W. AndersonPublisher:
ISBN:
Category : Phase transformations (Statistical physics)
Languages : en
Pages : 62
Book Description
Transformation Kinetics of Plutonium
Author: Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Isothermal reaction curves and T-T-T curves showing the effect of different variables on the beta-alpha transformations in plutonium are presented. Impurity content, stresses, beta heat-treating time and temperature, hydrostatic pressing, specimen size, and thermal cycling influenced the kinetics of the beta- alpha transformation. Decreasing the impurlty content increased the rate of transformation. High tensile stress retarded the beta-alpha transformation. Increasing the beta heat-treating time and temperature markedly decreased the rate of transformation. Hydrostatic pressing at 90,000 psi accelerated the beta- alpha transformation under pressure but decreased any subsequent beta-alpha transformations by as much as two orders of magnitude. Specimen size had no effect on the start of the transformation but increasing the specimen size from 0.010 to 0.37 inch decreased the rate of completion of transformation several orders of magnitude. Thermal cycling less than 15 cycles did not affect the rate of transformation. The density of high purity plutonium during hydrostatic pressing at l80 deg C and cooling under pressure increased from 19.60 to 19.65 g/ cm3to 19.70 to 19.75 g/cm3. This increase was shown to be attributed to decreasing the volume of microcracks rather than transformation of any metastable beta phase. A T-T-T curve of the alpha-beta transformation is given which shows the start of the transformation is 16 hours at 116.5 deg C with the rate decreasing extremely rapidly with decreasing temperature. The times for the start and completion of the transformation were significantly shorter than the early work reported. The faster rate was attributed to less impurities, The gamma-beta-alpha and alpha-beta-gamma transformations are discussed also. Isothermal reaction curves and T-T-T curves for these transformation are included. (auth).
Thermal Cycling of Plutonium
Author: R. D. NelsonPublisher:
ISBN:
Category : Nuclear reactors
Languages : en
Pages : 72
Book Description
Effects on the Long Term Storage Container by Thermal Cycling Alpha Plutonium
Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 21
Book Description
Experiments were conducted to determine the validity of the steady state temperature limit of 100 C established by the DOE-STD-3013-96 for storing alpha plutonium metal. Studies with an alpha plutonium ingot combined with strain gauge measurements indicate that the stainless steel storage container, yields very little (0.005 in.) to the expanding plutonium metal as it undergoes alpha beta phase transformation at temperatures above 112 C. Another experiment using an alpha plutonium rod for point loading of the container wall showed no measured deformation of the container. The results of strain measurements for alpha beta and beta alpha transformations for twenty five thermal cycles are reported. Finite element modeling using the measured data predicts that the compressive yield strength is 3,500 psi versus the literature value of 13,000 psi.
Transformation Kinetics of Plutonium
Author: R. D. NelsonPublisher:
ISBN:
Category : Chemical kinetics
Languages : en
Pages : 126
Book Description
Nuclear Science Abstracts
Author: The Beta-alpha and Alpha-beta Transformations in Plutonium Under Applied Stresses
Author: R. D. NelsonPublisher:
ISBN:
Category : Plutonium
Languages : en
Pages : 40
Book Description
Thermal Cycling of Plutonium. Part I. Observations of the Physical Damage Resulting from Thermal Cycling Plutonium Through Its Low Temperature Phase Transformations
Author: Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Plutonium, thermally cycled through the low-temperature allotropic transformations, exhibited extensive physical damage. The physical damage was greater than that reported for any other metal or alloy. The extent of physical damage was determined by measurements of fluid displacement and the dimensional changes. The internal porosity was examined metallographically. Physical damage varied considerably, depending on the cycling conditions and the characteristics of the metal (particularly inclusions and casting imperfections). Observations showed that increasing the specimen size produced a greater decrease in density as a function of the number of cycles. The degree of void formation was directly proportional to volume change associated with the phase transformation. Other variables such as the length-diameter ratio (constant diameter) had little or no influence on the amount of physical damage. The dimensional growth was both radial and longitudinal. The tensile strength and the yield strength of tensile specimens cycled ten times between the gamnna and alpha phases were decreased to an average of 30,000 and 26,000 psi, respectively. (auth).
Author: