[en] Yttrium is becoming an important element in iron-base alloys. This paper provides thermodynamic properties of yttrium and Y-S-O, a/sub o/-a/sub s/, a/sub y/-a/sub c/, equilibrium diagrams in liquid iron. These new data are useful for the development and application of yttrium in iron-base alloys

[en] Spectrometer grade, room-temperature radiation detectors have been produced on Cd_0.90Zn_0.10Te grown by the low-pressure Bridgman technique. Small amount of indium has been used to compensate the uncompensated Cd vacancies for the crystals to be semi-insulating. The properties of the detectors are critically dependent on the amount of excess Te introduced into the growth melts of the Cd_0.90Zn_0.10Te crystals and the best detectors are fabricated from crystals grown with 1.5% excess Te. Detector resolution of ⁵⁷Co and ²⁴¹Am radiation peaks are observed on all detectors except the ones produced on Cd_0.90Zn_0.10Te grown from the melt in the stoichiometric condition. The lack of resolution of these stoichiometric grown detectors is explained by a p/n conduction-type inhomogeneity model

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[en] This report presents analytical solutions of the dissolution and hydrogeologic transport of radionuclides in geologic repositories. Numerical examples are presented to demonstrate the equations resulting from these analyses. The subjects treated in this report are: solubility-limited transport with transverse dispersion (chapter 2); transport of a radionuclide chain with nonequilibrium chemical reactions (chapter 3); advective transport in a two-dimensional flow field (chapter 4); radionuclide transport in fractured media (chapter 5); a mathematical model for EPA's analysis of generic repositories (chapter 6); and dissolution of radionuclides from solid waste (chapter 7). Volume 2 contains chapters 5, 6, and 7

[en] This report presents analytical solutions of the dissolution and hydrogeologic transport of radionuclides in geologic repositories. Numerical examples are presented to demonstrate the equations resulting from these analyses. The subjects treated in this present report are: Solubility-limited transport with transverse dispersion (Chapter 2); Transport of a radionuclide chain with nonequilibrium chemical reactions (Chapter 3); Advective transport in a two-dimensional flow field (Chapter 4); Radionuclide transport in fractured media (Chapter 5); A mathematical model for EPA's analysis of generic repositories (Chapter 6); and Dissolution of radionuclides from solid waste (Chapter 7)

No abstract available

No abstract available

[en] Because the IEAR-1 reactor is old and it has been operating more and more for radioisotope production, an improvement program for its facilities was needed. Among others actions, a Continuous Vibration Monitoring System (CVMS) for the reactor rotating machines was installed. The present study objective was to establish a vibration monitoring strategy for the IEAR-1 reactor primary pumps, and to verify to what extent the strategy can be implemented by the CVMS. Three information sources were used to analyze the adequacy of some widely known vibration analysis techniques: historical data from the primary pumps monitoring, the experimental results from a mechanical defects simulation device and the specialized literature. The results showed that, although the CVMS seems to be enough for the fault detection of the selected defects, it is advisable to use an additional analysis for an earlier detection and a more precise diagnosis. A monitoring strategy was also established. (authors)

[en] Optical modulation response is used to study the influence of radiative, Shockley-Read-Hall, and Auger recombination processes on the minority carrier lifetime in a mid-wave infrared InAs/InAsSb superlattice. A comparison of calculated and measured temperature dependencies shows that the lifetime is influenced mainly by radiative recombination at low temperatures, resulting in an increase of the minority carrier lifetime from 1.8 μs at 77 K to 2.8 μs at 200 K. At temperatures above 200 K, Auger recombination increases rapidly and limits the lifetime. Shockley-Read-Hall limited lifetimes on the order of 10 μs are predicted for superlattices with lower background doping concentration

[en] Influence of proton radiation on the minority carrier lifetime and on carrier concentrations in InAs/InAsSb superlattices has been studied for radiation doses up to 300 krad. The lifetime decreased from 1.8 μs down to 430 ns as the dose was increased. A variation of the carrier concentration in the range 1–2 × 10"1"5 with increasing radiation dose was observed. The lifetime drop was however mainly caused by added Shockley-Read-Hall defects in the material. The position of these Shockley-Read-Hall centers was estimated to ∼60 meV below the conduction band edge from comparison between calculated and measured temperature dependencies of the minority carrier lifetime.