[en] The article presents information about irradiation basis for radiation material science at the IR-8 reactor. It is shown that the results of neutron-physical, thermophysical and strength calculations allowed justifying the possibility of testing structural materials in IR-8 reactor at given parameters

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[en] The residential amount(s) of fissionable materials remaining in process equipment after the runout of bulk materials processed is referred to as ''Process Holdup of Special Nuclear Materials.'' Locating regions of holdup and estimating the quantity of fissile materials remaining as holdup are important not only to materials accountability but also to process safety. Holdup is often referred to as a ''Hidden Inventory.'' In materials accounting terminology, hidden inventories are part of ''Materials Unaccounted For'' (MUF) or ''Inventory Difference'' (ID). MUF or ID could be construed as ''Loss'' or ''Diversion''. From a safeguards perspective, all these designations are undesirable. Another terminology that is relevant to holdup is ''In-Process Inventory.'' During process operations and temporary shutdown, the holdup within the facility is also known as the in-process inventory. Estimating this inventory is just as challenging as residuals after process runout. The role of hidden inventories, or holdup, as a safeguards problem is now recognized by almost everyone interested in establishing effective safeguards for special nuclear materials. As part of this effort to organize the first INMM-sponsored Technical Workshop on Process Holdup of Special Nuclear Materials, an attempt was made to update an earlier survey of open literature publications of relevance to holdup. An attempt was made to exclude from this list those documents recognized as internal documents, progress reports, preliminary reports, abstracts, etc

[en] The results of a physical inventory at a reference bulk materials handling facility (described in the appendix) are evaluated and the materials balance and the material unaccounted for (MUF) obtained. The uncertainty associated with MUF and its importance are explained. The procedures needed to determine whether the MUF indicates a real loss of greater than a given magnitude has occurred, or whether it is more reasonable to conclude that no loss has occurred, are described. 5 refs., 3 figs., 10 tabs

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[en] The United States Nuclear Regulatory Commission requires licensees who process special nuclear material (SNM) of strategic significance to monitor processes per 10 CFR Part 74.53. The main purpose of process monitoring is to have a program capable of detecting an abrupt loss of five formula kilograms of SNM within a specified time limit. Process monitoring of Babcock and Wilcox's (B and W) uranium extraction process is a challenge since it is a continuous process. Uranium is purified and concentrated by processing uranium feed solutions through a series of aqueous and organic stages. Effective monitoring of this continuous process requires measuring total input and output within a specified time segment, and taking discreet measurements of in-process material. Several subprocesses in the system do not lend itself readily to in-process measurements, and an estimate must be calculated. To be able to detect an abrupt loss, measurements of input, output and in-process must be accomplished. B and W effectively performs process monitoring of this continuous process using discreet

[en] Metal matrix composites, (MMC), are engineered combinations of two or more materials (one of which is a metal) in which tailored properties are achieved by systematic combinations consisting of continuous or discontinuous fibers, whiskers, or particles in a metal result in combinations of very high specific strength. Furthermore, systematic design and procedures can be developed to achieve unique combinations of engineering properties such as high elevated-temperature strengths, damping or electrical properties. In this paper, the theory and practice of MMC are reviewed and discussed. The different techniques used in the manufacturing of MMC in general and aluminum matrix composites in particular e.g. unidirectional solidification, squeeze casting, vortex method and compocasting are presented and discussed. The parameters involved in these techniques and their effects on the characteristics of MMC product are also given and discussed. These include: crucible size and shape, melt temperature, size and shape of the impeller, stirring speed, rate of addition of the particles, the degree of agitation and cooling rate. Furthermore, the effect of these parameters on the mechanical strength and machinability are also presented and discussed. Finally, recent research results in aluminum matrix composites and their future developments are outlined and discussed. (author)

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[en] The objective of this project is to describe the impact that NDA measurements have on the material balance evaluation and the determination of MUF.