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Division Spotlight
Fuel Cycle & Waste Management
Devoted to all aspects of the nuclear fuel cycle including waste management, worldwide. Division specific areas of interest and involvement include uranium conversion and enrichment; fuel fabrication, management (in-core and ex-core) and recycle; transportation; safeguards; high-level, low-level and mixed waste management and disposal; public policy and program management; decontamination and decommissioning environmental restoration; and excess weapons materials disposition.
Meeting Spotlight
Utility Working Conference and Vendor Technology Expo (UWC 2024)
August 4–7, 2024
Marco Island, FL|JW Marriott Marco Island
Standards Program
The Standards Committee is responsible for the development and maintenance of voluntary consensus standards that address the design, analysis, and operation of components, systems, and facilities related to the application of nuclear science and technology. Find out What’s New, check out the Standards Store, or Get Involved today!
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Nuclear Science and Engineering
August 2024
Nuclear Technology
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Latest News
Four million nuclear jobs by 2050: Who will do them?
Industry leaders from around the globe met this month to discuss the talent development that will be necessary for the long-term success of the nuclear industry.
The International Conference on Nuclear Knowledge Management and Human Resources Development, hosted by the International Atomic Energy Agency, was held in Vienna earlier this month. Discussed there was the agency’s forecast for nuclear capacity to more than double—or hopefully triple—by 2050 and the requirement of more than four million professionals to support the industry.
Robert V. Strain, Lawrence A. Neimark, John E. Sanecki
Nuclear Technology | Volume 87 | Number 1 | August 1989 | Pages 187-190
Technical Paper | TMI-2: Materials Behavior / Nuclear Safety | doi.org/10.13182/NT89-A27645
Articles are hosted by Taylor and Francis Online.
Detailed microstructural and microchemical examinations of samples of debris extracted from the lower plenum region of the Three Mile Island Unit 2 reactor were performed using optical and electron-beam instrument microscopy. Results of this study indicate that this material was a previously molten ceramic consisting primarily of UO2 and ZrO2 with smaller amounts of iron, chromium, nickel, and aluminum present also as oxides. The microstructures of the samples were typical of cast multicomponent materials, i.e., rounded grains with additional phases in the grain boundaries. In most cases, the primary grains appeared to be singlephase material as would be expected if a UO2-ZrO2 solid solution were rapidly cooled from the liquid state. However, portions of these grains showed indications of segregation into two distinct phases, and in some areas the whole grains were segregated into two phases. The segregated grains are indicative of a slower cooling rate for part of the material. In addition to the primary urania-zirconia grains, there were large areas of eutectic structure in some of the samples. One of the phases in the eutectic structure consisted of iron and chromium with small amounts of aluminum and nickel, all as oxides. This material was also present in many grain boundaries in the primary grain structure. The grain boundary phase could have a solidus temperature as low as ∼1600K. This low melting point compared to the bulk of the material has led to speculation that the grain boundaries may have remained liquid after the grains themselves had solidified. This would allow the material to flow like wet sand through the structure above the lower plenum at temperatures near or possibly below the melting point of stainless steel (1670 K). At these temperatures, the moving mass would not have severely melted the stainless steel structure near the bottom of the vessel.