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Division Spotlight
Thermal Hydraulics
The division provides a forum for focused technical dialogue on thermal hydraulic technology in the nuclear industry. Specifically, this will include heat transfer and fluid mechanics involved in the utilization of nuclear energy. It is intended to attract the highest quality of theoretical and experimental work to ANS, including research on basic phenomena and application to nuclear system design.
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Utility Working Conference and Vendor Technology Expo (UWC 2024)
August 4–7, 2024
Marco Island, FL|JW Marriott Marco Island
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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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Latest News
Vogtle-3 shuts down for valve issue
One of the new Vogtle units in Georgia was shut down unexpectedly on Monday last week for a valve issue that has since been investigated and repaired. According to multiple local news outlets, Georgia Power reported on July 17 that Unit 3 was back in service.
Southern Company spokesperson Jacob Hawkins confirmed that Vogtle-3 went off line at 9:25 p.m. local time on July 8 “due to lowering water levels in the steam generators caused by a valve issue on one of the three main feedwater pumps.”
Isao Murata, Shigeo Yoshida, Akito Takahashi
Fusion Science and Technology | Volume 36 | Number 2 | September 1999 | Pages 181-193
Technical Paper | doi.org/10.13182/FST99-A101
Articles are hosted by Taylor and Francis Online.
Heavy concrete is a promising candidate material for a fusion reactor shield. It provides strong shielding performance, though it has a heterogeneous structure due to random arrangement of the heavy aggregates contained as absorbers. To obtain data for future fusion reactor shield designs, D-T neutron irradiation experiments using both heterogeneous and homogeneous heavy concrete samples were carried out to investigate how much the heterogeneity due to the aggregates affects shield performance. Leakage neutron spectra and reaction rates of activation foils were measured, and they were compared with the analyses by the Monte Carlo code MCNP-CFP. From the comparison of results, the measured heterogeneity effect was well reproduced by MCNP-CFP, though there was a slight disagreement in the thermal region. For a point neutron source, a heterogeneous shield was found to be advantageous compared with a homogeneous one from the standpoint of shielding performance above 1 MeV. This conclusion was exactly opposite to what was anticipated. Analysis of the results confirmed that the effect was strongly associated with the manufacturing process used for the heavy concrete. For thermal neutrons, a homogeneous shield is still regarded to be most preferable. To suppress the heterogeneity effect above 1 MeV, it is necessary to use a sufficiently large heavy concrete shield. Then analysis with a conventional calculation method is feasible except for the thermal neutron region. If a smaller shield is employed, a specialized Monte Carlo code with a heterogeneous treatment like MCNP-CFP should be used for the precise analysis.