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Nuclear Criticality Safety
NCSD provides communication among nuclear criticality safety professionals through the development of standards, the evolution of training methods and materials, the presentation of technical data and procedures, and the creation of specialty publications. In these ways, the division furthers the exchange of technical information on nuclear criticality safety with the ultimate goal of promoting the safe handling of fissionable materials outside reactors.
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ANS Student Conference 2025
April 3–5, 2025
Albuquerque, NM|The University of New Mexico
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Latest News
First astatine-labeled compound shipped in the U.S.
The Department of Energy’s National Isotope Development Center (NIDC) on March 31 announced the successful long-distance shipment in the United States of a biologically active compound labeled with the medical radioisotope astatine-211 (At-211). Because previous shipments have included only the “bare” isotope, the NIDC has described the development as “unleashing medical innovation.”
Chiaki Kino, Yoshihiro Morita, Masao Chaki (The Inst of Applied Energy)
Proceedings | Advances in Thermal Hydraulics 2018 | Orlando, FL, November 11-15, 2018 | Pages 201-211
Reactor core isolation cooling system (RCIC) is designed to operate using saturated steam extracted from a main steam line. On the other hand, RCIC in Unit-2 of Fukushima Daiichi Nuclear Power Plant was activated before the tsunami hit and continued to operate under two phase flow conditions during the accident. When RCIC continuously operates without control by electric power, reactor water level would reach the main steam line resulting in turbine efficiency degradation and subsequent RCIC stop. The mechanism for RCIC of Unit-2 to have continuously operated under such two phase flow conditions is still unclear. Currently, a project is progressing to understand the true operating limitations of RCIC system under beyond design basis event. The Institute of Applied Energy is developing the new RCIC system model for the SAMPSON code in the project. The present paper proposes a trial model for RCIC system under two phase flow conditions. The model takes the effect of quality and pressure on turbine efficiency into consideration. SAMPSON calculation based on the model could reproduce qualitatively RPV pressure behavior of Fukushima Daiichi Unit-2 accident. However there are many uncertainties, such as water temperature of S/P, isentropic efficiency, and so on, so the model will be improved based on experiment and CFD results planned in the project.