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Nuclear Energy Conference & Expo (NECX)
September 8–11, 2025
Atlanta, GA|Atlanta Marriott Marquis
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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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Powering the future: How the DOE is fueling nuclear fuel cycle research and development
As global interest in nuclear energy surges, the United States must remain at the forefront of research and development to ensure national energy security, advance nuclear technologies, and promote international cooperation on safety and nonproliferation. A crucial step in achieving this is analyzing how funding and resources are allocated to better understand how to direct future research and development. The Department of Energy has spearheaded this effort by funding hundreds of research projects across the country through the Nuclear Energy University Program (NEUP). This initiative has empowered dozens of universities to collaborate toward a nuclear-friendly future.
S. Y. Jiang, X. X. Wu, Y. J. Zhang
Nuclear Science and Engineering | Volume 135 | Number 2 | June 2000 | Pages 177-189
Technical Paper | doi.org/10.13182/NSE00-A2133
Articles are hosted by Taylor and Francis Online.
The experiment was performed on the test loop HRTL-5, which simulates the geometry and system design of the 5-MW nuclear heating reactor developed by the Institute of Nuclear Energy Technology, Tsinghua University. The flow behavior for a wide range of inlet subcoolings, in which the flow experience varies from single- to two-phase, is described in a natural circulation system at different pressures (p = 0.1, 0.24, and 1.5 MPa). Several kinds of flow instability are investigated, including geysering, flashing-related flow instability, and high-frequency flow oscillation at p = 0.1 and 0.24 MPa, as well as low steam quality density wave oscillation at p = 1.5 MPa. The mechanisms of geysering, which has new features, and flashing-related flow instability, which has never been studied well enough in this field, are particularly interpreted. The experimental results show the following: First, for a low-pressure natural circulation system, the two-phase flow is unstable in most inlet subcooling conditions, and the two-phase stable flow can be reached only with very low inlet subcoolings. Second, at high inlet subcoolings, the flow instability is dominated by subcooling boiling in the heated section, and at intermediate inlet subcoolings, it is dominated by void flashing in the adiabatic long riser. Third, in the two-phase stable flow region, the conditions for boiling out of the core, namely, single-phase flow in the heated section and two-phase flow in the riser due to vapor flashing, can be realized. The experimental results are of significance for the design and accident analysis of vessel and swimming pool-type natural circulation nuclear heating reactors.