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Conference Spotlight
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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DOE issues new NEPA rule and procedures—and accelerates DOME reactor testing
Meeting a deadline set in President Trump’s May 23 executive order “Reforming Nuclear Reactor Testing at the Department of Energy,” the DOE on June 30 updated information on its National Environmental Policy Act (NEPA) rulemaking and implementation procedures and published on its website an interim final rule that rescinds existing regulations alongside new implementing procedures.
Sang-Nyung Kim, Byung-Marn Koh, Joon-Suk Ji
Nuclear Technology | Volume 153 | Number 3 | March 2006 | Pages 304-314
Technical Paper | Thermal Hydraulics | doi.org/10.13182/NT06-A3709
Articles are hosted by Taylor and Francis Online.
When reactivity insertion such as refueling occurs in Canada deuterium uranium (CANDU) reactors, the power and the water level are tilted in the upper outer zone of the liquid zone control system (LZCS) and fluctuate unstably for a certain period of time (1 to 5 days). Such instability is observed in most of the CANDU reactors in service around the world, but neither its root cause has been identified nor have solutions against it been established. Therefore, this study experimentally and analytically attempted to prove that the root cause lies in the holdup of light water on the top of the tube support plate (TSP) due to the mismatch between the net volumetric flow rate of light water and helium crossing the narrowed porous TSP installed within the LZCS compartment by performing hydrodynamic simulation of the inflow/outflow of light water and helium. Two solutions against the aforementioned instability of LZCS were suggested. One is to regulate volumes of helium gas flowing into the compartment and light water flowing therefrom, and the other is to enlarge the flowing paths of helium and light water within the TSP. The former may be applicable to nuclear reactors in service and the latter to those planned to be constructed.