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Division Spotlight
Fusion Energy
This division promotes the development and timely introduction of fusion energy as a sustainable energy source with favorable economic, environmental, and safety attributes. The division cooperates with other organizations on common issues of multidisciplinary fusion science and technology, conducts professional meetings, and disseminates technical information in support of these goals. Members focus on the assessment and resolution of critical developmental issues for practical fusion energy applications.
Meeting Spotlight
International Conference on Mathematics and Computational Methods Applied to Nuclear Science and Engineering (M&C 2025)
April 27–30, 2025
Denver, CO|The Westin Denver Downtown
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
May 2025
Nuclear Technology
Fusion Science and Technology
Latest News
TerraPower begins U.K. regulatory approval process
Seattle-based TerraPower signaled its interest this week in building its Natrium small modular reactor in the United Kingdom, the company announced.
TerraPower sent a letter to the U.K.’s Department for Energy Security and Net Zero, formally establishing its intention to enter the U.K. generic design assessment (GDA) process. This is TerraPower’s first step in deployment of its Natrium technology—a 345-MW sodium fast reactor coupled with a molten salt energy storage unit—on the international stage.
Guanyi Wang, Yikuan Yan, Shanbin Shi, Zhuoran Dang, Xiaohong Yang, Mamoru Ishii
Nuclear Technology | Volume 205 | Number 1 | January-February 2019 | Pages 297-306
Technical Paper | doi.org/10.1080/00295450.2018.1493317
Articles are hosted by Taylor and Francis Online.
As one of the future directions of nuclear energy development, small modular reactor (SMR) designs meet the demands of safety, sustainability, and efficiency by eliminating circulating pumps and using natural circulation–driven flows to transfer fission energy to power. However, natural circulation–driven flows could be affected by two-phase-flow instability that may occur during accidental scenarios of pressurized water reactor (PWR)-type SMRs due to relatively small driving force. In view of the influence of two-phase-flow instability during accident transients for a PWR-type SMR, experiments are performed in a well-scaled test facility to investigate potential thermal-hydraulic flow instabilities during blowdown events. The test facility has a height of 3.44 m, and the operating pressure limit is 1.0 MPa. The scaling analyses ensure that the scaled phenomena, i.e., depressurization of the reactor pressure vessel (RPV) and emergency core cooling system valve actuation, could be accurately simulated in the test facility. Important thermal-hydraulic parameters including RPV pressure, containment pressure, local void fraction and temperature, pressure drop, and natural circulation flow rate are measured and analyzed during the blowdown events. Test results show that throughout the experiment the liquid level is always maintained above the heated core and the RPV pressure decreases. Oscillations of the natural circulation flow rate, water level, and pressure drop are observed during blowdown transients. Specific reasons for and mechanisms of the observed instability phenomena are discussed.
