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Division Spotlight
Robotics & Remote Systems
The Mission of the Robotics and Remote Systems Division is to promote the development and application of immersive simulation, robotics, and remote systems for hazardous environments for the purpose of reducing hazardous exposure to individuals, reducing environmental hazards and reducing the cost of performing work.
Meeting Spotlight
Nuclear and Emerging Technologies for Space (NETS 2023)
May 7–11, 2023
Idaho Falls, ID|Snake River Event Center
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
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February 2023
Latest News
Donalds, Barnard call for streamlining NRC’s regulatory process
Barnard
Donalds
“To be frank, any emissions-related climate goals are moonshots without nuclear energy, and next-generation nuclear technology is something that the United States can and SHOULD lead on.” So writes U.S. Rep. Byron Donalds (R., Fla.) and Christopher Barnard, vice president of external affairs for the American Conservation Coalition, in an essay published by RealClear Energy.
Good news: Donalds, one of the strongest advocates for nuclear energy in the U.S. House, and Barnard, publisher and coauthor of Green Market Revolution, begin their essay by noting some recent positive developments for nuclear power. They characterize the initial criticality of Vogtle-3, the first new nuclear reactor built in the United States in about 30 years, as “a monumental achievement for the American nuclear industry.” They praise the Biden administration’s allocation of funds to keep established nuclear plants operational.
M. Chandra Kumar, A. Jasmin Sudha, V. Subramanian, S. Athmalingam, B. Venkatraman
Nuclear Science and Engineering | Volume 197 | Number 1 | January 2023 | Pages 132-143
Technical Paper | doi.org/10.1080/00295639.2022.2103338
Articles are hosted by Taylor and Francis Online.
Melting of the nuclear core is one of the severe accident scenarios in a Sodium-cooled Fast Reactor (SFR). During such an event, molten corium may come into contact with the coolant sodium. This interaction of the molten fuel and the coolant is commonly termed molten fuel–coolant interaction (MFCI) in the nuclear industry. In this study, a numerical analysis is carried out to study the solidification of a molten fuel droplet in the liquid sodium pool. In the first part of the study, the effect of constant internal heat generation on the solidification of the droplet is evaluated with convective heat dissipation prescribed at the droplet surface. The internal heat generation (decay power) and the heat transfer coefficient are varied as parameters, and the time required for complete solidification of the molten droplet is obtained. Based on the results, the freezing of the droplet is categorized into three regimes: conduction limited, transition, and internal heat generation dominated regimes. It is observed that the solidification process of nuclear fuel droplets generated during MFCI is not influenced by internal heat generation and lies in a conduction-limited regime for decay power level prevailing in a medium-sized SFR. Hence, in the next part of the study, the numerical analysis is carried out by incorporating the time-dependent decay power and the temperature-dependent heat transfer coefficient in the computational model by developing user-defined subroutines depicting a realistic scenario of an accident. The results of the analysis show that because of the high subcooling of sodium, film boiling is ruled out; nucleate boiling with a maximum heat transfer rate occurs briefly. The heat transfer coefficient then declines as the interface temperature between the droplet and the sodium decreases rapidly until the natural convective regime is reached. A parametric study on the droplet diameter is also carried out by varying the diameter from 0.5 to 10 mm, spanning the typical particle size spectrum expected during MFCI.
