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Isotopes & Radiation
Members are devoted to applying nuclear science and engineering technologies involving isotopes, radiation applications, and associated equipment in scientific research, development, and industrial processes. Their interests lie primarily in education, industrial uses, biology, medicine, and health physics. Division committees include Analytical Applications of Isotopes and Radiation, Biology and Medicine, Radiation Applications, Radiation Sources and Detection, and Thermal Power Sources.
Conference on Nuclear Training and Education: A Biennial International Forum (CONTE 2021)
February 9–11, 2021
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Nuclear Science and Engineering
Fusion Science and Technology
Notes on fusion
The ST25-HTS tokamak.
Governments around the world have been interested in fusion for more than 70 years. Fusion research was largely secret until 1968, when the Soviets unveiled exciting results from their tokamak (a magnetic confinement fusion device with a particular configuration that produces a toroidal plasma). The Soviets realized that tokamaks were not useful as weapons but could produce plasma in the million-degree temperature range to demonstrate Soviet scientific and technical prowess to the world.
Following this breakthrough, government laboratories around the world continued to pursue various methods of confining hot plasma to understand plasma physics under extreme conditions, getting closer and closer to the conditions necessary for fusion energy production. Tokamaks have been by far the most successful configuration. In the 1990s, the Tokamak Fusion Test Reactor at the Princeton Plasma Physics Laboratory produced 10 MW of fusion power using deuterium-tritium fusion. A few years later, the Joint European Torus (JET) in the United Kingdom increased that to 16 MW, getting close to breakeven using 24 MW of power to heat the plasma.
M. P. Sharma, A. K. Nayak
Nuclear Technology | Volume 197 | Number 2 | February 2017 | Pages 158-170
Technical Paper | dx.doi.org/10.13182/NT15-127
Articles are hosted by Taylor and Francis Online.
The Advanced Heavy Water Reactor (AHWR) is a vertical pressure tube–type, heavy water–moderated, and boiling light water–cooled natural-circulation–based reactor. The fuel bundle of AHWR contains 54 fuel rods arranged in three concentric rings of 12, 18, and 24 fuel rods. This fuel bundle is divided into a number of imaginary interacting flow passages called subchannels. Transition from a single-phase-flow condition to a two-phase-flow condition occurs in the reactor rod bundle with increase in power. Prediction of the thermal margin of the reactor has necessitated the determination of intersubchannel mixing due to void drift. Void drift is due to redistribution of the non-equilibrium void fraction to attain an equilibrium void fraction. This redistribution occurs in the reactor rod bundle until it reaches the state of equilibrium void fraction. Hence, it is vital to evaluate void drift between subchannels of AHWR rod bundles.
In this paper, experiments were carried out to investigate the void drift phenomena in simulated subchannels of AHWR. The size of the rod and the pitch in the test section were the same as those of the actual rod bundle in the prototype. Three subchannels are considered in 1/12th of the cross section of the rod bundle. Water and air were used as the working fluid, and the experiments were carried out at atmospheric condition without the addition of heat. The void fraction in the simulated subchannels was varied from 0 to 0.8 under various ranges of superficial liquid velocities. The void drift between the subchannels was measured. The test data were compared with existing models in the literature. It was found that the existing models could predict the measured equilibrium void fraction in the rod bundle of the reactor within the range +8% to −14%.