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Nuclear and Hydro Power
Published in Anco S. Blazev, Energy Security for The 21st Century, 2021
When many neutrons are absorbed by uranium-235 nuclei, a nuclear chain reaction occurs. If controlled, the reaction heats the liquid in the reactor, sending it as steam into the steam turbine where it generates electricity. The steam is then condensed in the cooling towers and sent back into the reactor to repeat the heating-steam-power generation cycle.
The Other Energy Markets
Published in Anco S. Blazev, Global Energy Market Trends, 2021
When many neutrons are absorbed by uranium-235 nuclei, a nuclear chain reaction occurs. If properly controlled, the reaction produces heat, which heats the liquid in the reactor, sending it as steam into the steam turbine where it generates electricity. The steam is then condensed in the cooling towers and sent back into the reactor to repeat the heating-steam-power generation cycle.
Thermal Energy Production in Nuclear Power Plants
Published in Robert E. Masterson, Nuclear Reactor Thermal Hydraulics, 2019
Control rods are made from materials such as boron and cadmium that absorb excess neutrons and make it easier to control the nuclear chain reaction. Control rods change the power profile in both the radial and axial directions, and they tend to depress the power generation rate in their immediate vicinity. This effect is illustrated for a single control rod in Figure 5.29. Hence, the core power profile returns to its original shape as soon as a control rod is withdrawn. Reactors contain literally hundreds of control rods, and the control rods are placed strategically throughout the core to assist with power control. In most commercial PWRs, one out of every four fuel assemblies contains a cluster of control rods, which is sometimes called a control rod bank. In BWRs, larger cruciform-shaped control rods are surrounded by four fuel assemblies. The placement of these control rods is shown in Figure 5.40.
Improved Disposition of Surplus Weapons-Grade Plutonium Using a Metallic Pu-Zr Fuel Design
Published in Nuclear Technology, 2023
Braden Goddard, Aaron Totemeier
The criticality of the fuel is a fundamental indicator if there is sufficient fissile material to sustain the nuclear chain reaction throughout the fuel’s life. To determine the amount of plutonium needed to replace a uranium fuel rod, k-code MCNP simulations were performed. Figure 2 shows the k∞ value of the modeled MOX fuel rods over their 3-year (44 000 MWd/tonne HM) lifespan in the core. The end-of-life k∞ value should be near 1, indicating that the fuel rod has the minimum reactivity to maintain the neutron chain reaction. Values slightly below 1 are also acceptable since the surrounding fuel rods and assemblies may have noticeably less burnup, thus effecting the core average burnup. The k∞ value shown in this research does not account for the neutron absorption of structural components, such as grid spacers.
The ingredients of a successful atomic exhibition in Cold War Italy
Published in Annals of Science, 2023
At the exhibition’s opening in Rome, U.S. ambassador Luce acknowledged ‘the immense contribution made by the Italian genius in the field of nuclear studies’, as reported by a newspaper (Il Popolo 1954). No name was mentioned, but it must have been clear to everybody that Luce referred to nuclear physicist Enrico Fermi (1901–54) and his group.45 Fermi had been awarded the Nobel Prize in 1938 and emigrated to the U.S. immediately after receiving the award to protect his family from racial persecution in Fascist Italy, as his wife was Jewish. In December 1942, Fermi’s lab in Chicago had produced the first self-sustaining nuclear chain reaction, an experiment that contributed decisively to the construction of the atomic bomb. Fermi had been part of the Manhattan Project, member of the General Advisory Committee of the Atomic Energy Commission (1947–50), and President of the American Physical Society (1953–54) (Bonolis 2004; Maltese 2003, XVII-XXII).
Extraction of cerium(III) with N, N′-dimethyl-N, N′-dioctyl-diglycolamide in [Bmim][PF6] compared in 40% octanol/kerosene
Published in Journal of Nuclear Science and Technology, 2019
Meng Zhang, Yu Du, Guoxin Tian, Yu Zhou, Yang Gao, Hongguo Hou, Zhi Zhang, Chunhui Li, Liman Chen, Zhenyu Han
Nuclear waste is one of the most important concerns about the rapidly increasing utilization of nuclear energy. The major high-level radioactive nuclear waste is generated from spent nuclear fuel reprocessing. Typical spent nuclear fuel discharged from light water cooled reactors consists of mainly unused uranium (~96%), fission products (3%), plutonium (1%), and very small amount of minor actinides (Ans). Among the fission products, lanthanides (Lns) are a major component and a very harmful neutron poison, and their accumulation in nuclear fuel interferes with the nuclear chain reaction. The minor actinides contribute to long-term radiotoxicity of nuclear waste. The development of advanced nuclear fuel recycling would improve the utilization of the limited uranium resource by recovering the unused uranium and the by-produced plutonium to make new fuel. Furthermore, the separation of Lns and Ans would reduce the volume and toxicity of the nuclear waste and save the very costly capacity of geological repository [1].