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Introduction to Electric Motors
Published in Wei Tong, Mechanical Design and Manufacturing of Electric Motors, 2022
Nuclear radiation, also known as ionizing radiation, is defined as energy transmission through certain kinds of ionizing particles and photons during nuclear reactions. Nuclear radiation includes α-rays, β-rays, x-rays, and the more energetic portion of the electromagnetic spectrum. Electric servomotors and drives used in nuclear power plants are subjected to nuclear radiation, high temperature, and high humidity. These severe environmental conditions can degrade the performance of the servo system in different ways: (a) The radiation with high-energy particles can demagnetize PMs in the motor [1.101, 1.102]. (b) Ionizing radiation can break down materials within electrical equipment (e.g., motors switches, incandescent lights, wiring, and solenoids). For instance, when wiring is exposed to γ-rays, no change is noticed until the wiring is flexed or bent. The wire’s insulation becomes brittle and may cause short circuits in the equipment [1.103]. (c) The gamma and neutron radiation can cause extensive damage to integrated circuit devices [1.104]. (d) Aging mechanisms could significantly affect electric motors/components. Under a nuclear radiation condition, aging effects are most commonly due to radiation exposure and heat, as well as other phenomena such as mechanical vibration and chemical degradation.
Nuclear and Hydro Power
Published in Anco S. Blazev, Energy Security for The 21st Century, 2021
Neutron radiation arises from nuclear fission, such as the fission of U-235, which produces 2 or 3 neutrons each with several MeV of power. Since the protons have no charge, they pass through matter, unless they collide with other nucleus.
The Other Energy Sources
Published in Anco S. Blazev, Power Generation and the Environment, 2021
Neutron radiation arises from nuclear fission, such as the fission of U-235, which produces 2 or 3 neutrons each with several MeV. Since the protons have no charge, they pass through matter, unless they collide with other nuclei. If they strike a proton, such as a hydrogen ion, the energy is equally shared. If a neutron strikes heavy nuclei it may be deflected with little energy loss, or it may be absorbed and incorporated into the heavier nuclei, as in the collision with a U-238 nuclei: −238U+neutron=−239U
Overview of biological mechanisms of human carcinogens
Published in Journal of Toxicology and Environmental Health, Part B, 2019
Nicholas Birkett, Mustafa Al-Zoughool, Michael Bird, Robert A. Baan, Jan Zielinski, Daniel Krewski
The general mechanisms by which neutron radiation is carcinogenic are similar to those described above. Neutrons are electrically neutral and interact with the body predominantly through interactions with atomic nuclei. This leads to molecular damage being clustered in space, which was suggested to decrease the effectiveness of DNA repair. According to the Monograph there is inadequate evidence that neutron radiation is carcinogenic to humans, due to lack of data on human exposure to ‘pure’ neutrons, which is extremely rare. The classification of neutron radiation as a Group-1 human carcinogen was based predominantly upon data from animal investigations (sufficient evidence in animals) and on similarities with X- and γ-radiation with respect to biological effects and physical properties.
Experimental study of pulse neutron irradiation damage in SiGe HBT
Published in Journal of Nuclear Science and Technology, 2018
Olarewaju Mubashiru Lawal, Zhuoqi Li, Shuhuan Liu, Aqil Hussain, JiangKun Yang, Hongchao Zhao, Cen Xiong
Silicon germanium hetero-junction bipolar transistors (SiGe HBTs) are important semiconductor devices in modern electronic circuits [1]. SiGe HBT technology has garnered significant attention in the commercial and government sectors due to its ability to leverage the superior current drive, low-noise performance, and device-matching characteristics with low-cost silicon manufacturing into a single SiGe BiCMOS platform [2]. However, the electronic systems that operate in space radiation environment are inevitably affected by radiation damage (RD) [3]. The neutron radiation emitted from nuclear reactions such as particle interactions with cosmic rays or within nuclear reactors threatens the electronic systems. Just like other charged particles such as protons and electrons, neutron does not ionize atoms directly because neutrons have no charge, but induced RD in SiGe HBTs.