This chapter takes a more detailed examination of the theory behind the behavior of neutrons in a reactor. The steady-state one-speed diffusion equation is derived from a neutron balance and the incorporation of Fick’s law. Solutions to the diffusion equation provide the geometric buckling from which the neutron nonleakage probability for a particular reactor shape is quantified. By defining a neutron migration area, modified one-group diffusion theory is realized. The heterogeneous nature of most reactors magnifies most of the four-factor formula parameters, thereby enhancing criticality. Multigroup theory is introduced and the interrelationship between the two-group variant and the four-factor formula parameters is explained.

This chapter attempts to concisely describe the role that nuclear power may take in the meeting the world’s future energy needs. Historically, economic considerations have triumphed all other considerations when selecting an energy source. Nuclear power growth stagnated in the late twentieth century for a variety of reasons. A revival in nuclear reactor construction is beginning in the United States and elsewhere at the start of the twenty-first century. World energy—and especially electricity—use is increasing and sustainable approaches to meeting this need are sought. With rising concern about climate change, nuclear power is found to be the lowest contributor to carbon dioxide emissions, even compared to solar and wind power. Besides electricity generation, power reactors can be utilized for large-scale desalination and hydrogen generation.

Marine reactors have been applied to floating nuclear power plants, naval vessels such as submarines, and civilian ships such as icebreakers. Nuclear-powered shipping is gaining increased interest because of decarbonization goals motivated by climate change. Enhanced reactor safety can potentially reduce regulatory and liability challenges to the adoption of nuclear propulsion systems for merchant ships. This gives strong impetus for reviewing past use of nuclear reactor systems in marine environments, especially from the perspective of any accident scenarios, lest planners be caught unaware of historical incidents. To that end, a loss of coolant accident (LOCA) in a Lenin icebreaker reactor in 1965 and disposal at sea of some of its damaged fuel and reactor vessel as well as the entire tri-reactor compartment is recounted.

In this work, an analysis of total ionizing dose (TID) effects in metal-nitride-oxide-semiconductors (MNOSs) was performed using electrical characterization and electron holography. Technology computer-aided design (TCAD) simulations were also performed to reproduce the holography findings. By matching the simulation results with electron holography data and capacitance-voltage (CV) measurement results, the distributions of holes and electrons in the nitride and oxide film are extracted. Close matching between the experimental data and simulation results establishes that charge buildup within the dielectric layers after irradiation can be directly imaged and quantified. Electron and hole trapping in the nitride layer near the SiO2/Si3N4 interface, identified using the holography measurements, is also shown to be consistent with models presented in previous studies.

The ability to directly image charge accumulation in the irradiated oxide film of the metal-oxide-semiconductor capacitor is demonstrated using the electron holography technique. Capacitors with 100 nm thickness of oxide film are fabricated and irradiated using a 60 Co gamma source to a target total dose of 450 krad(SiO 2 ). Electric and materials analyses are performed before and after irradiation to study the total ionizing dose (TID) effect. The observed leftward shift in the capacitance-voltage (C-V) curve and a larger potential drop near the Si/SiO 2 interface mapped by electron holography indicate charge buildup at the irradiated oxide layer. Technology computer-aided design simulations are performed to analyze and validate the electrostatic potential data from holography, and also quantify the charge distributions across the oxide layer for both pre- and post-irradiated devices. A larger amount of positive volumetric charges is added near the oxide/silicon interface for the irradiated sample in order to fit both C-V measurement data and electron holography profiles. The good matching between the experimental and simulation results shows evidence that electron holography provides the ability to directly image the charge accumulation at the irradiated oxide layer due to TID effects.

The results of total ionizing dose (TID) experiments on fully depleted silicon-on-insulator (FDSOI) static random access memory (SRAM) are presented. Using 60Co gamma irradiation, tests were conducted at multiple voltages and with and without read and write assists. The results demonstrate cell stability past 200 krad(Si) TID in standard operational modes. The impact of read and write assists and read timing via margin mode tests are examined. We also report input–output (IO)-level translation circuit failures, as well as anomalous circuit failures attributable to IO at relatively low TID dose. Finally, we show post-TID anneal and low-voltage SRAM results.

Total ionizing dose (TID) has a significant effect on silicon on insulator circuits, manifest primarily as a front gate threshold voltage (V textsubscript t) shift. This paper presents a simple ring oscillator (RO) test structure that is amenable to packaging and gamma irradiation. RO current and frequency changes due to TID are experimentally measured in-situ. The RO responses are then used to extract the transistor level ${\mathrm{ V}}_{\mathrm{ t}}$ shifts using an optimization approach. Since the optimization uses the actual circuits, the resulting ${\mathrm{ V}}_{\mathrm{ t}}$ shifts may be directly applied to post TID modeling of circuit behavior. The approach simplifies the effort for design and testing to determine TID degradation. The test chip fabricated and measured for this work is implemented on a 22 nm fully depleted silicon on insulator (FDSOI) with thin oxides. The approach is, however, applicable to any fabrication process. Finally, we show the extracted ${\mathrm{ V}}_{\mathrm{ t}}$ changes due to TID vary with the transistor ${\mathrm{ V}}_{\mathrm{ t}}$ (doping and well type).

The changes caused by total ionizing dose (TID) in the conductance of the analog response of Ag-Ge30Se70 conductive bridge random access memory (CBRAM) based synapses are studied. The conductance was seen to be severely affected by 60Co gamma ray exposure. The devices were tested up to a TID of 1 Mrad(Ge30Se70). Scanning electron microscopy imaging supports the conclusion that the device degradation is due to loss of filament contact after irradiation. The effect of irradiation was further analyzed by simulating the devices in an artificial neural network. The training accuracy was seen to degrade from 85% to 15% with increasing TID levels.

With a considerable shift toward integrated generation within the electrical distribution network, a Distributed Energy Resource Management System (DERMS) is a solution that can integrate the two-way interactions between the network and the end users. A DERMS solution will assist in modernizing the electric distribution system that should be safe, reliable, and affordable. In this paper we examine the reason peak demand adversely affects the grid and explain how both the customer and utility can benefit from our solution. Once background knowledge and context have been established, then the proposed DERMS design is introduced as a viable solution that can integrate seamlessly into the grid. Additionally, we analyze the technological, regulatory, environmental, and economic implications of the solution to demonstrate its effectiveness in mitigating peak demand issues.

Total ionizing dose (TID) has a significant effect on silicon-on-insulator (SOI) circuits, manifesting primarily as a front-gate threshold voltage ( $V_{t}$ ) shift. This article presents data on ring oscillator (RO) responses of 22-nm fully depleted (FD-SOI) thin oxide (core logic) devices to gamma-ray doses above 1 Mrad(Si). We show large current and frequency TID response differences between ROs comprised of different logic gates. Moreover, the extensive experimental results presented here show that these responses vary significantly with $V_{t}$ and well type. The measurements show that depending on the expected dose and transistor $V_{t}$ used, TID-induced standby current ( $I_{\mathrm {SB}}$ ) increases may have a substantial impact on overall power in spaceborne integrated circuits (ICs) using this fabrication process. The TID impact on digital circuit timing margins is also discussed.

Atmospheric nitrous oxide (N 2 O) is a potent greenhouse gas thought to be mainly derived from microbial metabolism as part of the denitrification pathway. Here, we report that in unexplored peat soils of Central and South America, N 2 O production can be driven by abiotic reactions (≤ 98 %) highly competitive to their enzymatic counterparts. Extracted soil iron positively correlated with in-situ abiotic N 2 O production determined by isotopic tracers. Moreover, we found that microbial N 2 O reduction accompanied abiotic production, essentially closing a coupled abiotic-biotic N 2 O cycle. Anaerobic N 2 O consumption occurred ubiquitously (pH 6.4-3.7), with proportions of diverse clade II N 2 O-reducers increasing with consumption rates. Our findings show denitrification in tropical peat soils is not a purely biological process, but rather a “mosaic” of abiotic and biotic reduction reactions. We predict hydrological and temperature fluctuations differentially affect abiotic and biotic drivers and further contribute to the high N 2 O flux variation in the region.

The minimum mass for a critical reactor is well studied whereas the minimum heat production from a nuclear reactor has received little attention. The thermal power of a (sub)critical reactor originates from fission as well as radioactive decay. Fission includes neutron-induced and spontaneous fission. For an idealized critical core, we find that the minimum theoretical power is ER/Λ, whereas for a subcritical reactor comprising fissionable material undergoing spontaneous fission, the minimum power is dictated by subcritical multiplication. Interestingly, radioisotopic heat generation exceeds the minimum theoretical fission power for most of the fissile materials examined in this study.

Emerging nonvolatile memories (eNVMs) have demonstrated satisfactory accuracy on various applications in deep learning. Characterized by high density and low leakage power consumption, resistive random access memory (RRAM) becomes very attractive in synaptic devices for deep neural networks (DNNs). RRAM-based synaptic devices include both analog and discrete versions. Unlike analog RRAM synapses which suffer from nonlinearity, discrete but multistate RRAM synapses are better suited for neural network hardware implementation. In this article, the multistate operation in RRAM arrays has been proposed as a synaptic device for DNN inference. Four-state conductance has been achieved in HfO x -based RRAM synaptic arrays. The impact of total ionizing dose (TID) on the multistate behavior of HfO x -based RRAM is investigated by irradiating a one-transistor-one-resistor (1T1R) 64-kb array with CMOS peripheral decoding circuitry fabricated at the 90-nm technology node with Co-60 gamma rays ( 60 Co γ-ray irradiation).

Handbook of Renewable Energy Technology, pp. 225-246 (2011) No AccessSolar Thermal Electric Power PlantsKeith E. HolbertKeith E. HolbertSchool of Electrical Computer and Energy Engineering, Arizona State University, P.O. Box 875706, Tempe, AZ 85287-5706, USAhttps://doi.org/10.1142/9789814289078_0010Cited by:0 PreviousNext AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack CitationsRecommend to Library ShareShare onFacebookTwitterLinked InRedditEmail Abstract: Concentrating solar power appears to be the method of choice for large capacity, utility-scale electric generation in the near term. In particular, distributed trough systems represent a reasonably mature approach, and the power tower configuration is also a viable candidate. Both of these technologies have the possibility of energy storage and auxiliary heat production during sunlight unavailability. Other systems examined in this chapter include dish-Stirling engines, solar chimneys and solar ponds. Economics inevitably drives the choice of technology. FiguresReferencesRelatedDetails Handbook of Renewable Energy TechnologyMetrics History PDF download

Greenhouse gas emissions from fossil power plants contribute significantly toward climate change. Simultaneously, the increase in ambient air and water temperatures reduces thermal power generation. Coal, nuclear and natural gas plants experience a 0.25%-0.72% reduction in power output for a 1°C increase in the ambient temperature. As ambient temperatures increase, generation losses from coal, nuclear and natural gas together are predicted to increase at an average rate of around 700 GWh/y. At this rate, average annual generation losses could add up to around 29 TWh for coal, nuclear and natural gas combined in 2050. Approximately ten additional 600 MW power plants might be needed to replace this lost electricity by 2050. Concurrently, average losses in generation income could total $1400 million for these thermal plants in 2050. Changes in solar and hydro power are also briefly compared. Finally, the importance of water availability and the effects of extreme climate events on thermal power plants are discussed.

Total ionizing dose response of 14-nm bulk-Si FinFETs has been studied with a specially designed test chip. The radiation testing shows evidence of interface trap build-up on 14-nm Bulk FinFET technologies. These defects created in the isolation layer give rise to a new radiation-induced leakage path which might lead to a reliability issue in CMOS technologies at or below the 14-nm node. TCAD simulations are performed and an analytical model for TID-induced leakage current is presented to support analysis of the identified TID mechanism. TCAD simulation and analytical model results are consistent with the experimental data.

Handbook of Renewable Energy Technology & Systems, pp. 181-200 (2021) No AccessCHAPTER 7: Solar Energy CalculationsKeith E. Holbert and Devarajan SrinivasanKeith E. HolbertSchool of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, Arizona 85287-5706, US and Devarajan SrinivasanPoundra, Tempe, Arizona, UShttps://doi.org/10.1142/9781786349033_0007Cited by:0 PreviousNext AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack CitationsRecommend to Library ShareShare onFacebookTwitterLinked InRedditEmail Abstract: This chapter presents calculations of the sun's position as a function of location, date, and time. In addition, direct, diffuse, and reflected components of solar insolation on a tilted surface are also determined. This computational approach is applicable to both thermal collection/conversion processes and photovoltaics (PVs). Although sun charts are widely used, there are situations in which charts are inadequate and precise computations are preferred. For example, consider fixed PV modules atop residential or industrial buildings in which the value of the electricity varies with date and time. These calculations can be used to determine angles for positioning one and two axis tracking systems to maximize solar energy utilization. Keywords: AlbedoAzimuth angleCollector angleExtinction coefficientSolar constantSolar insolationSolar spectraZenith angle FiguresReferencesRelatedDetails Handbook of Renewable Energy Technology & SystemsMetrics History KeywordsAlbedoAzimuth angleCollector angleExtinction coefficientSolar constantSolar insolationSolar spectraZenith anglePDF download

NOTE: The first page of text has been automatically extracted and included below in lieu of an abstract Session 2632 PowerZone: Artificial Intelligence Educational Modules for Power Engineering Keith E. Holbert, Gerald T. Heydt, George G. Karady, Daniel J. Tylavsky Arizona State University Abstract PowerZone is an NSF sponsored Combined Research and Curriculum Development project aimed at improving electric power industry competitiveness. Educational modules centered on artificial intelligence (AI) techniques are introduced into senior-level undergraduate and first- year graduate power engineering courses. Four independent modules are developed including: (1) fuzzy logic for decision making and signal processing, (2) visualization and intelligent systems for electrical power quality studies, (3) short term load forecasting using neural networks and fuzzy logic, and (4) fast simulation through sparsity coding visualization. These modules are being disseminated using the project initiated PowerZone website located at http://ceaspub.eas.asu.edu/PowerZone/. 1. Introduction Power engineering education has gone through a tortuous history including a golden era of the implementation of electrification (deemed as the top engineering feat of the twentieth century by the National Academy of Engineering [1]), an era of computer applications and control, and most recently a period of restructuring / deregulation. Deregulation of the electric utility industry is forcing most utilities to work harder and smarter. As deregulation takes hold across the country, electric utilities will be (and are being) forced to look at methods that will give them a competitive advantage. To be competitive, utilities need engineers at all levels who are trained to deliver a better product, at a lower cost, with more reliability. The goal of this project is to help improve electric power utility competitiveness by incorporating instructional modules that can be used to train people in these critical areas. The National Science Foundation (NSF) Combined Research-Curriculum Development (CRCD) Program [2] emphasizes the need to incorporate exciting research advances in important technology areas into the upper-level undergraduate and graduate engineering curricula. The electric power industry is currently in need of instructional modules covering a broad range of topics. This is evidenced by the large number of short courses taught every year on a wide range of practices impacted by deregulation. The instructional modules developed focus on the area of the application of artificial intelligence (AI) and visualization to operation, control and simulation of electric power systems. The modules are largely based on ongoing and/or already completed research by the authors. Proceedings of the 2001 American Society for Engineering Education Annual Conference & Exposition Copyright © 2001, American Society for Engineering Education