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At least 397 records · Page 22

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DOE OSTI2017

Achieving reasonable confidence in the validation of control room designs and modifications: A summary of the 2015 NEA experts' workshop - 124

Defining and achieving reasonable confidence in the validation of nuclear power plant control room designs is a complex challenge for many reasons; not the least of which is that validation is a test of strength rather than a test of truth. In 2015, the Nuclear Energy Agency, Committee for Safety of Nuclear Installations' Working Group on Human and Organizational Factors (WGHOF) hosted an experts' workshop to identify and critically examine potential means to address the challenge of achieving reasonable confidence in control room design validations. The experts' principal task was to answer four challenge questions. (1) What are the critical considerations in defining validation objectives and how do these impact achieving reasonable confidence? (2) What methods, approaches, resources, or rationales might be used for deriving performance requirements, selecting measures, and establishing acceptance criteria so as to support reasonable confidence? (3) What methods might be used to develop scenarios that maximize the amount and relevance of information in support of the validation conclusions and achieving reasonable confidence? (4) How should the validation results be aggregated and analyzed to determine the final validation conclusions? This paper provides an overview of the experts' responses to these challenges and briefly touches upon their implications for future directions. (authors)

22 GENERAL STUDIES OF NUCLEAR REACTORS↗

DOE OSTI2017

Computerized operator support system and human performance in the control room - 262

An operator aid technology to assist nuclear plant operators maintain situation awareness and detect faults earlier than would be possible using conventional control room technologies is described. Coined the Computerized Operator Support System (COSS), this technology is aimed at the human-machine interface. The COSS has been implemented as a prototype system operating in the control room environment of a full-scale simulator for a commercial nuclear power plant. A human factors assessment that involved two licensed reactor crews was performed to evaluate crew performance. This paper describes the development of the COSS, the underlying fault-detection architecture, and feedback received based on operator-in-the-loop studies. (authors)

22 GENERAL STUDIES OF NUCLEAR REACTORS↗

DOE OSTI2017

Human Performance Measures for the Evaluation of Nuclear Power Plant Control Room Interfaces: A Systematic Review - 265

The purpose of this study was to review the literature related to measuring human performance in the design and evaluation of the human-system interface (HSI) of nuclear power plant (NPP) control rooms and synthesize lessons learned and future directions for research and practice in this field. The design and evaluation of digital or hybrid HSI requires comprehensive measurement of human performance to ensure quality and safety of the nuclear power process control. Human factors evaluation frameworks have been proposed to guide the measurement of human performance constructs. However, there are few guides for selecting appropriate measures for those constructs. A systematic review of empirical research literature was conducted. Studies were identified through academic publication databases and grey literature searches. Eligible studies were coded and information regarding human performance measures was extracted and analyzed. A total of 80 studies met the criteria. Human performance measures extracted from the reviewed studies included measures of: behavioral performance; workload; situation awareness; human-human or human-machine cooperation; other cognitive performance indicators; and system performance. Behavioral performance (speed and accuracy), workload, and situation awareness were the most frequently measured constructs with validated and domain-specific instruments. The results of the literature review provided an overview of the human performance constructs and their corresponding measures for NPP control room HSI evaluation. These results can be used as an initial guide to establish appropriate and comprehensive measurements of human performance for such evaluations. Future directions in measure development are also discussed. (authors)

22 GENERAL STUDIES OF NUCLEAR REACTORS↗

DOE OSTI2017

Technical constraints to conducting operator studies in a reconfigurable control room simulator - 269

The Human Systems Simulation Laboratory (HSSL) at Idaho National Laboratory (INL) is a full scope, full scale, and reconfigurable digital representation of an analog nuclear power plant control room. The HSSL is used to conduct human factors research studies on digital technologies being introduced into legacy nuclear power plant control rooms. With the aging nuclear fleet approaching an average of 35 years, utilities are beginning to replace their analog systems with more modern technologies, and utilizing the HSSL to accomplish these tasks. This document will describe some of the constraints identified when conducting operator studies in the HSSL. (authors)

22 GENERAL STUDIES OF NUCLEAR REACTORS↗

DOE OSTI2017

Study on main control room and human-system interface of generation III in China - 313

This paper focuses on the study on Main Control Room (MCR) and Human-System Interface (HSI) of Generation III in China. An intelligent HSI has been developed to enhance the safety and availability of Nuclear Power Plant (NPP) by improving operational reliability. The key elements of the proposed HSI such as Advanced Alarm System, State Oriented Procedures (SOP), Large Display Panel (LDP), Computerized-base procedures..., that affects what information the operator sees or the system's response to a control input must be empirically evaluated to ensure that the new design does not compromise HSI effectiveness. Based on CPR1000's experience in China, this paper presents the approach used as well as the most relevant aspects of this kind of project for the next generation. This approach will be used in new Generation III nuclear power plant, and also used in modernizing I and C system in currently operative nuclear power plants, in addition to meeting safety requirements and the plant's operational requirements, to improve cost-effective plant and human performance and to reduce likelihood of human errors, to gain maximum benefit of the implemented technology and to increase the performance, resulting in improved plant safety, availability, reliability, and cost-effective operation. The proposed HSI has been validated and demonstrated using the CPR1000 simulator of National Key Laboratory. After sufficient validation, the characteristic design features of the proposed HSI will be reflected in the design of the main control room of the next generation reactors in China. (authors)

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗

DOE OSTI2017

Human factors engineering process to support human-system interface design in control room modernization - 351

The primary objective of the United States (U.S.) Department of Energy (DOE) Light Water Reactor Sustainability (LWRS) program is to sustain operation of the existing commercial nuclear power plants (NPPs) through a multi-pathway approach in conducting research and development (R and D). The Advanced Instrumentation, Information, and Control (II and C) System Technologies pathway conducts targeted R and D to address aging and reliability concerns with legacy instrumentation and control (I and C) and other information systems in existing U.S. NPPs. Control room modernization is an important part following this pathway, and human factors experts at Idaho National Laboratory (INL) have been involved in conducting R and D to support migration of new digital main control room (MCR) technologies from legacy analog and legacy digital I and C. This paper describes a human factors engineering (HFE) process that supports human-system interface (HSI) design in MCR modernization activities, particularly with migration of old digital to new digital I and C. The process described in this work is an expansion from the LWRS Report INL/EXT-16-38576, and is a requirements-driven approach that aligns with NUREG-0711 requirements. The work described builds upon the existing literature by adding more detail around key tasks and decisions to make when transitioning from HSI Design into Verification and Validation (V and V). The overall objective of this process is to inform HSI design and elicit specific, measurable, and achievable human factors criteria for new digital technologies. Upon following this process, utilities should have greater confidence with transitioning from HSI design into V and V. (authors)

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗

DOE OSTI2017

Nuclear Power Plant Control Room Modernization - Simulation Based Design

As many plants age and equipment modifications are implemented, the industry has the opportunity to address the issue of control room obsolescence through technology application and enhanced engineering techniques using existing systems. This paper addresses the practice of Simulation Based Design (SBD) for control room modernization driven by plant modifications and upgrades.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗

DOE OSTI2024

Digital Twin + AI: Control Room of the Future

A digital twin enhances power grid control room operations by providing real-time monitoring, predictive insights, simulation capabilities, remote control, training opportunities, data integration, and decision support. This technology empowers control room operators to effectively manage the grid, optimize performance, and ensure reliable and efficient energy distribution.

control room of the future↗

DOE OSTI2025

Terrace‐Edge‐Induced Domain Nucleation in Room‐Temperature 2D Magnetic Van Der Waals Heterostructures

Abstract Terrace‐edges, which are step‐like height discontinuities formed during layer stacking or exfoliation, can locally modify magnetic characteristics. Magnetic domain behavior and its structural dependence in a 2D van der Waals (vdW) heterostructure composed of two distinct room‐temperature ferromagnets: Fe 3 GaTe 2 , an intrinsic vdW ferromagnet, and vanadium‐doped WSe 2 , a transition metal dichalcogenide exhibiting defect‐induced magnetism, is investigated. Using magnetic transmission X‐ray microscopy, the formation and annihilation of magnetic domains are directly observed and it is found that domains preferentially form at terrace‐edges of the heterostructure. Micromagnetic simulations reveal that in‐plane magnetization tilting near the terrace‐edge results in a localized maximum in total magnetic energy that promotes domain formation. The findings highlight the significant role of structural edge features and interfacial magnetic interactions in determining domain formation in hybrid 2D vdW magnetic systems, offering a new route to spatially controlled magnetization at room temperature.

Lee, Jieun↗

DOE OSTI2022

Cold-Starting All-Solid-State Batteries from Room Temperature by Thermally Modulated Current Collector in Sub-Minute

All-solid-state batteries (ASSBs) show great potential as high-energy and high-power energy storage devices but their attainable energy/power density at room temperature is severely reduced because of the sluggish kinetics of lithium-ion transport. Here we first reported a thermally modulated current collector (TMCC), which can rapidly cold-start ASSBs from room temperature to operating temperatures (70–90 °C) in less than one minute, and simultaneously enhance the transient peak power density by 15-fold compared to one without heating. This TMCC is prepared by integrating a uniform, ultrathin (~200 nm) nickel layer as a thermal modulator within an ultralight polymer-based current collector. By isolating the thermal modulator from the ion/electron pathway of ASSBs, it can provide fast, stable heat control yet does not interfere with regular battery operation. Moreover, this ultrathin (13.2 μm) TMCC effectively shortens the heat transfer pathway, minimizes heat losses, and mitigates the formation of local hot spots. The simulated heating energy consumption can be as low as ~3.94% of total battery energy. This TMCC design with good tunability opens new frontiers towards smart energy storage devices in the future from the current collector perspective.

25 ENERGY STORAGE↗

DOE OSTI2018

Chemical Immobilization and Conversion of Active Polysulfides Directly by Copper Current Collector: A New Approach to Enabling Stable Room-Temperature Li-S and Na-S Batteries

Here, room–temperature Li/Na–S batteries are promising energy storage solutions, but unfortunately suffer from serious cycling problems rooted in their polysulfide intermediates. The conventional strategy to tackle this issue is to design host materials for trapping polysulfides via weak physical confinement and interfacial chemical interactions. Even though beneficial, their capability for the polysulfide immobilization is still limited. Herein, the unique sulfiphilic nature of metallic Cu is revisited. Upon the exposure to polysulfide in aqueous or aprotic solution, the surface sulfidization rapidly takes place, resulting in the formation of Cu 2 S nanoflake arrays with tunable texture. When the sulfidized Cu current collector is directly used as the sulfur–equivalent cathode, it enables high–performance Li/Na–S batteries at room temperature with reasonable high sulfur loading. Specific capacities up to ≈1200 mAh g –1 for Li–S and ≈400 mAh g –1 for Na–S are measured when normalized to the amount of equivalent sulfur, and can be readily sustained for >1000 cycles.

25 ENERGY STORAGE↗

DOE OSTI2019

Room–Temperature Insulating Ferromagnetic (Ni,Co) 1+2 x Ti 1– x O 3 Thin Films

Insulating uniaxial room–temperature ferromagnets are a prerequisite for commonplace spin wave–based devices, the obstacle in contemporary ferromagnets being the coupling of ferromagnetism with large conductivity. It is shown that the uniaxial A 1 + 2x Ti 4+ 1 – x O 3 (ATO), A = Ni 2+ ,Co 2+ , and 0.6 < x ≤ 1, thin films are electrically insulating ferromagnets already at room temperature. Here, the octahedra network of the ATO and the corundum and ilmenite structures are the same yet different octahedra–filling proved to be a route to switch from the antiferromagnetic to ferromagnetic regime. Octahedra can continuously be filled up to x = 1, or vacated (–0.24 < x < 0) in the ATO structure. TiO–layers, which separate the ferromagnetic (Ni,Co)O–layers and intermediate the antiferromagnetic coupling between the ferromagnetic layers in the NiTiO 3 and CoTiO 3 ilmenites, can continuously be replaced by (Ni,Co)O–layers to convert the ATO–films to ferromagnetic insulator with abundant direct cation interactions.

36 MATERIALS SCIENCE↗

DOE OSTI2022

Near‐Room‐Temperature Magnetoelectric Coupling via Spin Crossover in an Iron(II) Complex

Abstract Magnetoelectric coupling is achieved near room temperature in a spin crossover Fe II molecule‐based compound, [Fe(1bpp) 2 ](BF 4 ) 2 . Large atomic displacements resulting from Jahn–Teller distortions induce a change in the molecule dipole moment when switching between high‐spin and low‐spin states leading to a step‐wise change in the electric polarization and dielectric constant. For temperatures in the region of bistability, the changes in magnetic and electrical properties are induced with a remarkably low magnetic field of 3 T. This result represents a successful expansion of magnetoelectric spin crossovers towards ambient conditions. Moreover, the observed 0.3–0.4 mC m −2 changes in the H ‐induced electric polarization suggest that the high strength of the coupling obtained via this route is accessible not just at cryogenic temperatures but also near room temperature, a feature that is especially appealing in the light of practical applications.

Owczarek, Magdalena↗

DOE OSTI2022

Near‐Room‐Temperature Magnetoelectric Coupling via Spin Crossover in an Iron(II) Complex

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2025

B‐Staging and Crosslinking of Polycarbosilane at Room Temperature: Cure Mechanism and Properties

The viscosity of polycarbosilane (PCS) polymers is not advantageous for free forming. Various fillers and heat are used to obtain a formable paste. Due to the low yield stress, structures and preforms tend to slump or resin will flow out, especially during the curing of the polymer. B-staging of PCS allows for a more stable structure from room temperature until the full cure of the allyl groups occurs with heat. Additionally, hydrosilation is an effective means of crosslinking at room temperature and controlling viscosity. A network structure was formed in SMP-10 using silane and a vinyl-based crosslinker to bridge each polymer chain. Pt addition catalysts were added to enhance the increase in viscosity to make a lightly crosslinked gel to aid in thickening and forming and to improve the ceramic yield at 1000°C. In conclusion, this enables several options for controlling rheology and improving the properties of preceramic polymers to avoid slumping during curing.

inorganic polymers↗

DOE OSTI2021

Bioinspired Activation of N 2 on Asymmetrical Coordinated Fe Grafted 1T MoS 2 at Room Temperature

Inspired by the nitrogen fixation process on MoFe nitrogenase, asymmetrical coordinated Fe grafted onto 1T MoS 2 were successfully synthesized. The unique electron -rich structure with asymmetrical coordination made the 1T Fe 0.1 Mo 0.9 S 2 layered material actively react with water and dinitrogen at room temperature and atmosphere pressure. Subsequently, ammonia can be produced with a yield of 800 pmol (NH 4 + ) g -1 (12.5% yield in mole). The activation, fixation and reduction of dinitrogen were confirmed by isotopically labeled experiments. The location and the specific coordination environment of grafted Fe in Fe-Mo-S were further determined by X-ray absorption spectroscopy analysis. Our work demonstrates that the nitrogen fixation and reduction for ammonia at room temperature without any chemical and electrochemical assistance is distinctly different from traditional bionic -inspired nitrogen fixation process. The mechanism of the activation and reduction of N 2 was further investigated by density functional theory calculation and Raman spectra. Compared with 1T MoS 2 , the enriched electron nature and asymmetrical coordination of Fe in Fe-Mo-S materials play a critical role in the bioinspired activation of N 2 at ambient condition.

1T MoS2↗

DOE OSTI2025

Room‐Temperature Mid‐Infrared Detection Using Metasurface‐Absorber‐Integrated Phononic Crystal Oscillator

Mid-infrared (MIR) detectors find extensive applications in chemical sensing, spectroscopy, communications, biomedical diagnosis, and space exploration. Alternative to semiconductor MIR photodiodes and bolometers, mechanical-resonator-based MIR detectors show advantages in higher sensitivity and lower noise at room temperature, especially toward longer wavelength infrared. Here, uncooled room-temperature MIR detectors based on lithium niobate surface acoustic wave phononic crystal (PnC) resonators integrated with wavelength-and-polarization-selective metasurface absorber arrays are demonstrated. The detection is based on the resonant frequency shift induced by the local temperature change due to MIR absorptions. The PnC resonator is configured in an oscillating mode, enabling active readout and low-frequency noise. The 1-GHz oscillator-based MIR detector shows a relative frequency deviation of 5.24 × 10 −10 Hz −1/2 at an integration time of 50 µs, leading to an incident noise equivalent power of 197 pW Hz −1/2 when input 6-µm MIR light is modulated at 1.8 kHz, and a large dynamic range of 10 7 in incident MIR power. The device architecture is compatible with the scalable manufacturing process and can be readily extended to a broader spectral range by tailoring the absorbing wavelengths of metasurface absorbers.

Xi, Zichen [Virginia Polytechnic Inst. and State U↗

DOE OSTI2023

Mitigating Heavy Ion Irradiation‐Induced Degradation in p‐type SnO Thin‐Film Transistors at Room Temperature

The study investigates the mitigation of radiation damage on p‐type SnO thin‐film transistors (TFTs) with a fast, room‐temperature annealing process. Atomic layer deposition is utilized to fabricate bottom‐gate TFTs of high‐quality p‐type SnO layers. After 2.8 MeV Au 4+ irradiation at a fluence level of 5.2 × 10 12 ions cm −2 , the output drain current and on/off current ratio ( I on / I off ) decrease by more than one order of magnitude, field‐effect mobility ( μ FE ) reduces more than four times, and subthreshold swing (SS) increases more than four times along with a negative shift in threshold voltage. The observed degradation is attributed to increased surface roughness and defect density, as confirmed by scanning electron microscopy (SEM), high‐resolution micro‐Raman, and transmission electron microscopy (TEM) with geometric phase analysis (GPA). A technique is demonstrated to recover the device performance at room temperature and in less than a minute, using the electron wind force (EWF) obtained from low‐duty‐cycle high‐density pulsed current. At a pulsed current density of 4.0 × 10 5 A cm −2 , approximately four times increase in I on / I off is observed, 41% increase in μ FE , and 20% decrease in the SS of the irradiated TFTs, suggesting effectiveness of the new annealing technique.

Al-Mamun, Nahid Sultan↗