Engineering topics

Ulrich, Thomas

Publications and source records attributed to Ulrich, Thomas.

11 records

DOE OSTI2024

System design and analysis of thermal power dispatch systems for boiling water reactors

Nuclear power plants are crucial to meeting net zero emission goals and achieving energy sustainability. Integrating these plants with clean energy technologies such as high-temperature steam electrolysis (HTSE) may improve the efficiency and economic competitiveness of these plants. Here, the current study investigates the design and operation of a thermal power dispatch (TPD) system for coupling boiling water reactors (BWRs) to HTSE plants. The TPD system extracts a portion of the steam from the reactor’s main steam line and transfers its thermal energy to an HTSE plant through a power transport loop. A TPD system for 5 % steam extraction has been designed and the system performance during steady and transient operations has been analyzed. The TPD system dispatched a total of 197 MW thermal energy to the HTSE plant under nominal design conditions. Saturated steam at 7.17 MPa from the BWR plant was condensed and subcooled to a temperature of 168 °C, while a mass flow rate of 91.1 kg/s of superheated steam was dispatched to the HTSE plant. Furthermore, the system performance during transient operation showed a continuous transition from the initial hot standby mode to the nominal power dispatch level. The transient simulation results emphasized the importance of investigating component level performance for the TPD system design. The current results will guide future works on the development of integrated energy systems for hydrogen production or process heat applications.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗

DOE OSTI2024

Opportunities, Challenges, and Research Needs for Remote Microreactor Operations

As the nuclear industry develops new advanced reactor technologies, many companies are embracing this advancement by pursuing the development of microreactors. The term microreactor generally refers to a nuclear reactor with an operating power of 20 MW(thermal) or less. The power range of microreactors makes them appealing for many use cases, such as powering remote communities, mining sites, and military bases. Most of the microreactor designs being pursued are expected to incorporate remote facility operations into the final product. However, no framework has yet been developed to determine what remote operations systems require for reliable, resilient, and secure operation of a microreactor. Here, this work identifies the research needs for challenges that are unique to remote operations and monitoring for microreactors, specifically regarding instrumentation and control, communication methods, regulatory requirements, and operational policies. The types of commands and sensor measurements that must be transmitted between the facilities, as well as methods for verifying the trustworthiness of these signals, are assessed. This work evaluates the security, reliability, and performance requirements that must be met when considering the selection of communication hardware and protocols for use in remote operations. Also, an assessment was performed to study how remote operations fit within current regulatory requirements and what may need to be updated in regulatory policy to allow for remote operation. Finally, the operational contingencies unique to remote operations that must be in place for responses to abnormal events are identified. This paper identifies the challenges and research opportunities within the areas of importance for the design of remote operation systems.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗

DOE OSTI2024

Light Water Reactor Sustainability Program: Use of Time Distributions to Predict Operator Procedure Performance in Dynamic Human Reliability Analysis

The Human Unimodel for Nuclear Technology to Enhance Reliability (HUNTER) framework affords software capable of conducting human reliability analysis (HRA) using a dynamic approach built around operating procedures (OPs) from nuclear power plants (NPPs). Previous HUNTER reports document the development of this software tool, the coupling of HUNTER to the simulator code, the collection of operator performance data by using simulators to calibrate HUNTER models, and linking HUNTER to probabilistic risk assessment (PRA) software. The present report largely addresses two topics. The first is a new function in HUNTER called the HUNTER Procedure Performance Predictor (P3). HUNTER P3 uses HUNTER’s built in Monte Carlo tools featuring human performance variability to identify potential error traps in procedures. The second topic is time distribution analysis to generate time inputs for dynamic HRA. The current analysis was performed to investigate time distributions for task primitives, which are the minimum task unit of analysis used in dynamic HRA modeling. Using the time distribution data, the elapsed time for human actions in an extended loss of AC power (ELAP) scenario is then investigated. Time data and prediction are essential for modeling procedure performance.

99 GENERAL AND MISCELLANEOUS↗

NASA NTRS2019

SCREAM: Space-based Cognitive Reliability Error Analysis Method

Given both ground-based performance shaping factors (PSFs) collected by the U.S. Nuclear Regulatory Commission (USNRC) and potential space-based PSFs collected by JSC's HH&P, this year's task is to determine how to combine them for future human reliability analysis (HRA) of space missions. All HRA to date for space missions have been based on ground data (i.e. 1-G environment). There is no space-based HRA approach. The target of this project to produce a "first of its kind" HRA approach for space missions. As humans go beyond Earth orbit and missions become longer, human performance and reliability is expected to degrade. The questions become by how much, when, and what, leading to defining the overall effect on crew risk. Knowing this information earlier rather than later will help us mitigate this risk by vehicle design, crew training, and operational workarounds.

Boyer, Roger L.↗

DOE OSTI2017

Analog, Digital, or Enhanced Human-System Interfaces? Results of an Operator-in-the-Loop Study on Main Control Room Modernization for a Nuclear Power Plant

The second Operator Study of System Overviews (OSSO-2) was conducted with a three-person reactor operator crew in the Human Systems Simulation Laboratory (HSSL) at Idaho National Laboratory (INL) in August, 2017. The study supported control room modernization at a nuclear power plant and featured a benchmark comparison of three variants of a turbine control system (TCS): the existing analog TCS, a proposed standalone digital TCS with two displays, and the digital TCS with the addition of a third display consisting of a system overview screen. TCS prototypes were developed at INL to allow evaluation of operator performance and preferences during realistic turbine scenarios in the full-scope simulator. The study revealed that completion of turbine startup was several minutes faster with the digital TCS variants than with the conventional analog TCS. Eye tracking scan paths were more widely distributed in the overview vs. standalone TCS condition, suggesting the overview screen was cueing reactor operators to verify values across the boards. There was no significant difference in workload or situation awareness across the three interfaces. Reviewing key plant parameters showed smoother transitions during load following for the digital vs. analog TCS. Despite some performance advantages for the digital TCS variants, operators preferred the existing analog TCS. Open-ended responses suggested this finding may be more an artifact of familiarity than a reflection of dissatisfaction with the new TCS. OSSO-2 provides compelling evidence that the new digital TCS was used successfully by the operators without extensive training of rewriting of the operating procedures, suggesting high usability for the digital TCS design. Further advantages were realized through the addition of the system overview screen to provide crews with at-a-glance indicators of key turbine parameters.

99 GENERAL AND MISCELLANEOUS↗

DOE OSTI2017

Automated Work Packages: Radio Frequency Identification, Bluetooth Beacons, and Video Applications in the Nuclear Power Industry

The need to move conventional paper-based work packages into an electronic state motivated the development of a large span of electronic work package forms that ranged from simple Portable Document Format (PDF) files to adaptive and intelligent electronic forms. In parallel to this development, the Department of Energy Light Water Reactor Sustainability Program (LWRS) initiated the automated work package as a pilot project to evaluate implementing state of the art automation techniques into the work package process to improve the economic and safety of the work process. Through a multiple year’s effort, the automated work package project have developed a vision of the future work package that relies on automation in all critical and human factor challenging tasks. The vision identified gaps in the work process, the means to automate them, and evaluated the implementation, feasibility and benefits of these means. This was conducted through continues engagement with the nuclear power industry. The aim of this report is to study the potential of three automation technologies, which have been advancing in various industries, in the current work process of nuclear power plants. The study is to determine the feasibility and benefits of incorporating the technologies and determine potential gaps, if any, that need to be addressed to facilitate deployment of the studied technologies. The three automation technologies identified for this effort are ultra-high frequency (UHF) radio frequency identification (RFID), Bluetooth low energy (BLE) beacons, and video monitoring and recording. As part of this effort, the Idaho National Laboratory (INL) collaborated with Xcel Energy Inc. to evaluate these technologies. During the research and development scope of the effort, INL engaged Xcel Energy Inc. periodically and exchanged valuable insight on the means to implement these technologies in a nuclear power plant. Multiple pilot prototypes were developed and tested in a user study conducted at Xcel Energy Inc. in Minneapolis, Minnesota. The outcome of this effort resulted in significant findings that included the detailed means to custom fit the technologies to fit the nuclear power industry need, and identifying and evaluating several applications of high economic or safety potential. The limitations and obstacles that could impact deployment of the technologies were also identified, and the means of how to address these limitations and obstacles were studied.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

DOE OSTI2017

Comparison of Mutual Awareness in Analog vs. Digital Control Rooms

Control rooms in nuclear power plants are complex, collaborative working environments rife with potential for human error. As control rooms evolve from analog to digital interface environments, crew communication strategies must change as well. Operators in the analog control room operate the plant and communicate with each other with the help of control boards with large control panels, meters, and switches. Reactor operators could choose a particular set of controls on the particular control board which corresponds to the part of the system of interest. Visual display units (VDU), which became a fixture in the control rooms with the shift to digital human-machine interfaces (HMI), bring benefits for safety and flexibility combining information from various sources. With the increase in automation and the use of digital HMIs operators received their personal sitting workstations where they are able to navigate and operate the plant. The amount of information increased as well as the complexity of monitoring and analyzing the system states. Also computerized systems cause operators to get absorbed by their personal screens and reduce interaction between the crew members. Therefore, the collaboration and coordination of task demands requires vigilance and mutual awareness. The level of automation has an influence on the level of mutual awareness experienced by operators in the control rooms. Teams function to carry out highly interdependent tasks, requiring synthesis and sharing of information to achieve common goals. Improving the performance of the team necessitates the operators to focus on the system, the surrounding environment, and situational awareness about the system states. Collaboration of team members is critical when employing the digital operating systems as the acute awareness of the overall progress of the group and individual activities of the operators drives the team to the desired end-states of the plant operations. Out-of-the loop (OOTL) performance problems can be referred to as the lack of supervisory control, system monitoring, and information processing in the digital HMIs. Under some circumstances Senior Reactor Operators (SRO) struggle to follow the actions of other Reactor Operators (RO) because with the new digital interfaces SROs lose track of how the procedures are carried out by ROs, which results in the loss of three way communication. Mutual awareness plays a significant role in keeping the SROs in the loop of plant operations. This paper will investigate, through literature review and expert interviews, the impact and human errors attributed to the increasing complexity of new digital main control rooms. Comparison of the new digital interfaces with the analog interfaces in nuclear power plants has the potential to shed light on increasing mutual awareness and three way communications between the SROs and ROs. Further, identification of the human errors and human actions can provide beneficial information, suggesting significant and critical improvements that can be implemented in the main control rooms to increase safety and reliability of new technology. Additionally, insights on mutual awareness for analog vs. digital control rooms can serve to improve human reliability.

99 GENERAL AND MISCELLANEOUS↗

DOE OSTI2016

Integration of Human Reliability Analysis Models into the Simulation-Based Framework for the Risk-Informed Safety Margin Characterization Toolkit

This report presents an application of a computation-based human reliability analysis (HRA) framework called the Human Unimodel for Nuclear Technology to Enhance Reliability (HUNTER). HUNTER has been developed not as a standalone HRA method but rather as framework that ties together different HRA methods to model dynamic risk of human activities as part of an overall probabilistic risk assessment (PRA). While we have adopted particular methods to build an initial model, the HUNTER framework is meant to be intrinsically flexible to new pieces that achieve particular modeling goals. In the present report, the HUNTER implementation has the following goals: • Integration with a high fidelity thermal-hydraulic model capable of modeling nuclear power plant behaviors and transients • Consideration of a PRA context • Incorporation of a solid psychological basis for operator performance • Demonstration of a functional dynamic model of a plant upset condition and appropriate operator response This report outlines these efforts and presents the case study of a station blackout scenario to demonstrate the various modules developed to date under the HUNTER research umbrella.

98 NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL P↗

DOE OSTI2015

Benefits of Advanced Control Room Technologies: Phase One Upgrades to the HSSL, Research Plan, and Performance Measures

Control Room modernization is an important part of life extension for the existing light water reactor fleet. None of the 99 currently operating commercial nuclear power plants in the U.S. has completed a full-scale control room modernization to date. A full-scale modernization might, for example, entail replacement of all analog panels with digital workstations. Such modernizations have been undertaken successfully in upgrades in Europe and Asia, but the U.S. has yet to undertake a control room upgrade of this magnitude. Instead, nuclear power plant main control rooms for the existing commercial reactor fleet remain significantly analog, with only limited digital modernizations. Previous research under the U.S. Department of Energy’s Light Water Reactor Sustainability Program has helped establish a systematic process for control room upgrades that support the transition to a hybrid control room. While the guidance developed to date helps streamline the process of modernization and reduce costs and uncertainty associated with introducing digital control technologies into an existing control room, these upgrades do not achieve the full potential of newer technologies that might otherwise enhance plant and operator performance. The aim of the control room benefits research is to identify previously overlooked benefits of modernization, identify candidate technologies that may facilitate such benefits, and demonstrate these technologies through human factors research. This report describes the initial upgrades to the HSSL and outlines the methodology for a pilot test of the HSSL configuration.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗

DOE OSTI2014

Human Factors Engineering Design Phase Report for Control Room Modernization

In this report, we review recent work performed at the Human System Simulation Laboratory (HSSL) at the Idaho National Laboratory. The U.S. Department of Energy has sponsored work under the Light Water Reactor Sustainabilty (LWRS) program to assist U.S. utilities in extending the operating life of the U.S. fleet of commercial reactors. Control room modernization is a key research and demonstration area within LWRS. The U.S. Nuclear Regulatory Commission’s Human Factors Engineering Program Review Model (NUREG-0711) outlines four phases of developing a new human-system interface (HSI). One of the key steps in NUREG-0711 is the design phase. In this report, we outline the process and findings from several simulator workshops, which centered on early design phase activities. Prototypes for a turbine control system upgrade for a main control room at a commercial nuclear power plant were developed and evaluated using licensed reactor operators at the HSSL. This iterative design-evaluation cycle succeeded in refining the design of the HSI and readying it for final implementation and formal validation and verification exercises. This report serves as a useful template to explicate design steps that are not currently required by NUREG-0711 but that ensure a usable and safe control room replacement system.

99 GENERAL AND MISCELLANEOUS↗

DOE OSTI2014

Light Water Reactor Sustainability Program Operator Performance Metrics for Control Room Modernization: A Practical Guide for Early Design Evaluation

As control rooms are modernized with new digital systems at nuclear power plants, it is necessary to evaluate the operator performance using these systems as part of a verification and validation process. There are no standard, predefined metrics available for assessing what is satisfactory operator interaction with new systems, especially during the early design stages of a new system. This report identifies the process and metrics for evaluating human system interfaces as part of control room modernization. The report includes background information on design and evaluation, a thorough discussion of human performance measures, and a practical example of how the process and metrics have been used as part of a turbine control system upgrade during the formative stages of design. The process and metrics are geared toward generalizability to other applications and serve as a template for utilities undertaking their own control room modernization activities.

99 GENERAL AND MISCELLANEOUS↗