Integrated System Validation Research Articles

Engineering-Scale Integrated Energy System Data Projection Demonstration via the Dynamic Energy Transport and Integration Laboratory

The objective of this study is to demonstrate and validate the Dynamic Energy Transport and Integration Laboratory (DETAIL) preliminary scaling analysis using Modelica language system-code Dymola. The DETAIL preliminary scaling analysis includes a multisystem integral scaling package between thermal-storage and hydrogen-electrolysis systems. To construct the system of scaled equations, dynamical system scaling (DSS) was applied to all governing laws and closure relations associated with the selected integral system. The existing Dymola thermal-energy distribution system (TEDS) facility and high-temperature steam electrolysis (HTSE) facility models in the Idaho National Laboratory HYBRID repository were used to simulate a test case and a corresponding scaled case for integrated system HYBRID demonstration and validation. The DSS projected data based on the test-case simulations and determined scaling ratios were generated and compared with scaled case simulations. The preliminary scaling analysis performance was evaluated, and scaling distortions were investigated based on data magnitude, sequence, and similarity. The results indicated a necessity to change the normalization method for thermal storage generating optimal operating conditions of 261 kW power and mass flow rate of 6.42 kg/s and the possibility of reselecting governing laws for hydrogen electrolysis to improve scaling predictive properties. To enhance system-scaling similarity for TEDS and HTSE, the requirement for scaling validation via physical-facility demonstration was identified.

Application of Systems Usability Case in an Integrated System Validation of Control Room

The Systems Usability Case (SUC) approach enables a requirement-based human factors (HF) evaluation of complex technical systems that may cover the entire verification and validation process. SUC is based on the Safety Case approach and on the Systems Usability (SU) construct. One of the main aims of establishing a Safety Case is to bring the arguments and evidence for safety to the front in such a way that the reasoning supports the work of a regulator or licensing organization. In the end, the approach enables evaluating the SU of a system and making a reasonable solid argument about the acceptance of the system for use. The question is how the conclusions are reached through a reasoning process in which the arguments are made about the evidence [i.e., identified human engineering discrepancies (HEDs)] to approve or reject the claim concerning the quality of the system. The paper presents an application of SUC to real data from an integrated system validation of the modernized control room (CR) of the Loviisa nuclear power plant. The results of the validation are discussed from the point of view of how the SUC approach enables forming a statement about the acceptance of the CR. Moreover, practical examples are given to demonstrate the identified HF issues and how they were handled in the validation process. The paper provides a general framework for handling of HEDs and for their resolution that can be used in the consolidation of validation test results in a real-world validation project.

Regulatory Considerations for the Potential Use of a Multi-Stage Validation Testing Approach to Support Human Factors Engineering Technical Reviews for Proposed Nuclear Power Plant Control Room Design Modifications

Traditionally, integrated system validation (ISV) testing for proposed nuclear power plant control room design changes has been completed prior to the U.S. Nuclear Regulatory Commission (NRC) approving the proposed change. This, however, can pose scheduling challenges for proposed changes to operating facilities. The NRC is therefore considering possible alternatives for licensees to provide the human factors engineering validation information necessary to demonstrate reasonable assurance of safety for proposed design changes. One such alternative could be the use of early-stage testing results from a multi-stage validation (MSV) program. If early-stage results, along with other design considerations, can provide sufficient supporting information, the NRC may be able to make a safety determination for a proposed design change prior to the completion of ISV testing. Licensees proposing such an approach should consider available industry standards discussing MSV, in conjunction with existing NRC guidance where applicable, when developing their validation program and establishing success criteria. The NRC intends to engage in future discussions with stakeholders regarding the potential development of additional NRC-endorsed guidance on the use of MSV to support proposed changes to existing facilities, as well as designs for new reactor control facilities.

Designing a control system for traffic lights by VANET protocol

In this paper, VANET protocol is used to reduce traffic jams and accidents on the roads. The proposed algorithm is dependent on the wireless network between cars. The system is part of a wireless control node located at the intersection, which determines the optimal values of the phases of traffic lights. The protocol used in this research provides traffic fluency when compared to adaptive systems based on the use of cameras. It has also been developed as an integrated system validation simulator. The simulation framework consists of a realistic vehicle navigation model and a wireless network simulator. The proposed system designed as a work system that can be analyzed for peak hours and we got acceptable results. Average delay, fuel consumption and pollution are significantly reduced.

Workload measurement using physiological and activity measures for validation test: A case study for the main control room of a nuclear power plant

In design of safety-critical and social-technical systems such as a nuclear power plant, practitioners are required to conduct a performance-based Integrated System Validation (ISV) test to verify that the system design could support the safe operation of the plant. Measurement of workload should be included. However, subjective workload measurements could not provide detailed information and continuous monitoring of the changing workload. This study compared physiological (heart rate difference, heart rate variability, respiration rate and breathing wave amplitude) and activity (number of walking steps, peak acceleration, activity level, and inclination) measures with workload defined as intensity of task demand and estimated with a task complexity measure in an ISV test. The test was conducted on a full-scale simulator using a beyond design-basis accident scenario. The results show that heart rate difference and respiration rate are positively correlated with the estimated workload, while heart rate variability and breathing wave amplitude are negatively correlated with the estimated workload. For operations using traditional panels, high workload is accompanied by larger number of walking steps, higher activity level, and smaller angles of inclination. It is suggested that continuous monitoring of cardiovascular, respiration, and activity measures can detect workload change during the ISV test. Relevance to industry: This study provides recommendations for continuous monitoring of workload during an ISV test of a nuclear power plant. The identified physiological and activity measures can be applied in detecting workload change. The findings are supportive in meeting regulatory requirements and improving system design in the nuclear domain.

Application of Eye Tracking for Measurement and Evaluation in Human Factors Studies in Control Room Modernization

An important element of human factors engineering (HFE) pertains to measurement and evaluation (M&E). The role of HFE-M&E should be integrated throughout the entire control room modernization (CRM) process and be used for human–system performance evaluation and diagnostic purposes to resolve potential human engineering deficiencies and other human–machine interface design issues. NUREG-0711 describes how HFE in CRM should employ a hierarchical set of measures, particularly during integrated system validation, including plant performance, personnel task performance, situation awareness, cognitive workload, and anthropometric/physiological factors. Historically, subjective measures have been primarily used since they are easier to collect and do not require specialized equipment. However, there are pitfalls with relying solely on subjective measures in M&E such as negatively impacting reliability, sensitivity, and objectivity. As part of comprehensively capturing a diverse set of measures that strengthen findings and inferences made about the benefits from emerging technologies like advanced displays, this paper discusses the value of using eye tracking as an objective method that can be used in M&E. A brief description of eye tracking technology and relevant eye tracking measures is provided. Additionally, technical considerations and the unique challenges with using eye tracking in full-scale simulations are addressed. Finally, this paper shares preliminary findings regarding the use of a wearable eye tracking system in a full–scale simulator study. These findings should help guide future full–scale simulator studies using eye tracking as a methodology to evaluate human-system performance.

SHPbench – A Smart Hybrid Prototyping Based Environment for Early Testing, Verification and (user based) Validation of Advanced Driver Assistant Systems of Cars

Statistical analysis show that more than 90 percent of all car accidents result from human mistakes. Advanced Driver Assistant Systems (ADAS) are intended to support and assist the car driver, and therefore contribute significantly to the reduction of accidents. ADAS become more and more complex and demanding regarding hard- and software fulfilling the requirements applied onto assistant systems nowadays and in the future. They have to be considered as multi-functional multi-domain mechatronic systems. Smart Hybrid Prototyping (SHP) is a by now proven approach for handling ADAS’ demands during and to the development process, specifically for early integrated component and system testing, its verification and validation with the focus on the interaction with the driver can only be reasonably and economically met by utilizing the SHP technology. For those mentioned purposes the SHPbench, an integrated development and validation environment, has been recently developed. The SHPbench's architecture and specification is presented and evaluated by applying a representative use case of an ADAS development process. This paper documents the use case setup, process steps and test results.

Envy In V&V

Verification and validation (V&V) as applied in the nuclear power community has tended to involve efforts such as integrated system validation, which comes at the tail end of the design stage. In this opinion paper, I suggest the value of early-stage V&V and highlight how this early-stage V&V can help improve the design process for control room modernization. I argue that there is a need to overcome two shortcomings of V&V in current practice—the propensity for late-stage V&V and the use of increasingly complex psychological assessment measures for V&V.

Guideline for Operational Nuclear Usability and Knowledge Elicitation (GONUKE)

As nuclear power plants undertake main control room modernization, a challenge is the lack of a clearly defined human factors process to follow. To fill in guidance gaps and create a step-by-step process for control room modernization, we have developed the Guideline for Operational Nuclear Usability and Knowledge Elicitation (GONUKE). This approach builds on best practices in the software industry, which prescribe an iterative user-centered approach featuring multiple cycles of design and evaluation. Nuclear regulatory guidance for control room design emphasizes summative evaluation—which occurs after the design is complete. In the GONUKE approach, evaluation is also performed at the formative stage of design—early in the design cycle using mockups and prototypes for evaluation. The evaluation may involve expert review (e.g., software heuristic evaluation at the formative stage and design verification against human factors standards like NUREG-0700 at the summative stage). The evaluation may also involve user testing (e.g., usability testing at the formative stage and integrated system validation at the summative stage). An additional, often overlooked component of evaluation is knowledge elicitation, which captures operator insights into the system. In this paper we outline these evaluation types across design phases that support the overall modernization process. The objective is to provide industry-suitable guidance for steps to be taken in support of the design and evaluation of a new human-machine interface (HMI) in the control room.

Human Factors Design, Verification, and Validation for Two Types of Control Room Upgrades at a Nuclear Power Plant

This paper describes the NUREG-0711 based human factors engineering (HFE) phases and associated elements required to support design, verification and validation (V&V), and implementation of a new plant process computer (PPC) and turbine control system (TCS) at a representative nuclear power plant. This paper reviews ways to take a human-system interface (HSI) specification and use it when migrating legacy PPC displays or designing displays with new functionality. These displays undergo iterative usability testing during the design phase and then undergo an integrated system validation (ISV) in a full scope control room training simulator. Following the successful demonstration of operator performance with the systems during the ISV, the new system is implemented at the plant, first in the training simulator and then in the main control room.

Data extraction and analysis for integrated system validation of a nuclear power plant

The design, construction, and operation of nuclear power plants require human factors engineering review to ensure the safety of the system. As one of the important part of the human factors engineering review, integrated system validation (ISV) is the integrated evaluation of the system under high fidelity simulation condition. It validates whether the design of the integrated system can support safe operations of the plant based on the performance of both the plant and operators in the test. This study demonstrates the data extraction and analysis for the ISV of the digital monitoring and control system of a nuclear power plant, with focuses on human–system interaction behaviors to reveal problems associated with interface design. Suggestions are provided for the design of human–system interface and also the measures, data collection, and data processing of validation test.

Using a Benchmark-Referenced Approach for Validating a Power Plant Control Room: Results of the Baseline Study

When performing a validation study of a new system, a question arises as to what constitutes acceptable performance. One approach to setting acceptance criteria is to compare performance obtained with the new system to performance with an existing system that serves as a ‘benchmark‘. This paper describes an integrated system validation for a modernized power plant control room that takes the benchmark-referenced approach. In preparation for the planned integrated system validation, a baseline study of crew performance with the existing control room technology was performed using a high fidelity simulator. This paper reports the results of the baseline study and discusses their implications for validation studies of complex systems more generally. Most notably, the results establish an empirical link between process measures of performance (e.g., target detection, diagnosis, workload, teamwork, and situation awareness) and operationally significant outcome measures of performance, which reinforces the value of including process measures in validation studies.

Advanced Human-System Interfaces: Insight of a Validation Process in a Control Room of a Swiss Nuclear Power Plant

For implementation of advanced human-system interfaces (HSIs) for the control room of the Swiss nuclear power plant Beznau, the Swiss Federal Nuclear Safety Inspectorate (HSK) requires an integrated system validation as part of the safety assessment. The validation was performed on a Westinghouse full-scope simulator with operating crews from the Beznau plant. Considering the expertise acquired by the Institute for Protection and Nuclear Safety (IPSN) in assessing the computerized control systems of the N-4 series, HSK asked IPSN for its support in assessing the HSIs. This paper deals with the methodological aspects, as well as with the results of the validation. Findings are related to issues such as situational awareness, workload, communication and management of the system failure, and raise some recommendations.