Sacit M. Cetiner

An Analysis of Testing Requirements for Fluoride Salt Cooled High Temperature Reactor Components

This report provides guidance on the component testing necessary during the next phase of fluoride salt-cooled high temperature reactor (FHR) development. In particular, the report identifies and describes the reactor component performance and reliability requirements, provides an overview of what information is necessary to provide assurance that components will adequately achieve the requirements, and then provides guidance on how the required performance information can efficiently be obtained. The report includes a system description of a representative test scale FHR reactor. The reactor parameters presented in this report should only be considered as placeholder values until an FHR test scale reactor design is completed. The report focus is bounded at the interface between and the reactor primary coolant salt and the fuel and the gas supply and return to the Brayton cycle power conversion system. The analysis is limited to component level testing and does not address system level testing issues. Further, the report is oriented as a bottom-up testing requirements analysis as opposed to a having a top-down facility description focus.

Development of an Automated Decision-Making Tool for Supervisory Control System

This technical report was generated as a product of the Supervisory Control for Multi-Modular Small Modular Reactor (SMR) Plants project within the Instrumentation, Control and Human-Machine Interface technology area under the Advanced Small Modular Reactor (AdvSMR) Research and Development Program of the US Department of Energy. The report documents the definition of strategies, functional elements, and the structural architecture of a supervisory control system for multi-modular AdvSMR plants. This research activity advances the state of the art by incorporating real-time, probabilistic-based decision-making into the supervisory control system architectural layers through the introduction of a tiered-plant system approach. The report provides background information on the state of the art of automated decision-making, including the description of existing methodologies. It then presents a description of a generalized decision-making framework, upon which the supervisory control decision-making algorithm is based. The probabilistic portion of automated decision-making is demonstrated through a simple hydraulic loop example.

Update on Small Modular Reactors Dynamic System Modeling Tool: Web Application

Previous reports focused on the development of component and system models as well as end-to-end system models using Modelica and Dymola for two advanced reactor architectures: (1) Advanced Liquid Metal Reactor and (2) fluoride high-temperature reactor (FHR). The focus of this report is the release of the first beta version of the web-based application for model use and collaboration, as well as an update on the FHR model. The web-based application allows novice users to configure end-to-end system models from preconfigured choices to investigate the instrumentation and controls implications of these designs and allows for the collaborative development of individual component models that can be benchmarked against test systems for potential inclusion in the model library. A description of this application is provided along with examples of its use and a listing and discussion of all the models that currently exist in the library.

Nuclear Hybrid Energy Systems FY16 Modeling Efforts at ORNL

A nuclear hybrid system uses a nuclear reactor as the basic power generation unit. The power generated by the nuclear reactor is utilized by one or more power customers as either thermal power, electrical power, or both. In general, a nuclear hybrid system will couple the nuclear reactor to at least one thermal power user in addition to the power conversion system. The definition and architecture of a particular nuclear hybrid system is flexible depending on local markets needs and opportunities. For example, locations in need of potable water may be best served by coupling a desalination plant to the nuclear system. Similarly, an area near oil refineries may have a need for emission-free hydrogen production. A nuclear hybrid system expands the nuclear power plant from its more familiar central power station role by diversifying its immediately and directly connected customer base. The definition, design, analysis, and optimization work currently performed with respect to the nuclear hybrid systems represents the work of three national laboratories. Idaho National Laboratory (INL) is the lead lab working with Argonne National Laboratory (ANL) and Oak Ridge National Laboratory. Each laboratory is providing modeling and simulation expertise for the integration of the hybrid system.

Update on Small Modular Reactors Dynamics System Modeling Tool -- Molten Salt Cooled Architecture

The Small Modular Reactor (SMR) Dynamic System Modeling Tool project is in the third year of development. The project is designed to support collaborative modeling and study of various advanced SMR (non-light water cooled) concepts, including the use of multiple coupled reactors at a single site. The objective of the project is to provide a common simulation environment and baseline modeling resources to facilitate rapid development of dynamic advanced reactor SMR models, ensure consistency among research products within the Instrumentation, Controls, and Human-Machine Interface (ICHMI) technical area, and leverage cross-cutting capabilities while minimizing duplication of effort. The combined simulation environment and suite of models are identified as the Modular Dynamic SIMulation (MoDSIM) tool. The critical elements of this effort include (1) defining a standardized, common simulation environment that can be applied throughout the program, (2) developing a library of baseline component modules that can be assembled into full plant models using existing geometry and thermal-hydraulic data, (3) defining modeling conventions for interconnecting component models, and (4) establishing user interfaces and support tools to facilitate simulation development (i.e., configuration and parameterization), execution, and results display and capture.

Dynamic Simulation of Small Modular Reactors Using Modelica

Small modular reactors (SMRs) offer potential for addressing the nation’s long-term energy needs. However, the project design cycle for new reactor concepts is lengthy. As part of the Department of Energy’s Advanced SMR research and development program, Oak Ridge National Laboratory (ORNL) is developing a Dynamic System Modeling Tool (MoDSIM) to facilitate rapid instrumentation and controls studies of SMR concepts.Traditional nuclear reactor design makes use of verified and validated codes to meet the strict quality assurance requirements of the licensing process for the Nuclear Regulatory Commission. However, there are significant engineering analyses and high-level decisions required prior to the rigorous design phase. These analyses typically do not require high-fidelity codes. Different organizations and researchers may examine various plant configuration options prior to formal design activities. Engineers and managers must continuously make down-selection decisions regarding potential reactor architectures and subsystems. Traditionally, the modeling of these complex systems has been based on legacy models. Considerable time and effort are necessary to understand and manipulate these legacy models. For trade-space studies, two developments in the model-based systems engineering space represent a significant advancement in the ability of engineering tools to meet these demands. The first is Modelica: a nonproprietary, equation-based, object-oriented modeling language for cyber-physical systems. The second is the Functional Mockup Interface: a standardized, open interface for model exchange, simulation, and deployment.ORNL’s MoDSIM tool makes use of these developments and is intended to provide a flexible and robust dynamic system-modeling environment for SMRs. This includes single or multiple reactors, perhaps sharing common resources, or producing both electricity and process heat for local consumption or feeding a regional grid. MoDSIM uses the open-source modeling language (Modelica) and incorporates a user interface, coupled dynamic models, and analysis capabilities that will enable non-expert modelers to perform sophisticated end-to-end system simulations of both neutronic and thermal-hydraulic models. This approach enables open-source and crowd-source-type collaborations for model development of SMRs in an approach similar to open-source and open-design techniques currently used for software production and complex system design. As part of the tool development, an example SMR was chosen (advanced liquid metal reactor [ALMR]) and the ALMR models developed and interface tools demonstrated. For initial verification purposes, the results from these Modelica simulations are compared with the results documented for the earlier ALMR power-reactor innovative small-module concept. These results, as well as initial demonstrations of the tool for different control strategies, are presented in this paper.Copyright

DEVELOPMENT OF A SUPERVISORY CONTROL SYSTEM CONCEPT FOR ADVANCED SMALL MODULAR REACTORS

Small modular reactors (SMRs) can provide the United States with a safe, sustainable, and carbon-neutral energy source. Because of their small size and, in many cases, simplified nuclear island configurations, it is expected that capital costs will be less for SMRs compared to that of large, Generation III+ light-water reactors. Advanced SMRs (AdvSMRs), which use coolants other than water as the primary heat transport medium, introduce several passive safety concepts and controls features that further reduce the complexity of primary system designs by eliminating redundant components and systems.Under U.S. Department of Energy (DOE) Office of Nuclear Energy (NE), the Supervisory Control of Multi-Modular SMR Plants project was established to enable innovative control strategies and methods to supervise multi-unit plants, accommodate shared systems, identify opportunities to increase the level of automation, define economic metrics based on the relationship between control and staffing levels, and permit flexible co-generation operational regimes.This paper documents current findings from the Supervisory Control project. Specifically, it defines and documents strategies, functional elements, and an architectural structure for supervisory control of a representative generic AdvSMR plant. More specifically, this research advances the state-of-the art by incorporating decision making into the supervisory control system architectural layers through the introduction of tiered taxonomy of plant systems and subsystems.The proposed architecture has the features of planning and scheduling, analyzing plant status, diagnosing problems as they develop and predicting potential future problems, making decisions based on these features, and generating validated commands to lower control layers in the architecture.Copyright

Supervisory Control System Architecture for Advanced Small Modular Reactors

This technical report was generated as a product of the Supervisory Control for Multi-Modular SMR Plants project within the Instrumentation, Control and Human-Machine Interface technology area under the Advanced Small Modular Reactor (SMR) Research and Development Program of the U.S. Department of Energy. The report documents the definition of strategies, functional elements, and the structural architecture of a supervisory control system for multi-modular advanced SMR (AdvSMR) plants. This research activity advances the state-of-the art by incorporating decision making into the supervisory control system architectural layers through the introduction of a tiered-plant system approach. The report provides a brief history of hierarchical functional architectures and the current state-of-the-art, describes a reference AdvSMR to show the dependencies between systems, presents a hierarchical structure for supervisory control, indicates the importance of understanding trip setpoints, applies a new theoretic approach for comparing architectures, identifies cyber security controls that should be addressed early in system design, and describes ongoing work to develop system requirements and hardware/software configurations.