Software safety analysis of function block diagrams using fault trees

This study analyzed the particulates and gaseous emissions from 2005 to 2022 for power plants in South Korea (Utility scale: 125 MW (B-1) and 200 MW (B-2), respectively), which recently successfully converted from coal to wood pellets. The analysis showed that (1) NOx reduction was 78.9 to 90.0% (with outlet denitrification facility), (2) SOx reduction was 95.0 to 99.6% (without desulfurization facility condition), and (3) total suspended particles (TSP) reduction was 70.3 to 87.2% (with improved filtration and dust collection facility). This research confirmed the capabilities of wood pellets as a baseload power source and demonstrated their superior NOx reduction compared to coal. In the case of SOx, the desulfurization facility was discontinued at the stage of the fuel switch, so the value was affected by exogenous variable factors other than fuel. The TSP appears to be a combination of the ‘fine dust’ contained in the wood pellets and the performance of the filtration dust collector. The results suggest that fuel switching to wood pellets is a viable alternative to fossil fuels as an appropriate climate technology.

Doosan starts installation of hydrogen-fueled 50 MW fuel cell power plant in South Korea

The trip computers for the two reactor shutdown systems of the Ontario Power Generation (OPG) Darlington Nuclear Power Generating Station are being refurbished due to hardware obsolescence. For one of the systems, the general purpose computer originally used is being replaced by a programmable logic controller (PLC). The trip computer application software has been rewritten using function block diagrams (FBDs), a commonly used PLC programming language defined in the IEC 61131-3 standard. The replacement project’s quality assurance program requires that formal verification be performed to compare the FBDs against a formal software requirements specification written using tabular expressions (TEs). The PVS theorem proving tool is used in formal verification. Custom tools developed for OPG are used to translate TEs and FBDs into PVS code. In this paper, we present a method to rigorously translate the graphical FBD language to a mathematical model in PVS using an abstract syntax to represent the FBD constructs. We use an example from the replacement project to demonstrate the use of the model to translate a FBD module into a PVS specification. We then extend that example to demonstrate the method’s applicability to a Simulink-based design.

Chapter 5 - Some Case Studies of Software and Microprocessor Failures

Sorption behavior of cesium on silt and clay soil fractions

Quantification of SO2 and CO2 emission rates from coal-fired power plants in the Korean peninsula via airborne measurements.

Regional Differences in Willingness to Pay for Mitigation of Air Pollution from Coal-Fired Power Plants in South Korea

The purpose of this study was to establish the dose-response curves for biological dosimetry of the Dong Nam Institute of Radiological and Medical Sciences to monitor radiation exposure of local residents in the vicinity of the nuclear power plant. The blood samples of five healthy volunteers were irradiated with gamma ray, and each sample was divided equally for analysis of chromosomal aberrations by Giemsa staining and three-color fluorescence in situ hybridization painting of the triplet (chromosomes #1, #2, and #4). The results of chromosomal aberrations followed the Poisson distribution in all individual and averaged data which include inter-individual variation in radiation susceptibility. Cytogenetics Dose Estimate Software version 5.2 was used to fit the dose-response curve and to determine the coefficients of linear-quadratic equations. The goodness of fit of the curves and statistical significance of fitted α and β-coefficients were confirmed in both Giemsa-based dicentric analysis and FISH-based translocation analysis. The coefficients calculated from the five-donor average data were almost identical in both of the analyses. We also present the results that the dose-response curve for dicentric chromosomes plus fragments could be more effective for dose estimation following low-dose radiation accidents.

Traditional programmable logic controllers (PLCs) remain central to industrial automation but are often expensive due to stringent compliance requirements. To address this challenge, this work proposes a low-cost and customizable framework for automation systems built upon open-source hardware and software components. The proposed solution integrates Linux-capable boards with an intermediate hardware module for input/output (I/O) management. A graphical user interface (GUI) based on the function block diagram (FBD) paradigm enables intuitive, visual logic programming, making the system accessible to users with different levels of expertise. Control logic is executed dynamically using a directed acyclic graph approach, which facilitates flexible processing and supports real-time updates without interrupting operation. The open-source design promotes flexibility and customization, positioning the framework as a versatile alternative to traditional PLCs. It is particularly suited for research laboratories, educational environments, small-scale industrial automation, and other cost-sensitive applications. Two case studies demonstrate its effectiveness in real-time control tasks, highlighting its practicality and ease of use. Given its open and modular nature, the framework is intended for educational use, research laboratories, and non-critical automation scenarios.

A RESEARCH ON SEAMLESS PLATFORM CHANGE OF REACTOR PROTECTION SYSTEM FROM PLC TO FPGA

IEC 61131-3 is an open standard that provides guidelines for programmable logic controllers and control systems. The standard defines specifications for control system programming languages, both textual and graphical. A control system application developed using these languages can go through several changes over the course of the project's life-cycle. While differences in textual programs can be detected using traditional text difference algorithms, there exist no effective means for tracking changes at a granular, semantic level for graphical control system programs. In this paper, we present an approach for comparison of graphical IEC 61131-3 programs, specifically those written using the Function Block Diagram and Sequential Function Chart notations. To perform this comparison, we represent the programs in an XML format, and use this to compare individual elements. The differences are computed and the programs are then rendered in a customized graphical viewer that highlights changes between programs. We implement a prototype comparison utility for graphical IEC 61131-3 programs and show how it can help reduce the effort involved in manual review and maintenance activities.

Stability and steady state analysis of control and safety systems of Nuclear Power Plants

Industrial risk prevention by robust filter for manufacturing control system

An appropriate simulation environment for testing real-time software applications, especially PLC (programmable logic controller) programs, is in demand for many reasons. One of the them might be found in the altered conditions of cooperation (teamwork, teleworking, etc.) under which PLC software projects have to be carried out. Most areas of automation engineering lack largely formalizable procedures, in particular within the specification and testing phase, and almost no tools are available for the development of real-time software. The consequence is that PLC programs are usually not developed before the facility to be controlled is installed, and putting it into operation is often the only test. This results in unacceptable waste of time during the installation phase, unacceptable high risks, and unacceptable high costs of the outcome. The availability of simulation tools including real-time hardware and software platforms open interesting perspectives pertaining to an integrated approach of analysis and design of PLC programs and the corresponding testing environments.

A safety class field programmable gate array based system in nuclear power plant has been developed to improve the diversity. Testbench is necessary to satisfy the technical reference, IEC-62566, for verification and validation of register transfer level code. We use the open verification methodology(OVM) developed by standard body. We show that our testbench can use random input for test. And also we show that reusability of block level testbench for the integration level testbench, which is very efficient for large scale system like nuclear reactor protection system.