Showing papers on "Inherent safety published in 2023"
TL;DR: In this paper , the authors provide some insights and recommendations for the future development of new research activities, in national and international frameworks, in relation to thermal hydraulics of SMRs.
1 citations
TL;DR: In this article , a nodal dynamic modeling methodology with explicitly modified point kinetics equation and Mann's model for heat transfer is used to evaluate six parameters that can impact MSR safety.
1 citations
TL;DR: In this article , an inherently safer design method for batch chemical reactors is proposed, which maximizes the yield of target product while minimizes Dow's fire and explosion index, and two examples for specific reaction systems with given kinetics are performed to demonstrate the feasibility and validity of the proposed method.
Abstract: The economic attractiveness of an industrial process depends a large extent on its safe and reliable operation. The inherently safer design can help reduce the potential hazard on a fundamental level and eliminate escalation at the early stage of process development. In this work, an inherently safer design method for batch chemical reactors is proposed, which maximizes the yield of target product while minimizes Dow’s fire and explosion index. Process safety time is introduced as criterion to respond to the thermal runaway risk risen by unexpected failures. Finally, two examples for specific reaction systems with given kinetics are performed to demonstrate the feasibility and validity of the proposed method. The results indicate that the product yield optimized with the proposed method is significantly higher than that obtained from literature approach involving temperature limit or divergence criterion under the same PST. With the same yield, the PST optimized with the proposed method is longer.
1 citations
TL;DR: In this article , a knowledge-driven model was proposed to assess inherent safety in process infrastructure under uncertainty, considering chemical, reaction, process, equipment, human factors, and organizational concerns associated with process plants.
Abstract: Process safety has drawn increasing attention in recent years and has been investigated from different perspectives, such as quantitative risk analysis, consequence modeling, and regulations. However, rare attempts have been made to focus on inherent safety design assessment, despite being the most cost-effective safety tactic and its vital role in sustainable development and safe operation of process infrastructure. Accordingly, the present research proposed a knowledge-driven model to assess inherent safety in process infrastructure under uncertainty. We first developed a holistic taxonomy of contributing factors into inherent safety design considering chemical, reaction, process, equipment, human factors, and organizational concerns associated with process plants. Then, we used subject matter experts, content validity ratio (CVR), and content validity index (CVI) to validate the taxonomy and data collection tools. We then employed a fuzzy inference system and the Extent Analysis (EA) method for knowledge acquisition under uncertainty. We tested the proposed model on a steam methane-reforming plant that produces hydrogen as renewable energy. The findings revealed the most contributing factors and indicators to improve the inherent safety design in the studied plant and effectively support the decision-making process to assign proper safety countermeasures.
1 citations
TL;DR: In this article , the authors proposed a systematic methodology for designing the energy-efficient extractive dividing wall column processes by applying heat pump and feed preheating techniques to separate binary azeotrope.
Abstract: Inherently safer design during the preliminary design stage is vital to reduce the potential risks and accidents of new process design. So far, little effort has been paid to incorporating inherent safety assessment into the techno-evaluation of heat-integrated extractive dividing wall column processes toward sustainable development. To this end, this paper proposes a systematic methodology for designing the energy-efficient extractive dividing wall column processes by applying heat pump and feed preheating techniques to separate binary azeotrope. The proposed approach gradually recovers the waste heat within the process, and the separation of acetonitrile and water is selected as a case. The results show that the total energy consumption, total annual cost, and the CO2 emissions of heat-integrated extractive dividing wall column processes are significantly reduced compared to conventional design, and the thermodynamic efficiency is simultaneously improved. In the process evaluation stage, the inherent safety analysis is performed regarding the Process Route Index and Process Stream Index. Such indices give insights into process safety performance in terms of the overall process and individual streams. The results of the inherent safety investigation show the intensified extractive dividing wall column by a single heat pump performs better than the dual heat pump-assisted process. This multi-criterion evaluation demonstrates a trade-off between inherent safety performance and energy saving in applying a heat pump system in conjunction with the distillation process.
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TL;DR: In this paper , the authors discuss several indices that can measure the inherent safety level of the available process alternatives, including material properties, reaction pathway aspects, equipment characteristics, economics, health, and environment.
Abstract: The enormous increase in the number and scale of chemical process industries has made safety more critical than ever. The safety level of the process can be improved by various approaches like improving the control systems and employing add-on safety systems. These techniques reduce the risk level but the hazard still exists and the failure of these add-on systems can lead to catastrophes. If the hazard potential of the plant can be reduced or even eliminated by careful selection of the process and robust design of the plant, then the need for add-on safety systems and controls is reduced—making the plant inherently safer. In this chapter, we discuss several indices that can measure the inherent safety level of the available process alternatives. We provide a broad classification of these indices based on factors each of these indices considers for evaluating the inherent safety characteristics of a process. These factors typically include material properties, reaction pathway aspects, equipment characteristics, economics, health, and environment.
TL;DR: In this article , the authors focus on the inherently safer operation concept, its probable outcomes, and possible ways to execute inherent safety studies at the operational stage, and several examples of implementing inherent safety in existing process plants are discussed to demonstrate its usage.
Abstract: Process plants manufacture chemical products to meet modern world needs. For safer operation, process safety is envisaged via four strategies, namely inherent, passive, active, and procedural. Among them, the inherent strategy covers all stages of the process life cycle. However, it is best to be applied at the design stage and has lesser application towards the operational process plant. For this reason, the precise technique for the inherently safer operation is difficult to get in the open literature. Therefore, the main emphasis of this chapter is on the inherently safer operation concept, its probable outcomes, and possible ways to execute inherent safety studies at the operational stage. Several examples of implementing inherent safety in existing process plants are also discussed to demonstrate its usage. However, inherently safer operations and dynamic risk assessment via the industrial revolution 4.0 are expected to play a vital role in sustainable operational process plants.
TL;DR: An overview of safety strategies especially the inherently safer approach to process safety is provided in the Methods in Chemical Process Safety (MPS) series as discussed by the authors , where the authors present a hierarchy of controls for process safety and briefly introduce inherently safer design strategies.
Abstract: The chemical industries contribute significantly to the advancement of human lifestyle by producing diversified products including fuel, textiles, fertilizers, pharmaceuticals, food additives, plastics, and electronics. Materials being processed in the chemical industries, however, are potentially hazardous due to their inherent properties including high reactivity, flammability, explosiveness, toxicity, and requiring extreme operating conditions such as high temperature and pressure. Inappropriate handling, storage, or transportation of these substances can increase the likelihood of catastrophic accidents causing fire, explosion, and release of toxic chemicals. Thus, processing systems have been continuously striving to develop and implement new technologies and innovative processes that minimize risk and increase safety and sustainability. This chapter provides an overview of safety strategies especially the inherently safer approach to process safety. Section 1 presents the hierarchy of controls for process safety and Section 1 briefly introduces inherently safer design (ISD) strategies. The advantages, limitations, and implications of ISD have been presented in Section 3 and the applications of ISD in chemical and nonchemical industrial applications have been introduced in Section 4. Finally, Section 5 outlines an overview and development of this Volume 7 of the Methods in Chemical Process Safety series.
TL;DR: Schmidt et al. as discussed by the authors presented a structure containing three modules for the new safety device. For each module, a detailed evaluation of available methods and devices to meet the requirements of reliability, flexibility, and precise countermeasures for the safety device have been performed.
Abstract: Mechanical safety devices and safety integrity systems are widely spread in the industry to protect chemical reactors against runaway reactions. However, these devices are limiting the productivity and flexibility of the plants due to their fixed set conditions and discharge areas. Hence, a new, intelligent, and adaptive safety device is required in the industry. This article presents a structure containing three modules for the new safety device. For each module, a detailed evaluation of available methods and devices to meet the requirements of reliability, flexibility, and precise countermeasures for the safety device have been performed. Concluding, a basic structure of the adaptive safety devices is outlined. Mechanical safety devices and safety integrity systems are widely spread in the industry to protect chemical reactors against runaway reactions. However, these devices are limiting the productivity and flexibility of the plants due to their fixed set conditions and discharge areas. Hence, a new, intelligent, and adaptive safety device is required in the industry. This article presents a structure containing three modules for the new safety device. For each module, a detailed evaluation of available methods and devices to meet the requirements of reliability, flexibility, and precise countermeasures for the safety device have been performed. Concluding, a basic structure of the adaptive safety devices is outlined. The article represents the extended manuscript for publication in (Schmidt et al., 2022).
TL;DR: In this article , the authors proposed a method called Failure Mode Risk Decision (FMRD) to review the inherent hazards of a micro-refinery unit (MRU) that converts flared and wasted natural gas to long chain hydrocarbons.
Abstract: Laboratory hydrogen generators, medical oxygen, and micro-breweries are examples of modular and micro technologies that are commercial successes. Researchers, patients, and unskilled workers operate these facilities but more complex processes require highly qualified personnel to ensure they operate safely. Modular-micro processes in isolated locations meet economic objectives when operated remotely thereby minimizing labor costs. Mitigating the risk requires a comprehensive hazards analysis with advanced control systems particularly for explosive and toxic compounds. Here, we propose a method called Failure Mode Risk Decision (FMRD) to review the inherent hazards of a micro-refinery unit (MRU) that converts flared and wasted natural gas to long chain hydrocarbons. This approach combines the Process Flow Failure Mode (PFFM) methodology as a systematic and reliable technique with a novel numerical risk assessment to improve the analytical evaluation of hazardous conditions. The objective is to combine causes and consequences in a single metric, where scaled probability of evident causes and severity of consequences are used to derive a risk level measure. With the proposed metric, the magnitude of a potential hazard is directly correlated with the risk level. This mechanism identifies extra risk scenarios compared to the classical hazard analysis method and provides a straightforward comprehensive numerical assessment to represent the inherent and residual risks to facilitate justifying the hazardous scenarios. Accordingly, we design a safety loop and supply all the required facilities to remove the potential risks at the process plant. Not only the proposed methodology clarifies the risks of the MRU presented in this study, but can be extended to review the hazards of other chemical process plants.
TL;DR: Wang et al. as discussed by the authors analyzed the safety performance of a 100 MW (e) small modular lead-bismuth eutectic cooled nuclear power plant with ATHLET/MOD 3.
Abstract: Nuclear energy plays an important role in the green low-carbon energy. The lead-based reactor is one of the most popular small modular reactor types. The pre-conceptual design of a 100 MW(e) small modular lead-bismuth eutectic cooled reactor was developed by Shanghai Nuclear Engineering Research & Design Institute CO., LTD. to meet the market demand of advanced small-scale nuclear plant. Representative accidents were analyzed for the 100 MW(e) small modular lead-bismuth reactor using ATHLET/MOD 3. The result shows that under the design basis conditions, the performance of the reactor can meet the safety criteria with the protection system working normally. The coolant solidification in the primary circuit under these transients should be prevented. Under the design extension condition, the highest cladding temperature is much lower than the melting point. In the unprotected reactivity insertion condition, there may be a short time of local melting of the fuel, which also meet the acceptance criteria. The safety analysis demonstrated the passive safety of the design with the negative temperature coefficient, strong natural circulation capability, and the passive residual heat removal system.
TL;DR: In this paper , the authors focus on safety aspects while addressing the fundamental safety requirement that are derived from fundamental safety principles, the acceptance criteria, the expected/envisaged safety targets and not only the economic impact/considerations.
Abstract: Abstract Many countries are considering Small and Modular Reactors as a viable alternative to counter the climate-change/global-warming with a quick deployment of green, carbon free nuclear energy option in the energy mix. Proponents of SMRs claim that these designs rely more on enhanced inherent/engineered safety and passive features with novel concepts. SMRs are being designed to be fabricated at a factory and then transported as ‘modules’ to the sites for installation either as a single module or multiple module plant. There are many variant of SMRs under considerations/design/construction/commissioning/operation states and majority of the, more than 70 odd SMRs are in the design stage. The paper focuses on safety aspects while addressing the fundamental safety requirement that are derived from fundamental safety principles, the acceptance criteria, the expected/envisaged safety targets and not only the economic impact/considerations. The assessment basis for requirements towards safety enhancements and their extent of assurance in the design are highlighted against the claims made. Ensuring SMR safety with respect to the fundamental safety functions will depend on the foreseen/predicted fission product releases, following overheating of the fuel, during the worst/credible accident conditions and likelihood of occurrence of these accidents. Innovations in the development of advanced fuel, deploying passive safety systems, novel concepts in main heat transport system configuration and advanced features in instrumentation can help in realising the goal of ensured enhanced safety in the SMRs, both in preventive and mitigation domains during severe accidents. Enhancements in the acceptance criteria and deterministic and probabilistic safety targets is also expected and may be envisaged. The paper brings out the challenges faced in the design and regulation of the new NPPs, while addressing fundamental safety principles implementation, generic, specific safety issues, and only genuine innovations can ensure and improve the safety. Aspects related to passive systems and the optimal main heat removal system configuration of the NPPs are also discussed. The aspects related to concurrent design and regulation of new NPPs including SMRs also has been brought out in the paper.
01 Jul 2023
TL;DR: Schmidt et al. as discussed by the authors presented a structure containing three modules for the new safety device. For each module, a detailed evaluation of available methods and devices to meet the requirements of reliability, flexibility, and precise countermeasures for the safety device have been performed.
Abstract: Mechanical safety devices and safety integrity systems are widely spread in the industry to protect chemical reactors against runaway reactions. However, these devices are limiting the productivity and flexibility of the plants due to their fixed set conditions and discharge areas. Hence, a new, intelligent, and adaptive safety device is required in the industry. This article presents a structure containing three modules for the new safety device. For each module, a detailed evaluation of available methods and devices to meet the requirements of reliability, flexibility, and precise countermeasures for the safety device have been performed. Concluding, a basic structure of the adaptive safety devices is outlined. Mechanical safety devices and safety integrity systems are widely spread in the industry to protect chemical reactors against runaway reactions. However, these devices are limiting the productivity and flexibility of the plants due to their fixed set conditions and discharge areas. Hence, a new, intelligent, and adaptive safety device is required in the industry. This article presents a structure containing three modules for the new safety device. For each module, a detailed evaluation of available methods and devices to meet the requirements of reliability, flexibility, and precise countermeasures for the safety device have been performed. Concluding, a basic structure of the adaptive safety devices is outlined. The article represents the extended manuscript for publication in (Schmidt et al., 2022).
TL;DR: In this article , the Integrated Risk-Informed Safety Classification (IRISC) procedure is presented, which is a novel extension of the IAEA recommended process with dedicated probabilistic treatment of research reactor designs.