Showing papers on "Inherent safety published in 2003"
TL;DR: The proposed ISD measurement procedure has a major advantage of expanding consideration in future to incorporate economic, regulatory, pollution control and worker health aspects, as well as factors such as the experience one has or 'the comfort level' one feels with each of the processes under consideration.
102 citations
TL;DR: The present paper introduces the use of fuzzy logic for the measurement of inherent safety and describes the development of an overall index for use in process simulation and process synthesis to generate inherently safer alternatives and to evaluate them in a systematic and rapid way.
86 citations
TL;DR: The inherent safety index developed by Heikkila is taken as a base and is compared with the results of the proposed prototype index, which shows the benefits of using fuzzy logic.
Abstract: During the past several years, researchers in the U.S. and Europe have developed measurement techniques and analysis tolls to estimate the inherent safety of a plant or a processing unit. These tolls are based on traditional Boolean mathematical methodologies that are limited by the uncertain and subjective nature of the information analyzed. Preliminary results reported here are on the development of an inherent safety index based on fuzzy logic theory that is an extension of the Boolean theory. The basic ideas of fuzzy logic theory and its application are presented by the inherent safety evaluation of a storage tank. The inherent safety index developed by Heikkila is taken as a base and is compared with the results of the proposed prototype index. It shows the benefits of using fuzzy logic. Strengths and limitations of the proposed methodology are also presented.
73 citations
TL;DR: In this paper, a detailed study was conducted to analyze the performance of available hazard indices with reference to various inherent safety principles (guidewords), and the results showed that none of the indexing procedures can capture all of the inherent safety guidewords.
Abstract: Inherent safety is a proactive approach for loss prevention during process plant design. It has been proven that, considering the lifetime costs of a process and its operation, an inherent safety approach can lead to a cost-optimal option. Application of inherent safety at the early stages of process design yields the best results with respect to process selection, conceptual design, and engineering design. However, in spite of being an attractive and cost-effective approach to loss prevention, it is not widely used. Reasons have been suggested for this lack of widespread use, but the lack of systematic tools to apply inherent safety principles is perhaps the most important one.
A detailed study was conducted to analyze the performance of available hazard indices with reference to various inherent safety principles (guidewords). The performance of four main indices (Dow, Mond, Inherent Safety, and Safety Weighted Hazard [SweHI] indices) was studied for five inherent safety guidewords. None of the indexing procedures can capture all of the inherent safety guidewords, although the SWeHI and Dow Index were found to be robust on many accounts. It is recommended that a new specific index be developed for inherently safer design evaluation. The SWeHI and Dow indexing procedures may be a good basis on which to build.
68 citations
TL;DR: In this paper, the authors developed a hierarchical approach to reveal the degree of non-ideality of chemical processes with regard to safety, health and environment aspects at different layers: the properties of the chemical substances involved (substance layer); possible interactions between the substances (reactivity layer); the possible scenarios resulting from the combination of substances and operating conditions in the various equipments involved (equipment layer); and the safety and end-of-pipe technologies that are required to run a process safely and in accordance with legal regulations (safety technology layer).
50 citations
TL;DR: Inherent Safety is generally recognised as an important concept in the design of chemical plants as discussed by the authors, however, it is often regarded as the sole province of engineers and is not considered as a feasible concept in many industrial environments.
45 citations
TL;DR: In this article, an integrated system for generation of sustainable process alternatives with respect to new process design as well as retrofit design is presented, which is based on a recently developed path flow analysis approach.
Abstract: This paper presents an integrated system for generation of sustainable process alternatives with respect to new process design as well as retrofit design. The generated process alternatives are evaluated through sustainability metrics, environmental impact factors as well as inherent safety factors. The process alternatives for new process design as well as retrofit design are generated through a systematic method that is simple yet effective and is based on a recently developed path flow analysis approach. According to this approach, a set of indicators are calculated in order to pinpoint unnecessary energy and material waste costs and to identify potential design (retrofit) targets that may improve the process design (in terms of operation and cost) simultaneously with the sustainability metrics, environmental impact factors and the inherent safety factors. Only steady state design data and a database with properties of compounds, including, environmental impact factor related data and safety factor related data are needed. The integrated computer-aided system generates the necessary data if actual plant or experimental data are not available. The application of the integrated system is highlighted through a number of examples including the well-known HDA process.
30 citations
TL;DR: In this paper, the authors take a deep look at the costs related to process safety, including the costs of trips and alarms, compliance with regulations and worker training, but also take into consideration many aspects considered standard process design practice.
23 citations
TL;DR: The fundamentals of Inherently Safer Design were not fully appreciated in the initial design (or re-design) in the following series of case histories.
19 citations
29 Sep 2003
TL;DR: The 2 Young Engineers’ Satellite (YES2) features An Inherently-safe Re-entry vehicle (AIR), which is lighter than any previous re- entry vehicle design, and has an extremely low ballistic coefficient.
Abstract: The 2 Young Engineers’ Satellite (YES2) features An Inherently-safe Re-entry vehicle (AIR). AIR is lighter than any previous re-entry vehicle design, and has an extremely low ballistic coefficient. Therefore it will decelerate very early in the re-entry (at 80 km rather than typical 50 km) and will remain relatively cool, in its turn allowing for a lightweight thermal protection system. The low terminal velocity of the vehicle (soccer ball impact energy) and inherent safety may allow it to land Western Europe. Such a capsule can return samples from Space Station quickly and directly to the customer. The design of AIR started with a design brainstorm in which 18 universities around Europe participated, based on a minimal set of requirements: weight, inherent safety, recoverability, payload capability. About 25 concepts were entered, in various levels of detail. The paper discusses the concept evaluation logic, design approach and prototyping. The preferred concepts for further study were the inherently safe “cold re-entry” vehicles, very light (few kg) or single-stage inflatable without any hard parts (except for ~1 kg payload and recovery system). If inflation is performed, it is done already before re-entry. Most of the support systems are released before atmospheric entry, further reducing the capsule’s weight. The vehicle is axially symmetric, is uncontrolled and has no lift to reduce landing site errors. The remaining designs that satisfied the requirements were (temporarily) stripped of all particular features that add complexity, and were merged into 3 high-level concepts (COLD, MOLD, FOLD). Mock-ups for each concept were tested with drop test and aerodynamic measurements. Next, at least one flight-prototype per concept will be built. For the detailed design, the main design driver is manufacturability, so a material search and characterization was a large part of the initial design activity. Heat resistant fabrics and lightweight insulators such as Nextel, Pyrogel and Alumina were selected and tested in a re-entry simulation chamber. Because the inflatable for re-entry purposes is a new technology and the flexibility of the vehicle interacts with the aerodynamic performance, an iterative CAD/FEM/CFD design is required, which has to be verified by test. Results of aerodynamics, stability analysis and re-entry simulations are used to optimize the shape within limits of manufacturability. Production of flightscale prototypes has started.
8 citations
TL;DR: Newly proposed design features enable the GTHTR300 to be an efficient and economically competitive reactor in 2010's and take advantage of its inherent safety characteristics.
Abstract: Japan Atomic Energy Research Institute (JAERI) has undertaken the study of an original design concept of gas turbine high temperature reactor, the GTHTR300. The general concept of this study is development of a greatly simplified design that leads to substantially reduced technical and cost requirements. Newly proposed design features enable the GTHTR300 to be an efficient and economically competitive reactor in 2010's. Also, the GTHTR300 fully takes advantage of its inherent safety characteristics. The safety philosophy of the GTHTR300 is developed based on the HTTR (High Temperature Engineering Test Reactor) of JAERI which is the first HTGR in Japan. Major features of the newly proposed safety philosophy for the GTHTR300 are described in this article. (authors)
TL;DR: In this article, the authors argue that risk is proportional to the square of the operating cost and that risk equals likelihood times consequence, where likelihood is a function of cause which is usually human error or omission.
TL;DR: The database that is developed contains process incidents which could have been averted by the application of inherent safety (IS) principles, and potential applications are presented.
Abstract: An inherently safer process relies on naturally occurring phenomena and robust design to eliminate or greatly reduce the need for instrumentation or administrative controls. Such a process can be designed by applying inherent safety (IS) principles such as intensification, substitution, attenuation, limitation of effects, simplification, etc, throughout the design process, from conception until completion. While the general principles and benefits of IS are well known, a searchable collection of inherently safer designs that have been implemented in industry has not been reported. Such a database of inherently safer design (ISD) examples would assist the process designer in the early stages of the design lifecycle when critical design decisions are made. In addition to examples of IS design which have been successfully carried out, the database that we have developed contains process incidents which could have been averted by the application of ISD. In this paper, details of the database, the query engine, and potential applications are presented.
01 Jan 2003
TL;DR: For the first time, PRA analysts and designers can easily determine the probabilistic implications of different design configurations and operating conditions in various combinations for the entire range of initiating events.
Abstract: True design optimization of a plant=s inherent safety and performance characteristics results when a probabilistic risk assessment (PRA) is integrated with the plant-level design process. This is the approach being used throughout the design of the International Reactor Innovative and Secure (IRIS) nuclear power plant to maximize safety. A risk-based design optimization tool employing a “one-button” architecture is being developed by the Oak Ridge National Laboratory to evaluate design changes; new modeling approaches, methods, or theories; modeling uncertainties and completeness; physical assumptions; and data changes on component, cabinet, train, and system bases. Unlike current PRAs, the one-button architecture allows components, modules, and data to be interchanged at will with the probabilistic effect immediately apparent. Because all of the current and previous design, modeling, and data sets are available via the one-button architecture, the safety ramifications of design options are evaluated, feedback on design alternatives is immediate, and true optimization and understanding can be achieved. Thus, for the first time, PRA analysts and designers can easily determine the probabilistic implications of different design configurations and operating conditions in various combinations for the entire range of initiating events. The power of the one-button architecture becomes evident by the number of design alternatives that can be evaluatedC11 component choices yielded 160 design alternatives. Surprisingly, the lessons learned can be counter-intuitive and significant. For example, one of the alternative designs for IRIS evaluated via this architecture revealed that because of common-cause failure probabilities, using the most reliable components actually decreased systems’ reliablity.
01 Jan 2003
TL;DR: In this paper, a brief description on CANDU Reactor's benefits, such as use of natural uranium as the fuel, high capacity factor, high inherent safety performance in certain aspects and mass isotope production capability at low cost, were briefly described in the paper.
Abstract: This paper provides a brief description on CANDU reactor's benefits, such as use of natural uranium as the fuel, high capacity factor, high inherent safety performance in certain aspects and mass isotope production capability at low cost, were briefly described in the paper. However problems including only 25 year lifetime for the pressure tube, complicate D 2O management and higher tritium release. It also presents the recent development of CANDU reactor, involving fuel design, fuel channel design, improvement of the heat transport system parameters, optimized construction and enhancement on passive safety performance etc.
01 Jan 2003
TL;DR: The South African Pebble Bed Modular Reactor (PBMR) as discussed by the authors is a small nuclear power plant with helium coolant, graphite moderator and fuel in the form of uranium oxide pellets embedded in carbon spheres or "pebbles".
Abstract: Publisher Summary Nuclear power provides a large scale source of electricity with no greenhouse emissions during operation and minimal amounts during construction, fuel preparation and decommissioning. Moreover, nuclear power has an unrivaled safety record in the West. At present, the disadvantages of nuclear power are poor public perceptions and high capital costs because existing designs need elaborate safety systems. A new generation of simple and small reactors offers inherent safety, where safety is built into the design, dispensing with the expensive safety systems and greatly reducing costs. One of these is the South African Pebble Bed Modular Reactor (PBMR). This is a small reactor of about 120 MWe, with helium coolant, graphite moderator, and fuel in the form of uranium oxide pellets embedded in carbon spheres or “pebbles”. It operates in a Brayton cycle where the heated gas from the reactor drives a gas turbine. It has low power density and passive or inherent safety. No human error or equipment failure can cause an accident that endangers the public. Nuclear radioactive waste is small, solid, stable, of finite life, and technically easy to dispose of safely. In contrast, coal waste is massively larger in mass and lasts much longer. It includes sulphur and nitrogen gaseous compounds, organic compounds, heavy metal toxins such as arsenic, which last forever, and radioactive substances such as thorium with half-lives of billions of years. Coal waste is hurled into the air people breathe or dumped onto huge open tips. In operation, nuclear power does not release greenhouse gases. Over its complete life, including mining of the uranium, fuel enriching, fuel preparation, operations and decommissioning, nuclear power releases among the lowest of any generating technologies, including solar, wind, and hydropower.