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The ESIS Executive Committee decided to nominate a new team for the leadership and management of the TC12/ESIS technical committee (TC), as well as update the TC name as "Risk Analysis and Safety of Large Structures and Components". In this paper, the new organization of the TC12/ESIS as well as the objectives and tasks, and forthcoming events are presented. In addition, this document has editorial purposes regarding the selected and published papers from the International Symposium on Risk Analysis and Safety of Large Structures and Component s (ISRAS-TC12) organized within of the "2nd International Conference of Structural Integrity (ICSI)", which took place at Madeira Island, Portugal, on 4–7 September 2017. As guest editors and TC12/ESIS members, we hope the ISRAS-TC12 Special Issue provides a remarkable impact in the research related to fatigue, fracture, structural integrity, risk analysis and safety of complex structures and components. We also would like to express our gratitude to all authors for their contributions and to all reviewers for their generous work to guarantee the excellence of the papers. Finally, the guest editors would like to express a special thanks to Professor Richard Clegg, Editor-in-Chief of Engineering Failure Analysis journal, and to Elsevier staff for their support during the preparation of this issue. [ABSTRACT FROM AUTHOR]

The contribution describes probabilistic approach for evaluation of earthing system safety, which can complement the conventional earthing design methodology given by standard EN 50522, similarly as mentioned in British Annex NA. The main part of the contribution is application of the probabilistic risk assessment approach on case study of distribution transformer station earthing system. For presentation of benefits of probabilistic approach, the system solidly earthed, isolated, resonant earthed and resistor earthed were respected as the part of the case study. The contribution stipulates all crucial aspects of this process including probable drawbacks flowing from high amount of non-well known input variables which are necessary for probability calculation, e.g. human body presence, respected risk scenarios, frequency and type of earth faults, fault/contact coincidence, etc. The last part of the contribution is focused on sensitivity analysis of all crucial input variables which can affect final individual risk probability. [ABSTRACT FROM AUTHOR]

Many research reactors are used all over the world. There is a higher probability of accidents in nuclear research reactors compared their wide applications in a broad spectrum of sciences and industries. Material Testing Reactor (MTR) type is one large species of nuclear research reactors. Safety criteria are of main concern issues in the entire nuclear research reactor lifetime to satisfy the defense in depth criteria. In this paper, the main focus is on Second Shutdown System (SSS) as an Engineered Safety Feature (ESF) considered to enhance safety which will transfer the reactor to a subcritical state at actuation of any command circuits when a specific parameters exceeds some pre-established set points. Tehran Research Reactor (TRR) is selected as an MTR case study and one SSS is designed and studied in detail using MCNPX 2.6.0 code with regard to its requirements. It turns out that this SSS improves the overall reactor safety, and has not considerable penalties on different capabilities and characteristics of the reactor such as neutronic characteristics, safety criteria, and performance applications. [ABSTRACT FROM AUTHOR]

In this study, factors relevant to nature-ripened Gouda cheese were evaluated for their potential to inhibit growth of Listeria monocytogenes . Factors included water activity, pH, undissociated acetic and lactic acid, diacetyl, free fatty acids, lactoferrin, nitrate, nitrite and nisin. In addition, the effect of temperature was evaluated. For each factor, the actual concentrations and values relevant to Gouda cheese were obtained and the inhibitory effect of these individual factors on growth of L. monocytogenes was assessed. This evaluation revealed that undissociated lactic acid is the most important factor for growth inhibition of L. monocytogenes in Gouda cheese and that, additionally, low water activity as present in the cheese rind and after prolonged ripening times can also cause full growth inhibition. Gouda cheeses have a typical total lactic acid content of 1.47% w/w. In a 2-week old Gouda cheese, with a pH value of 5.25 and a moisture content of 42% w/w, the concentration of undissociated lactic acid in the water phase is 10.9 mM. Growth of L. monocytogenes is not supported when the undissociated lactic acid concentration is >6.35 mM. Concentrations of undissociated lactic acid in the water phase of Gouda cheese will be higher than this value when the total lactic acid content is >0.86% w/w at a pH < 5.25 (relevant to young Gouda cheese), or >1.26% w/w at a pH < 5.50 for mature Gouda cheese (moisture content of 35% w/w). This study underlines the importance of undissociated lactic acid as growth inhibitor for L. monocytogenes in Gouda cheese. [ABSTRACT FROM AUTHOR]

The probability of unexpected urban flood hazards is steadily increasing due to global warming and climate change. Consequently, there is a growing need for safety criteria determining the trafficability of inundated roads to ensure a fast and safe evacuation of people in case of such events. In order to determine those criteria, experimental investigations on the stability of two scaled watertight vehicle models and of one prototype passenger car are conducted in a laboratory flume and a steel tank. The conducted flume experiments clearly show a dependency of vehicle stability on the flow angle, whereas the prototype experiments indicate that floating water depths are higher in prototype than in model scale, which is due to the use of a watertight vehicle model. Based on both experiments, a constant total head is proposed as decisive parameter for determining trafficability. This parameter approximates the measured stability curves and can be easily adopted in practice. Furthermore, it is in accordance with fording depths evaluated from relevant literature or by means of manufacturer inquiry. The recommended safety criteria for passenger cars and emergency vehicles are total heads of h E =0.3 m= const . and h E =0.6 m= const ., respectively. [ABSTRACT FROM AUTHOR]

This paper describes an experimental procedure consisting of impact tests that simulate a collision of a human head with an industrial robot with the aim to validate a safety index named as New Index for Robots (NIR) and its outputs. The experiments in this paper are based on lab tests. It is an attempt to characterize the NIR index underlying the main parameters that are involved in crash interaction and to highlight limitations and weakness of suggested impact tests. [ABSTRACT FROM AUTHOR]

Abstract: New nuclear fuels offering enhanced operational safety levels are being developed. A tool for qualitatively assessing their safety credentials is proposed in the form of twelve key “behavioral characteristics” at the level of the 'fuel meat'-cladding-coolant system. The assessment of safety credentials for new fuel variants should be made using guidelines that are more generic than the industry criteria for standard Zr-clad uranium oxide fuels, otherwise safety margin benefits may not be adequately recognized. [Copyright &y& Elsevier]

The EU-DEMO (referred to as DEMO) tokamak complex currently consists of three buildings, like in ITER: the tokamak building, the tritium building and the diagnostics building. The tokamak building houses the tokamak itself and the numerous plant systems that interface with the necessary systems to produce and control the plasma. It is designed to permit assembly, operation and maintenance of the DEMO tokamak. The vacuum vessel is organized in 8 sectors, with radial ports at the lower and equatorial levels and one vertical upper port. The general architectural structure is arranged around the tokamak with a cylindrical bioshield of 2m thickness around the cryostat and floor levels corresponding to the cryostat penetrations. Additional levels are used for the integration of auxiliary equipment for the various plant systems and for accident mitigation systems. Currently, the tokamak building also represents the final nuclear confinement barrier for the radioactive material towards the environment and the public. This safety function requires the plant and safety systems to limit the release of radioactive substances during normal operation and in accidental conditions well below the safety limits. The complexity of a fusion power plant, like DEMO, with regards to integration of plant systems is much higher than that in a fission power plant due to the larger number of plant systems. Three main criteria drive the integration work of the plant systems inside the tokamak building: (i) safety requirements, (ii) functional requirements of the plant systems themselves and (iii) the maintenance approach. Cost considerations are also taken into account together with the normal and accidental environmental conditions in the various areas of the tokamak building that might challenge the qualifications of structures, systems and components (SSC). The layout of the tokamak building has to be further developed in the Concept Design Phase to follow the plant design evolution providing feedback to the various designers in order to assure that DEMO meets the cited design criteria with an optimized and licensable layout of the most complex nuclear building. [ABSTRACT FROM AUTHOR]

Abstract: In this research, neutronic calculation of current low enriched uranium control fuel elements replacement with high enriched uranium control fuel elements in the reference core of Tehran Research Reactor (TRR) has been investigated and the results of calculations are compared with the TRR neutronic safety criteria. Results show that all neutronic parameters of the reference and each mixed-core are lower than the safety criteria. Nuclear reactor analysis codes including MTR_PC package and MCNP5 were employed to carry out these calculations. [Copyright &y& Elsevier]

Abstract: This paper proposes an alternative theoretical methodology to evaluate the risks of CO2 leakage from reservoirs using a stochastic approach. The methodology suggested here makes use of three main concepts: [–] Features, Events and Processes (FEPs) [–] Interaction Matrix, IM [–] Stochastic Representation Both, FEPs and Interaction Matrix have been introduced by other researchers but for different objectives. The methodology that is proposed here modifies the original concept of Interaction Matrix in such a way that it may produce probabilistic results as outcome. A practical example is given at the end of this paper. [Copyright &y& Elsevier]

Abstract: The development of a methodology for defining safety criteria for CO2 geological storage, realised under the ongoing CRISCO2 project, is depicted in this paper. Generic lists of eleven risk events and nine types of targets are proposed to serve an expert panel for identifying risk scenarios. Assessing the effects of risk events and comparing targets exposure to critical thresholds should lead to setting safety requirements. We focus on simple modelling, such as abacuses, analytical or semi-analytical models. An uncertainty management framework completes this methodology. Further work will concentrate on effectively deducing safety criteria. [Copyright &y& Elsevier]

This paper describes methods and tools for safety analysis of UML statechart specifications. A comprehensive set of general safety criteria including completeness and consistency is applied in automated analysis. Analysis techniques are based on OCL expressions, graph transformations and reachability analysis. Two canonical intermediate representations of the statechart specification are introduced. They are suitable for straightforward implementation of checker methods and for the support of the proof of the correctness and soundness of the applied analysis. One of them also serves as a basis of the metamodel of a variant of UML statecharts proposed for the specification of safety-critical control systems. The analysis is extended to object-oriented specifications. Examples illustrate the application of the checker methods implemented by an automated tool-set. [Copyright &y& Elsevier]

• Estimation of reactivity feedback has been studied for an inherent safety fast reactor in unprotected transients. • The asymptotic approximation has been applied to estimate fuel and coolant temperatures. • Determination of safety criteria has been carried out to avoid fuel melting and coolant boiling. The effect of feedback reactivity on the safety of a fast reactor has been studied based on the asymptotic approximation for unprotected transients. The asymptotic approximation adopts the steady state heat transfer equation for calculating temperatures of coolant and fuel with the use of the relevant core power and mass flow. The feedback reactivity can be approximately estimated from the temperatures. This approximation is applied to the UTOP (unprotected transient overpower) and ULOF (unprotected loss of flow) accidents of a sodium-cooled fast reactor with a sodium plenum and GEM (gas expansion module). The reactivity feedback has been estimated, and the constraints of the feedback reactivity for maintaining the safety of the core have been predicted. For the UTOP accident the constraint for the control rod reactivity and the Doppler (+fuel expansion) reactivity coefficient is presented to prevent the fuel melting. For the ULOF accident the constraint of the parameter R is introduced which is the normalized ratio of the power to mass flow rate. The parameter does not exceed the critical point corresponding to the onset of the coolant boiling, and the coolant boiling does not occur because of the large negative reactivity insertion by the GEM. Thus the core safety can be approximately estimated by the present method without detailed calculations, though the accurate analyses are required by the use of transient analyses. [ABSTRACT FROM AUTHOR]

• A method for goal-oriented construction of reactor runaway criteria was presented. • The critical equation-based classifier was identified by genetic programming. • Tailored criteria were developed for batch and continuous stirred-tank reactors. • The resultant critical equations outperform the well-known criteria. Common thermal runaway criteria (e.g., divergence criterion and the Maxi criterion) may predict a thermal runaway unreasonably as the Maximum Allowable Temperature (MAT) is not taken into account. This contribution proposes a method for the goal-oriented construction of reactor runaway criteria by Genetic Programming (GP). The runaway prediction problem is formulated as a critical equation-based classification task, and GP is used to identify the optimal structure of the equations that also take into account the MAT. To demonstrate the applicability of the method, tailored criteria were developed for batch and continuous stirred-tank reactors. The resultant critical equations outperform the well-known criteria in terms of the early and accurate indication of thermal runaways. [ABSTRACT FROM AUTHOR]