Risk Informed Support of Decision Making in Nuclear Power Plant Emergency Zoning - Generic Framework towards Harmonising NPP Emergency Planning Practices

The report provides a systematic overview of the essential aspects of risk informed support of decision making (RIDM) in nuclear power plant (NPP) emergency zoning (EZ) as a contribution to harmonising strategic practices in the area. Owing to the state-of-the-art understanding and increased characterisation of NPP severe accidents, overall management of them should be analysed as an integrated complex process. The interrelationship of NPP emergency operating procedures, safety and risk assessments, severe accident management guidelines, and emergency off-site actions should be planned and organised to minimize the consequences of such accidents. A deterministic approach, coupled with both probabilistic safety assessment (PSA) technology and PSA results can play significant role in the development of relevant nuclear utility, regulatory and all stakeholders policies. The report describes the background, objectives and current state of a corresponding activity within JRC-IE's Analysis and Management of Nuclear Accidents (AMA) Action on probabilistic safety / risk assessment methodologies and practices for RIDM approach applied to NPP EZ. The approach is interdisciplinary, based on integration of PSA technology, severe accident phenomenology, and radiological protection.JRC.F.4-Nuclear design safet

Smart Grid Interoperability Laboratory

The Smart Grid Interoperability Laboratory in Petten was inaugurated on 29/11/2018. The Smart Grid Interoperability Laboratory is designed to foster a common European approach to interoperable digital energy, focussing on the smart home, community and city levels. The facility in Petten is part of a larger activity of the Joint Research Centre, as the science and knowledge service of the European Commission, encompassing electric vehicles, smart grids and batteries. The activities in 2019 are highlighted in this report.JRC.C.3-Energy Security, Distribution and Market

Early onset lung cancer, cigarette smoking and the SNP309 of the murine double minute-2 (MDM2) gene

The polymorphism SNP309 (rs2279744) in the promoter region of the MDM2 gene has been shown to alter protein expression and may play a role in the susceptibility to lung cancer. The MDM2 protein is a key inhibitor of p53 and several mechanisms of MDM2/p53 interactions are presently known: modulating DNA-repair, cell-cycle control, cell growth and apoptosis

Simulation of helium release in the Battelle Model Containment facility using OpenFOAM

The open source CFD code OpenFOAM has been validated against an experiment of jet release phenomena in the Battelle Model Containment facility (BMC), a 560 m3 multi-compartment experimental facility. In the selected test, HYJET Jx7, helium was released into the containment at a speed of 42 m/s over a time of 200 s. The SST turbulence model and two grids (a coarse and a finer hexahedral grid) are considered to model helium release and dispersion. Simulation results are also compared with analogous calculations performed with the commercial CFD code CFX 5.7. The overall behaviour is captured adequately. However, there are still some noticeable differences between the CFX and OpenFOAM solutions. It is therefore likely that the two turbulence models are not exactly the same. This may be due to differences in the used version of the model or their coefficients.. The study confirms the potentiality of using open source OpenFOAM CFD code for nuclear safety applications. Nevertheless further investigations and improvements are needed.JRC.F.5-Nuclear Reactor Safety Assessmen

CFD Modelling of Accidental Hydrogen Release from Pipelines

Although nowadays hydrogen is distributed mainly by trailers, in the future distribution by means of pipelines will be more suitable if larger amounts of hydrogen are produced on industrial scale. Therefore from the safety point of view it is essential to compare hydrogen pipelines to natural gas pipelines, whose use is well established today. Within the paper we compare safety implications in accidental situations. In the analysis we do not consider technological aspects such as compressors or seals. Using a CFD (Computational Fluid Dynamics) tool, it is possible to investigate the effects of different properties (density, diffusivity, viscosity and flammability limits) of hydrogen and methane on the dispersion process. In addition CFD tools allow studying the influence of different release scenarios, geometrical configurations and atmospheric conditions. An accidental release from a pipeline is modelled. The release is simulated as a flow through a small hole between the high-pressure pipeline and the environment. A part of the pipeline is included in the simulations as high-pressure reservoir. Due to the large pressure difference between the pipeline and the environment, the flow conditions at the release become critical. For the assumed scenarios larger amount of flammable mixture could be observed in case of hydrogen release. On the other hand, because of buoyancy and a higher sonic speed at the release, the hydrogen clouds are farther from the ground level or buildings than in case of the methane clouds, decreasing the probability of ignition and reducing the flame acceleration due to obstacles in case of ignition. Results on the effect of wind in the release scenarios are also described.JRC.F.4-Nuclear design safet

An Adaptive 3-D CFD Solver for Modelling Explosions on Large Industrial Environmental Scales.

Abstract not availableJRC.(ISIS)-Institute For Systems, Informatics And Safet

Risk Assessment of Hydrogen Explosion for Private Car with Hydrogen-Driven Engine

The aim of the study is to identify and quantify the additional risks related to hydrogen explosions during the operation of a hydrogen driven car. In a first attempt the accidents or failures of a simple one-tank hydrogen storage system has been studied as a main source of risk. Three types of initiators are taken into account: crash accidents, fire accidents without crash (no other cars are involved) and hydrogen leakages in normal situation with following ignition. The consequences of hydrogen ignition and/or explosion depend strongly on environmental conditions (geometry, wind, etc.), therefore the different configurations of operational and environmental conditions are specified. Then Event Tree / Fault Tree methods are applied for the risk assessment. The results of quantification permit to draw conclusions about the overall added risk of hydrogen technology as well as about the main contributors to the risk. Results of this work will eventually contribute to the on-going pre-normative research in the field of hydrogen safety.JRC.DDG.F.2-Cleaner energ

CFD Simulations of Hydrogen Combustion in a Simplified EPR Containtment with CFX and REACFLOW

The prediction of over-pressures and temperatures that are generated by hydrogen explosions in case of a severe nuclear accident is a crucial stage of the safety analysis of the containment. The investigation presented in this paper is a continuation of the numerical studies of validation and benchmarking that were carried out in the European co-sponsored project HYCOM. In the present work, numerical simulations of hydrogen deflagrations within a simplified, real-scale EPR (European Pressure Reactor) containment have been performed with two CFD codes, CFX4 and REACFLOW. The analysis has been focused not only on overpressure peaks and pressure oscillations, but also on pressure differences between the two sides of the same wall of internal compartments. Different geometrical configurations have been considered in term of presence of vents between internal compartments and in term of vents number, size and position. Single and multiple ignition points have also been taken into account. The paper describes the main results of the investigation and it is a demonstration of how CFD modelling can provide significant indications for real-scale safety applications within the limits of uncertainty of the accident scenarios.JRC.F.4-Nuclear design safet

Simulation of Containment Jet Flows Including Condensation

The validation of a CFD code for light-water reactor containment applications requires among others the presence of steam in the different flow types like jets or buoyant plumes and leads to the need to simulate condensation phenomena. In this context the paper addresses the simulation of two ¿HYJET¿ experiments from the former Battelle Model Containment by the CFD code CFX. These experiments involve jet releases into the multicompartment geometry of the test facility accompanied by condensation of steam at walls and in the bulk gas. In both experiments mixtures of helium and steam are injected. Helium is used to simulate hydrogen. One experiment represents a fast jet whereas in the second test a slow release of helium and steam is investigated. CFX was earlier extended by bulk and wall condensation models and is able to model all relevant phenomena observed during the experiments. The paper focuses on the simulation of the two experiments employing an identical model set-up. This provides together with other validation exercises the information on how well a wider range of flowing conditions in a full containment simulation can be covered with a single set of models (e.g. turbulence and condensation model). Some aspects related to numerical and modelling uncertainties of CFD calculations are included in the paper by investigating different turbulence models together with the modelling errors of the differencing schemes applied.JRC.DDG.F.2-Cleaner energ

CFD Modelling of Gas-Transport and Mixing Phenomena in the Batelle Experimental Facility for Nuclear Safety Applications

This paper describes the results of CFD (Computational Fluid Dynamics) analysis of jet release, dispersion and mixing phenomena of light gases in nuclear environments for safety applications. A validation exercise with three CFD codes (CFX4, CFX5.7 and CD-ACE) was performed against experimental data of a test in the Batelle Model Containment facility.JRC.F.4-Nuclear design safet