Uncertainty Assessment for PA Models

A mathematical model comprises input variables, output variables and equations relating these quantities. The input variables may vary within some ranges, reflecting either our incomplete knowledge about them (epistemic uncertainty) or their intrinsic variability (aleatory uncertainty). Moreover when solving numerically the equations of the model, numerical errors are also arising. The effects of such errors and variations of the inputs have to be quantified in order to asses the model¿s range of validity. The goal of uncertainty analysis is to asses the effects of parameter uncertainties on the uncertainties in computed results. The purpose of this report is to give an overview of the most useful probabilistic and statistic techniques and methods to characterize uncertainty propagation. Some examples of application of these techniques for PA applied to radioactive waste disposal are given.JRC.F.4-Safety of future nuclear reactor

Review of Sensitivity Analysis Methods and Experience for Geological Disposal of Radioactive waste and Spent Nuclear Fuel

This reports gives an overview of sensitivity methods (screening, global and response surface based) that are suitable for safety analysis of a repository for radioactive waste or spent nuclear fuel. The theorerical background of the methods, their limitations and suitability for different analyses are discussed and illustrated by examples.JRC.F.7-Energy systems evaluatio

Global Sensitivity Analysis: An Approach Based on the Contribution to the Sample Mean Plot

The contribution to the sample mean plot, originally proposed by Sinclair (1993), is revived and further developed as practical tool for global sensitivity analysis. The potentials of this simple and versatile graphical tool are discussed. Beyond the qualitative assessment provided by this approach, a statistical test is proposed for sensitivity analysis. A case study that simulates the transport of radionu- clides through the geosphere from an underground disposal vault containing nuclear waste (OECD 1993) is considered as a benchmark. The new approach is tested against a very efficient sensitivity analysis method based on state dependent parameter meta-modelling (Ratto et al. 2007).JRC.G.9-Econometrics and statistical support to antifrau

IMPROVEMENTS IN THE EU GAS TRANSMISSION NETWORK BETWEEN 2009 AND 2014

The report compares the European gas infrastructure between 2009 and 2014 to demonstrate how Reg. (EC) 994/2010 has promoted and reinforced security of gas supply. Infrastructure improvements and results of a country-based simulation model analysing a Ukrainian and a Russian shortage of gas are presented.JRC.F.3-Energy Security, Systems and Marke

Formal Expert Judgement - An Overview

The scope of the document is to provide an overview on the formal process of expert judgement and it is targeted to readers that are not very familiar with the issue, but are interested to hvae a condensed summary on the topic. An emphasis is put on the use of formal expert judgement in the field of structural integrity, this being an area of interest in plant life management of ageing nuclear power installations. Moreover, the document can also be seen as a basis for developing an approach for formal expert judgement in other plant life management areas such as, for example, maintenance and in-service inspectionJRC.F.4-Nuclear design safet

Assessing the impact of investments in Cross-border pipelines on the security of gas supply in the EU

The European Union (EU) is highly dependent on external natural gas supplies and has experienced severe gas cuts in the past, mainly driven by the technical complexity of the high-pressure natural gas system and political instability in some of the supplier countries. Declining indigenous natural gas production and growing demand for gas in the EU has encouraged investments in cross-border transmission capacity to increase the sharing of resources between the member states, particularly in the aftermath of the Russia-Ukraine gas crisis in January 2009. This article models the EU interconnected natural gas system to assess the impact of investments in the gas transmission network by comparing the performance of the system for scenarios of 2009 and 2017, using a mathematical optimization approach. The model uses the technical data of the infrastructures, such as production, storage, regasification, and exchange capacity through cross-border pipelines, and proposes an optimal collaborative strategy which ensures the best possible coverage of overall demand. The actual peak demand situations of the extreme cases of 2009 and 2017 are analyzed under hypothetical supply crises caused by geopolitical or commercial disputes. The application of the proposed methodology leads to results which show that the investments made in this system do not decongest the cross-border pipeline network but improve the demand coverage. Countries such as Spain and Italy experience a lower impact on gas supply due to the variety of mechanisms available to cover their demand. Furthermore, the findings prove that cooperation facilitates the supply of demand in crisis situations

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