Kaisa Simola

European Commission | ec · Joint Research Centre (JRC)

Risk-informed in-service inspection (RI-ISI) approaches are used to define inspection programmes based on analysis of consequences and probability for leakage in pressure components important to reactor safety. By using plant specific consequence analysis and detailed review of degradation susceptibility and analysis of failure probability, the ris...

The 55th ESReDA seminar held in Bucharest the 9th and 10th of October 2018, was organized by the European Safety and Reliability Data Association and the Romanian Railway Investigating Agency – AGIFER, to invite participants to exchange ideas on “Accident Investigation and Learning to Improve Safety Management in Complex System: Remaining Challenge...

Critical Infrastructures Preparedness and Resilience is a major societal security issue in modern society. Critical Infrastructures (CIs) provide vital services to modern societies. Some CIs’ disruptions may endanger the security of the citizen, the safety of the strategic assets and even the governance continuity.The importance of CI’s has been re...

JRC participated in the OECD/NEA FASTRUN benchmark reviewing fast-running software tools to model fission product releases during accidents at nuclear power plants. The main goal of fast-running software tools is to foresee the accident progression, so that mitigating actions can be taken and the population can be adequately protected. Within the F...

Reliability, Risk and Safety – Back to the Future. Ale, Papazoglou & Zio (eds), 1513-1518 Reliability estimates of piping (and other structural components) are needed e.g. in probabilistic safety assessment (PSA) studies, risk-informed ISI applications, and other structural reliability assessments. The reliability of piping components is affected b...

Advanced lifetime prediction methodologies are necessary in securing the safe and reliable operation of nuclear power plants. Stress corrosion cracking is the most common corrosion mechanism, which can cause a major integrity loss in metallic components. The cracking is caused by the combined action of corrosion, tensile stresses and a susceptible...

SAFIR2010. The Finnish Research Programme on Safety 2007-2010. Final Report. Puska, Eija Karita & Suolanen, Vesa. VTT Research Notes 2571, 357 - 367 The overall objective of the PURISTA project was to support the implementation of risk-informed in-service inspection (RI-ISI) at Finnish nuclear power plants by studying relevant issues related to RI-...

Insight Vol.52 Nr.12, 657 - 663 The use of probability of detection curves to quantify NDT reliability is common in the aeronautical industry, but relatively less so in the nuclear industry, at least in European countries. The main reason for this lies in the very nature of the components being inspected. Sample sizes of inspected flaws tend to be...

ATW International Journal for Nuclear Power Vol.55 Nr.7, 450 - 457 Between 2005 and 2009 JRC and OECD/NEA coordinated a project for benchmarking various risk-informed in-service inspection (RI-ISI) methodologies. In the project, called RISMET, various RI-ISI methodologies were applied to the same case, consisting of 4 selected piping systems at the...

International Journal of Pressure Vessels and Piping Vol.87 Nr. 2 - 3, 111 - 116 The European methodology for qualification of non-destructive testing is a well-established approach adopted by nuclear utilities in many European countries. According to this methodology, qualification is based on a combination of technical justification and practical...

The European Network for Inspection and Qualification (ENIQ) is a utility-driven network that works towards a harmonised European approach on reliable and effective in-service inspection (ISI), primarily in the nuclear power industry. The ENIQ has two task groups: a Task Group on Qualification (TGQ), which works on issues related to the qualificati...

A growing need exists for a quantitative measure of inspection effectiveness as an input to quantitative risk-informed in-service inspection (RI-ISI). A Probability of Defection (POD) curve could provide a suitable metric, but there can be significant problems associated with generating realistic POD curves by practical trials. The ENIQ inspection...

The European Network for Inspection Qualification (ENIQ) was established in 1992 in response to increasing recognition of the importance of qualification of non-destructive inspection systems used in in-service inspection programmes for nuclear power plants. Driven by European Nuclear utilities and managed by the European Commission Joint Research...

Proceedings of PSAM 9, paper 0380 The OECD/NEA-JRC coordinated benchmark on risk-informed in-service inspection (RI-ISI) methodologies has been conducted in 2006-2008. Through the benchmarking of different RI-ISI methodologies it should be possible to identify how their implementation impact reactor safety and whether they lead to significantly dif...

This report summarises the results of a research project on risk-informed in-service inspection (RI-ISI) methodology conducted in the Finnish national nuclear energy research programme SAFIR (2003-2006). The purpose of this work was to increase the accuracy of risk estimates used in RI-ISI analyses of nuclear power plant (NPP) piping systems, and t...

International Journal of Pressure Vessels and Piping Vol.83 Nr. 9, 654 - 662 Non-destructive inspections are performed to give confidence of the non-existence of flaws exceeding a certain safe limit in the inspected structural component. The principal uncertainties related to these inspections are the probability of not detecting an existing flaw l...

The nuclear power plants (NPPs) world-wide are generally very robustly designed and constructed, capable to stand very extreme conditions. Small design differences from this point of view can be found among the various reactor types of the same generation; PWR, WWER, etc. The NPP structures are thus designed to accommodate all originally thinkable...

This paper introduces a stochastic filtering modeling approach for predicting the remaining lifetime of a component based on information on the stochastic degradation process and uncertain condition monitoring measurements. The model is illustrated by a case study, where the degradation is assumed to be a simplified fatigue crack growth process. Th...

The European methodology for qualification of non-destructive testing has been adopted as the basis of inspection qualifications for nuclear utilities in many European countries. According to this methodology, the inspection qualification is based on a combination of technical justification and practical trials. The methodology is qualitative in na...

Lifetime Management of Industrial Systems Proceedings of the 26th ESReDA Seminar, 219 - 226 On-line monitoring plays an important role in lifetime management of machinery. An especially interesting element of machinery is oil – as a lubricant or hydraulic fluid. The present paper introduces a model that has been developed for evaluating film thickn...

This paper describes the comparative study of two approaches to estimate pipe leak and rupture frequencies for piping. One method is based on a probabilistic fracture mechanistic model while the other one is based on statistical estimation of rupture frequencies from a large database. In order to be able to compare the approaches and their results,...

The paper introduces ageing models of repairable components based on Bayesian approach. Models for the development of both failure rate and the probability of failure on demand are presented. The models are based on the assumption that the failure probability or rate has random changes at certain time points. This is modelled by assuming that the s...

The aim of nuclear power plant ageing management is to maintain an adequate safety level throughout the lifetime of the plant. In ageing studies, the reliability of components, systems and structures is evaluated taking into account the possible time-dependent degradation. The phases of ageing analyses are generally the identification of critical c...

This paper describes the use of statistical models for the evaluation of the reliability of non-destructive inspections. Probability models for the uncertainty in the flaw size determination and the flaw detection are constructed. The flaw sizing models are based on the assumption that the measured and true flaw sizes are related in a simple way: t...

The purpose of this study was to find out the possible correlation between the crack propagation and the shut-downs and start-ups of the nuclear power plant. These transients can promote intergranular stress corrosion cracking (IGSCC) through stress variations and changes in water chemistry. This work was conducted by studying cracks found from the...

The purpose of the analysis is to ensure that the plant safety and reliability are maintained at a desired level through the designed, and a possibly extended, lifetime. The use of probabilistic models in the evaluation of the ageing of nuclear power plant components is discussed. The principles of nuclear power plant ageing studies are described a...

Eight years of operating experiences of 104 motor operated closing valves in different safety systems in nuclear power units were analyzed in a systematic way. The qualitative methods used were Failure Mode and Effect Analysis (FMEA) and Maintenance Effects and Criticality Analysis (MECA). These reliability engineering methods are commonly used in...

SRE symp. 1988. Västerås, Sweden, 10 - 12 Oct. 1988, 1 - 23

Vetenskapligt semin. Teroteknologi. Stockholm, 3 - 4 Nov. 1988, 1 - 28

Nuclear Power Plant Lifetime Assurance. Stockholm, 10 - 12 Oct. 1990

IAEA TCM on Pilot Studies on the Evaluation and Management of Safety Aspects of NPP Ageing. Wien, Austria, 5 - 9 Nov. 1990, 20

Scandinavian SRE Symposium. Nyköping, Sweden, 8 - 10 Oct. 1990

Conclusive Workshop of EuReDatA Benchmark Exercise on Reliability Data Analysis. Ispra, 5 April 1990, 34

Tiedotteita / Valtion teknillinen tutkimuskeskus 903 Julkaisussa kuvataan joitakin yleisiä laitteiden ja putkistojen ikääntymisen ja eliniän arviointiin soveltuvia todennäköisyysmalleja. Laitteen tai materiaalin vioittumiseen kuluvaa aikaa voidaan kuvata eliniän todennäköisyysjakaumalla, kun taas ikääntymisilmiötä voidaan mallintaa stokastisten pro...

Proceedings of the Eighth International Conference on Probabilistic Safety Assessment and Management The European Network for Inspection and Qualification (ENIQ) is a utility driven network working towards a harmonized European approach on reliable and effective in-service inspection (ISI). More specifically ENIQ works on qualification of ISI syste...

EUR 22675 EN The European methodology for qualification of non-destructive testing has been adopted as the basis of inspection qualification for nuclear utilities in many European countries. The inspection qualification is based on a combination of technical justification and practical trials. The methodology is qualitative in nature, and it does n...

EUR 21902 EN The report discusses the link between risk-informed in-service inspection (RI-ISI) and assumptions made concerning the probability of flaw detection. The purpose is to investigate the reasonable and practical requirements that should be set for assumptions about the accuracy of probability of detection (POD) curves from a RI-ISI point...

Proceedings of PSAM 9, paper 0308 There are both activities and trends at the Nordic nuclear power plants that will result in changes in Technical Specifications (TS), e.g. modernizations, increase of electrical power, risk informed strategies. At the same time, authorities are increasing the requirements on risk informed evaluation of the TS. The...

20th International Conference on Structural Mechanics in Reactor Technology. SMiRT 20. Book of abstracts. Vol. 2. Vuori, Seppo; Rintamaa, Rauno (eds.). VTT Symposium 257, 302 - 303

20th International Conference on Structural Mechanics in Reactor Technology. SMiRT 20. Book of abstracts. Vol. 2. Vuori, Seppo; Rintamaa, Rauno (eds.). VTT Symposium 256, 316 - 317

ENIQ report 36 EUR 23928 EN The report is the outcome of a project to investigate approaches to quantifying the confidence associated with inspection qualification. Two methods for quantifying the outcome from inspection qualification are described. The first method is a relatively simple process based on direct expert judgement. The second method...

8th International Conference on NDE in Relation to Structural Integrity for Nuclear and Pressurised Components, Berlin, Germany, from 29th of September to 1st of October 2010