Risk Informed In-Service-Inspection Activities of the ENIQ Task Group on Risk

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 Centre (JRC), ENIQ represents a network in which the available resources and expertise can be pooled at European level. ENIQ has recognized the importance of addressing, at European level, the issue of optimizing inspection strategies on the basis of risk by establishing a Task Group on Risk (TGR). Membership of TGR is drawn from European nuclear utilities and consultants. ENIQ TGR is focused on Risk-Informed In-Service Inspection (RI-ISI) methodologies. Its work is directed towards harmonisation in the field of codes, standards and best practice for RI-ISI methodologies, with the objective of increasing the safety of European nuclear power plants. In March 2005 TGR published a European Framework Document for RI-ISI. This publication provides guidance for both developing new RI-ISI approaches and using or adapting established approaches to a European environment, taking into account utility-specific characteristics and national regulatory requirements. More recently, ENIQ TGR has been working at producing more detailed recommended practices and discussion documents on several RI-ISI related issues, such as the role of ISI within the philosophy of defence-in-depth, the verification and validation of structural reliability models (SRMs) to be used in RI-ISI programmes, the use of expert panels and the applicability of RI-ISI to the reactor pressure vessel. Work is ongoing to develop a discussion document on updating of RI-ISI programmes, and new initiatives were launched to study topics such as what magnitude of risk reduction is reasonable to achieve through ISI, and how to set inspection targets, following the selection of ISI sites. In addition, TGR has been active in initiating international projects linked closely to its work, such as the JRC-OECD/NEA co-ordinated RI-ISI benchmark exercise (RISMET), and the project on the relation between inspection qualification and RI-ISI. This paper describes the key activities and publications of TGR to date.