Regulatory Guidance for Risk-Informed In-Service Inspection of Nuclear Power Plants in Bulgaria

Abstract

Risk-Informed In-Service Inspection (RI-ISI) aims to integrate service experience, plant and operating conditions, other deterministic information, and risk insights in developing augmented in-service inspection (ISI) programmes for Nuclear Power Plant (NPP). RI-ISI is a developing methodology which is increasingly being adopted world-wide, and is seen as having the potential to make ISI programmes more effective and efficient in terms of both nuclear safety and the economical operation of nuclear plant. The Nuclear Regulatory Agency (NRA) bears responsibility for regulating nuclear facilities in Bulgaria. In anticipation of a forthcoming application by Kozloduy NPP to adopt an RI-ISI programme for selected systems in WWER-1000 plant, the NRA required a suitable regulatory guidance document to help assess such an application. The UK Department of Trade and Industry-funded Project NSP/04-B23 “Assistance with the Regulatory Aspects of Risk-informed In-Service Inspection (RI-ISI)” has enabled the development of a guidance document, the initial draft of which was produced by Serco Assurance in close consultation with the NRA and other Bulgarian stakeholders. This paper presents a description of how current international best practice has been tailored to Bulgarian NPP, and provides a summary of the draft guidance document produced as the principal output of Project NSP/04-B23.