Why a safety culture matters (Attributes and Issues) Michael Corradini Nuclear Engr. & Engr. Physics University of Wisconsin, Madison WI

Wisconsin Institute of Nuclear Systems Concept of Engineering Safety Engineers consider safety integral to system design Engineering systems have a number of safety levels: – Engineering system should imbed safety in the design – System operation strives for high reliability – An engineering system designs for off-normal events – Robust engineering systems consider rare events Nuclear power safety => Defense-in-depth – Design/operate facilities to prevent and mitigate radioactivity releases. Create multiple, diverse and redundant layers of defense to compensate for potential human and mechanical failures so that no single layer, no matter how robust, is exclusively relied upon. – Risk analysis is inherently part of defense-in-depth to help decide when one has enough layers of defense

Wisconsin Institute of Nuclear Systems Improve Nuclear Power Operation Operational safety is based on plant owners and operators minimizing operational incidents and maximizing plant reliability – Reduction in the number of reportable incidents – Reduction of unanticipated plant shutdowns – Improved maintenance and operational procedures – Continued credible and responsible regulation by the nuclear industry regulator (e.g., USNRC) – Utility/regulatory/industry focus on generic issues

Wisconsin Institute of Nuclear Systems Industry Focus: Safety, Early Detection Integrated approach in industry to address generic issues: e.g., materials aging Identify areas for improvement Focus on early detection of these issues Example: replacement of reactor vessel head as best option to assure reliability against corrosion at vessel penetrations

Wisconsin Institute of Nuclear Systems Measure Safety Performance Risk-informed reactor oversight process includes: Quantitative performance indicators (NRC ROP) Inspection program and enforcement program geared to safety-significance of findings based on operational procedures Performance indicators dictate level of regulatory oversight, beyond “ baseline ” inspection program

Wisconsin Institute of Nuclear Systems Human Defense-in-Depth Reliable Operation Safety is foremost ‘ Doing it right ’ Credible Regulation Risk-informed standards Public access Improved Engineering Simpler designs Better instrumentation Materials for harsh environments Recruit and retain top-notch people for all sectors

Wisconsin Institute of Nuclear Systems Safety Culture Concept IAEA: That assembly of characteristics, attitudes and behaviors in organizations and individuals, which establishes that as an overriding priority, nuclear safety and security issues receive the attention warranted by their significance. USNRC: Nuclear Safety Culture is the core values and behaviors resulting from collective commitment by leaders and individuals to emphasize safety over competing goals to ensure protection of people and the environment.

Wisconsin Institute of Nuclear Systems Safety Culture Issues Improvements to safety and effectiveness falter through efforts to overly prescribe correct behavior and to apply rigid scoring systems. Need to emphasize thinking and safety awareness over scorecards of metrics that can induce complacency and rote compliance. There is qualitative evidence that ‘culture traits’ lead to real improvements in safety. Culture cannot be legislated but can be seen and publicized by peer-to-peer examples