Why a safety culture matters
(Attributes and Issues)
Michael Corradini
Nuclear Engr. & Engr. Physics
University of Wisconsin, Madison WI
Concept of Engineering Safety
• Engineers consider safety integral to system design
• Engineering systems have a number of safety levels:
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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
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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
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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
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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
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Human Defense-in-Depth
Reliable Operation
Safety is foremost
‘Doing it right’
Improved Engineering
Simpler designs
Better instrumentation
Materials for harsh
environments
Credible Regulation
Risk-informed standards
Public access
Recruit and retain top-notch people for all sectors
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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.
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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
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