atw Vol. 63 (2018) | Issue 3 ı March
Determination of greater defense
barriers, lower costs, Selection of
limiting cases for detailed quantitative
analysis, less energy dissipation, Performance
of detailed quantitative
analysis for each limiting case, Evaluation
of compliance to the acceptance
criteria and safety margins, etc.
Conclusion
In general, when the analysis of
nuclear accidents are separately done
by deterministic and probabilistic
approaches are faced with shortcomings
and drawbacks. It is not
possible to provide a comprehensive
prediction for nuclear accidents. In
deterministic approach, many effective
factors in the event are not considered
but in probabilistic approach,
most effective factors in the event are
used for determining the frequency of
occurrence and total error. Therefore,
for better understanding and comprehensive
analysis of events, deterministic
and probabilistic assessment
is necessary at the same time.
This review indicates that the integrated
risk-informed approach has
great potential to improve safety level
by using probabilistic and deterministic
approaches. By using IRIDM
approach, determining of initiating
events, multiple failures and event
sequences are possible. The final decision
should be based on integrated
risk-informed rather than the risk,
itself. Risk assessment should only
be part of the decision process. For
the final decision, integrated risk
informed should be based on combination
of deterministic and probabilistic
approach.
Adopting an IRIDM model is way
of helping prevent these incidents and
accidents as well as other benefits
such as:
• Safer and more secure operations
have reduced risks through more
comprehensive understanding of
operational risks;
• Greater resilience, including the
ability to cope with unforeseen
threats and adverse events;
• Better integration of operations
and technical systems, with financial
and human resource management;
• Greater efficiency, including more
productive operations, higher staff
morale, lower staff turnover, more
efficient and effective control
measures;
• Greater ability to identify weaknesses
so that they can be actively
corrected to prevent opportunities
for accidents to happen.
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ENVIRONMENT AND SAFETY 157
Environment and Safety
The Importance of Integration of Deterministic and Probabilistic Approaches in the Framework of Integrated Risk Informed Decision Making in Nuclear Reactors
Mohsen Esfandiari, Kamran Sepanloo, Gholamreza Jahanfarnia and Ehsan Zarifi
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