Destruction to critical nuclear infrastructures would have a
debilitating effect on national public health safety, national
economy, security, etc. For this reason, analysts perform safety
risk analyses to quantify and understand the nature of unwanted
events. Since the world has gone through many changes after the
terrorist attacks of 9/11, nuclear security risk analysis became a
necessity. So far, the safety and security risk analyses were done
separately without a combined analyses and evaluation. This
research thesis contains three major analysis sections that
provides security, safety, and combined safety-security risk
analysis that studied and analyzed possible accident scenarios.
This research starts with the security pathway analysis, which
eventually calculated the initiating event frequency of a
successful adversary attack and estimated the security risk value.
The safety analysis represented a series of natural (random) safety
systems failure events. On the other hand, the safety-security
analysis considered a security initiating event followed by safety
systems failure. Fault and event trees were formed using the
SAPHIRE software and used for the description of failure
The main outcome of this research is a methodology development
to perform combined safety-security initiating event analysis to
compute the joint top event system failure frequency. Along with
the calculation of the systems' failure frequency, estimation of
the public risk associated for sample failure scenarios, and the
determination of how security initiating events in a series of
safety events failure affect the total risk value was also carried
- M.A. Hawila and S. Chirayath,
"Probabilistic Risk Assessment of Spent Fuel Pool Cooling System Failure Considering Safety and Security Initiating Events,"
ANS Winter Meeting & Expo, Las Vegas, NV, 06-10 November 2016.
- S. Chirayath and M.A. Hawila,
"Methodology for Combined Nuclear Security and Safety Risk Analysis,"
57th Annual Meeting of the Institute for Nuclear Materials Management (INMM), Atlanta, Georgia, 24-28 July 2016.