Safety Analysis   

Safety assessments are systematic processes to verify that applicable safety requirements are met in all the lifecycle phases of a nuclear power plant (NPP). These assessments are performed for various aspects of safety, security and safeguards (such as management practices, quality assurance, human performance, safety culture, training, design adequacy, safety analysis, equipment fitness for service, emergency preparedness, environmental protection, and radiation protection). 

A safety assessment includes the performance of a safety analysis, which is an analytical quantitative study performed mainly to demonstrate the safety of a nuclear power plant and the adequacy of its design and performance. Deterministic safety analysis (DSA), probabilistic safety assessment (PSA) and hazards analysis are three types of safety analyses. 

(Source: GD-310, Guidance on Safety Analysis for Nuclear Power Plants, CNSC, 2012)

(Source: IAEA Workshop Presentation, Amin Patel, Raducu Gheorghe)

The objectives of deterministic analysis are to: 

  1. confirm that the design of an NPP meets design and safety requirements 
  2. derive or confirm operational limits and conditions that are consistent with the design and safety requirements for the NPP 
  3. assist in establishing and validating accident management procedures and guidelines 
  4. assist in demonstrating that safety goals, which may be established to limit the risks posed by the NPP, are met.

(Source: REGDOC 2.4.1, Deterministic Safety Analysis, CNSC, 2014)


(Source: IAEA Workshop Presentation, Amin Patel, Raducu Gheorghe)

PSA considers the likelihood and consequences of various plant transients and accidents. The primary objectives of the PSA are to help with: 

  • identifying the sequences of events and their probabilities, which lead to challenges to fundamental safety functions, loss of integrity of key structures, release of radionuclides into the environment and public health effects
  • developing a well balanced NPP design
  • assessing the impact of changes to procedures and/or components on the likelihood of core

(Source: GD-310, Guidance on Safety Analysis for Nuclear Power Plants, CNSC, 2012)

(Source: USNRC)

(Source: IAEA Series 50-P-8)


(Source: IAEA)

(Source: IAEA 50-P-12)

Modelling & Computational Simulation  

Modelling is concerned with developing  mathematical models and equations that describe physical and technological processes and with solving such equations, usually by relying on computational algorithms implemented in digital-computer codes (programs).

Simulation is concerned with applying models and computer codes to predicting the behaviour of complex natural or technological systems.