Task Group on Safety Margin Applications and Assessment (SM2A)

Following on from the CSNI Action Plan in the Area of Safety Margins (SMAP), a task group had been set up carry out a pilot project using the methodology propsed in the final SMAP report published in 2007. In this pilot project, the SMAP methodology was applied to the Zion nuclear power plant in consideration of the US NRC loss-of-coolant accident rulemaking change and a power uprate of 10%. This application followed three steps:

  • defined the base case (reactor conditions) to which the power uprate of 10% was applied;
  • established event trees and selected the sequences for thermal-hydraulic calculations;
  • performed thermal-hydraulic calculations with uncertainty analysis.

The final objective of this exercise was to check the applicability of the SMAP methodology and to calculate the change in frequency of exceedance of the safety limit(s) resulting from the change of the plant operating conditions.

With the completion of its programme of work in 2007, the group disbanded.


Czechia, Finland, France, Germany Japan, Mexico, Republic of Korea, Spain, Switzerland, United States. The International Atomic Energy Agency (IAEA) is also participating in the pilot project.

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