Tools and features in ISAAC

ISAAC is a software to be used by analysts working with structural integrity and FFS in various industries such as nuclear, oil and gas, process, manufacturing and transportation.

The theory implemented in the software is described in the Fracture Mechanics Handbook SSM Report 2018:18 – Procedure for Safety Assessment of Components with Defects – Handbook Edition 5 provided by the Swedish Radiation Safety Authority.

ISAAC consists of several tools for fracture assessments which are listed below.


Crack Growth

  • Fatigue
  • Stress Corrosion

Fracture Assessment

  • R6 Based Fracture Assessment
  • ASME XI Appendix A: Ferritic Steel Components
  • ASME XI Appendix C: Piping Components

Heat Transfer

  • OneTherm – A procedure for one dimensional heat transfer problems


  • Several visual aids to simplify analyses and post processing
  • Includes 17 geometries with both stress intensity factor and limit load solutions
  • Built-in crack growth laws for both fatigue and SCC as well as the possibility for user specified crack growth laws either by coefficients or tables
  • Easy to use aids for curve fitting options of stresses
  • Incorporated recommended safety factors for nuclear applications as well as the possibility for user defined safety factors for use in other industries
  • Implementation of Master Curve for fracture toughness calculations
  • Possibility to analyze several load cases at once
  • Possibility to combine different load cases both sequentially and mixed during crack growth analyses
  • Acceptance calculation along a crack growth path

History and Future Development

ISAAC is the successor to the software ProSACC and is the result of a complete conversion and modernization of the software. ISAAC is undergoing active development in order to be at the forefront of safety assessments of components containing defects.