Reinforce Nuclear Safety Through Digital Transformation

The nuclear industry might be the most closely regulated industry in the world. The serious implications after an accident occurs make any substantial malfunction simply unacceptable. Nuclear power plant (NPP) manufacturers and OEMs must be ultra-cognizant of the complex industry rules and standards, while still pushing the envelope on innovation. Another challenge facing NPP manufacturers is how to grow their business. It comes as no surprise that the cost of these plants is a major factor limiting many countries with fewer financial resources from developing them. But with the advancement of small modular reactors SMR (manufactured in a plant and assembled on-site), this opens the door to an entirely new business opportunity. Here too, the same stringent international regulatory rules apply, which has this industry looking for simple solutions that will increase their business opportunities.

The challenges facing nuclear power plant manufacturers make highly accurate simulations essential for the pre-certification of components as they aim to ensure the safety of installations in an area where real testing is impossible.  

Thanks to simulation, nuclear players can implement precise “as-built” models according to numerous and diversified “in use” load condition scenarios, allowing them to make key decisions and offering significant gains in terms of reliability.

ESI SYSTUS is the result of continuous innovation over the past 20 years. Today, it is the only industry solution that allows nuclear engineers to pre-qualify new component designs in accordance with nuclear industry regulations. SYSTUS offers a complete resolution to analysis challenges in mechanics, heat transfer, and electrotechnics.

SYSTUS aims to help you verify the behavior of energy components – such as nozzles, primary circuit pumps, the reactor, and the steam generator, also in addition to other industrial components such as valves – during the design phase and accelerate decision-making during maintenance operations. Additionally, you can also integrate the effects of the manufacturing process (welding residual stresses, casting, machining) into the component study to ensure it meets safety regulations.

Benefits of SYSTUS

  • Ensure design compliance and performance
  • Acquire precise simulations with access to basic and advanced material behavior laws and damage models
  • Reduce time to market and expenditures by shortening the product validation cycle
  • Ensure Traceability of the simulation process
  • Add a proven solution for the nuclear industry to your toolbox
  • Access to advanced applications for nuclear regulatory analyses and fracture mechanics

We virtually completed […a] stress report for the replacement of steam generators provided by Mitsubishi Heavy Industries for EDF French nuclear power plants and [successfully] demonstrated the equipment’s full conformity with French nuclear regulation.


Dr. François Billon
Technical and Innovation Director / ONET Technologies


Regulatory Analyses

ESI SYSTUS allows energy stakeholders to pre-qualify new component designs in accordance with regulations. Perform fatigue analyses for the design of Class 1 and Class 2 nuclear components and easily execute a complete study of the components, starting from mesh design, through the thermomechanical analysis (including nonlinearities), and up to justification. SYSTUS complies with the following requirements:

  • RCC-M code (Design and Construction Rules for Mechanical Components of PWR Nuclear Islands), for which it integrates the up-to date-evolutions published by Afcen
  • ASME code (the American standard issued by the American Society of Mechanical Engineers)
  • RCC-MRx (Design and Construction Rules for Mechanical Components in high-temperature structures, experimental reactors, and fusion reactors)

With a dedicated, user-friendly interface, you can define and check every input of the regulatory analyses and launch computations as well as graphically confirm the respect of criteria depending on the level of analyses performed.

Cross sections interactive definition 

Cross sections Results visualization

Regulatory Analyses results visualization

Fracture Mechanics

ESI SYSTUS enables manufacturers to perform brittle, ductile, and fatigue fracture analyses using simplified to advanced methods.

  • With a global approach, it is possible to evaluate crack initiation and fracture by computing the stress intensity factors K and the rate of energy restitution G
  • With a local approach, reproduce the macroscopic physical phenomena by which the initiation and the propagation of crack occur. These analyses are respectively based on WEIBULL statistical models for brittle fracture and on damage models
  • With the innovative X-FEM (Extended Finite Element) method, it is possible to compute the same parameters K and G without the need of meshing the crack in the studied structure, which is time-consuming, yet significantly facilitates the crack propagation analyses

Dynamic Analyses

ESI SYSTUS enables the pre-qualification of buildings and components under earthquake solicitation. This is done in accordance with the RG 1.92 rules of the NRC (US Nuclear Regulatory Commission), with mono- and multispectral analysis, where excitations are exclusive movements of the supports defined by their pseudo-acceleration spectrum.

  • Beyond that, ESI SYSTUS provides a large panel of applications including:
  • Harmonic response analysis defining excitation amplitude in terms of frequency
  • Modal response analysis under time history solicitations  
  • Stochastic response analysis (random vibrations) associating its power spectrum density (PSD) with each ergodic zero mean value stationary type excitation; they are computed using transfer functions such as response PSD and mathematical expectation of the response and various statistical parameters

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