Nuclear thermal-hydraulic analyses

We ensure the safety of your facility. Reliably and independently, using qualified computer codes.

What codes do we use?

Do you want to build a new reactor? Or do you want to modify your existing reactor? We use independent software packages to help you perform nuclear thermal-hydraulic design analyses and safety studies. Our team is ready to assist you to continue operation. The codes we use are:

  • MELCOR, the US NRC severe accident code for modelling the progression of accidents within light water reactors.
  • RELAP5, the US NRC thermal-hydraulic code to perform best-estimate transient simulations of the coolant system and core for design basis accidents.
  • TRACE/PARCS, the US NRC thermal-hydraulic code to analyse large and small break LOCAs and system transients in PWRs and BWRs.
  • SPECTRA, the NRG thermal-hydraulic code. This code is used in various kinds of reactors and can be used to analyse thermal accident scenarios, such as loss-of-coolant accidents, operational transients and other accident scenarios in nuclear facilities.


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Paul Breijder

Nuclear thermal-hydraulic analyses

Areas of expertise

The team of dedicated experts has implemented the nuclear thermal-hydraulic codes in a wide range of reactors. These include:

  • Pressurized water reactors (PWR)
  • Boiling water reactors (BWR)
  • High temperature reactors (HTR)
  • Liquid metal fast reactor (LMFR)
  • Molten salt reactor (MSR)
  • Research reactors
  • Chemical reactors

For these reactor types, we work on the international standard problems (ISP), research projects, code-to-code benchmarks and more. Our in-house developed SPECTRA code is highly versatile and can handle many reactor types and configurations. Contact us for more information.

Interactive simulators

Are you looking for new employees with hands-on experience in your nuclear facility on day 1? Want to validate your facility design? Evaluate your facility in real time when things go wrong? Using the interactive simulators developed by NRG, you are in control. Our thermal-hydraulics team is experienced in generating interactive simulators for nuclear installations. Our codes allow you to:

  • Perform tailored simulations of your entire facility
  • Train new and existing personnel
  • Complete design & accident progression analysis

Contact us for more information!

Nuclear thermal-hydraulic analyses
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Quality control

The quality of our work is paramount, for ourselves as well as for our clients. Together with you we define the project to fit your specific demands. During the project we:

  • Work according our ISO 9001 certified management system
  • Apply international standards in multi-disciplinary teams
  • Focus on continuously supporting you
  • Review our results together with you