What is the SPECTRA code?

SPECTRA (Sophisticated Plant Evaluation Code for Thermal-hydraulic Response Assessment) is a system thermal-hydraulic analysis code developed at NRG. The program is applicable to various reactor types, including LWR, HTR, MSR, LMFR, and various types of coolants. SPECTRA can be used for safety analyses, design-support analyses and interactive simulators.




SPECTRA capabilities

SPECTRA was developed to perform various types of thermal-hydraulic analyses:

  • Reactor design analyses
  • Design basis accident analyses, for example
    • Loss of coolant accidents (LOCAs)
    • Operational transients
  • Beyond-design basis accident analyses
  • Construction of interactive simulators

This is achieved through the use of various calculation packages, including:

  • Multidimensional two-phase flow
  • Non-equilibrium thermo-dynamics
  • Multi-dimensional transient heat conduction in solid structures
  • General heat and mass transfer (natural and forced convection, condensation and boiling)
  • Fluid properties (water, steam, non-condensable gases, liquid metals, molten salts)
  • Reactor kinetics (control rods, thermal feedback)
  • Radioactive particle transport (sorption and condensation)
  • Hydrogen burning (deflagrations, flame acceleration, detonations)
  • High temperature oxidation models (oxidation Zircaloy, steel, graphite, etc.)

Specific advantages of SPECTRA over other codes include:

  • Full flexibility in designing the input model
  • Modeling of components specific to HTRs, for example turbine and compressors
  • Possibility of analysing accidents using small time steps, as well as long term stationary state analyses using large time steps (obtaining dust and fission product distributions during plant life-time)
  • Various dust-related models
    • Turbulent deposition
    • Inertial impaction
    • Resuspension
    • Sorption of fission product vapors on metallic plates (plateout) and dust particles

SPECTRA provides clear documentation including program description, users guide, verification and validation manual. Input errors are handled in a clear and user friendly manner.


Interested in SPECTRA?

Are you interested in our code or would you like to receive our user manuals? Contact our Thermal Hydraulics Analyse Team.

Stempniewicz Mthumb

Marek Stempniewicz
Thermal Hydraulics Expert


Validation and quality control

SPECTRA is developed within an ISO 9001 certified framework. The quality assurance program within which SPECTRA is developed has previously been externally audited and found satisfactory.

Verification and validation (V&V) is performed according to the American Nuclear Society (ANS) guidelines (ANSI/ANS-10.4-1987), and is documented in the Spectra Code Manuals. Included here are comparisons of separate effects tests and integrated system tests to other codes (such as RELAP5 and MELCOR). For application specific V&V, please contact the developers.

What is included in SPECTRA?

SPECTRA is delivered with:

  • Code executable file, version for Windows and/or for Linux
  • Code manuals
  • Input and output files for the installation test runs
  • Graphical/visualization tool Visor
  • Optional training and support

Are you interested in SPECTRA, or do you want to know what licences are available? Contact us for the possibilities.