PANTHER - An Advanced 3D Nodal Code for Reactor Core Analysis

PANTHER is a modern code developed over the past 10 years at EDF Energy by a team driven by the challenge and responsibility for improving the performance of it's own nuclear reactor plant.

PANTHER's strength is based on advanced and very general calculational capabilities and an open data structure which makes integration with existing reactor physics systems straightforward.

What can PANTHER be used for?

PANTHER can be used to provide quick, reference quality calculations for all Pressurised Water Reactors. In addition it has been successfully applied to the analysis of BWR, VVER, RBMK, AGR, Magnox and Research Reactor systems.

This comprehensive breadth of usage provides a more robust valid action of the algorithms and nuclear data than is achieved for software developed for specific reactor types.

Starting from a single reactor model PANTHER can perform calculations for:

  • Steady-state performance
  • Fuel management
  • Transient analysis for safety studies
  • Station operation support via on-line core follow

At Sizewell B, PANTHER is coupled with the SCORPIO core monitoring system to provide quick, easy access to information needed to make effective decisions about core operation.

Why are PANTHER models easier to set up?

PANTHER has been designed in modular form. Each of the basic elements of the reactor calculation is executed by a separate module called by the user.

PANTHER has its own easy-to-use interface by which the user controls the execution of modules and the data flow between them.


The user input to PANTHER is in full English phrases, so input datasets are readily understandable.


The user can tailor outputs either for display in PANTHER's output stream or for passing on to other programs.


Users can construct a wide range of calculational and output sequences into a single program run. Regularly-used sequences can be defined and stored as macros.

If you need assistance you can turn to our helpline.

Why do customers find PANTHER so flexible?


PANTHER solves the multi-group homogeneous neutron diffusion equations in both steady-state or transient form using an advanced nodal method.

Calculations can be performed in 0, 1, 2 or 3 dimensions in rectangular and hexagonal geometries and power distributions reconstructed within each channel.

A standard k-effective calculation and a wide range of search options are available in the steady-state. Any of these can be combined with thermal hydraulics and poison (xenon and samarium) feedback effects.


A generalised thermal-hydraulics feedback model is available for PWR, BWR, VVER and RBMK reactors and there are additional models for gas-cooled reactors. Any parameters may be given time dependence to drive a transient. Full links with RELAP enable integrated 3D whole plant kinetic calculations to be performed.


Integrated links exist between PANTHER and:

  • VIPRE thermal hydraulics code for DNBR hot channel analysis
  • ENIGMA fuel performance code for fission gas and pellet clad interaction
  • RELAP for fully integrated LOCA transient feedback analyses
  • SCORPIO core monitoring system

What validation supports my calculation?

PANTHER has been validated by comparisons with data from operating commercial plant for all the reactor types that it models. PANTHER's track record in international benchmark comparisons has been excellent.

PANTHER imports few-group nuclear data from the lattice code WIMS. The interface is openly defined and will accept data from other lattice codes.

What hardware is PANTHER available on?

PANTHER is available on most major workstations

Where do I find out more?

For further information contact the ANSWERS Customer Support Team.

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