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FISPACT-II (Package NEA-1890)


FISPACT-II is an enhanced multi-physics, inventory and source-term code system providing a wide variety of advanced, predictive, spectral and temporal simulation methods employing the most up-to-date and complete nuclear data forms for both neutron and charged-particle interactions.


Non-commercial license

The NEA Data Bank Computer Program Service offers license that does not include commercial applications.

For use cases outside those covered by the NEA Data Bank license, contact

Supplementary material

Nuclear data

FISPACT-II requires multi-group processed nuclear data libraries with incident particle data for all reactions that should be included in the inventory calculation process. The default libraries for FISPACT-II are the TALYS-based Evaluated Nuclear Data Library (TENDL). A list of UKAEA-provided data libraries is provided on the public NEA GitLab repository for FISPACT-II nuclear data.

The Data Bank Joint Evaluated Fission and Fusion (JEFF) project nuclear data test libraries are continuously integrated with pipelines generating FISPACT-II data libraries, which can be accessed through the JEFF development GitLab pages. This includes fully reproducible and containerised processes using the NJOY, PREPRO and CALENDF codes, with all inputs, scripts, logs and the complete code containers available upon request. These are not currently public but you can request more information from the JEFF Secretariat.

Benchmark problems

As part of the verification and validation of the FISPACT-II code system, a set of time-dependent decay heat experiments have been simulated with reference calculation inputs provided. The reference results for calculations with the recent JEFF test activation library are provided by UKAEA. Detailed documentation on the fission, fusion and other verification and validation tests can be found on the UKAEA FISPACT-II website.


More information can be found online at FISPACT-II homepage and the FISPACT-II wiki.


J-Ch. Sublet, J. W. Eastwood, J. G. Morgan, M. R. Gilbert, M. Fleming, and W. Arter, “FISPACT-II: An Advanced Simulation System for Activation, Transmutation and Material Modelling,” Nuclear Data Sheets 139 (2017) 77-137, DOI:10.1016/j.nds.2017.01.002


The NEA Data Bank organises training courses on the FISPACT-II code with the UKAEA. Course material can be found on the FISPACT-II GitHub and presentations served on the FISPACT-II GitHub Pages.

The UKAEA regularly organises training courses through the NEA Data Bank. You can find more information on the currently scheduled events online here. If there are no courses available for the training that you are looking for, please contact the Data Bank team and/or UKAEA.