Activation & inventory · Nuclear data
FusionFissionGeneral nuclear

ALARA.

Analytic and Laplacian Adaptive Radioactivity Analysis

ALARA is an activation code that works out which radionuclides build up in the materials of a nuclear system under neutron irradiation, following every chain of transmutation and decay through an arbitrary pulsed irradiation schedule and set of cooling times, and choosing an analytic or Laplace-transform solution per chain. From the inventory it reports number densities, specific activity, decay heat, photon sources, contact dose and waste-disposal ratings, and it can run in reverse to find which starting nuclides produce a chosen target.

Reference listingListedSources checked 2026-10-10
Engineering questions it helps answer
  • How much decay heat and activity will a first wall, blanket or vessel component carry at given cooling times after shutdown?
  • Will an activated component meet a waste-disposal rating or clearance index, and which nuclides drive the rating?
  • What photon source should feed a shutdown dose rate calculation, and what contact dose will maintenance staff face?
Physics scope
  • Neutron-induced activation and transmutation from a multigroup flux spectrum
  • Decay chains with correct handling of loops
  • Adaptive analytic or Laplacian solution per chain
  • Hierarchical pulsed irradiation schedules and arbitrary cooling times
  • Activity, decay heat, photon source, contact dose, waste disposal and clearance ratings
  • Reverse (adjoint) mode to trace pathways to a target nuclide

Limitations

Neutrons only; the user supplies a multigroup flux from a separate transport run and must convert activation libraries into ALARA's binary format first. The documentation site lags the code (it describes an older build), there are no tagged releases and no stated citation policy, and the governing licence is ambiguous because a BSD-style LICENSE coexists with an older restrictive COPYING notice.

Fusion relevance

Written for fusion activation analysis at the University of Wisconsin Fusion Technology Institute with ARIES programme support; its worked examples irradiate materials with first-wall neutron spectra and current group projects target rapid fusion-material activation assessment. The documentation states it applies to fission reactors and accelerators as well.

Upstream examples

Published by the project itself. These are the project's own tutorials, not Morton Labs runs.

Reference workflows on this site

No reference workflow documents this tool yet. Its evidence status is “Listed”: A reviewed catalog entry with upstream links.

People

Developed by University of Wisconsin–Madison, Computational Nuclear Engineering Research Group (CNERG), under the Svalinn GitHub organisation; originally the UW Fusion Technology Institute. No individual profiles are published for this project yet.

Roles name a specific relationship with evidence. Authorship of a paper is not maintainership, and a listed person is not a Morton Labs partner or endorser.

Source collections

This entry was written by Morton Labs from public sources and last checked on 2026-10-10. Spotted an error, or want something changed or removed? Email zach@mortonlabs.ai with the page address.

Sources checked for this page (3)
  • ALARA LICENSE — BSD-style licence text (2010–2013) (checked 2026-10-10)
  • ALARA README — Purpose, build and fusion programme users (checked 2026-10-10)
  • CNERG group site — Stewardship by UW–Madison CNERG (checked 2026-10-10)