Research: ASTEC, an international reference in nuclear reactor core meltdown accident modeling

  • Nuclear safety

  • Research


IRSN and GRS are jointly developing the ASTEC software system dedicated to nuclear meltdowns in the different types of reactors currently in operation. A January 2013 meeting of the ASTEC Users Club in Aix-en-Provence in southeastern France bolstered its position as an international reference and consolidated its scope of applications, which has progressively been extended to include most types of reactors, existing and future.

Over the past decade, ASTEC has earned its status as an international reference in the simulation of core meltdown accidents in pressurized water reactors – including the Russian-designed VVER – with the help of the SARNET network [1] in particular.

Today, no fewer than 36 organizations use ASTEC, and three major events have just strengthened its position as the leading reference in this type of software:

  • the selection of ASTEC by JRC/IET [2] for use in its core meltdown accident research laboratory,
  • China Nuclear Power Engineering’s decision to acquire a five-year commercial user license for ASTEC,
  • the beginning of the Code for European Severe Accident Management [3] project of the 7th FRDP.

The modular nature of ASTEC allows its scope of application to be extended to a wide range of reactors such as boiling water reactors, to enable a detailed analysis of the Fukushima Daiichi accidents and of the IPHWR [4] for collaboration with India’s BARC [5]. ASTEC is already being applied to naval propulsion reactors, but will benefit from certain improvements following IRSN-led development work as part of an agreement with the CEA/DAM [6].

For accidents in other types of reactors, ASTEC is being used to model accidents involving the ingress of air or water into the vacuum vessel of fusion facilities such as the ITER and is being adapted for sodium-cooled fast reactors as part of the 7th FRDP project entitled "Joint Advanced Severe Accidents Modelling and Integration for Na-Cooled Fast Neutron Reactors" coordinated by IRSN.



  1. Excellence network specialized in research on severe nuclear reactor accidents.
  2. Institute for Energy and Transport of the Joint Research Centre of the European Union, located in Petten (the Netherlands).
  3. Coordinated by GRS working closely with IRSN, this project brings 17 partners together to improve the modeling and functionality  of the ASTEC software for severe accident management.
  4. Indian Pressurized Heavy Water Reactors (developed by India).
  5. Bhabha Atomic Research Centre.
  6. Military applications division of the French Alternative Energies and Atomic Energy Commission.