NJOY Training Course
Date: 2-6 December 2024
Place: OECD/NEA Headquarters
            46, Quai Alphonse Le Gallo
            92100 Boulogne-Billancourt (Paris) - FRANCE
Minimum enrollment: 15 participants
Maximum enrollment: 20 participants
Course fee: 700 EUR (please see information below)
Registration deadline: 11 October 2024


The four-and-a-half-day event includes four days of classroom sessions and a half-day devoted to user questions and individual support. The course will be given in English.

Participants are required to bring their own laptops.

For information on how to get to the Nuclear Energy Agency and for nearby hotels, click here.

For any questions about this course, please send an email to programs@oecd-nea.org


The NJOY Nuclear Data Processing System is a modular computer software package designed to read evaluated data in the Evaluated Nuclear Data File (ENDF) format, transform the data in various ways, and output the results as libraries designed to be used in various applications.

NJOY2016 is still the main production code at LANL and we will therefore continue to maintain this version of NJOY for the foreseeable future. Apart from maintaining a production version of NJOY2016, LANL is also working on the NJOY modernisation project which aims to modernise all aspects of the NJOY processing software. This includes the introduction of the GNDS evaluated nuclear data structure as an alternative to the current ENDF format.

This class will introduce participants to the Evaluated Nuclear Data File (ENDF) format, the NJOY2016 Nuclear Data Processing System and some of the modernized NJOY components that are already available to users.

Topics addressed in this class include:
• Introduction to nuclear data, the ENDF format and the ENDFtk toolkit
• Introduction to NJOY both old and new
• Processing data for MCNP (incident neutron files and thermal scattering files)
• Using the ACEtk toolkit to extract, visualise and manipulate MCNP ACE data files
• Multigroup and covariance data processing
• Demonstration of modern NJOY components

Time will be available to discuss NJOY capabilities that are of interest to class participants at the end of the course. For those participants willing to present their work and on how they use nuclear data we will offer the possibility to do so.


The registration fee is 700 EUR. This includes lunch and coffee breaks, and does not cover accommodation.

As soon as your registration has been accepted, you will receive the necessary information to proceed with payment, either directly by credit card on the NEA website, or by bank transfer. Course fees MUST be paid within three weeks of course confirmation.

Registrations will be open until places run out. We draw your attention to the fact this course can only host 20 participants, so please do not delay in registering and paying the course fee.

Practical information

Participants will need to bring their own laptop (with charger and cable), with the following requirements: 

• A computer capable of connecting to our Wi-Fi and allowing connections to the internet.
• A modern browser installed, preferably Google Chrome. Up to date versions of Microsoft Edge, FireFox, or Brave should also be supported.