The Joint Evaluated Fission and Fusion File (JEFF)  Nuclear Data Library Project is a collaboration between NEA Data Bank participating countries. The JEFF library combines the efforts of its different working groups to produce a common set of evaluated nuclear data, mainly for fission and fusion applications. The JEFF project meets twice a year, in autumn and spring. The next edition of the Nuclear Data Week will take place on 14-18 April 2025, and will host both the JEFF Co-ordination Group and the JEFF technical sessions.

• Fusion session: 14 April 2025 (preferably afternoon).
• Other sessions: Experiments, Thermal Scattering Law, Fission Observables, Decay Data, Theory and Models, Evaluation Methods, Nuclear Data Uncertainties, Processing, Benchmarking, Depletion, JEFF-4 Status (dates to be finalised based on contributions).
• JEFF CG: 18 April 2025 (morning).

• 10 February: Registration opens.
• 17 March: Draft timetable released.
• 24 March: Registration closes for speakers.
• 25 March: Finalisation of agenda.
• 1 April: Registration closes for audience members.