Joint Evaluated Fission and Fusion (JEFF) Library version 3.3
JEFF-3.3 is a thorough update of the neutron, decay data, fission yields, dpa and neutron activation libraries in the EAF format, with neutron thermal scattering files for 20 compounds. Special sub-libraries for incident alphas, deuterons, gammas, helium-3, protons and tritons have been contributed by the TENDL-2017 library and adopted as part of the JEFF-3.3 release. JEFF-3.3 was officially released on November 20, 2017.
The JEFF-3.3 library and sub-libraries contens are described and provided in the following sections.
JEFF-3.3 library was released in 2017
Please note that the most recent release is JEFF-4.0 library, released in June 2025 and available at the JEFF-4.0 release webpage.
Neutron-induced cross sections evaluations
The JEFF-3.3 evaluated nuclear data library was released in November 2017 as the official reference library of the OECD Nuclear Energy Agency’s Data Bank. It provides general-purpose evaluated nuclear data for reactor physics, fusion technology, shielding, criticality safety, and other applications. The library contains neutron-induced reaction data for 562 isotopes, fission yields, thermal scattering law data, and decay data, based on contributions from the JEFF project and international partners. Data were processed and verified using modern nuclear data codes and benchmarked against extensive integral experiments to ensure quality and reliability. JEFF-3.3 remains widely used for both research and industrial applications across Europe and internationally.
The JEFF-3.3 evaluated neutron cross sections have been processed with the NJOY system to produce ACE-formatted libraries. Data are provided at multiple temperatures, from 293 K up to 1800 K, enabling accurate treatment of Doppler broadening in reactor physics, shielding, and criticality safety applications. These processed files support high-fidelity simulations and benchmark calculations, complementing the JEFF-3.3 evaluated data by providing temperature-dependent cross sections ready for use in transport calculations.
| Release | Format | Code | Content | # files | Download |
|---|---|---|---|---|---|
| JEFF-3.3 | ENDF6 | - | Cross section evaluations (download all) | 562 |  |
| JEFF-3.3 | ACE | NJOY2016.42 | Continuous-energy cross section data at 293.6, 600, 900, 1200, 1500, 1800 K | 562 |  |
The JEFF-3.3 release includes a neutron activation library distributed in the European Activation File (EAF) format, based on TENDL-2017 evaluations. This library provides cross sections for activation reactions across a wide range of target nuclides, supporting inventory, transmutation, and shielding calculations. Complementing the activation library, JEFF-3.3 also provides covariance data in EAF format, enabling uncertainty quantification in activation calculations. The combined use of cross sections and their associated covariances allows more robust assessment of uncertainties in applications such as material performance, waste management, and safety studies.
| Release | Format | Code | Content | # files | Download |
|---|---|---|---|---|---|
| JEFF-3.3 | EAF | - | Neutron activation and activation covariance files | 2797 |  |
The JEFF-3.3.1 release provides updated neutron activation data in the European Activation File (EAF) format. Two group-wise versions are included: a 709-group and a 211-group library. The datasets cover all isotopes from TENDL-2017, along with a focused subset of isotopes from the traditional EAF selection, supporting activation, transmutation, and inventory studies. In contrast to the JEFF-3.3 activation library, which combined TENDL-2017 with TALYS-based calculations for selected isotopes (H-1, H-2, H-3, He-3, He-4, Li-6, Li-7, Be-9, B-10, B-11, C-12, C-13, N-14, N-15, O-16, O-17, F-19, Th-232, U-233, U-235, U-238, and Pu-239), the JEFF-3.3.1 activation data are taken entirely from TENDL-2017. This ensures a consistent basis across the full set of isotopes while retaining compatibility with established EAF formats for activation calculations.
| Release | Format | Code | Content | # files | Download |
|---|---|---|---|---|---|
| JEFF-3.3.1 | PENDF | - | Neutron activation | 1 |  |
| JEFF-3.3.1 | EAF | - | Neutron activation 211g and 709g (all TENDL isotopes and subset of EAF isotopes only) | 2797 |  |
Fission Yields (FY)
The JEFF-3.3 library provides independent and cumulative fission product yield data for a wide range of actinides undergoing neutron-induced and spontaneous fission. These evaluations support reactor physics, fuel cycle analysis, decay heat calculations, and radiological assessments by supplying consistent yield distributions that underpin many applications in nuclear technology and safety. The JEFF-3.3 yields represent an update over earlier releases, incorporating revised evaluations and benchmark testing to improve reliability across energy ranges and fissioning systems.
| Release | Format | Content | # files | Download |
|---|---|---|---|---|
| JEFF-3.3 | ENDF6 | Neutron-induced and Spontaneous Fission Product Yields | 2 |  |
Thermal Scattering Law (TSL)
The JEFF-3.3 release includes an updated thermal scattering law (TSL) library providing S(α,β) data for a range of moderator and structural materials. These files describe the interaction of thermal neutrons with bound atoms in media such as light water, heavy water, graphite, beryllium, and other relevant materials. The inclusion of thermal scattering data enables more accurate simulations of neutron moderation and transport in reactor physics, shielding, and benchmark calculations, complementing the evaluated neutron cross-section library.
The JEFF-3.3 thermal neutron scattering sublibrary contains 20 evaluations for 16 materials. Notably, the evaluation for heavy water is updated and now has components for deuterium and oxygen bound in heavy water. Nine new materials (sapphire-Al2O3, silicon, mesitylene, toluene, ortho- and para- hydrogen, ortho- and para-deuterium, and light water ice) have been included in this release. The remaining evaluations are carried forward from JEFF-3.2.
The thermal scattering law (TSL) evaluations from JEFF-3.3 have been processed with the NJOY system to produce ACE-formatted libraries. These datasets provide S(α,β) thermal scattering information for materials such as light water, heavy water, graphite, and beryllium, across a range of temperatures relevant to reactor applications. The processed files enable accurate treatment of bound-atom effects on neutron moderation and transport, supporting high-fidelity reactor physics, shielding, and benchmark simulations.
| Release | Format | Content | # files | Download |
|---|---|---|---|---|
| JEFF-3.3 | ENDF6 | Thermal Scattering Law Evaluations (download all) | 20 |  |
| JEFF-3.3 | ACE | Continuous-energy cross section data at all temperatures available | 20 |  |
Decay data
The JEFF-3.3 release includes a comprehensive radioactive decay data library, providing evaluated information on half-lives, branching ratios, decay modes, and emitted radiation for thousands of isotopes. The data are distributed both as a set of individual isotope files and as a single combined file covering all nuclides. This library supports reactor physics, fuel cycle analysis, decay heat calculations, and radiological assessments by supplying consistent and traceable decay data aligned with the JEFF-3.3 evaluation.
| Release | Format | Content | # files | Download |
|---|---|---|---|---|
| JEFF-3.3 | ENDF6 | Radioactive decay data | 1 |  |
Proton data
The JEFF-3.3 release includes a library of proton-induced nuclear reaction data taken from TENDL-2017. These evaluations provide cross sections and related quantities for a wide range of target nuclides, supporting applications in activation analysis, shielding studies, medical physics, and fusion-related research. By incorporating proton-induced data, JEFF-3.3 expands beyond neutron and photonuclear libraries to offer a broader, multi-particle resource for nuclear science and engineering.
The JEFF-3.3 proton-induced evaluations, taken from TENDL-2017, have been processed with the NJOY system to produce ACE-formatted libraries. The dataset covers 283 stable target nuclides and is provided at 0 K (unbroadened). These processed files enable simulations of proton-induced reactions for activation, shielding, medical physics, and fusion-related studies, extending JEFF-3.3 beyond neutron and photonuclear data to support a wider range of nuclear applications.
| Release | Format | Content | # files | Download |
|---|---|---|---|---|
| JEFF-3.3 | ENDF6 | Incident proton (download all) | 2804 |  |
| JEFF-3.3 | ACE | Incident proton (stable targets), NJOY2012.099 | 283 |  |
Alpha data
As part of the JEFF-3.3 release, a dedicated library of alpha-induced nuclear data was included, taken entirely from the TENDL-2017 evaluation. These files provide cross sections and related quantities for α-particle interactions across a broad range of isotopes, supporting applications in activation, shielding, and fuel cycle studies where alpha reactions are significant.
The JEFF-3.3 alpha-induced evaluations, taken entirely from TENDL-2017, have been processed with the NJOY system to produce ACE-formatted libraries for Monte Carlo transport codes. The dataset covers 283 stable target nuclides and is provided at 0 K (no Doppler broadening). These processed files support the simulation of α-particle reactions in activation, shielding, and fuel cycle applications, extending the JEFF-3.3 library beyond neutron-induced data to support a broader range of nuclear science and engineering studies.
| Release | Format | Content | # files | Download |
|---|---|---|---|---|
| JEFF-3.3 | ENDF6 | Incident alpha (download all) | 2809 |  |
| JEFF-3.3 | ACE | Incident proton (stable targets), NJOY2012.099 | 283 |  |
Photon data
The JEFF-3.3 release includes a dedicated set of photonuclear (γ-induced) reaction data, taken entirely from the TENDL-2017 evaluation. These files provide cross sections and related quantities for photon-induced reactions across a wide range of isotopes. The library extends JEFF beyond neutron and charged-particle induced reactions, supporting applications such as shielding, radiation transport, activation studies, and safety assessments involving high-energy photon interactions.
The JEFF-3.3 gamma-induced evaluations, taken from TENDL-2017, have been processed with the NJOY system to produce ACE-formatted libraries. The dataset is provided at 0 K (unbroadened) and contains photonuclear reaction data for a wide range of isotopes. These processed files support simulations of γ-induced reactions in shielding, activation, radiation transport, and safety studies, extending JEFF-3.3 beyond neutron- and charged-particle–induced data to provide a more comprehensive resource for nuclear applications.
| Release | Format | Content | # files | Download |
|---|---|---|---|---|
| JEFF-3.3 | ENDF6 | Incident photon (download all) | 2809 |  |
| JEFF-3.3 | ACE | Incident photon (stable targets), NJOY2012.099 | 283 |  |
Deuteron data
The JEFF-3.3 release includes a library of deuteron-induced nuclear reaction data taken from TENDL-2017. These evaluations provide cross sections and related quantities for reactions on a wide set of target nuclides, supporting applications such as activation analysis, shielding, and fusion-related studies. By incorporating deuteron-induced data, JEFF-3.3 expands beyond neutron, photon, and other charged-particle reactions, offering a more comprehensive resource for nuclear science and engineering.
| Release | Format | Content | # files | Download |
|---|---|---|---|---|
| JEFF-3.3 | ENDF6 | Incident deuteron (download all) | 2811 |  |
Triton data
The JEFF-3.3 release includes a set of triton-induced nuclear reaction data taken from TENDL-2017. These evaluations provide cross sections and related information for a broad range of isotopes, supporting applications such as activation, shielding, and fusion-related studies. By incorporating triton-induced data, JEFF-3.3 extends beyond neutron and photonuclear reactions to offer a more comprehensive resource for nuclear science and engineering.
| Release | Format | Content | # files | Download |
|---|---|---|---|---|
| JEFF-3.3 | ENDF6 | Incident triton (download all) | 2806 |  |
Helion data
The JEFF-3.3 release includes a library of helion-induced nuclear reaction data taken from TENDL-2017. These evaluations provide cross sections and related quantities for reactions induced by He-3 projectiles on a broad set of target nuclides. The data support activation studies, shielding assessments, and fusion-related applications, extending JEFF-3.3 beyond neutron, photon, and other charged-particle reactions to deliver a more complete resource for nuclear science and engineering.
| Release | Format | Content | # files | Download |
|---|---|---|---|---|
| JEFF-3.3 | ENDF6 | Incident helion (download all) | 2806 |  |
DPA
The JEFF-3.3 distribution includes a dedicated DPA library providing arc-dpa and NRT-dpa cross sections for 81 materials in ENDF-6 format. These evaluations support the calculation of radiation damage in structural and reactor materials by quantifying atomic displacements under neutron irradiation. The DPA data complement the standard neutron cross-section libraries, enabling more complete assessments of material performance, degradation, and lifetime in nuclear energy and fusion applications.
The JEFF-3.3 distribution includes ACE-formatted libraries of arc-dpa and NRT-dpa displacement cross sections for 81 materials. These datasets, processed from ENDF-6 format, provide energy-dependent displacement cross sections suitable for use in transport and damage simulations. The DPA ACE files complement the evaluated neutron data libraries by enabling direct calculations of radiation damage and material performance under irradiation.
| Release | Format | Content | # files | Download |
|---|---|---|---|---|
| JEFF-3.3 | ENDF6 | arc-dpa and NRT-dpa cross sections | 81 |  |
| JEFF-3.3 | ACE | arc-dpa and NRT-dpa cross sections | 81 |  |
Reference
The official reference for the JEFF-3.3 library is the peer-reviewed publication made in the European Physical Journal A by the JEFF Chair and collaborators:
Citation
A.J.M. Plompen, et al., "The joint evaluated fission and fusion nuclear data library, JEFF-3.3", European Physical Journal A, Volume 56, 181, July 2020, DOI:10.1140/epja/s10050-020-00141-9