IAEA Handbook of
Nuclear Data for Safeguards

May 2021

Updates of the Fission yields data tables and Delayed neutrons group parameters

October 2015

Updating of data for the neutron yields in reactor fuel for the interest of Nuclear Safeguards. Detailed information available in Nuclear Data Sheets, v. 139, January 2017, p.190 and Report INDC(SEC)-0111, Oct 2015

March 2015

Recommended Total T1/2 and Spontaneous T(SF)1/2 Fission Half-lives, Spontaneous Fission Neutron Yields n-Yield, Spontaneous Fission Multiplicities ν(SF) for 18 isotopes of trans-actinides from 232Th to 252Cf can be found in this summary

October 2008


A set of recommended nuclear data were assembled in January 2007 that were judged to be suitable for universal adoption with respect to nuclear materials accounting techniques. These data were fully documented in IAEA report INDC(NDS)-0502, January 2007, and superseded the tabulations to be found within IAEA report INDC(NDS)-376, December 1997. Following the issue of this material, the authors were asked by users to extend the decay database to encompass a specific number of activation products, and also include additional fission product yield data. These requests were addressed in May-July 2008, resulting in the creation of Section D dedicated to decay data for relevant activation products, and extension to Section C of the fission product yield database.


Section A contains recommended decay data, thermal neutron capture cross section data, resonance integrals and neutron emission yields per fission for relevant actinides and their natural decay products.

Section B includes recommended decay and thermal neutron capture cross section data for some important fission products.

Section C lists recommended fission product yield data for selected actinides.

Section D provides recommended decay data for specific activation products.

Selection rules

The following criteria were applied in the course of selecting the data:

Preference was given to evaluated data recommended by international working groups and projects, reported in recent publications, or available on the web.

If the first criterion was not applicable, data were adopted from available evaluated nuclear data libraries: ENSDF for decay data and ENDF/B-VII or JEFF-3.1 for nuclear reaction data.

If uncertainties were not quantified in the evaluated nuclear data source, these parameters were either adopted from the original documentation related to the selected source, or estimated from the experimental data available in the EXFOR library and published in recent relevant papers or reports.


The recommended data sets can be inspected as tables in an INDC(NDS) report , or through the adoption and use of appropriate software. Users are referred to the Interactive Chart of Nuclides for an introduction to a web-download that can be used to undertake rapid inspections of the assembled database. Every effort has been made to ensure that the recommended data are credible and correct with respect to their original sources. Despite these best endeavours, absolute correctness can not be fully guaranteed - any errors detected by data users should be communicated to the International Atomic Energy Agency, Nuclear Data Section, to ensure their elimination and correction (e-mail: online@iaeand.iaea.org)