The UK Heavy Element and Actinide Decay Data Library: UKHEDD2.6

The latest version of the UK Heavy Element and Actinide Decay Data Library (UKHEDD2.6, February 2008) is described in detail in JEFDOC-1224.pdf (see below).

The decay data of various radionuclides have been evaluated on the basis of a series of well-defined requirements and specifications of the UK nuclear power, fuel reprocessing and waste management programmes. UKHEDD2.6 contains recommended decay data for the actinides that constitute reactor fuels and are formed through an extensive series of neutron reactions prior to and including their natural radioactive decay. Recommended data include half-lives, branching fractions, alpha, beta and gamma-ray energies and emission probabilities, total decay energies, mean alpha, beta and gamma energies, internal conversion coefficients, and all associated uncertainties. Computer-based files have been generated in ENDF-6 format, including lists of the references used to produce the proposed decay schemes and comments that identify any observed inadequacies.

Decay scheme data for UKHEDD were first evaluated and assembled as an ENDF-formatted database by A L Nichols and M F James between 1977 and 1981; all subsequent re-evaluations have been carried out by A L Nichols.

The previous version of the library, UKHEDD2.5, was released in February 2007. This library had been assembled over a number of years and the structure of many of the older files no longer conformed to modern standards, causing difficulties in the assimilation of data from UKHEDD into the JEFF-3 decay data file. Thus, all data sets within UKHEDD2.6 have been updated to bring them to the required standard and to facilitate the assimilation of the data into JEFF-3 and future libraries. No new evaluations have been undertaken for this release, with the changes being confined to the basic structure of the files.

The following data files and reports are available for download:

• UKHEDD26: The ENDF-6 formatted library (3.4 Mb)
• Documentation, A.L. Nichols and R.J. Perry (JEFDOC-1224 in PDF format)

Last updated: 14 April 2008.