Logo Basic

Measurement of 235U enrichment for a variety of Uranium items


This project was to provide quantitative 235U enrichment data for a variety of bulk uranium-bearing items at the Imperial College Reactor Centre, Ascot. A High Resolution Gamma ray Spectrometry (HRGS) system was used. The technique is based on use of the standard Multi-Group Analysis (MGAU) software which measures the low energy gamma rays from Uranium. Measurements were performed at the Imperial College Reactor Centre in Berkshire, UK.

Key Drivers:

Imperial College’s key requirement for this project was to ascertain the 235U enrichment on a variety of Uranium items. Robust historical inventory data was not available and so measurements were needed to provide essential nuclear material inventory data to determine the options for future storage / treatment of these items.

Instruments & Techniques Used:

  1. Instruments
    – ISOCS™ (collimated BEGe detector)
  2. Software
    – Multi-Group Analysis (MGAU) software/li>

CANBERRA™ Solution:

In order to perform non destructive assay work on site, the CANBERRA solution to Imperial College’s key drivers included:

  • Setup and mobilization of portable HRGS equipment configured with MGAU analysis software.
  • Development of complete step by step procedures.
  • Verifying the system calibrations with actual QC standards.
  • Performing a nondestructive measurement of the entire item volume to identify the Uranium nuclides responsible for the gamma emissions and determine the 235U enrichment value.
  • Reporting the relative abundances of the uranium isotopes in the items.

A CANBERRA spectroscopy specialist visited the site and carried out the measurements. Data analysis and reporting was conducted, later, using off-line analysis of the measured spectra.


The UK measurements team successfully ascertained the 235U enrichment on 11 items and confirmed that 9 were natural and 2 were enriched Uranium. One of the enriched Uranium items was originally identified as being natural Uranium and this aided the Reactor Centre in the re-classification of the item. The work also provided essential data to allow the Imperial College Reactor Centre to update their inventory records.

Download the PDF

Related Articles


Looking for Services or Support?
We're here to help.