REIMEP-18: Isotopic abundances of uranium

In the REIMEP-18 campaign laboratories were invited to measure uranium isotopic ratios in nitric acid. Each participating laboratory was provided with four samples each containing 2.5 mg of depleted to slightly enriched uranium (²³⁵U abundance between ca. 0.2 % and 4.5 %) in 0.5 mL of 0.5 M nitric acid.

Laboratories were invited to measure and report:

• the isotopic amount ratios:
  n(²³⁴U)/n(²³⁸ U), n(²³⁵ U)/n(²³⁸U), n(²³⁶ U)/n(²³⁸U),

• the isotopic abundances:
  n(²³⁴U)/n(U), n( ²³⁵U)/n(U), n(²³⁶U)/n(U), n( ²³⁸U)/n(U), and

• the isotopic mass fractions:
  m(²³⁴U)/m(U), m (²³⁵U)/m(U), m(²³⁶U)/m(U), m (²³⁸U)/m(U).

The campaign ran along the lines of the previous REIMEP campaigns:

1. IRMM supplied the samples blind, i.e. without certified isotopic abundance values.

2. On receipt of the measured values IRMM sent the certified values to the participant.

3. IRMM published a participants’ report showing the results relative to the certified values in a graphical form.

4. The links between results and identity of the participating laboratory are not published.

The total nuclear activity of the four REIMEP-18 samples is less than 1000 Bq so materials were shipped using DHL or a similar carrier. The material was not declared as radioactive and therefore no license declarations were required from participants.

IRMM charged a fee of € 200 for administrative and transport costs. This fee was waived for specific laboratories, in particular those from the new Member States and the Acceding Countries to the EU: please inquire directly.

Schedule

If you have questions about REIMEP-18, please contact Stephan Richter, the campaign coordinator (E-mail ).

Registration

Registration for participation in the campaign was performed on-line.

The registration forms were available on-line until 28 February 2006. A signed copy of the registration form was to be faxed to Stephan Richter (fax: +32-(0)14 571 863), REIMEP-18 co-ordinator by the end of February 2006.

Important: Registration was only definitive when the copy of the signed registration form was received by IRMM.

Sample dispatch

The sample packages were mailed to the participants after the registration was closed in February 2006 and contained:

• four samples each containing 2.5 mg of depleted to slightly enriched uranium ( ²³⁵U abundance between ca. 0.2% and 4.5%) in 0.5 mL of 0.5 M nitric acid and

• an instruction letter containing the allocated sample codes and password to be used for the on-line results reporting.

• a letter signed by a radioprotection and security officer of IRMM mentioning the activity and the fact that the items are exempted from regulatory requirements for transport

Results reporting

The measurement results were to be reported via the IRMM web database system. The result reporting pages were accessible from this site. To open the reporting pages the password allocated to each participant had to be used when logging into the system. This password is unique to the participant and campaign.

The results reporting is composed of two parts:

1. results of measurements

2. questionnaire.

The result input pages appear with the name of the participant and the codes of the samples sent to the participant. They are designed for reporting result of measurements of

• the isotopic ratios:
  n(²³⁴U)/n(²³⁸U), n (²³⁵U)/n(²³⁸U), n(²³⁶U)/ n (²³⁸U)

• the isotopic abundances:
  n(²³⁴U)/n(U), n( ²³⁵U)/n(U), n(²³⁶U)/n(U), n( ²³⁸U)/n(U), and

• the isotopic mass fractions:
  m(²³⁴U)/m(U), m (²³⁵U)/m(U), m(²³⁶U)/m(U), m (²³⁸U)/m(U),

but reports with partial results i.e. only some of these ratios were also  accepted.

The result reporting forms had to be submitted by the end of May 2006.