Analysis of expedited chromatographic separation systems for application to the decommissioning of nuclear facilities

Abstract

To decrease cost and time for nuclear decommissioning, a move towards automation in the waste characterisation process has been the subject of increasing study in recent years. This thesis utilised an Automated Sequential Radionuclide Separator (ASRS) to investigate the effects of expediting the separation and purification of Sr, Pu, Th and U from concrete matrices. This benchtop separation system consists of 8 chromatographic columns with forced flow of solutions through the columns being achieved using peristaltic pumps. Sr separation was found to be largely unaffected by increasing the flowrates up to those capable by the separator, and chemical recoveries of over 90 % were achieved. Pu, Th and U separation using three chromatographic materials demonstrated practically how different active site bonding method to the polymer support can affect uptake kinetics. The active site coated resin TEVA resin achieved equilibrium within 1 hour whereas Anion Exchange resin (that has the active site forming part of the polymer) took 2.5 hours. A sample analysis method incorporating expedited chromatographic separation was tested using a simulated concrete digest. Purified fractions of U, Th, Pu and Sr were produced at elevated flow rates using a Sr-spec column as well as a series of TEVA and UTEVA columns. Chemical yields were found to be adequate and fully corrected measurements were accurate and precise. Separation times for the 4 analytes were significantly reduced, from over 2 hours 40 minutes to 25 minutes. This thesis has proven the application of an expedited chromatographic separation system to the analysis of concrete samples for common radionuclides measured at nuclear facilities. The time savings, versatility, automation, and ability to be incorporated into fully shielded procedures make it an attractive prospect for both decommissioning organisations and multi-purpose laboratories.

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Identifiers

ORCID for Alexander, James Hately: orcid.org/0000-0003-4601-3168

ORCID for Phillip Warwick: orcid.org/0000-0001-8774-5125

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