On-Demand Production of Protactinium-233 for Nuclear Dating Applications

Abstract

As one of the world’s largest producers and processors of uranium, Canada is interested in developing analytical tools to characterize uranium samples found outside of regulatory control. The ²³⁵U/²³¹Pa isotope pair can be used as a nuclear chronometer in forensics investigations, but usually requires access to the shorter-lived protactinium tracer ²³³Pa (t_½ = 27 d), which is not currently available in Canada. The purpose of this work was to establish a domestic supply of Pa-233 that can be produced on-demand for research purposes or incident response.Protactinium-233 was produced by neutron activation of thorium compounds at the McMaster Nuclear Reactor (MNR). Several different approaches were examined to isolate the Pa-233, and a series additives was screened to identify an agent that can prevent Pa-233 from irreversibly depositing on glass surfaces during transportation. MNR can now produce MBq quantities of solution-stable protactinium-233 for distribution within 48 h of a request.