Measurement of Actinides in Molybdenum-99 Solution Analytical Procedure

Technical Report · Sun Nov 01 00:00:00 EDT 2015

DOI:https://doi.org/10.2172/1244821· OSTI ID:1244821

Soderquist, Chuck Z. ^[1]; Weaver, Jamie L. ^[1]

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1. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

This document is a companion report to a previous report, PNNL 24519, Measurement of Actinides in Molybdenum-99 Solution, A Brief Review of the Literature, August 2015. In this companion report, we report a fast, accurate, newly developed analytical method for measurement of trace alpha-emitting actinide elements in commercial high-activity molybdenum-99 solution. Molybdenum-99 is widely used to produce ^99mTc for medical imaging. Because it is used as a radiopharmaceutical, its purity must be proven to be extremely high, particularly for the alpha emitting actinides. The sample of ⁹⁹Mo solution is measured into a vessel (such as a polyethylene centrifuge tube) and acidified with dilute nitric acid. A gadolinium carrier is added (50 µg). Tracers and spikes are added as necessary. Then the solution is made strongly basic with ammonium hydroxide, which causes the gadolinium carrier to precipitate as hydrous Gd(OH)₃. The precipitate of Gd(OH)₃ carries all of the actinide elements. The suspension of gadolinium hydroxide is then passed through a membrane filter to make a counting mount suitable for direct alpha spectrometry. The high-activity ⁹⁹Mo and ^99mTc pass through the membrane filter and are separated from the alpha emitters. The gadolinium hydroxide, carrying any trace actinide elements that might be present in the sample, forms a thin, uniform cake on the surface of the membrane filter. The filter cake is first washed with dilute ammonium hydroxide to push the last traces of molybdate through, then with water. The filter is then mounted on a stainless steel counting disk. Finally, the alpha emitting actinide elements are measured by alpha spectrometry.

• Research Organization: Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1244821
• Report Number(s): PNNL-24918; NN9100000; TRN: US1601171
• Country of Publication: United States
• Language: English

Related Subjects

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
NITRIC ACID
PRECIPITATION
MEMBRANES
CARRIERS
SUSPENSIONS
MOLYBDENUM 99
SOLUTIONS
GADOLINIUM HYDROXIDES
ACTINIDES
GADOLINIUM
AMMONIUM HYDROXIDES
ALPHA SPECTROSCOPY
FILTERS
TRACE AMOUNTS
ALPHA DECAY RADIOISOTOPES
RADIOMETRIC ANALYSIS
Molybdenum-99
Tc-99m