Method development for the analysis of nuclear forensic signatures with ICP-MS

Abstract

Nuclear forensic analysis is a field of analytical chemistry that focuses specifically on analyzing signatures of nuclear material for criminal investigation. Promising nuclear forensic signatures include rare earths element pattern and uranium and plutonium isotopes ratios. Uranium isotope ratios that deviate from natural indicates enrichment activities. The presence of plutonium and the 239Pu/240Pu isotopic ratio indicate irradiation of uranium for weapons production purposes. Samples for nuclear forensic analysis are often urgent, and therefore must be analyzed quickly, with good accuracy and precision. Robust methodologies must be developed for analysis of samples from potential nuclear scenarios with suitable speed, accuracy, and precision. In this dissertation, a method was developed to analyze uranium isotope ratios from solid particles on the surface of environmental swipe samples for the purpose of quickly and accurately determining whether uranium enrichment was occurring in the facility. A method to quantify rare earth impurities in uranium ore concentrates using high performance ion chromatography (HPIC) and inductively coupled plasma mass spectrometry (ICP-MS) was tested, as was a method to rapidly dissolve inorganic material using ammonium bifluoride and subsequently quantify the rare earth concentration using a newly developed high performance ion chromatography method coupled with ICP-MS detection. The method was demonstrated by accurate measurement of rare earth elements in igneous USGS minerals. Finally, the method was used to separate fresh fission products from a uranium tracer with detection by gamma ray spectroscopy.