Environmental Monitoring of Hanford Nuclear Facility Effluents by Thermal Ionization Mass Spectrometry

Abstract

Thermal ionization mass spectrometry (TIMS) is a sensitive method for environmental monitoring of effluent radionuclides around nuclear material production facilities. Isotopic analysis by positive and negative TIMS is an essential tool for the assessment of both the inventory and migration of radionuclides in the environment. Instrumentation used for trace-level isotope ratio measurements is described. Examples are given of environmental measurements of plutonium and radioiodine at the Hanford Site, a former nuclear material production site. In favorable cases, complete isotopic analyses are obtained on total analytes in the femtogram range, and minor isotopes in the attogram range are measured. The method of direct particle-inlet mass spectrometry (PIMS) for real-time analysis of airborne particles is also described, along with PIMS instrumentation. Examples are given that demonstrate the capability of PIMS to measure uranium isotope ratios in individual particles without isolating them from complex, heterogeneous samples.