ENVIRONMENTAL MONITORING OF HANFORD NUCLEAR FACILITY EFFLUENTS BY THERMAL IONIZATION MASS-SPECTROMETRY

Thermal ionization mass spectrometry (TIMS) is a sensitive method for environmental monitoring of effluent radionuclides around nuclear mate rial production facilities. Isotopic analysis by positive and negative TIMS is an essential tool for the assessment of both the inventory an d 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 th e Hanford Site, a former nuclear material production site. In favorabl e cases, complete isotopic analyses are obtained on total analytes in the femtogram range, and minor isotopes in the attogram range are meas ured. The method of direct particle-inlet mass spectrometry (PIMS) for real-time analysis of airborne particles is also described, along wit h PIMS instrumentation. Examples are given that demonstrate the capabi lity of PIMS to measure uranium isotope ratios in individual particles without isolating them from complex, heterogeneous samples.