A study of in-line plutonium isotopic analysis for gaseous plutonium hexafluoride

In-line plutonium isotopic analysis of gaseous plutonium hexafluoride (PuF6) is very important for process control and special nuclear material accountability in any plutonium-isotope-separation process that requires a gaseous phase. Although much effort had been devoted to analyze arbitrary plutonium samples, no isotopic analysis had been done on gaseous PuF6 samples. We have initiated a study on the use of a high-resolution, gamma-ray spectroscopy technique to analyze gaseous plutonium hexafluoride. For the first time, PuF6 gas samples with pressures varying from 0.15 to 31 torr, which were directly fed into a gas cell from a process flow loop, were measured. The isotopic results of these measurements agree very well with those of mass spectrometry measurements of solid PuF4. The precision of a 10-min measurement of a 10-torr reactor-grade PuF6 is 1.5% for 238Pu, 0.22% for 239Pu, 0.87% for 240Pu, and 17.5% for 241Pu