237Np analytical method using239Np tracers and application to a contaminated nuclear disposal facility.
Environmental237Np analyses are challenged by low237Np concentrations and lack of an available yield tracer; we report a rapid, inexpensive237Np analytical approach employing the short lived239Np (t1/2= 2.3 days) as a chemical yield tracer followed by237Np quantification using inductively coupled plasma-mass spectrometry.239Np tracer is obtained via separation from a243Am stock solution and standardized using gamma spectrometry immediately prior to sample processing. Rapid digestions using a commercial, 900 W "Walmart" microwave and Parr microwave vessels result in 99.8 ± 0.1% digestion yields, while chromatographic separations enable Np/U separation factors on the order of 106and total Np yields of 95 ± 4% (2σ). Application of this method to legacy soil samples surrounding a radioactive disposal facility (the Subsurface Disposal Area at Idaho National Laboratory) reveal the presence of low level237Np contamination within 600 m of this site, with maximum237Np concentrations on the order of 103times greater than nuclear weapons testing fallout levels.
Idaho National Laboratory, PO Box 1625, Idaho Falls, ID 83415-2805, USA; Washington State University, PO Box 644630, Pullman, WA 99164-4630, USA. Electronic address: mathew.snow@inl.gov.
Mathew S
MS
Snow
Washington State University, PO Box 644630, Pullman, WA 99164-4630, USA; Pacific Northwest National Laboratory, PO Box 999, MSIN J4-80, 902 Battelle Blvd., Richland, WA 99352, USA.
Samuel S
SS
Morrison
Washington State University, PO Box 644630, Pullman, WA 99164-4630, USA; Pacific Northwest National Laboratory, PO Box 999, MSIN J4-80, 902 Battelle Blvd., Richland, WA 99352, USA.
Sue B
SB
Clark
Idaho National Laboratory, PO Box 1625, Idaho Falls, ID 83415-2805, USA.
John E
JE
Olson
Idaho National Laboratory, PO Box 1625, Idaho Falls, ID 83415-2805, USA.
Matthew G
MG
Watrous
D007061:Idaho; D009405:Neptunium / Q000032:analysis*; D011834:Radiation Monitoring / Q000379:methods*; D011850:Radioactive Waste / Q000032:analysis*; D012990:Soil Pollutants, Radioactive / Q000032:analysis*
D011850:Radioactive Waste; D012990:Soil Pollutants, Radioactive; D009405:Neptunium
Np-237; Np-239; Subsurface disposal area