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Bennett, Megan E.

Publications and source records attributed to Bennett, Megan E..

6 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

New determination of the 229 Th half-life

A new determination of the 229 Th half-life was made based on measurements of the 229 Th massic activity of a high-purity solution for which the 229 Th molality had previously been measured. The 229 Th massic activity was measured by direct comparison with SRM 4328C using 4παβ liquid scintillation counting, NaI counting, and standard addition liquid scintillation counting. The 229Th massic activity was confirmed by isotope dilution alpha spectrometry measurements. The 229 Th half-life calculated from the activity measurements is (7825 ± 87) years (k = 2).

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2017

A new thorium-229 reference material

A new reference material was characterized for 229 Th molality and thorium isotope amount ratios. This reference material is intended for use in nuclear forensic analyses as an isotope dilution mass spectrometry spike. The reference material value and expanded uncertainty (k = 2) for the 229 Th molality is (1.1498 ± 0.0016)×10 -10 mol g -1 solution. The value and expanded uncertainty (k = 2) for the n( 230 Th)/n( 229 Th) ratio is (5.18 ± 0.26)×10 -5 and the n( 232 Th)/n( 229 Th) ratio is (3.815 ± 0.092)×10 -4 .

07 ISOTOPE AND RADIATION SOURCES↗
DOE OSTI2016

Development Of ABEC Column For Separation Of Tc-99 From Northstar Dissolved Target Solution

Batch and column breakthrough experiments were performed to determine isotherms and mass-transfer parameters for adsorption of Tc on aqueous biphasic extraction chromatographic (ABEC) sorbent in two solutions: 200 g/L Mo, 5.1 M K + , 1 M OH - , and 0.1 M NO 3 - (Solution A) and 200 g/L Mo, 9.3 M K + , 5 M OH - , and 0.1 M NO 3 - (Solution B). Good agreement was found between the isotherm values obtained by batch and column breakthrough studies for both Solutions A and B. Potassium-pertechnetate intra-particle diffusivity on ABEC resin was estimated by VERSE simulations, and good agreement was found among a series of column-breakthrough experiments at varying flow velocities, column sizes, and technetium concentrations. However, testing of 10 cc cartridges provided by NorthStar with Solutions A and B did not give satisfactory results, as significant Tc breakthrough was observed and ABEC cartridge performance varied widely among experiments. These different experimental results are believed to be due to inconsistent preparation of the ABEC resin prior to packing and/or inconsistent packing.

36 MATERIALS SCIENCE↗
DOE OSTI2016

A non-destructive internal nuclear forensic investigation at Argonne: discovery of a Pu planchet from 1948

A plutonium alpha standard dating from 1948 was discovered at Argonne National Laboratory and characterized using a number of non-destructive analytical techniques. The principle radioactive isotope was found to be 239 Pu and unique ring structures were found across the surface of the deposition area. Due to chronological constraints on possible sources and its high isotopic purity, the plutonium in the sample was likely produced by the Oak Ridge National Lab X-10 Reactor. As a result, it is proposed that the rings are resultant through a combination of polishing and electrodeposition, though the hypothesis fails to address a few key features of the ring structures.

239Pu↗
DOE OSTI2015

FY-15 Progress Report on Cleanup of irradiated SHINE Target Solutions Containing 140g-U/L Uranyl Sulfate

During FY 2012 and 2013, a process was developed to convert the SHINE Target Solution (STS) of irradiated uranyl sulfate (140 g U/L) to uranyl nitrate. This process is necessary so that the uranium solution can be processed by the UREX (Uranium Extraction) separation process, which will remove impurities from the uranium so that it can be recycled. The uranyl sulfate solution must contain <0.02 M SO 4 2- so that the uranium will be extractable into the UREXsolvent. In addition, it is desired that the barium content be below 0.0007 M, as this is the limit in the Resource Conservation and Recovery Act (RCRA).

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗