Abstract
Three gravimetric mixtures with 241Am/243Am isotope ratios at nominally 1:1, 20:1, and 200:1 were prepared for calibration of the thermal ionization mass spectrometer instruments used for americium isotopic and assay measurements by isotope dilution mass spectrometry. The total evaporation analytical technique that has already been demonstrated to provide accurate (within ±0.03%) 235U/238U and 240Pu/239Pu ratios was developed to obtain highly reproducible Am isotopic ratios. The technique was also applied to Am assay measurements using isotope dilution mass spectrometry. The Am isotope ratio and assay measurement techniques were utilized to characterize batches of americium oxide separated from plutonium materials in storage at Los Alamos National Laboratory in support of commercial use of 241AmO2. LA-UR-20–23098.
| Original language | English |
|---|---|
| Article number | 116430 |
| Journal | International Journal of Mass Spectrometry |
| Volume | 458 |
| DOIs | |
| State | Published - Dec 2020 |
| Externally published | Yes |
Funding
Plutonium (Pu) materials contain radioactive decay products, the abundances of which together with the abundances of the parent Pu isotopes, are used as characteristic signatures that can uniquely identify the processing history as well as intended use of the nuclear material [ 1–6 ]. Decay products of Pu materials include isotopes of Americium (Am), Neptunium (Np), and Uranium (U). In recovery of the 241 Am isotope for commercial use, separations starting with high-dose (old) Pu materials have been demonstrated as a viable option [ 7–9 ]. The plutonium facility at Los Alamos National Laboratory (LANL) was funded by the Office of Science to produce 241 AmO 2 for industrial manufacture of 241 AmBe neutron sources. The plutonium facility at LANL has demonstrated expertise in the routine recovery and processing of 241 Am from high-dose Pu materials in storage at LANL. Actinide Analytical Chemistry (CAAC) division at LANL developed analytical methodologies for characterization of the separated 241 Am materials to meet product acceptance criteria. Analytical efforts in support of the Am isotopic and assay measurements are detailed here. We acknowledge CAAC colleagues Khal Spencer, Floyd Stanley, Donivan Porterfield, Lav Tandon, and Mariam Thomas for help in procuring the 243 Am ORNL material and the Eckert & Ziegler standards used in this work. Khal is also thanked for help with dissolution of the ORNL americium oxide material. Programmatic support from LANL colleagues Leisa Davenhall (Pit Production Integration) and Eva Birnbaum (Science Program Office) is also gratefully acknowledged. We express our gratitude to the plutonium assay team (Elmer Lujan, Mary Knaak, Angela Lawver, and Katherine Garduno) at CAAC for careful dissolution of the Americium oxide production samples. We acknowledge CAAC colleagues Khal Spencer, Floyd Stanley, Donivan Porterfield, Lav Tandon, and Mariam Thomas for help in procuring the 243Am ORNL material and the Eckert & Ziegler standards used in this work. Khal is also thanked for help with dissolution of the ORNL americium oxide material. Programmatic support from LANL colleagues Leisa Davenhall (Pit Production Integration) and Eva Birnbaum (Science Program Office) is also gratefully acknowledged. We express our gratitude to the plutonium assay team (Elmer Lujan, Mary Knaak, Angela Lawver, and Katherine Garduno) at CAAC for careful dissolution of the Americium oxide production samples.
| Funders | Funder number |
|---|---|
| Eva Birnbaum | |
| LANL colleagues Leisa Davenhall | |
| Office of Science | |
| Oak Ridge National Laboratory | |
| Civil Aviation Administration of China |
Keywords
- Americium
- Nuclear forensics
- Nuclear safeguards
- Plutonium
- Thermal ionization mass spectrometry