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At least 811 records · Page 45
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DOE OSTI2020

Materials Data on LaLuC3 by Materials Project

LuLaC3 is Plutonium carbide-derived structured and crystallizes in the cubic I2_13 space group. The structure is three-dimensional. Lu3+ is bonded in a 6-coordinate geometry to six C2- atoms. There are three shorter (2.56 Å) and three longer (2.60 Å) Lu–C bond lengths. La3+ is bonded in a 9-coordinate geometry to nine C2- atoms. There are a spread of La–C bond distances ranging from 2.62–2.85 Å. There are two inequivalent C2- sites. In the first C2- site, C2- is bonded to two equivalent Lu3+, two equivalent La3+, and one C2- atom to form distorted CLa2Lu2C trigonal bipyramids that share corners with twelve equivalent CLa4Lu2C pentagonal bipyramids, edges with three equivalent CLa4Lu2C pentagonal bipyramids, and edges with four equivalent CLa2Lu2C trigonal bipyramids. The C–C bond length is 1.34 Å. In the second C2- site, C2- is bonded to two equivalent Lu3+, four equivalent La3+, and one C2- atom to form distorted CLa4Lu2C pentagonal bipyramids that share corners with eight equivalent CLa4Lu2C pentagonal bipyramids, corners with twelve equivalent CLa2Lu2C trigonal bipyramids, edges with two equivalent CLa4Lu2C pentagonal bipyramids, edges with three equivalent CLa2Lu2C trigonal bipyramids, and faces with four equivalent CLa4Lu2C pentagonal bipyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K6Tl17 by Materials Project

K6Tl17 is beta Plutonium-derived structured and crystallizes in the orthorhombic Cccm space group. The structure is three-dimensional. there are five inequivalent K sites. In the first K site, K is bonded in a 10-coordinate geometry to ten Tl atoms. There are a spread of K–Tl bond distances ranging from 3.67–3.93 Å. In the second K site, K is bonded in a 8-coordinate geometry to two equivalent K and eight Tl atoms. Both K–K bond lengths are 4.05 Å. There are a spread of K–Tl bond distances ranging from 3.77–3.87 Å. In the third K site, K is bonded in a 10-coordinate geometry to twelve Tl atoms. There are a spread of K–Tl bond distances ranging from 3.92–4.21 Å. In the fourth K site, K is bonded in a 9-coordinate geometry to one K and nine Tl atoms. The K–K bond length is 4.26 Å. There are a spread of K–Tl bond distances ranging from 3.66–3.99 Å. In the fifth K site, K is bonded in a 2-coordinate geometry to four K and nine Tl atoms. There are a spread of K–Tl bond distances ranging from 3.67–4.12 Å. There are twelve inequivalent Tl sites. In the first Tl site, Tl is bonded in a 10-coordinate geometry to five K and five Tl atoms. There are a spread of Tl–Tl bond distances ranging from 3.34–3.52 Å. In the second Tl site, Tl is bonded in a 12-coordinate geometry to three K and nine Tl atoms. There are a spread of Tl–Tl bond distances ranging from 3.35–3.66 Å. In the third Tl site, Tl is bonded in a 12-coordinate geometry to three K and nine Tl atoms. There are a spread of Tl–Tl bond distances ranging from 3.23–3.50 Å. In the fourth Tl site, Tl is bonded in a 2-coordinate geometry to two K and seven Tl atoms. There are one shorter (3.48 Å) and two longer (3.52 Å) Tl–Tl bond lengths. In the fifth Tl site, Tl is bonded in a 12-coordinate geometry to four K and eight Tl atoms. There are a spread of Tl–Tl bond distances ranging from 3.18–3.41 Å. In the sixth Tl site, Tl is bonded in a 12-coordinate geometry to three K and nine Tl atoms. There are a spread of Tl–Tl bond distances ranging from 3.32–3.64 Å. In the seventh Tl site, Tl is bonded in a 2-coordinate geometry to two equivalent K and five Tl atoms. The Tl–Tl bond length is 3.47 Å. In the eighth Tl site, Tl is bonded to four K and eight Tl atoms to form distorted TlK4Tl8 cuboctahedra that share corners with two equivalent TlK2Tl10 cuboctahedra and faces with four equivalent TlK4Tl8 cuboctahedra. In the ninth Tl site, Tl is bonded to four K and eight Tl atoms to form TlK4Tl8 cuboctahedra that share corners with two equivalent TlK4Tl8 cuboctahedra and faces with four TlK2Tl10 cuboctahedra. Both Tl–Tl bond lengths are 3.36 Å. In the tenth Tl site, Tl is bonded to two K and ten Tl atoms to form a mixture of distorted face and corner-sharing TlK2Tl10 cuboctahedra. Both Tl–Tl bond lengths are 3.39 Å. In the eleventh Tl site, Tl is bonded in a 4-coordinate geometry to four K and five Tl atoms. In the twelfth Tl site, Tl is bonded in a 2-coordinate geometry to two equivalent K and eight Tl atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ca6Ge7Au15 by Materials Project

Ca6Au15Ge7 is beta Plutonium-derived structured and crystallizes in the monoclinic Pm space group. The structure is three-dimensional. there are six inequivalent Ca sites. In the first Ca site, Ca is bonded in a 4-coordinate geometry to eleven Au and five Ge atoms. There are a spread of Ca–Au bond distances ranging from 3.15–3.72 Å. There are a spread of Ca–Ge bond distances ranging from 3.19–3.36 Å. In the second Ca site, Ca is bonded in a 1-coordinate geometry to nine Au and five Ge atoms. There are a spread of Ca–Au bond distances ranging from 3.13–3.41 Å. There are a spread of Ca–Ge bond distances ranging from 3.15–3.37 Å. In the third Ca site, Ca is bonded in a 11-coordinate geometry to eleven Au and three Ge atoms. There are a spread of Ca–Au bond distances ranging from 3.12–3.49 Å. There are two shorter (3.21 Å) and one longer (3.40 Å) Ca–Ge bond lengths. In the fourth Ca site, Ca is bonded in a 4-coordinate geometry to nine Au and five Ge atoms. There are a spread of Ca–Au bond distances ranging from 3.17–3.36 Å. There are a spread of Ca–Ge bond distances ranging from 3.19–3.41 Å. In the fifth Ca site, Ca is bonded in a 8-coordinate geometry to ten Au and two Ge atoms. There are a spread of Ca–Au bond distances ranging from 3.09–3.68 Å. There are one shorter (3.16 Å) and one longer (3.17 Å) Ca–Ge bond lengths. In the sixth Ca site, Ca is bonded in a 8-coordinate geometry to eleven Au and one Ge atom. There are a spread of Ca–Au bond distances ranging from 3.09–3.71 Å. The Ca–Ge bond length is 3.15 Å. There are fifteen inequivalent Au sites. In the first Au site, Au is bonded in a 2-coordinate geometry to four Ca, four Au, and two equivalent Ge atoms. There are three shorter (2.94 Å) and one longer (2.99 Å) Au–Au bond lengths. Both Au–Ge bond lengths are 2.58 Å. In the second Au site, Au is bonded in a 10-coordinate geometry to four Ca, four Au, and two equivalent Ge atoms. There are a spread of Au–Au bond distances ranging from 2.91–2.96 Å. Both Au–Ge bond lengths are 2.60 Å. In the third Au site, Au is bonded in a 10-coordinate geometry to four Ca, four Au, and two equivalent Ge atoms. There are a spread of Au–Au bond distances ranging from 2.91–2.98 Å. Both Au–Ge bond lengths are 2.58 Å. In the fourth Au site, Au is bonded in a 10-coordinate geometry to four Ca, four Au, and two equivalent Ge atoms. There are a spread of Au–Au bond distances ranging from 2.94–3.01 Å. Both Au–Ge bond lengths are 2.57 Å. In the fifth Au site, Au is bonded in a 1-coordinate geometry to four Ca, two Au, and three Ge atoms. The Au–Au bond length is 2.78 Å. There are one shorter (2.56 Å) and two longer (2.80 Å) Au–Ge bond lengths. In the sixth Au site, Au is bonded in a 1-coordinate geometry to five Ca, two Au, and three Ge atoms. The Au–Au bond length is 2.81 Å. There are one shorter (2.54 Å) and two longer (2.80 Å) Au–Ge bond lengths. In the seventh Au site, Au is bonded in a 3-coordinate geometry to four Ca, two Au, and three Ge atoms. The Au–Au bond length is 2.81 Å. There are one shorter (2.54 Å) and two longer (2.75 Å) Au–Ge bond lengths. In the eighth Au site, Au is bonded in a 1-coordinate geometry to four Ca, two Au, and one Ge atom. The Au–Au bond length is 2.86 Å. The Au–Ge bond length is 2.53 Å. In the ninth Au site, Au is bonded in a 1-coordinate geometry to four Ca, seven Au, and one Ge atom. There are a spread of Au–Au bond distances ranging from 2.82–3.02 Å. The Au–Ge bond length is 2.68 Å. In the tenth Au site, Au is bonded in a distorted linear geometry to four Ca, six Au, and two Ge atoms. There are two shorter (2.97 Å) and two longer (3.02 Å) Au–Au bond lengths. There are one shorter (2.68 Å) and one longer (2.69 Å) Au–Ge bond lengths. In the eleventh Au site, Au is bonded in a 12-coordinate geometry to four Ca, five Au, and three Ge atoms. There are one shorter (2.74 Å) and two longer (2.87 Å) Au–Ge bond lengths. In the twelfth Au site, Au is bonded in a 12-coordinate geometry to four Ca, five Au, and three Ge atoms. There are one shorter (2.81 Å) and two longer (2.86 Å) Au–Ge bond lengths. In the thirteenth Au site, Au is bonded in a 12-coordinate geometry to four Ca, five Au, and three Ge atoms. There are one shorter (2.76 Å) and two longer (2.89 Å) Au–Ge bond lengths. In the fourteenth Au site, Au is bonded to four Ca, seven Au, and one Ge atom to form distorted face-sharing AuCa4GeAu7 cuboctahedra. Both Au–Au bond lengths are 2.93 Å. The Au–Ge bond length is 2.81 Å. In the fifteenth Au site, Au is bonded in a 1-coordinate geometry to four Ca, three Au, and one Ge atom. The Au–Ge bond length is 2.61 Å. There are seven inequivalent Ge sites. In the first Ge site, Ge is bonded in a 4-coordinate geometry to three Ca and five Au atoms. In the second Ge site, Ge is bonded in a 3-coordinate geometry to three Ca, four Au, and one Ge atom. The Ge–Ge bond length is 2.67 Å. In the third Ge site, Ge is bonded in a 3-coordinate geometry to three Ca, four Au, and one Ge atom. The Ge–Ge bond length is 2.70 Å. In the fourth Ge site, Ge is bonded in a 3-coordinate geometry to three Ca, four Au, and one Ge atom. The Ge–Ge bond length is 2.65 Å. In the fifth Ge site, Ge is bonded in a 9-coordinate geometry to three Ca, five Au, and one Ge atom. In the sixth Ge site, Ge is bonded in a 9-coordinate geometry to three Ca, five Au, and one Ge atom. In the seventh Ge site, Ge is bonded in a 9-coordinate geometry to three Ca, five Au, and one Ge atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mg16Al12Pt by Materials Project

Mg16PtAl12 is beta Plutonium-derived structured and crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are sixteen inequivalent Mg sites. In the first Mg site, Mg is bonded in a 6-coordinate geometry to four Mg and twelve Al atoms. There are a spread of Mg–Mg bond distances ranging from 3.15–3.37 Å. There are a spread of Mg–Al bond distances ranging from 3.07–3.30 Å. In the second Mg site, Mg is bonded in a 12-coordinate geometry to seven Mg and five Al atoms. There are a spread of Mg–Mg bond distances ranging from 3.04–3.13 Å. There are a spread of Mg–Al bond distances ranging from 2.95–3.13 Å. In the third Mg site, Mg is bonded in a 1-coordinate geometry to two Mg, one Pt, and five Al atoms. The Mg–Pt bond length is 2.82 Å. There are a spread of Mg–Al bond distances ranging from 3.03–3.14 Å. In the fourth Mg site, Mg is bonded in a 1-coordinate geometry to five Mg, one Pt, and five Al atoms. There are a spread of Mg–Mg bond distances ranging from 3.09–3.14 Å. The Mg–Pt bond length is 2.94 Å. There are a spread of Mg–Al bond distances ranging from 2.99–3.30 Å. In the fifth Mg site, Mg is bonded in a 12-coordinate geometry to four Mg, one Pt, and five Al atoms. There are a spread of Mg–Mg bond distances ranging from 3.01–3.33 Å. The Mg–Pt bond length is 3.16 Å. There are a spread of Mg–Al bond distances ranging from 2.85–3.14 Å. In the sixth Mg site, Mg is bonded in a 12-coordinate geometry to seven Mg and five Al atoms. There are a spread of Mg–Mg bond distances ranging from 3.10–3.15 Å. There are a spread of Mg–Al bond distances ranging from 2.88–3.23 Å. In the seventh Mg site, Mg is bonded in a 1-coordinate geometry to three Mg, one Pt, and five Al atoms. There are a spread of Mg–Mg bond distances ranging from 3.10–3.19 Å. The Mg–Pt bond length is 2.76 Å. There are a spread of Mg–Al bond distances ranging from 2.87–3.18 Å. In the eighth Mg site, Mg is bonded in a 10-coordinate geometry to four Mg and six Al atoms. There are one shorter (3.04 Å) and one longer (3.05 Å) Mg–Mg bond lengths. There are a spread of Mg–Al bond distances ranging from 3.04–3.15 Å. In the ninth Mg site, Mg is bonded in a 1-coordinate geometry to seven Mg, one Pt, and five Al atoms. There are a spread of Mg–Mg bond distances ranging from 3.06–3.23 Å. The Mg–Pt bond length is 3.18 Å. There are a spread of Mg–Al bond distances ranging from 2.87–3.23 Å. In the tenth Mg site, Mg is bonded in a 12-coordinate geometry to four Mg and five Al atoms. There are one shorter (3.17 Å) and one longer (3.18 Å) Mg–Mg bond lengths. There are a spread of Mg–Al bond distances ranging from 2.89–3.05 Å. In the eleventh Mg site, Mg is bonded in a 12-coordinate geometry to five Mg and five Al atoms. The Mg–Mg bond length is 3.09 Å. There are a spread of Mg–Al bond distances ranging from 2.91–3.07 Å. In the twelfth Mg site, Mg is bonded in a 1-coordinate geometry to seven Mg, one Pt, and five Al atoms. There are a spread of Mg–Mg bond distances ranging from 3.00–3.14 Å. The Mg–Pt bond length is 3.15 Å. There are a spread of Mg–Al bond distances ranging from 2.85–3.24 Å. In the thirteenth Mg site, Mg is bonded in a 10-coordinate geometry to two Mg and seven Al atoms. There are a spread of Mg–Al bond distances ranging from 3.08–3.37 Å. In the fourteenth Mg site, Mg is bonded in a 2-coordinate geometry to three Mg, one Pt, and four Al atoms. The Mg–Pt bond length is 2.79 Å. There are a spread of Mg–Al bond distances ranging from 2.86–3.18 Å. In the fifteenth Mg site, Mg is bonded in a 12-coordinate geometry to seven Mg and five Al atoms. The Mg–Mg bond length is 3.33 Å. There are a spread of Mg–Al bond distances ranging from 2.88–3.23 Å. In the sixteenth Mg site, Mg is bonded in a 12-coordinate geometry to three Mg, one Pt, and five Al atoms. The Mg–Pt bond length is 3.16 Å. There are a spread of Mg–Al bond distances ranging from 2.85–3.15 Å. Pt is bonded in a 11-coordinate geometry to eight Mg and three Al atoms. There are a spread of Pt–Al bond distances ranging from 2.60–2.64 Å. There are twelve inequivalent Al sites. In the first Al site, Al is bonded in a 1-coordinate geometry to seven Mg, one Pt, and three Al atoms. There are two shorter (2.73 Å) and one longer (2.76 Å) Al–Al bond lengths. In the second Al site, Al is bonded in a 11-coordinate geometry to eight Mg and three Al atoms. There are one shorter (2.73 Å) and one longer (2.76 Å) Al–Al bond lengths. In the third Al site, Al is bonded in a 10-coordinate geometry to seven Mg and three Al atoms. There are one shorter (2.68 Å) and two longer (2.72 Å) Al–Al bond lengths. In the fourth Al site, Al is bonded in a 1-coordinate geometry to eight Mg, one Pt, and three Al atoms. There are one shorter (2.70 Å) and one longer (2.71 Å) Al–Al bond lengths. In the fifth Al site, Al is bonded in a 10-coordinate geometry to seven Mg and three Al atoms. There are one shorter (2.65 Å) and one longer (2.72 Å) Al–Al bond lengths. In the sixth Al site, Al is bonded in a 12-coordinate geometry to nine Mg and three Al atoms. The Al–Al bond length is 2.74 Å. In the seventh Al site, Al is bonded in a 11-coordinate geometry to eight Mg and three Al atoms. In the eighth Al site, Al is bonded in a 11-coordinate geometry to eight Mg and three Al atoms. There are a spread of Al–Al bond distances ranging from 2.69–2.73 Å. In the ninth Al site, Al is bonded in a 11-coordinate geometry to eight Mg and three Al atoms. There are one shorter (2.66 Å) and one longer (2.71 Å) Al–Al bond lengths. In the tenth Al site, Al is bonded in a 10-coordinate geometry to seven Mg and three Al atoms. In the eleventh Al site, Al is bonded in a 1-coordinate geometry to five Mg, one Pt, and three Al atoms. In the twelfth Al site, Al is bonded in a 10-coordinate geometry to seven Mg and three Al atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mg4Si3 by Materials Project

Mg4Si3 is beta Plutonium-derived structured and crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are four inequivalent Mg sites. In the first Mg site, Mg is bonded in a 5-coordinate geometry to five Si atoms. There are a spread of Mg–Si bond distances ranging from 2.65–2.79 Å. In the second Mg site, Mg is bonded in a 1-coordinate geometry to six Si atoms. There are a spread of Mg–Si bond distances ranging from 2.87–3.13 Å. In the third Mg site, Mg is bonded in a 5-coordinate geometry to seven Si atoms. There are a spread of Mg–Si bond distances ranging from 2.76–3.25 Å. In the fourth Mg site, Mg is bonded in a 12-coordinate geometry to six Si atoms. There are a spread of Mg–Si bond distances ranging from 2.90–3.11 Å. There are four inequivalent Si sites. In the first Si site, Si is bonded in a 11-coordinate geometry to nine Mg and two Si atoms. There are one shorter (2.72 Å) and one longer (2.83 Å) Si–Si bond lengths. In the second Si site, Si is bonded in a 2-coordinate geometry to eight Mg and three Si atoms. There are one shorter (2.61 Å) and one longer (2.68 Å) Si–Si bond lengths. In the third Si site, Si is bonded in a 10-coordinate geometry to six Mg and four Si atoms. Both Si–Si bond lengths are 2.87 Å. In the fourth Si site, Si is bonded in a 12-coordinate geometry to eight Mg and four Si atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

EFRC Materials Science of Actinides (Final Report)

The Energy Frontier Research Center Materials Science of Actinides (MSA) conducted basic research from 2009-2019. The scientific personnel and participating institutes changed several times during the evolution of the Center, and in total included 24 senior investigators, four national laboratories, and ten universities. Workforce development was a motivating goal of the university-led Center, which included many undergraduate, graduate, and post-doctoral researchers. The center focused on the actinide elements, which arise from the sequential filling of the 5f electron orbitals. Although the specific themes evolved during the Center’s history, the final research themes were: (1) Nanoscale Cage Clusters, (2) Complex Ceramic and Metallic Materials, and (3) Materials Under Extreme Environments. To date, the Center has produced 254 peer-reviewed journal publications and book chapters that acknowledged only the EFRC funding, and an additional 161 journal publications and book chapters that acknowledged funding from the EFRC and additional sources (a few manuscripts are still in preparation). Broad highlights include: (1) Development of an extensive family of actinide nanomaterials that self-assemble in aqueous solution, an understanding of their formation mechanisms and stabilities, and possible uses in nuclear fuel cycles; (2) Establishment of facilities and methodologies to conduct high-temperature calorimetry on transuranium materials, and extensive thermodynamic-based studies of uranium and thorium compounds important to the nuclear fuel cycle; (3) A vastly improved understanding of the behavior of actinide materials in extreme conditions, including high radiation fields, temperatures, and pressures, as well coupled effects of two or more of these; (4) Development of resonance ultrasound spectroscopy and direct measurement of aging of plutonium alloys.

36 MATERIALS SCIENCE↗
DOE OSTI2020

TA55-PMDS Programmatic Maintenance [Slides]

DOE Order 433.1B states: “The contractor must maintain real property assets in a manner that promotes operational safety, worker health, environmental compliance, property preservation and cost-effectiveness while meeting the program mission”. P950 Conduct of Maintenance serves as LANL’s Nuclear Maintenance Management Program specific to M/L 1 and M/L 2 SSC. PA-AP-01108 Maintenance Requirements for Programmatic Equipment defines the process for determining maintenance requirements, as defined in a maintenance plan, for all programmatic equipment owned by the Associate Directorate for Plutonium Science and Manufacturing (ADPSM) utilizing a formal, graded approach to maximize the reliability of permanently-installed programmatic equipment that does not perform a safety function. It bridges the gap between P950 and program equipment.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Phase Equilibria and Thermochemistry of Advanced Fuels: Modeling Burnup Behavior (Final Report)

Achieving the goal of developing advanced fuel concepts that meet the DOE objectives of being robust, demonstrating high performance, and are more tolerant of accident conditions than current fuel systems will require a thorough understanding of the thermophysical and thermochemical properties of the constituent materials. Non-oxide fuel systems are being explored under the Advanced Fuels Program that hold significant promise for improved performance and accident tolerance, including the uranium silicide-based system considered in the current work. Prospective cladding materials currently considered that contribute to improved accident tolerance include silicon carbide composites and ferritic alloys (Fe-Cr-Al base compositions). Thus, the effort developed thermochemical models and values, supported with targeted experiments, to evaluate the ferritic alloy and silicon carbide composite cladding systems in contrast to current zirconium alloy cladding. The developed detailed understanding will serve to aid in relatively early screening of candidate systems to avoid wasted effort, guide development of new fuel forms, and to provide a basis for predicting and modeling fuel performance. Major deliverables for the project included: Thermochemical assessment and models of phases in the U-Si and U-Si-N systems; thermochemical evaluation supported by experimental measurements of fuel-cladding interactions of silicide fuel with baseline zirconium, ceramic composite, and ferritic alloy cladding; thermochemical assessment and models of phases supported by experimental measurements for silicide fuel with key fission products provided in a dataset and reported in refereed publications. Within the project a significantly refined U-Si phase diagram was developed and reported that now includes homogeneity ranges for key phases, such at the U 3 Si 2 proposed fuel phase, and settles issues with regard to uncertainty in the stability of some phases. Computational efforts together with key experiments has determined phase formation in interactions between U 3 Si 2 and Zircaloy-4 cladding material, a ferritic FeCrAlY alloy of interest as an advanced cladding material, and silicon carbide, also of interest as a fiber-reinforced composite cladding. As expected, very significant reactions occur between U3Si2 and Zircaloy-4, with much less interaction at higher temperatures for the ferritic alloy, and finally interactions with SiC only in the region of contact. A potentially major issue is the stability of U 3 Si 2 fuel that has undergone significant burnup. The result is the loss of the uranium metal, liberating silicon, and the formation of concomitant fission product elements that either dissolve in the U 3 Si 2 phase or form independent, and possibly silicide phases. A combination of experimental determinations of phase formation of U 3 Si 2 reacted with representative fission products yttrium, gadolinium, cerium, zirconium, and molybdenum and first principles calculations has helped understand the fuel chemistry. The behavior of the U 3 Si 2 phase and the partitioning of silicon to possible fission product phases with burnup was thus determined, with significant dissolution in U 3 Si 2 of cerium, gadolinium, zirconium, and plutonium predicted along with independent phase formation of a U-Mo-Si ternary phase, yttrium silicide, and elemental selenium. It can be concluded that at significant burnup there will be a very minor amount of the U 3 Si 2 fuel phase that will decompose to a lower silicide or a uranium alloy as silicon preferentially forms a secondary phase.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2020

Integrating Data Sources for Improved Safeguards and Accountancy of Electrochemical Fuel Reprocessing Systems. Final Report

Electrochemical reprocessing (also commonly known as “pyroprocessing”) of used nuclear fuel is an alternative to aqueous reprocessing that confers a number of advantages, including the ability to process more recently-discharged fuel, smaller resultant waste volumes, and the lack of isolation of plutonium in the product stream. While electrochemical reprocessing systems have seen a significant research and development effort, nuclear safeguards and security of these systems remains under-developed, particularly given the significant differences in operating environment and process flowsheet compared with established aqueous methods. Objective 4 of DOE’s nuclear energy research and development activities in Nuclear Energy Research and Development Roadmap is: “Understand and minimize the risks of nuclear proliferation and terrorism.” Material Control & Accountancy (MC&A) programs at nuclear processing plants deter and detect theft and diversion of nuclear material by both outside and inside adversaries. Empirical modeling and data analytics of online measurements and state indicators can improve the timeliness of detection and reduce the uncertainty in accountancy measures. To support the development and demonstration of such methods, data are needed that capture expected measurement values collected throughout electrochemical reprocessing facilities. A review of the available literature of current research in measurements for electrochemical reprocessing systems identified twenty-two candidate measurement methodologies, which characterize fuel/salt composition, concentrations of various isotopes and elements, and operational parameters throughout the reprocessing facility. Four primary measurement methodologies have been simulated based on either physical simulations or empirical correlations: gamma emissions, neutron emissions, hybrid k-edge densitometry (HKED), and cyclic voltammetry. Initial investigation into the use of these measures for process monitoring and detection suggests the approach is viable and worthy of further investigation. This report summarizes efforts to generate signatures of key measurements during operation of electrochemical reprocessing facilities and initial investigation of data analytics to support process monitoring, diversion detection, and accountancy.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2020

Fissionable Materials Handlers Operators-Initial Training

These courses were designed for all Initial Fissionable Material Handlers Operators and Supervisors whose job activities will require the performance of Fissile Material Operations located within the Plutonium Facility (PF-4). The course requirements are based on DOE order 426.2, Personnel Section, Qualification, and Training Requirements for Fissionable Material Handlers. These courses are required training for all initial Fissionable Material Handlers and is specific to TA-55 FMH Certification. It covers the core areas and topics in Criticality Safety, Material-at-Risk, Nuclear Material Control and Accountability, Radiological Protection, TA-55 Material Handling and Movement.

61 RADIATION PROTECTION AND DOSIMETRY↗
DOE OSTI2020

Technical Basis for the International Export of Handheld Spectroscopy Detectors

The international export of handheld spectroscopy detectors by the National Nuclear Security Administration (NNSA) to partner states will provide state regulatory authorities and nuclear material owners a way to improve accountancy for accidental gains of nuclear material, including the provision of reports to the IAEA, in order to meet their safeguards agreements. International Atomic Energy Agency (IAEA) safeguards agreements for non-nuclear weapons states requires accountancy for all nuclear material. As defined in Article XX of the IAEA statute, nuclear material includes source materials: "uranium containing the mixture of isotopes occurring in nature," and special fissionable material: "plutonium-239; uranium-233; uranium enriched in the isotopes 235 or 233". For IAEA Member States to meet their requirements under comprehensive safeguards agreements (CSA), safeguards are to be applied on "all source or special fissionable material," which "includes all nuclear material subject to IAEA safeguards". Therefore, accidental gains and losses of nuclear material must be reported to the IAEA. An accidental gain occurs when a state unexpectedly adds nuclear material to their inventory by various means such as seizing smuggled material or the discovery of legacy items previously unaccounted for. The material type and quantity must be added to the State's inventory by updating domestic records and then communicated to the IAEA.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2020

AMPP Newsletter - May 2020

A message from Stacy McLaughlin, Division Leader: I am excited to introduce the second 2020 issue of Actinide Materials Processing and Power Division’s newsletter, with a focus on “excellence in Plutonium missions.” AMPP Division not only supports the 2020 Laboratory Agenda item 1, Excellence in Nuclear Security, but additionally directly supports Laboratory Agenda item 2, Excellence in Mission- Focused Science Technology & Engineering, focusing on sustaining and enhancing LANL’s science base. This issue highlights the diverse efforts of personnel in AMPP Division to enhance science, technology, and engineering (ST&E) at the Laboratory. As we reflect on work at the Laboratory, mostly from our homes due to COVID-19, it is gratifying to see the important, diverse contributions to ST&E across AMPP Division.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2020

Characterization and CST Batch Contact Equilibrium Testing of Modified Tank 9H Process Supernate Samples in Support of TCCR

The Tank Closure Cesium Removal (TCCR) system uses ion exchange columns filled with crystalline silicotitanate (CST) media to process radioactive waste solutions for the removal of ¹³⁷Cs. TCCR currently focuses on dissolving Savannah River Site (SRS) radioactive tank waste (primarily sodium saltcake solids) within Tank 10H followed by at-tank ion exchange column treatment. Two supernate batches from Tank 10H have been processed through the TCCR unit and processing of a third batch is expected soon. After processing of this supernate batch, plans are to replace the CST columns and process dissolved salt solution from Tank 9H through Tank 10H and then through the new CST columns installed in the TCCR unit. The new columns are expected to contain either a media similar to an archived CST batch (IE-911) or the R9120-B CST media used in the current TCCR columns (the two materials are fundamentally the same; just different specifications, product names, and preconditioning steps). Samples of Tank 9H dissolved saltcake were received at the Savannah River National Laboratory (SRNL) and characterized. The Tank 9H supernate contained a high sodium concentration (~9.6 M Na⁺) and will require dilution to near 6 M [Na⁺] prior to processing through the TCCR unit. The cesium concentration in Tank 9H is currently significantly higher than was observed with Tank 10H. Three dilutions of the Tank 9H supernate were conducted to mimic possible dilutions that could be conducted in the tank farm prior to TCCR processing using inhibited water, sodium hydroxide, and sodium nitrate solutions. Dilution #1 was prepared by diluting the Tank 9H supernate by a factor of 1.6 with inhibited water, Dilution #2 was prepared by diluting the Tank 9H supernate by a factor of 3.7 with a mixed sodium hydroxide/sodium nitrate diluent, and Dilution #3 was prepared by also diluting by a factor of 3.7 but with sodium hydroxide only. All three dilutions have similar Na⁺ concentrations (~6 M), but Dilutions #2 and #3 contain significantly less cesium. Major and key minor components of the diluted Tank 9H supernate samples are provided in Table ES-1. Batch contact equilibrium tests were conducted with the Tank 9H dilutions and the two different CST media batches being considered for use in the new TCCR columns. Results are summarized in Table ES-2 and compared to ZAM model predictions. The highest cesium distribution coefficient and percent removal were observed with Dilution #3. IE-911 CST (an archived CST media batch) was more effective at removing cesium than the more recently prepared R9120-B CST media, though both media samples removed >88% of the cesium and the differences may not be statistically different considering the overall uncertainty. Based on the results, maximum cesium loadings were calculated for each CST media type and Tank 9H dilution. In general, maximum cesium loadings from dilutions of this supernate batch are quite high (approaching 0.1 mmol total Cs⁺/g CST for Dilution #1). The highest calculated maximum ¹³⁷Cs loading for the Tank 9H dilutions using the ZAM model with input of the tank compositions and batch contact results was 207 Ci/kg CST (Dilution #1 with IE-911 CST). In all cases, higher maximum cesium loading values were predicted for IE-911 CST versus R9120-B, although the differences varied considerably between the dilutions. The maximum loading value for IE-911 CST with Tank 9H Dilution #1 was only 7% higher than the maximum loading for R9120-B. The maximum loading value for IE-911 CST with Dilution #3 was 24% higher than the maximum loading for R9120-B. Dilution #2 was intermediate between these values. Note that these maximum loading values are the theoretical calculated values, and actual operating conditions will cause differences. A CST binder dilution (correction) factor near 0.7 (relative to pure powder CST) was required for each batch contact test with IE-911 engineered CST using the three Tank 9H dilutions. Correction factors calculated for R9120-B CST ranged from 0.56 to 0.66 for the three dilutions. Following the batch contact tests, the CST samples were isolated from the Tank 9H solution, washed, dried, and digested in acid following established procedures. The analysis results are provided in Table ES-3. Total cesium loading values determined by CST digestion were similar to the calculated loading values based on solution analysis (Table ES-2) for all samples. In addition, the CST was observed to load calcium (R9120-B sample only), iron, strontium, lead, uranium, and plutonium after contact with the waste supernate, as has been observed previously.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2020

Workshop on Improving Holdup Monitoring in the US

The characterization and quantification of nuclear deposits, or residual nuclear material retained in process equipment, generally referred to as holdup, continues to challenge nuclear processing facilities in DOE program areas such as nuclear criticality safety, material control and accountability, environmental management. The efficiency and effectiveness of nuclear operations in these facilities depends heavily on the results from nondestructive techniques designed to measure nuclear materials in situ. The traditional methods used to measure holdup were established more than 30 years ago and assume unrealistic conditions for most measurement cases. These blind, in situ measurements present unique challenges due to the following attributes: unique, non-ideal geometries; unknown deposit thicknesses; lack of representative calibration standards; large number of holdup deposit locations; and poor accessibility for many measurement locations. These difficulties and the poor assumptions made to handle them have resulted in measurement uncertainties that are often too large for many programs to effectively utilize. In an effort to address and identify solutions to the current holdup challenges facing the US nuclear industry, Oak Ridge National Laboratory hosted the Technical Workshop on Improving Holdup Monitoring in the US. The two-day workshop held August 21–22, 2019, was attended by 35 holdup measurement practitioners, program managers, stakeholders from US Department of Energy sites, the Nuclear Regulatory Commission, and representatives from commercial industry. The primary objectives were to identify critical elements of a successful and defensible holdup measurement program; identify technical challenges, needs, and potential improvements associated with measurement of holdup; and share best practices and lessons learned from recent accumulation events. Fourteen presentations were delivered on holdup topics including necessary elements for effective program management, measurement needs, emerging technologies and other measurement solutions, and lessons learned from recent events. These presentations highlighted best practices related to accumulation monitoring, considerations and proactive steps to facilitate holdup in new facility designs, imaging solutions to improve holdup assumptions, and new software developed in support of holdup measurements. Breakout sessions were also employed to determine additional needs and identify potential solutions to common holdup challenges. The primary discussions focused on causes and prevention of material accumulations, needs for uranium and plutonium measurements, and reduction of measurement uncertainty, all of which were explicitly identified as critical needs during the 2018 Workshop on Technical and Programmatic Needs for a Sustainable NDA Program for the US DOE.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2020

SAVY-4000 Corrosion Evaluation Plan

Nuclear material packages, with few exceptions, outside of an approved engineered contamination barrier must meet packaging, surveillance, and testing requirements designed to protect workers from airborne contamination per Department of Energy (DOE) Manual 441.1-1, Nuclear Material Packaging. The SAVY-4000 containers were developed at Los Alamos National Laboratory (LANL) in conjunction with Nuclear Filter Technology Inc. (NFT Inc.) as a general purpose vented manually-compliant container system for staging and storage of plutonium for LANL and the DOE complex. The SAVY-4000 containers have a 316L stainless steel containment barrier, which was selected based on its corrosion resistant properties. These containers were approved for use in 2014 with a five-year design life; LANL requested and DOE has approved lifetime extension from 5 to 15 years. The 10-year lifetime extension was proposed as a conservative recommendation based on the corrosion observations for the metal components in surveillance and results from laboratory studies. Extensive accelerated aging studies have been done on the SAVY-4000 O-ring with very little evidence of significant degradation when subjected to aggressive elevated temperature and radiation conditions. Therefore, our current conservative lifetime estimate for the O-ring and the filter is 40 years at 80°C. Additional work is ongoing in a phased approach to further extend the design life of the Manual compliant SAVY-4000 storage container; the limiting component for further life extension is still the 316L containment barrier.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Nuclear Materials Production [Slides]

This presentation covers the basics of the nuclear fuel cycle, mining and milling, enrichment technologies and processes, uranium fabrication, plutonium production, and basics of nuclear reactors.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2020

The Road to Trinity: Seventy-five years ago, Los Alamos scientists detonated the world’s first nuclear explosion

With a brilliant hot flash and a loud boom, the giant mushroom cloud with its fiery core filled the predawn sky above the New Mexico desert. The nuclear age had begun. It was 75 years ago on July 16, 1945, that Los Alamos scientists changed the world with the successful detonation of “the Gadget” – the device created to test the Fat Man implosion-type plutonium weapon before it was taken into combat. However, the road to Trinity, as the test was named by J. Robert Oppenheimer, who is thought to have been inspired by a line in a John Donne poem, was a difficult one.

45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEF↗
DOE OSTI2020

SRNL Coulometer for LANL - SRNL-Testing 2020 (Final Report)

SRNL fabricated two coulometers that have been delivered to LANL. All testing for electrical components is performed by R&D engineering and the results are attached to this report. Instrument testing for the first instrument was completed on August 2018 and installation at LANL was completed February 2019. This report addresses testing performed at FH Analytical Laboratory for the second instrument that arrived at LANL on June 5th, 2020. The testing is performed using Plutonium working standards. The instrument was kept in a radiologically clean area. The component calibration of the second LANL coulometer was completed in SRNL Building 723-A.

47 OTHER INSTRUMENTATION↗