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At least 649 records · Page 36

Effect of impurities on supercritical CO2 compatibility

Impurities may affect structural alloy compatibility in both indirect- and direct-fired supercritical CO2 (sCO2) cycles for high efficiency power generation with peak temperatures above 700°C. Using a new multi-pump gas control system, experiments with controlled impurity additions were compared to baseline results in research- or industrial-grade CO2 at 750°C/300 bar. Low level impurities, 50 ppm O2 and 50 ppm H2O, were not found to affect mass change or reaction products after 2,500 h exposures. However, in RG sCO2+1%O2+0.25%H2O, higher reaction rates were observed for both Ni- and Fe-based alloys, but especially Fe-based alloys were strongly affected by these high impurity levels. Analytical TEM was used to characterize the reaction products on alloy 625.

Pint, Bruce↗

Compatibility of Steels in Supercritical CO2 at 450°-650°C

Supercritical CO2 (sCO2) power cycles, particularly direct-fired cycles, have the possibility of revolutionizing clean fossil energy. However, in the lower temperature sections of the cycle, lower cost steels are needed in order to lower the cost of the sCO2 technology. Representative 9 and 12%Cr steels and conventional and advanced austenitic steels are being evaluated at 450-650°C using mass change, bulk carbon (C) content and room temperature tensile properties to determine the maximum use temperatures for both direct- and indirect-fired sCO2 cycles. After 1000 h exposures in research grade (RG) sCO2 at 300 bar and RG sCO2 with 1% O2 and 0.1% H2O additions, the results suggest that increasing the Cr content from 9 to 12% yielded no signficant benefit under these conditions but the higher Cr and Ni contents in S31025 provided better compatibility in RG sCO2 at 650°C but limited benefit at 550°C with impurities. For S31609, the formation of Fe-rich oxide after exposure to RG sCO2 at 650°C resulted in both an increase in the bulk C content and a large drop in room temperature ductility. The evidence suggests thin, protective oxides prevented C ingress in these conditions.

Pint, Bruce↗

Electrically Conductive and Protective Coating Compatibility with LSCF Cathodes

Ferritic stainless-steel interconnect materials are used in intermediate or high-temperature SOFCs because of their oxidation resistance, high formability, and low cost. Their corrosion resistance is due to the formation of a protective chromium oxide scale during operation. However, the protective oxide layer produces Cr-containing volatile species at SOFC operating temperatures and conditions, which can cause cathode poisoning. Spinel coatings have been developed to prevent cathode poisoning while maintaining an electrically conductive pathway through SOFC stacks. Generally, Mn-Co-O spinel has been the material of choice, but PNNL has developed an Mn-Cu-O spinel protective coating to remove the costly Co and enhance the electrical conductivity. This paper will focus on the electrically conductive coating’s compatibility with LSCF in high-temperature operating environments.

Choi, Jung-Pyung↗

Design and development of a high-temperature sodium compatibility testing facility

The use of advanced alloys within sodium-cooled fast reactors (SFRs) has been identified as a means of increasing plant efficiency and reducing construction costs. In particular, alloys such as NF-616, NF-709 and HT-UPS are promising because they exhibit greater strength than traditional structural materials such as 316-SS. However, almost nothing is known about the sodium compatibility of these new alloys. Therefore, research taking place at the Univ. of Wisconsin-Madison is focused on studying the effects of sodium corrosion on these materials under prototypic SFR operating conditions (600 [ deg. C], V Na=10 [m/s], C 0{approx} 1 [wppm]). This paper focuses on the design and construction of the testing facility with an emphasis on moving magnet pumps (MMPs). Corrosion data from a preliminary 500 [hr] natural convection test will also be presented. (authors)

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗

Chemical and Radiological Compatibility Testing of 3D Printed Materials

To dramatically increase the adaptability, performance, and safety of processes in support of the Defense Waste Processing Facility (DWPF), Savannah River National Lab (SRNL) plans to perform chemical and radiological compatibility testing on a wide variety of 3D printed materials of interest. The 3D printing process provides numerous strategic operational benefits such as rapid prototyping of complex designs and geometry specific to the needs of the nuclear waste disposition process, as well as on-demand rapid prototyping and iteration with materials that aren’t as accessible through traditional manufacturing methods. Reaction chemistry in simulated waste batches can be matched closely to its radioactive counterpart, but glass reactor vessels have limitations. Vessel geometry can play a big factor in mixing transport limitations, process chemistry, and degradation reaction kinetics. In addition, additive manufacturing allows for much more detailed vessel design than traditional alternatives. Waste processing techniques in DWPF also encounter extreme chemical environments including high pH, strong acids, abrasive slurries, and significant irradiation. To meet these challenges, a matrix of various polymer, ceramic, and metal additive manufacturing materials have been exposed to a suite of chemical environments of interest as well as radioactive dose (such as gamma radiation from 60 Co) to properly test their durability under these conditions. Mass change has been monitored over a period of up to a week in these conditions, as well as added characterization for surface modification through Scanning Electron Microscopy/Electron Dispersive X-ray analysis (SEM/EDX). Further chemical characterization has been monitored through Fourier-Transform InfraRed Spectroscopy (FTIR), with planned investigation via thermal and tensile strength degradation. While the direct product of this research is identification of material(s) that can withstand specific hazardous environments encountered by the mercury water wash tank in DWPF process simulation experiments, the reference base of materials will be used for many other nuclear processes in the pursuit of rapidly developed, cost-efficient, and highly specific devices for environmental remediation and much more.

Wilson, Nathan W. [Savannah River National Laborat↗

Cladding Alloys for Fluoride Salt Compatibility Final Report

This interim report provides an overview of several candidate technologies for cladding nickel-based corrosion protection layers onto high-temperature structural alloys. The report also provides a brief overview of the welding and weld performance issues associated with joining nickel-clad nickel-based alloys. From the available techniques, two cladding technologies were selected for initial evaluation. The first technique is a line-of-sight method that would be useful for coating large structures such as vessel interiors or large piping. The line-of-sight method is a laser-based surface cladding technique in which a high-purity nickel powder mixed into a polymer binder is first sprayed onto the surface, baked, and then rapidly melted using a high power laser. The second technique is a vapor phase technique based on the nickel-carbonyl process that is suitable for coating inaccessible surfaces such as the interior surfaces of heat exchangers. The final project report will feature an experimental evaluation of the performance of the two selected cladding techniques.

36 MATERIALS SCIENCE↗

Asymptotically compatible reproducing kernel collocation and meshfree integration for the peridynamic Navier equation

Here, we study reproducing kernel (RK) collocation method for peridynamic Navier equation. In the first part, we apply a linear RK approximation to both displacement and dilatation, and then back-substitute dilatation and solve the peridynamic Navier equation in a pure displacement form. The RK collocation scheme converges to the nonlocal limit for a fixed nonlocal interaction length and also to the local limit as nonlocal interactions vanish. The stability is shown by comparing the collocation scheme with the standard Galerkin scheme using Fourier analysis. In the second part, we apply the RK collocation to the quasi-discrete peridynamic Navier equation and show its convergence to the correct local limit when the ratio between the nonlocal length scale and the discretization parameter is fixed. The analysis is carried out on a special family of rectilinear Cartesian grids for the RK collocation method with a designated kernel with finite support. We assume the Lamé parameters satisfy λ ≥ μ to avoid extra assumptions on the nonlocal kernel. Finally, numerical experiments are conducted to validate the theoretical results.

42 ENGINEERING↗

Liquid metal compatibility of pre-oxidized FeCrAl in flowing Sn

Here, a flowing Sn thermal convection loop (TCL) experiment was conducted in FeCrAlMo (Kanthal alloy APMT) tubing for 1000 h with a peak temperature of 400 °C. Oxide dispersion strengthened (ODS) Fe-(10–12)Cr-6Al and APMT specimens were exposed and all were pre-oxidized to form an external alumina scale. Unlike static exposures at 400° and 500 °C where pre-oxidation prevented dissolution, large mass losses were observed in the TCL hot leg after the specimens were cleaned in Li. The observed pitting suggests that localized failure of the pre-formed alumina surface oxide caused significant metal loss. Specimen mass gains were not observed on the cold leg implying that mass transfer did not occur and the small levels of Fe and Cr in the Sn after the experiment implies that Sn-rich phases may have formed. Post exposure room temperature tensile testing showed limited impact of the Sn exposure on the 12Cr ODS FeCrAl alloy, comparable to a 1000 h anneal in Ar at 400 °C. These results suggest that pre-oxidation is not sufficient to protect FeCrAl alloys in contact with flowing liquid Sn at 350°-400 °C.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗

Compatibility of the Linear-Quadratic Formalism and Biologically Effective Dose Concept to High-Dose-Per-Fraction Irradiation in a Murine Tumor

Purpose: To evaluate the compliance of linear-quadratic (LQ) model calculations in the high-dose range as used in stereotactic irradiation in a murine tumor model. Methods and Materials: Female 10-week-old Balb/c mice bearing 1-cm-diameter EMT6 tumors in the hind legs were used. Single doses of 10-25 Gy were compared with 2-5 fractions of 4-13 Gy given at 4-hour intervals. Cell survival after irradiation was determined by an in vivo-in vitro assay. Using an {alpha}/{beta} ratio determined for in vitro EMT6 cells and the LQ formalism, equivalent single doses for the hypofractionated doses were calculated. They were then compared with actually measured equivalent single doses for the hypofractionated doses. These fractionation schedules were also compared simultaneously to investigate the concordance/divergence of dose-survival curves plotted against actual radiation doses and biologically effective doses (BED). Results: Equivalent single doses for hypofractionated doses calculated from LQ formalism were lower than actually measured doses by 21%-31% in the 2- or 3-fraction experiments and by 27%-42% in the 4- or 5-fraction experiments. The differences were all significant. When a higher {alpha}/{beta} ratio was assumed, the discrepancy became smaller. In direct comparison of the 2- to 5-fraction schedules, respective dose-response curves almost overlapped when cell survival was plotted against actual radiation doses. However, the curves tended to shift downward by increasing the fraction number when cell survival was plotted against BED calculated using an {alpha}/{beta} ratio of 3.5 Gy for in vitro EMT6 cells. Conclusion: Conversion of hypofractionated radiation doses to single doses using the LQ formalism underestimated the in vivo effect of hypofractionated radiation by approximately 20%-40%. The discrepancy appeared to be larger than that seen in the previous in vitro study and tended to increase with the fraction number. BED appeared to be an unreliable measure of tumor response.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

Recommendations for harmonized reporting of radiation Dosimetry by adoption of Compatibility in Irradiation Research Protocols Expert Roundtable (CIRPER)

Here, in radiobiology, radiation physics, and related areas, there is growing interest in transitioning from cesium-based irradiators to X-ray technologies. Therefore, it makes it imperative for reproducibility purposes, for researchers to provide specifications regarding device parameters, machine calibration details, and experimental setup when innovative X-ray technology is being employed. Several groups have already identified a glaring lack in completeness of critical information on experimental setups, equipment, and physical parameters in published radiation biology studies. The Alternative Technologies Meta Study Report by Brookhaven National Laboratory (BNL) examined 456 manuscripts published between 2017-2021. Only 64 of the reviewed studies (14.0%) consistently reported methods that could allow for replication of their studies. However, 85% provided information on the manufacturer, the irradiator model and the absorbed radiation dose. Approximately 66% provided information on the energy spectra and the dose rate, but only one third disclosed the filter used. Less than 15% of the reviewed studies reported information on calibration and field geometry, specifically field size and distance from source, which are critical parameters in determining the absorbed radiation dose.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

Formulation and Experimental Validation of an Agricultural Implement-Only MPR System for Maximum Compatibility with Existing Agricultural Tractors

Tightening emissions regulations and rising fuel costs have driven a desire across many industries for more efficient actuation systems. This is particularly true of the agricultural sector. An extremely common arrangement in this sector is the tractor and implement pairing, in which actuators on an implement are powered by a hydraulic supply system on the towing tractor. This arrangement complicates the development of energy efficient hydraulic systems, as many new system designs require modification of both machines to reap efficiency benefits. Past work by the authors’ team has demonstrated great potentials for Multi-Pressure-Rail (MPR) technology involving both the tractor and implement subsystems. However, applicability of this MPR technology in a more realistic scenario where only one vehicle is equipped with such technology was not addressed. This work proposes an implementation of the MPR technology to an agricultural planter that allows significant savings, while only modifying the implement machine. This is done by manipulating the load sense network of a stock tractor to set system pressures to those required by the MPR system. This greatly reduces the barrier to implementation of MPR technology in agriculture. The work begins by outlining the reference machine for the system, then reviews the MPR system working principle. After this, the proposed expansion to the MPR concept is laid out and applied to the reference system. Finally, experimental validation is carried out, demonstrating up to a 35% reduction in system power consumption when paired with a state of the art, double-LS System tractor, and 15% with a single-LS System tractor.

24 POWER TRANSMISSION AND DISTRIBUTION↗

Cladding Alloys for Fluoride Salt Compatibility

This report provides an overview of several candidate technologies for cladding nickel-based corrosion protection layers onto high-temperature structural alloys. The report also provides a brief overview of the welding and weld performance issues associated with joining nickel-clad nickel-based alloys. From the available techniques, two cladding technologies were selected for initial evaluation. The first technique is a line-of-sight method that would be useful for cladding large structures such as vessel interiors or large piping. The line-of-sight method is a laser-based surface cladding technique in which a high-purity nickel powder mixed into a polymer binder is first sprayed onto the surface, baked, and then rapidly melted using a high-power laser. The second technique is a vapor phase technique based on the nickel-carbonyl process that is suitable for cladding inaccessible surfaces such as the interior surfaces of heat exchangers. An initial evaluation for performed on the quality of nickel claddings processed using the two selected cladding techniques.

alloys↗

Cryocooler Electromagnetic Compatibility

Jet Propulsion Laboratory, under joint Ballistic Missile and Defense Organization/Air Force and NASA/Eos Atmospheric Infrared Sounder sponsorship is conducting extensive space cryocooler characterization to provide a reliable and accurate data base on cryocooler performance for use by the space community.

cryocooler electromagnetic compatibility cryocoole↗