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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 1,261 records · Page 70
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Improved control of electron computer-generated holographic grating groove profiles using ion beam gas-assisted etching

In a transmission electron microscope, electrons are described by matter-waves with wavelengths five orders of magnitude smaller than optical electromagnetic waves. Analogous to optical holography, electron wavefronts can be shaped using nanoscale holographic gratings. Here we demonstrate a novel, scalable nanofabrication method for creating off-axis holographic gratings that demonstrate near ideal diffraction efficiencies for binary, sinusoidal, and blazed grating groove profiles. We show that this method can produce up to 50 µm diameter area gratings that diffract up to 68% of the transmitted electron wave into a desired diffraction order with less than 7% into any other order. Additionally, we find that the amount of inelastically scattered electrons from the material gratings remaining in the coherent diffraction orders from the gratings is negligible in the far field.

Johnson, Cameron W.↗
DOE OSTI2018

Analysis of Tank 38H (HTF-38-18-43, -44) and Tank 43H (HTF-43-18-41, -42) Samples for Support of the Enrichment Control and Corrosion Control Programs

SRNL analyzed samples from Tank 38H and Tank 43H to support ECP and CCP. The total uranium in the Tank 38H surface sample was 38.8 mg/L while the sub-surface sample was 35.7 mg/L. The Tank 43H samples contained total uranium concentrations of 27.5 mg/L in the surface sample and 23.4 mg/L in the sub-surface sample. The U-235 weight fraction ranged from 0.62% to 0.63% for the Tank 38H samples and Tank 43H samples. The total uranium concentrations in the table are reasonably consistent with recent Tank 38H/43H sample uranium measurements. The plutonium results in the table are consistent with the range of concentrations measured in recent samples from these tanks with the exception of the Pu-238 value measured in the Tank 43H sub-surface sample. The Pu-238 in the Tank 43H sub-surface sample is higher than any recent measurement by a factor of two. The Cs-137 results show slightly lower concentrations in the surface samples versus the sub-surface samples from each tank. The non-radioactive components of the samples show some differences between the surface and sub-surface samples for each tank.

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DOE OSTI2018

Analysis of Tank 38H (HTF-38-18-43,-44) and Tank 43H (HTF-43-18-41, -42) Samples for Support of the Enrichment Control and Corrosion Control Programs

SRNL analyzed samples from Tank 38H and Tank 43H to support ECP and CCP. The total uranium in the Tank 38H surface sample was 38.8 mg/L while the sub-surface sample was 35.7 mg/L. The Tank 43H samples contained total uranium concentrations of 27.5 mg/L in the surface sample and 23.4 mg/L in the sub-surface sample. The U-235 weight fraction ranged from 0.62% to 0.63% for the Tank 38H samples and Tank 43H samples. The total uranium concentrations in the table are reasonably consistent with recent Tank 38H/43H sample uranium measurements. The plutonium results in t he table are consistent with the range of concentrations measured in recent samples from these tanks with the exception of the Pu-238 value measured in the Tank 43H sub-surface sample. The Pu-238 in the Tank 43H sub-surface sample is higher than any recent measurement by a factor of two. The Cs-137 reslts show slightly lower concentrations in the surface samples versus the sub-surface samples from each tank. The non-radioactive components of the samples show some differences between the surface and sub-surface samples for each tank.

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DOE OSTI2018

Analysis of Tank 38H (HTF-38-18-78, -79) and Tank 43H (HTF-43-18-80, -81, -83) Samples for Support of the Enrichment Control and Corrosion Control Programs

SRNL analyzed samples from Tank 38H and Tank 43H to support ECP and CCP. Compared with recent samples, the surface and sub-surface samples from Tank 38H show much lower concentrations of most species analyzed except for silicon. The Tank 38H samples show stratification in the tank with the concentration of species in the surface sample being much lower than in the sub-surface sample and both samples being much lower than recent results. The Tank 43H surface and two sub-surface samples generally showed consistent results across the three samples and compare well with recent analyses. The lowest sub-surface sample from Tank 43H contained slightly higher concentrations of uranium and plutonium likely due to the presence of a small amount of dark sludge solids in the sample.

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DOE OSTI2019

Analysis of Tank 38H (HTF-38-19-18, -19) and Tank 43H (HTF-43-19-20, -21) Samples for Support of the Enrichment Control and Corrosion Control Programs

SRNL analyzed samples from Tank 38H and Tank 43H to support ECP and CCP. Overall, the results of the analysis indicate the concentrations of species in the Tank 38H surface sample increased significantly from the previous sample with the sodium concentration increasing from 1.09 M in the previous sample to 3.19 M in the current sample. However, it should be noted that the previous Tank 38H surface sample was very dilute compared with typical Tank 38H samples of the recent past. The Tank 38H sub-surface sample shows a composition fairly similar to the previous sample’s composition. Both the Tank 43H surface and sub-surface samples appear slightly more dilute than the previous samples based on the sodium concentrations. For both Tank 38H and Tank 43H, the subsurface samples appear slightly more concentrated for most species than the surface samples. These results indicate some success in increasing the salt solution concentration and reducing stratification in Tank 38H, but some stratification is still evident in both Tank 38H and Tank 43H.

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DOE OSTI2019

Analysis of Tank 23H (HTF-23-19-23, -24, -25) Samples for Support of the Enrichment Control and Corrosion Control Programs

SRNL analyzed samples from Tank 23H to support ECP and CCP. The results of the analysis indicate the concentrations of species in Tank 23H increase with depth in the tank. The sample obtained from the lowest level of 60” from the bottom of the tank shows the highest concentrations for most species analyzed. The surface sample and the 140” sub-surface sample show similar compositions with the sub-surface sample being slightly more concentrated, and both are more dilute than the lowest 60” sub-surface sample for most species analyzed. The total uranium concentration in the three Tank 23H samples show a slight increase from the surface sample to the next lower sub-surface sample, but then a slight decrease in the uranium concentration in the lowest sub-surface sample. The U-235 weight fraction ranges from 0.94-1.2% in the Tank 23H samples. The sum of the major cations versus the sum of the major anions shows a difference of ~5% or less for all three of the Tank 23H samples indicating good data quality for the non-radioactive analytes in the table. Small %RSD values for the replicate analyses with the exception of species close to the detection limit (e.g., Fe) provide another indication of good data quality for the non-radioactive species. The silicon concentrations measured in the Tank 23H samples were all below detection.

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DOE OSTI2019

Analysis of Tank 38H (HTF-38-19-77, -78) and Tank 43H (HTF-43-19-79, -80) Samples for Support of the Enrichment Control and Corrosion Control Programs

SRNL analyzed samples from Tank 38H and Tank 43H to support ECP and CCP. Overall, the results indicate the concentrations of most species in the Tank 38H surface and sub-surface samples increased significantly from the previous sample results. The Tank 38H sub-surface sample is more concentrated than the surface sample indicating stratification within the tank. Both the Tank 43H surface and sub-surface samples are similar in composition to the previous samples for most species analyzed. The Tank 43H subsurface sample remains slightly more concentrated than the surface sample indicating a small amount of stratification remains in the tank. The total uranium concentrations for the two Tank 38H samples differ significantly due to the presence of sludge solids in the sub-surface sample that markedly increased the uranium concentration. Both the Tank 38H surface and sub-surface samples have higher uranium concentrations than the previous samples from the tank. The weight percent water insoluble solids on the Tank 38H sub-surface sample show the sample contained 0.30 wt% insoluble solids, well below the 1 wt% limit. The total uranium concentrations of the two Tank 43H samples differ by <10% and are similar to the previous sample results. The sum of the major cations versus the sum of the major anions shows a difference of ~1% for the both the Tank 38H and Tank 43H surface samples providing an indication of good data quality for the nonradioactive analytes in the surface samples. The silicon concentrations measured in the Tank 38H surface and sub-surface samples are higher than the previous sample results. Due to the presence of sludge solids, the Tank 38H sub-surface sample show a silicon concentration an order of magnitude higher than the previous result. The Tank 43H surface and sub-surface samples have similar silicon concentrations and are similar to the previous Tank 43H samples. The silicon concentration was below detectable levels in the process blank. The five samples analyzed show silicon concentrations ranging from 88 to 710 mg/L.

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DOE OSTI2020

Analysis of Tank 38H (HTF-38-20-7, -8) and tank 43H (HTF-43-20-9, -10) samples for Support of the Enrichment Control and Corrosion Control Programs

SRNL analyzed samples from Tank 38H and Tank 43H to support ECP and CCP. The results indicate the concentrations of most species in the Tank 38H surface sample decreased significantly from the previous surface sample. The Tank 38H sub-surface sample shows only small changes in concentration for most major species in the solution from the previous sample. The large differences in the concentrations of major components between the Tank 38H surface and sub-surface samples indicate significant stratification of solution species within the tank. The Tank 38H sub-surface sample contained a small amount of sludge solids (<1 wt%).

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

Analysis of Tank 38H (HTF-38-20-62, -63) and Tank 43H (HTF-43-20-60, -61) Samples for Support of the Enrichment Control and Corrosion Control Programs

SRNL analyzed samples from Tank 38H and Tank 43H to support ECP and CCP. The results indicate the concentrations of most species in the Tank 38H surface sample increased from the previous surface sample. The Tank 38H sub-surface sample shows only small changes in concentration for most major species in the solution from the previous sample. The large differences in the concentrations of major components between the Tank 38H surface and sub-surface samples indicate significant stratification of solution species within the tank. The Tank 38H surface and sub-surface samples both contained a small amount of sludge solids (<1 wt%). The Tank 43H surface and sub-surface samples are slightly more dilute than the previous samples. The Tank 43H sub-surface sample exhibits a composition more concentrated than the surface sample indicating some stratification within the tank. The Tank 38H surface and sub-surface sample both show large increases in the concentrations of uranium and plutonium likely due to the presence of sludge solids in both samples. (Note: the samples were digested and analyzed without filtration.) The total uranium concentrations of the two Tank 43H samples are similar to the previous sample results. The plutonium concentration in both Tank 43H samples appear to have decreased from the previous samples; however, the surface sample concentrations are close to the detection limit.

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DOE OSTI2021

Analysis of Tank 38H (HTF-38-20-103, -104) and Tank 43H (HTF-43-20-105, -106) Samples for Support of the Enrichment Control and Corrosion Control Programs

SRNL analyzed samples from Tank 38H and Tank 43H to support ECP and CCP. The results indicate the concentrations of most species in the Tank 38H surface sample decreased from the previous surface sample. The Tank 38H sub-surface sample shows only minor changes in concentration for soluble species in the solution (e.g., Na, Al, Cs-137) but a large drop in concentrations for species typically associated with sludge solids (e.g., U, Pu, Fe, Si) likely because of a decrease in sludge solids from the previous sample. The large differences in the concentrations of major components between the Tank 38H surface and sub-surface samples indicate significant stratification of solution species within the tank.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2021

Analysis of Tank 38H (HTF-38-21-95, -96) and Tank 43H (HTF-43-21-97, -98) Samples for Support of the Enrichment Control and Corrosion Control Programs

SRNL analyzed samples from Tank 38H and Tank 43H to support ECP and CCP. The results indicate the concentrations of most species in the Tank 38H surface sample increased from the previous surface sample. The Tank 38H sub-surface sample shows only minor changes in concentration for soluble species in the solution (e.g., Na, Al, Cs-137) relative to the previous sample, but a small decrease in concentrations for species typically associated with sludge solids (e.g., U, Pu, Fe, Si) likely because of a decrease in sludge solids from the previous sample. The large differences in the concentrations of major components between the Tank 38H surface and sub-surface samples indicate significant stratification of solution species within the tank.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2022

Analysis of Tank 38H (HTF-38-22-31, -32) and Tank 43H (HTF-43-22-33, -34) Samples for Support of the Enrichment Control and Corrosion Control Programs

SRNL analyzed samples from Tank 38H and Tank 43H to support ECP and CCP. The results indicate the concentrations of most soluble species in the Tank 38H surface sample increased from the previous surface sample. The Tank 38H sub-surface sample shows changes in concentration for soluble species in the solution with some increasing and some decreasing. The current Tank 38H sub-surface sample contains less sludge solids than the previous sample based on visual appearance. The small differences in the concentrations of major components between the Tank 38H surface and sub-surface samples indicate only minimal stratification of solution species within the tank.

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DOE OSTI2022

Analysis of Tank 38H (HTF-38-22-91, -92) and Tank 43H (HTF-43-22-93, -94) Samples for Support of the Enrichment Control and Corrosion Control Programs

SRNL analyzed samples from Tank 38H and Tank 43H to support ECP and CCP. The results indicate the concentrations of most soluble species in the Tank 38H surface sample increased slightly from the previous surface sample. The Tank 38H sub-surface sample shows changes in concentration for soluble species in the solution with some increasing and some decreasing. The current Tank 38H sub-surface sample contains more sludge solids than the previous sample based on visual appearance. The small differences in the concentrations of major components between the Tank 38H surface and sub-surface samples indicate only minimal stratification of solution species within the tank. The Tank 43H surface and sub-surface samples are similar in composition to the previous samples. The similar solution compositions measured in the Tank 43H surface and sub-surface samples indicate a minimal stratification within the tank. The total uranium and plutonium in the current Tank 38H surface sample remains similar to the previous analysis. The Tank 38H sub-surface sample shows an increase in uranium and plutonium concentrations compared to the previous sample likely because of an increase in sludge solids in the current sample. The total uranium concentration in the two Tank 43H samples is essentially unchanged from previous sample results. The plutonium concentration in the Tank 43H surface sample is similar to the previous sample results while the plutonium in the Tank 43H sub-surface sample increased relative to the previous analysis. The sum of the major cations versus the sum of the major anions shows a difference of <10% for both samples from Tank 38H and for both samples from Tank 43H providing an indication of good data quality for the non-radioactive analytes in the samples. The silicon concentrations measured in the Tank 38H sub-surface sample increased compared with the previous sample results likely due to the presence of more sludge solids in the current sample. The Tank 38H surface sample silicon concentrations is similar to the previous sample results. The Tank 43H surface and sub-surface sample silicon concentrations both increased compared to the previous sample results. The samples analyzed from Tanks 38H and 43H show silicon concentrations ranging from 61.5 to 97.3 mg/L.

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