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At least 523 records · Page 29

Materials Data on H18RuN5(ClO)2 by Materials Project

(RuN5H15O)2(H2O)2(HCl)2Cl2 crystallizes in the monoclinic P2_1/c space group. The structure is zero-dimensional and consists of four hydrochloric acid molecules, four hydrochloric acid molecules, four water molecules, and two RuN5H15O clusters. In each RuN5H15O cluster, Ru3+ is bonded to six N3- atoms to form edge-sharing RuN6 octahedra. There are a spread of Ru–N bond distances ranging from 2.03–2.17 Å. There are five inequivalent N3- sites. In the first N3- site, N3- is bonded in a distorted water-like geometry to two equivalent Ru3+ and two H1+ atoms. Both N–H bond lengths are 1.03 Å. In the second N3- site, N3- is bonded in a distorted trigonal non-coplanar geometry to one Ru3+ and three H1+ atoms. There is two shorter (1.03 Å) and one longer (1.09 Å) N–H bond length. In the third N3- site, N3- is bonded in a distorted trigonal non-coplanar geometry to one Ru3+ and three H1+ atoms. There is two shorter (1.02 Å) and one longer (1.03 Å) N–H bond length. In the fourth N3- site, N3- is bonded in a distorted trigonal non-coplanar geometry to one Ru3+ and three H1+ atoms. All N–H bond lengths are 1.03 Å. In the fifth N3- site, N3- is bonded in a distorted trigonal non-coplanar geometry to one Ru3+ and three H1+ atoms. There is one shorter (1.02 Å) and two longer (1.03 Å) N–H bond length. There are fifteen inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the second H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the third H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the fifth H1+ site, H1+ is bonded in a distorted single-bond geometry to one N3- and one O2- atom. The H–O bond length is 1.65 Å. In the sixth H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the seventh H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the eighth H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the ninth H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the tenth H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the eleventh H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the twelfth H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the thirteenth H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the fourteenth H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the fifteenth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. O2- is bonded in a distorted single-bond geometry to two H1+ atoms.

36 MATERIALS SCIENCE↗

Materials Data on HgH4C4(NCl2)2 by Materials Project

HgCl2(HC2N)2(HCl)2 crystallizes in the monoclinic P2_1/c space group. The structure is zero-dimensional and consists of eight aziridine molecules, eight hydrochloric acid molecules, and four mercuric chloride molecules.

36 MATERIALS SCIENCE↗

Materials Data on InH8C8N4Cl7 by Materials Project

InCl4(HC2N)4H2Cl(HCl)2 crystallizes in the orthorhombic P2_12_12 space group. The structure is zero-dimensional and consists of eight aziridine molecules, four hydrochloric acid molecules, two hydrogen hydrochloride molecules, and two InCl4 clusters. In each InCl4 cluster, In3+ is bonded in a 6-coordinate geometry to four Cl1- atoms. There are two shorter (2.44 Å) and two longer (2.46 Å) In–Cl bond lengths. There are two inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded in a single-bond geometry to one In3+ atom. In the second Cl1- site, Cl1- is bonded in a single-bond geometry to one In3+ atom.

36 MATERIALS SCIENCE↗

Materials Data on MnH12C2NCl3O2 by Materials Project

MnC2NH10O2Cl(HCl)2 crystallizes in the orthorhombic Cmce space group. The structure is zero-dimensional and consists of sixteen hydrochloric acid molecules and four MnC2NH10O2Cl clusters. In each MnC2NH10O2Cl cluster, Mn2+ is bonded in a 3-coordinate geometry to two equivalent H1+, two equivalent O2-, and one Cl1- atom. Both Mn–H bond lengths are 2.22 Å. Both Mn–O bond lengths are 1.70 Å. The Mn–Cl bond length is 2.19 Å. C2- is bonded to one N3- and three H1+ atoms to form corner-sharing CH3N tetrahedra. The C–N bond length is 1.48 Å. There is one shorter (1.09 Å) and two longer (1.10 Å) C–H bond length. N3- is bonded in a tetrahedral geometry to two equivalent C2- and two equivalent H1+ atoms. Both N–H bond lengths are 1.08 Å. There are five inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one C2- atom. In the second H1+ site, H1+ is bonded in a distorted single-bond geometry to one Mn2+ and one H1+ atom. The H–H bond length is 0.76 Å. In the third H1+ site, H1+ is bonded in a single-bond geometry to one C2- atom. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one C2- atom. In the fifth H1+ site, H1+ is bonded in a distorted single-bond geometry to one N3- and one O2- atom. The H–O bond length is 1.60 Å. O2- is bonded in a bent 120 degrees geometry to one Mn2+ and one H1+ atom. Cl1- is bonded in a single-bond geometry to one Mn2+ atom.

36 MATERIALS SCIENCE↗

Materials Data on CoH8(ClO2)2 by Materials Project

(Co(H3O2)2)2H2(HCl)2Cl2 crystallizes in the monoclinic P2_1/c space group. The structure is one-dimensional and consists of four hydrochloric acid molecules; four hydrochloric acid molecules; two hydrogen molecules; and two Co(H3O2)2 ribbons oriented in the (0, 1, 0) direction. In each Co(H3O2)2 ribbon, Co2+ is bonded in a distorted trigonal pyramidal geometry to four O2- atoms. There are a spread of Co–O bond distances ranging from 1.67–2.05 Å. There are six inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. In the second H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the third H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 1.00 Å. In the fourth H1+ site, H1+ is bonded in a distorted linear geometry to two O2- atoms. There is one shorter (1.03 Å) and one longer (1.52 Å) H–O bond length. In the fifth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the sixth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 1.00 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted water-like geometry to one Co2+ and two H1+ atoms. In the second O2- site, O2- is bonded in a distorted water-like geometry to one Co2+ and two H1+ atoms. In the third O2- site, O2- is bonded in a bent 150 degrees geometry to one Co2+ and one H1+ atom. In the fourth O2- site, O2- is bonded in a distorted water-like geometry to one Co2+ and two H1+ atoms.

36 MATERIALS SCIENCE↗

Materials Data on NiH44C12N8(ClO5)2 by Materials Project

Ni(H5O3)2(C5N4H12)2(CO)2(H2)2(H2O)2(HCl)2 crystallizes in the triclinic P-1 space group. The structure is zero-dimensional and consists of two 1,3,5,7-tetraazabicyclo[3.3.1]nonane molecules; two formaldehyde molecules; two hydrochloric acid molecules; two hydrogen molecules; two water molecules; and one Ni(H5O3)2 cluster. In the Ni(H5O3)2 cluster, Ni2+ is bonded in an octahedral geometry to six O2- atoms. There are a spread of Ni–O bond distances ranging from 1.99–2.32 Å. There are five inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 1.00 Å. In the second H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. In the third H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.97 Å. In the fifth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.97 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted water-like geometry to one Ni2+ and two H1+ atoms. In the second O2- site, O2- is bonded in a distorted water-like geometry to one Ni2+ and two H1+ atoms. In the third O2- site, O2- is bonded in a distorted single-bond geometry to one Ni2+ and one H1+ atom.

36 MATERIALS SCIENCE↗

Materials Data on H14C3NCl5 by Materials Project

(C3H7NH3)2(HCl)8Cl2 is Silicon tetrafluoride-derived structured and crystallizes in the monoclinic Cc space group. The structure is zero-dimensional and consists of four hydrochloric acid molecules, sixteen hydrochloric acid molecules, and four trimethylazanium molecules.

36 MATERIALS SCIENCE↗

Materials Data on Mg(H3Cl)2 by Materials Project

Mg(H2)2(HCl)2 crystallizes in the monoclinic C2/m space group. The structure is zero-dimensional and consists of four hydrochloric acid molecules, four hydrogen molecules, and two magnesium molecules.

36 MATERIALS SCIENCE↗

Materials Data on CoH15N6(ClO)2 by Materials Project

(CoN4H9OCl)2(H2)3(NH2NO)2(HCl)2 crystallizes in the orthorhombic Pna2_1 space group. The structure is zero-dimensional and consists of four hydrazino alcohol molecules, four hydrochloric acid molecules, eight hydrogen molecules, and four CoN4H9OCl clusters. In each CoN4H9OCl cluster, Co3+ is bonded in a 6-coordinate geometry to three N2-, two H1+, and one O2- atom. There are a spread of Co–N bond distances ranging from 1.95–2.11 Å. There is one shorter (1.92 Å) and one longer (1.97 Å) Co–H bond length. The Co–O bond length is 2.03 Å. There are four inequivalent N2- sites. In the first N2- site, N2- is bonded in a bent 120 degrees geometry to one N2- and two H1+ atoms. The N–N bond length is 1.34 Å. There is one shorter (1.01 Å) and one longer (1.02 Å) N–H bond length. In the second N2- site, N2- is bonded in a distorted L-shaped geometry to one Co3+ and one N2- atom. The N–N bond length is 1.25 Å. In the third N2- site, N2- is bonded in a distorted trigonal non-coplanar geometry to one Co3+ and three H1+ atoms. There is two shorter (1.02 Å) and one longer (1.03 Å) N–H bond length. In the fourth N2- site, N2- is bonded in a distorted trigonal planar geometry to one Co3+ and two N2- atoms. There are nine inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one N2- atom. In the second H1+ site, H1+ is bonded in a single-bond geometry to one N2- atom. In the third H1+ site, H1+ is bonded in a single-bond geometry to one N2- atom. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one N2- atom. In the fifth H1+ site, H1+ is bonded in an L-shaped geometry to one Co3+ and one H1+ atom. The H–H bond length is 0.78 Å. In the sixth H1+ site, H1+ is bonded in a single-bond geometry to one N2- atom. In the seventh H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. In the eighth H1+ site, H1+ is bonded in a 2-coordinate geometry to one Co3+ and one H1+ atom. In the ninth H1+ site, H1+ is bonded in a single-bond geometry to one O2- and one Cl1- atom. The H–O bond length is 1.02 Å. The H–Cl bond length is 1.98 Å. O2- is bonded in a distorted water-like geometry to one Co3+ and two H1+ atoms. Cl1- is bonded in a single-bond geometry to one H1+ atom.

36 MATERIALS SCIENCE↗

Materials Data on HgH4C2S2(N3Cl)2 by Materials Project

Hg(N2)2(CNHS)2(HCl)2 crystallizes in the orthorhombic Pbcn space group. The structure is zero-dimensional and consists of eight hydrochloric acid molecules, eight isothiocyanic acid molecules, four mercury molecules, and eight nitrogen molecules.

36 MATERIALS SCIENCE↗

Materials Data on H17RuN6Cl3O2 by Materials Project

RuN4H7O2Cl(NH3)2H2(HCl)2 crystallizes in the orthorhombic Pna2_1 space group. The structure is zero-dimensional and consists of eight ammonia molecules, eight hydrochloric acid molecules, four hydrogen molecules, and four RuN4H7O2Cl clusters. In each RuN4H7O2Cl cluster, Ru2+ is bonded in a trigonal bipyramidal geometry to two N2-, two O2-, and one Cl1- atom. There is one shorter (1.86 Å) and one longer (1.87 Å) Ru–N bond length. There is one shorter (1.90 Å) and one longer (2.06 Å) Ru–O bond length. The Ru–Cl bond length is 2.38 Å. There are four inequivalent N2- sites. In the first N2- site, N2- is bonded in a bent 120 degrees geometry to one N2- and two H1+ atoms. The N–N bond length is 1.32 Å. There is one shorter (1.02 Å) and one longer (1.03 Å) N–H bond length. In the second N2- site, N2- is bonded in a distorted trigonal planar geometry to one Ru2+ and two H1+ atoms. Both N–H bond lengths are 1.02 Å. In the third N2- site, N2- is bonded in a distorted trigonal planar geometry to one Ru2+ and two H1+ atoms. There is one shorter (1.02 Å) and one longer (1.03 Å) N–H bond length. In the fourth N2- site, N2- is bonded in a distorted water-like geometry to one N2- and one O2- atom. The N–O bond length is 1.26 Å. There are seven inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. In the second H1+ site, H1+ is bonded in a single-bond geometry to one N2- atom. In the third H1+ site, H1+ is bonded in a single-bond geometry to one N2- atom. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one N2- atom. In the fifth H1+ site, H1+ is bonded in a single-bond geometry to one N2- atom. In the sixth H1+ site, H1+ is bonded in a single-bond geometry to one N2- atom. In the seventh H1+ site, H1+ is bonded in a single-bond geometry to one N2- atom. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted water-like geometry to one Ru2+ and one H1+ atom. In the second O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Ru2+ and one N2- atom. Cl1- is bonded in a single-bond geometry to one Ru2+ atom.

36 MATERIALS SCIENCE↗

Cryogenic Carbon Capture™ Technoeconomic Analysis

The Cryogenic Carbon Capture™ (CCC) process significantly decreases cost and energy demands for CO 2 separation and pressurization to 150 bar compared to alternatives. The process is a post-combustion technology that cools CO 2 -laden flue gas to desublimation temperatures (-100 to -135 °C), separates solid CO 2 —that forms from the flue gas—from the light gases, uses the cold products to cool incoming gases in a recuperative heat exchanger, compresses the solid/liquid CO 2 to final pressures (100–200 bar), and delivers a compressed CO 2 stream separated from an atmospheric pressure light-gas stream. The overall energy and economic costs are about 30-50% lower than most competing processes that involve air separation units (ASUs), solvents, or similar technologies. In addition, the CCC process enjoys several ancillary benefits, including (a) it is a minimally invasive Bolton technology, (b) it provides highly efficient removal of most pollutants (Hg, SOx, NO 2 , HCl, etc.), and (c) possible energy storage capacity. This report outlines the process details and economic and energy comparisons relative to other well-documented alternatives. This paper presents the results of a detailed techno-economic comparison of CCC with amine-based systems. The comparison uses identical financial and economic assumptions similar process assumptions as the detailed analyses published by US DOE in the greenfield analysis. Specifically, the comparison assumes power plants that produce the same net output, one equipped with and a second without carbon capture. Separately, the paper compares similar analyses for retrofitting existing systems using typical plant characteristics in the US (initial capital costs have been paid, high plant utilization), though there are no DOE estimates available for direct comparison. Financial and technical assumptions for all comparisons are maintained as close to the DOE reference studies as possible. The results demonstrate about 30-50% lower costs and energy demands for capture from greenfield coal plants. Natural gas plants produce substantially lower CO 2 concentrations which makes the cost of capturing a ton of CO 2 at the same capture rate as the coal plant higher for all processes while the cost of CO 2 capture per unit of power generation is lower. However, CCC maintains about the same absolute energy and cost advantages for NG as for coal compared to amine systems. Finally, the costs of retrofitting a station are compared to those of building a new station with and without capture. The retrofit costs are comparable to (slightly lower than) new plant costs without capture. In all cases operating and capital cost comparisons show that the CCC process can be retrofitted to a variety of plants to cost effectively reduce CO 2 emissions. Further process integration into the upstream processes and unique process features like water recovery, and integrated energy storage bring the effective cost of carbon capture using the CCC process down further and increase its advantages over alternatives. This technoeconomic analysis shows that the CCC process has the potential to the be lowest cost carbon capture technology under development today.

20 FOSSIL-FUELED POWER PLANTS↗

Immobilization of high-level waste salt in dechlorinated zeolite waste forms. Final report

This project addressed the main challenges associated with the disposal of electrorefiner salt: maximization of fission products in a final waste form and the associated processing costs. Since over half of the mass of the ER salt is chlorine in the form of non-radioactive chloride ions, our approach for achieving dechlorination is through the formation of HCl gas during the exchange of the metal ions into ultrastable H-Y (USHY) zeolite. The zeolite containing the fission products was then sintered into a chemically durable waste form.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

SNF Interim Storage Canister Corrosion and Surface Environment Investigations (FY2020 Status Report)

This progress report describes work performed during FY20 at Sandia National Laboratories (SNL) to assess the localized corrosion performance of container/cask materials used in the interim storage of spent nuclear fuel (SNF). Of particular concern is stress corrosion cracking (SCC), by which a through-wall crack could potentially form in a canister outer wall over time intervals that are shorter than possible dry storage times. Work in FY20 further defined our understanding of the potential chemical and physical environment present on canister surfaces, evaluated the relationship between the environment and the resultant corrosion that occurs, and initiated crack growth rate testing under relevant environmental conditions. In FY20, work to define dry storage canister surface environments included several tasks. First, collection of dust deposition specimens from independent spent fuel storage installation (ISFSI) site locations helped to establish a more complete understanding of the potential chemical environment formed on the canister. Second, the predicted evolution of canister surface relative humidity RH) values was estimated using ISFSI site weather data and the horizontal canister thermal model used by the SNL probabilistic SCC model. These calculations determined that for typical ISFSI weather conditions, seasalt deliquescence to produce MgCl2-rich brines could occur in less than 20 years at the coolest locations on the canister surface, and, even after nearly 300 years, conditions for NaCl deliquescence (75% RH) are not reached. This work illustrates the importance of understanding the stability of MgCl2-rich brines on the heated canister surface, and the potential impact of brine composition on corrosion processes, including pitting and stress corrosion cracking. In an additional study, the description of the canister surface environment was refined in order to define more realistic corrosion testing environments including diurnal cycles, soluble salt chemistries, and inert mineral particles. The potential impacts of these phenomena on canister corrosion are being evaluated experimentally. Finally, work over the past few years to evaluate the stability of magnesium chloride brines continued in FY20. MgCl2 degassing experiments were carried out, confirming that MgCl2 brines slowly degas HCl on heated surfaces, converting to less deliquescent magnesium hydroxychloride phases and potentially leading to brine dryout.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

Boride-Carbon Hybrid Technology to Produce Ultra-Wear and Corrosion Resistant Surfaces for Applications in Harsh Conditions (Final Technical Report)

Engineered functional surfaces play an important role to enable new products and manufacturing processes that can endure harsh service conditions such as high impact and contact loads, highly abrasive wear, extreme temperatures, and corrosive environments. Engineered surfaces can also be instrumental to improving the efficient use of energy by reducing frictional losses and extending service life. The main objective of this project was to develop a hybrid surface engineering technology that combines the advantages of a novel ultrafast boriding process with the next generation of superhard carbon coatings. The hypothesis was that this hybrid process will offer an unprecedented combination of wear and corrosion resistance, low frictional losses and affordability for treated parts so that it can be utilized in many applications. During this project, a duplex process was developed that combines the advantages of ultra-fast electrochemical boriding with those of hard tetrahedral amorphous carbon coatings. Both technologies can be combined to form a hybrid technology that is characterized by low friction and wear properties combined with corrosion and fatigue resistance. Good adhesion of both layers to each other was one main goal of this project, that has been achieved with HF1 adhesion through the Rockwell-C adhesion test. In this project, the mechanical properties of the hybrid coating were modeled through a finite-element analysis approach. We can conclude that the FEA model resembles the actual samples and be utilized to predict mechanical behavior under impacts. Based on this model, application-oriented load conditions can be simulated for optimal layer design regarding thickness and mechanical properties. To exemplify, one conclusion that can be drawn from the nanoindentation model is a boride layer thickness of 50 µm is sufficient to effectively support the carbon coating on the identified AISI 1045 low carbon steel substrate material. The duplex treatment yields wear rates as low as 6 x 10 -8 mm 3 N -1 m -1 and a coefficient of friction of 0.14 when tested against a steel counter face in a ball-on-disk test setup. On the other hand, the wear rate of the only-borided AISI 1045 steel was 5 x 10 -5 mm 3 N -1 m -1 , about three orders of magnitude higher than the duplex coating. At the same time, duplex treated samples experience corrosion resistance, which could not be achieved with single-layer carbon coatings. The developed surface treatment withstands a 3-hour exposure to 15% HCl, while the only carbon coated counter sample shows severe delamination of the coating due to pin hole corrosion. The boride layer is chemically stable and pin hole free because it is formed through an electrochemical process under high current densities (700 mA/cm 2 ) and high temperature. Additionally, the hybrid coating led to at least 3x increase in fatigue strength of the steel substrate, which exceeds the target performance of 30% improvement. There are numerous potential applications for the duplex coatings. A representative application is bearing ball coatings for off-shore windmills. Compared to currently employed surface technologies in this field, the initial costs of applying our technology might be higher due to more process steps but the performance benefits lead to an increased life time of treated parts, which will lower the maintenance and replacement costs in the long-term. To validate the technology for this specific application, the team is currently investigating the process of white etching crack initiation of the duplex coating in collaboration with ANL. Overall, this project successfully validated that the boride-carbon hybrid technology can withstand harsh conditions. One possible approach to commercialization under consideration is to transfer the technology to a startup or an existing coatings company.

36 MATERIALS SCIENCE↗

Corrosion Research Survey: Corrosion-Surface Roughness Correlation on Carbon and Stainless Steels

Concerning the SAVY 4000 container LANL inspection acceptance of Ra (surface roughness) and its correlation to subsequent surface corrosion, a problem statement has been identified. The problem statement is as follows: When the 316L container has been subjected to accommodating materials producing high wattage, along with materials that eventually produce HCL (hydrochloric acid) will a higher or lower Ra on the inner surface of the SAVY 4000 container influence the rate or the amount of corrosion? In an effort to address this concern, a literature review covering more fundamental studies that examine the influence of roughness on corrosion in metals are surveyed. The scope is kept relevant to the less dynamic storage conditions that a SAVY container may be exposed to.

36 MATERIALS SCIENCE↗

Comparing elemental measurements at packaging and after storage for signatures of chloride salt radiolysis

Radiolysis of hydrated alkaline earth chloride salts by alpha radiation from plutonium produces the chloride containing gases HCl and Cl 2 . These gases are known to diffuse out of the plutonium-containing material and contribute to corrosion outside of the convenience container. The alkaline earth elements remain with the plutonium-containing material as oxides or hydroxides. The amount of chlorine within the material after storage will be reduced compared to the amount at packaging. The fraction of the alkaline earth elements that are soluble after storage will be reduced compared to the amount at packaging. These signatures may be observable by comparing the chemical analysis measurements made at packaging and after storage. Comparison of measurements on a single Hanford container shows that the chloride does decrease and the alkaline earth elements have reduced solubility in water. Differences seen with other elements make conclusions difficult.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

Effect of Microstructural Bands on the Localized Corrosion of Laser Surface-melted 316L Stainless Steel

The localized corrosion of laser surface melted (LSM) 316L stainless steel is investigated by a combination of potentiodynamic anodic polarization in 0.1M HCl and microscopic investigation of the initiation and propagation of localized corrosion. The pitting potential of LSM 316L is significantly lower than the pitting potential of wrought 316L. The LSM microstructure is highly banded as a consequence of the high laser power density and high linear energy density. The bands are composed of zones of changing modes of solidification, cycling between very narrow regions of primary austenite solidification and very wide regions of primary ferrite solidification. Pits initiate in the outer edge of each band where the mode of solidification is primary austenite plane front solidification and primary austenite cellular solidification. The primary austenite regions have low chromium concentration (and possibly low molybdenum concentration), which explains their susceptibility to pitting corrosion. The ferrite is enriched in chromium, which explains the absence of pitting in the primary ferrite regions. The presence of the low chromium regions of primary austenite solidification explains the lower pitting resistance of LSM 316L relative to wrought 316L. The influence of banding on localized corrosion is applicable to other rapidly solidified processes such as additive manufacturing.

36 MATERIALS SCIENCE↗