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At least 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS2011

A Multifunctional Coating for Autonomous Corrosion Control

This slide presentation reviews the effects of corrosion on various structures at the Kennedy Space Center, and the work to discover a corrosion control coating that will be autonomous and will indicate corrosion at an early point in the process. Kennedy Space Center has many environmental conditions that are corrosive: ocean salt spray, heat, humidity, sunlight and acidic exhaust from the Solid Rocket Boosters (SRBs). Presented is a chart which shows the corrosion rates of carbon steel at various locations. KSC has the highest corrosion rates with 42.0 mils/yr, leading the next highest Galeta Point Beach, in the Panama Canal Zone with 27 mils/yr corrosion. A chart shows the changes in corrosion rate with the distance from the ocean. The three types of corrosion protective coatings are described: barrier (passive), Barrier plus active corrosion inhibiting components, and smart. A smart coating will detect and respond actively to changes in its environment in a functional and predictable manner and is capable of adapting its properties dynamically. The smart coating uses microcapsules, particles or liquid drops coated in polymers, that can detect and control the corrosion caused by the environment. The mechanism for a pH sensitive microcapsule and the hydrophobic core microcapsule are demonstrated and the chemistry is reviewed. When corrosion begins, the microcapsule will release the contents of the core (indicator, inhibitor, and self healing agent) in close proximity to the corrosion. The response to a pH increase is demonstrated by a series of pictures that show the breakdown of the microcapsule and the contents release. An example of bolt corrosion is used, as an example of corrosion in places that are difficult to ascertain. A comparison of various coating systems is shown.

Calle, L. M.↗
DOE OSTI2013

Corrosion Control during Closure Activities at the Savannah River Site - 13514

Liquid radioactive wastes from the Savannah River Site (SRS) separation process are stored in large underground carbon steel tanks. Until the waste is removed from storage, transferred, and processed, the materials and structures of the tanks must maintain a confinement function by providing a barrier to the environment and by maintaining acceptable structural stability during normal service and design basis events (e.g., earthquake conditions). A corrosion control program is in place to ensure that degradation of the steel does not impact the structural and leak integrity functions of these waste tanks. The SRS is currently retrieving waste from older waste tanks and processing the waste through the vitrification for long term stabilization. The retrieval processes prepare the tanks for ultimate closure (i.e., grouting) by removing sludge by mechanical and/or sluicing methods, dissolving salt cake by adding water, and chemical cleaning of the residual sludge with oxalic acid. Each of these retrieval methods will result in waste chemistry that does not meet the requirements of the current corrosion control program. Given the short-term exposure and limited remaining service life for the tanks in which retrievals are being performed, an assessment of the need for corrosion controls in these tanks was performed. The assessment reviewed the corrosion rates in the more aggressive environments and the postulated loads on the structure during the closure activities. The assessment concluded that the current corrosion control program may be suspended for a short period of time while final retrieval of the waste is performed. (authors)

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DOE OSTI2021

Sequestration and release of nitrite and nitrate in alkali-activated slag: A route toward smart corrosion control

Intercalating the corrosion inhibitive ions in hydrotalcite is a promising approach to improve the long-term efficiency of inhibitors in corrosion protection of steel in reinforced concrete. In this work, the potential of autogenously generating nitrite- and nitrate-intercalated hydrotalcite in alkali-activated slag (AAS) is investigated. The results show that the added nitrite and nitrate ions are preferably uptaken in the interlayer structure of hydrotalcite in AAS, and the sequestered nitrite and nitrate are released upon chloride exposure in seawater and NaCl solution. The incorporation of nitrite and nitrate has little detrimental effects on the chloride binding capacity of AAS but slightly enhances the chloride ingress due to the pore coarsening effect. Similar to ordinary Portland cement (OPC), AAS is more permeable to the chloride in seawater than NaCl solution. However, unlike the release of bound chloride contributed by ettringite formation in seawater-exposed OPC, the enhanced chloride ingress in seawater-exposed AAS is primarily attributed to the aggravated pH reduction at the exposure front due to brucite formation. This study contributes to the design of alkali-activated binders with a smart inhibitor releasing ability for mitigating corrosion of steel in concrete.

36 MATERIALS SCIENCE↗
NASA NTRS2016

Corrosion Control in the Aerospace Industry

Nearly all metals and their alloys are subject to corrosion that causes them to lose their structural integrity or other critical functionality. It is essential to detect corrosion when it occurs, and preferably at its early stage, so that action can be taken to avoid structural damage or loss of function. Protective coatings are the most commonly used method of corrosion control. However, progressively stricter environmental regulations have resulted in the ban of many commercially available corrosion protective coatings due to the harmful effects of their solvents or corrosion inhibitors. This work concerns the development of a multifunctional, smart coating for the autonomous control of corrosion. This coating is being developed to have the inherent ability to detect the chemical changes associated with the onset of corrosion and respond autonomously to indicate it and control it..

Corrosion Control↗
DOE OSTI2015

Analysis of Tank 51H (HTF-51-15- 77) Subsurface Supernatant Sample in Support of Enrichment and Corrosion Control Programs

This report provides the results of analyses on Tank 51H subsurface supernatant liquid sample in support of the Enrichment Control Program (ECP) and the Corrosion Control Program (CCP). The purpose of the ECP sample taken from Tank 51H in early June was to determine if the later decants would be “acceptable feed” to the 2H and 3H evaporator systems.

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DOE OSTI2015

Analysis of Tank 51H (HTF-51-15-77) Subsurface Supernatant Sample in Support of Enrichment and Corrosion Control Programs

This report provides the results of analyses on Tank 51H subsurface supernatant liquid sample in support of the Enrichment Control Program (ECP) and the Corrosion Control Program (CCP).The purpose of the ECP sample taken from Tank 51H in early June was to determine if the later decants would be “acceptable feed” to the 2H and 3H evaporator systems.

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NASA NTRS1982

A corrosion control manual for rail rapid transit

In 1979, during the planning stage of the Metropolitan Dade County Transit System, the need was expressed for a corrosion control manual oriented to urban rapid transit system use. This manual responds to that need. The objective of the manual is to aid rail rapid transit agencies by providing practical solutions to selected corrosion problems. The scope of the manual encompasses corrosion problems of the facilities of rapid transit systems: structures and tracks, platforms and stations, power and signals, and cars. It also discusses stray electric current corrosion. Both design and maintenance solutions are provided for each problem. Also included are descriptions of the types of corrosion and their causes, descriptions of rapid transit properties, a list of corrosion control committees and NASA, DOD, and ASTM specifications and design criteria to which reference is made in the manual. A bibliography of papers and excerpts of reports and a glossary of frequency used terms are provided.

Gilbert, L. O.↗
NASA NTRS1983

Metallized coatings for corrosion control of Naval ship structures and components

In attempting to improve corrosion control, the U.S. Navy has undertaken a program of coating corrosion-susceptible shipboard components with thermally sprayed aluminum. In this report the program is reviewed in depth, including examination of processes, process controls, the nature and properties of the coatings, nondestructive examination, and possible hazards to personnel. The performance of alternative metallic coating materials is also discussed. It is concluded that thermally sprayed aluminum can provide effective long-term protection against corrosion, thereby obviating the need for chipping of rust and repainting by ship personnel. Such coatings are providing excellent protection to below-deck components such as steam valves, but improvements are needed to realize the full potential of coatings for above-deck service. Several recommendations are made regarding processes, materials, and research and development aimed at upgrading further the performance of these coatings.

Source record↗
NASA NTRS1982

A Corrosion Control Manual for Rail Rapid Transit

This manual addresses corrosion problems in the design, contruction, and maintenance of rapid transit systems. Design and maintenance solutions are provided for each problem covered. The scope encompasses all facilities of urban rapid transit systems: structures and tracks, platforms and stations, power and signals, and cars. The types of corrosion and their causes as well as rapid transit properties are described. Corrosion control committees, and NASA, DOD, and ASTM specifications and design criteria to which reference is made in the manual are listed. A bibliography of papers and excerpts of reports is provided and a glossary of frequently used terms is included.

Gilbert, L. O.↗
DOE OSTI2018

The Development of the Corrosion Control Limits for Direct Feed Low-Activity Waste Melter-Off Gas Returns to Hanford Tank Farms - 18196

The Savannah River National Laboratory has been developing a corrosion model to facilitate implementation of Hanford's Direct Feed Low Waste (DFLAW) flowsheet. Laboratory testing and statistical analysis have been used to determine the necessary corrosion controls for returning effluent from the Hanford Waste Treatment and Immobilization Plant's Low Activity Waste Vitrification melter off-gas treatment system to the tank farms. The stream compositions are projected to contain components at relative concentrations that are significantly more corrosive toward carbon steel, specifically halide and sulfate anions, than the current waste compositions in the tank farms. Administrative programs are in place to mitigate potential corrosion mechanisms and thereby maintain the structural and leak integrity functions of these waste tanks throughout their intended service life. Waste chemistry and temperature control are the means by which corrosion degradation of the waste tanks is minimized. The current administrative specification for chemical composition and temperature for the underground carbon steel waste tanks is not designed to control the higher halide or sulfate composition. The content of the DFLAW waste streams will be diverse and depend on several factors, such as the melter feed composition and melter idle time. Other factors, such as effluent management of the off gas water collections, will impact the variability of the return streams even more. The work performed by the Savannah River National Laboratory has confirmed that the halide ions are the most aggressive species in the return stream compositions projected using a flowsheet simulation, and nitrite is the most effective inhibitor at pH 10 and 40 deg. C. This test program has employed statistically designed test matrices to determine the dependent variables and the interaction terms between the variables that are significant for the corrosion model and definition of the corrosion control specifications. The first phase of testing focused on identifying aggressive species in off-gas condensate return compositions that present a propensity for localized corrosion attack, namely pitting corrosion. The second phase of testing focused on developing a corrosion model from the interaction terms that will predict the susceptibility of pitting in the double shell tank system based on waste composition and the required amount of corrosion inhibitor. The data collected from this testing program in conjunction with other testing programs, both at the Savannah River Site and the Hanford Site, along with operations knowledge, has determined the chemistry ranges and chemical species requirements for corrosion control in the Hanford double-shell tank system for the effluents generated in the Hanford Waste Treatment and Immobilization Plant's Low Activity Waste facility during the DFLAW phase of operations. (authors)

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NASA NTRS1974

Corrosion control and disinfection studies in spacecraft water systems

Disinfection and corrosion control in the water systems of the Saturn 5 Orbital Workshop Program are considered. Within this framework, the problem areas of concern are classified into four general areas: disinfection; corrosion; membrane-associated problems of disinfectant uptake and diffusion; and taste and odor problems arising from membrane-disinfectant interaction.

Shea, T. G.↗
DOE OSTI2015

Analysis of Tank 38H (HTF-38-15-119, 127) Surface, Subsurface and Tank 43H (HTF-43-15-116, 117 and 118) Surface, Feed Pump Suction and Jet Suction Subsurface Supernatant Samples in Support of Enrichment, Corrosion Control and Salt Batch Planning Programs

Compositional feed limits have been established to ensure that a nuclear criticality event for the 2H and 3H Evaporators is not possible. The Enrichment Control Program (ECP) requires feed sampling to determine the equivalent enriched uranium content prior to transfer of waste other than recycle transfers (requires sampling to determine the equivalent enriched uranium at two locations in Tanks 38H and 43H every 26 weeks) The Corrosion Control Program (CCP) establishes concentration and temperature limits for key constituents and periodic sampling and analysis to confirm that waste supernate is within these limits. This report provides the results of analyses on Tanks 38H and 43H surface and subsurface supernatant liquid samples in support of the ECP, the CCP, and the Salt Batch 10 Planning Program.

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DOE OSTI2010

PROBABILITY BASED CORROSION CONTROL FOR WASTE TANKS - PART II

As part of an ongoing study to evaluate the discontinuity in the corrosion controls at the SRS tank farm, a study was conducted this year to assess the minimum concentrations below 1 molar nitrate, see Figure 1. Current controls on the tank farm solution chemistry are in place to prevent the initiation and propagation of pitting and stress corrosion cracking in the primary steel waste tanks. The controls are based upon a series of experiments performed with simulated solutions on materials used for construction of the tanks, namely ASTM A537 carbon steel (A537). During FY09, an experimental program was undertaken to investigate the risk associated with reducing the minimum molar nitrite concentration required to confidently inhibit pitting in dilute solutions (i.e., less than 1 molar nitrate). The experimental results and conclusions herein provide a statistical basis to quantify the probability of pitting for the tank wall exposed to various solutions with dilute concentrations of nitrate and nitrite. Understanding the probability for pitting will allow the facility to make tank-specific risk-based decisions for chemistry control. Based on previous electrochemical testing, a statistical test matrix was developed to refine and solidify the application of the statistical mixture/amount model to corrosion of A537 steel. A mixture/amount model was identified based on statistical analysis of recent and historically collected electrochemical data. This model provides a more complex relationship between the nitrate and nitrite concentrations and the probability of pitting than is represented by the model underlying the current chemistry control program, and its use may provide a technical basis for the utilization of less nitrite to inhibit pitting at concentrations below 1 molar nitrate. FY09 results fit within the mixture/amount model, and further refine the nitrate regime in which the model is applicable. The combination of visual observations and cyclic potentiodynamic polarization scans indicates a potential for significant inhibitor reductions at nitrate concentrations near 1.0 M without a significant increase in corrosion risk. The complete data sets from FY08 and FY09 testing have determined the statistical basis to confidently inhibit against pitting using nitrite inhibition with the current pH controls. Future testing will complete the spectrum of nitrate concentrations around 1 molar. These results will be combined to provide a complete spectrum for corrosion controls with a risk based component.

36 MATERIALS SCIENCE↗
NASA NTRS2013

NASA's Beachside Corrosion Test Site and Current Environmentally Friendly Corrosion Control Initiatives

NASA began corrosion studies at the Kennedy Space Center (KSC) in 1966 during the Gemini/Apollo Programs with the evaluation of long-term corrosion protective coatings for carbon steel. KSC's Beachside Corrosion Test Site (BCTS), which has been documented by the American Society of Materials (ASM) as one of the most corrosive, naturally occurring, environments in the world, was established at that time. With the introduction of the Space Shuttle in 1981, the already highly corrosive conditions at the launch pad were rendered even more severe by the acid ic exhaust from the solid rocket boosters. In the years that followed, numerous studies have identified materials, coatings, and maintenance procedures for launch hardware and equipment exposed to the highly corrosive environment at the launch pad. This paper presents a historical overview of over 45 years of corrosion and coating evaluation studies and a description of the BCTS's current capabilities. Additionally, current research and testing programs involving chromium free coatings, environmentally friendly corrosion preventative compounds, and alternates to nitric acid passivation will be discussed.

Russell, Richard W.↗
DOE OSTI2015

Analysis of Tank 39H (HTF-39-15-61, 62) Surface and Subsurface Supernatant Samples in Support of Corrosion Control Program

This report provides the results of analyses on Tanks 39H surface and subsurface supernatant liquid samples in support of the Corrosion Control Program. Analyses included warm acid strike preparation followed by analysis for silicon, aluminum, and sodium and water dilution preparation followed by analysis for anions. Other reported analytical results include analyses results for uranium, Pu-241 and Pu-239.

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DOE OSTI2015

Analysis of Tank 39H (HTF-39-15-61, 62) Surface and Subsurface Supernatant Samples in Support of Corrosion Control Program

This report provides the results of analyses on Tanks 39H surface and subsurface supernatant liquid samples in support of the Corrosion Control Program. Analyses included warm acid strike preparation followed by analysis for silicon, aluminum, and sodium and water dilution preparation followed by analysis for anions. Other reported analytical results include analyses results for uranium, Pu-241 and Pu-239. The measured sodium concentration averaged, respectively, 4.28E+00 ± 9.30E-02 M and 4.32E+00 ± 1.076E-01 M in the Tank 39H surface sample and Tank 39H subsurface sample. In general, the nitrate, nitrite, free-OH and specific gravity of the Tank 39H surface and subsurface samples were all about the same in magnitude, respectively, averaging 1.98 M, 0.314 M, 1.26 M and 1.24. The measured silicon concentration for the Tank 39H surface and subsurface samples were, respectively, 3.84E+01± 5.51E+00 and 4.14E+01± 1.17E + 00 mg/L. Based on the uranium, Pu-241 and Pu-239 concentrations, the calculated U-235 equivalent is 21.41 wt% for the surface sample and 21.32 wt% for the subsurface sample.

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