Corrosion of Candidate Iron-Base Waste Package Structural Barrier Materials in Moist Salt Environments

1984 ◽  
Vol 44 ◽  
Author(s):  
R. E. Westerman ◽  
S. G. Pitman

AbstractMild steels are considered to be strong candidates for waste package structural barrier (e.g., overpack) applications in salt repositories. Corrosion rates of these materials determined in autoclave tests utilizing a simulated intrusion brine based on Permian Basin core samples are low, generally μm (1 mil) per year. When the steels are exposed to moist salts containing simulated inclusion brines, the corrosion rates are found to increase significantly. The magnesium in the inclusion brine component of the environment is believed to be responsible for the increased corrosion rates.

1983 ◽  
Vol 26 ◽  
Author(s):  
J.L. Nelson ◽  
R.E. Westerman ◽  
F.S. Gerber

ABSTRACTThe corrosion behavior of several iron-base and titanium-base alloys was studied in synthetic Grande Ronde Basalt groundwater at temperatures of 150°C to 2500°C and under irradiation dose rates to 2 × 106 rad/hr. The objective of these ongoing studies is to help select one or more materials for waste-package canisters that will maintain their integrity for time periods up to 1,000 yr in a nuclear waste repository constructed in basalt. The corrosion rates of iron-base alloys under irradiated conditions were generally 2 to 3 times as high as those obtained on similar materials under nonirradiated conditions. The titanium alloys exhibited low corrosion rates but absorbed significant amounts of hydrogen under irradiated conditions.


1983 ◽  
Vol 26 ◽  
Author(s):  
L. R. Pederson ◽  
D. E. Clark ◽  
F. N. Hodges ◽  
G. L. Mcvpy ◽  
D. Rai

ABSTRACTThis paper discusses results of recent efforts to define the very near-field (within approximately 2m) environmental conditions to which waste packages will be exposed in a salt repository. These conditions must be considered in the experimental design for waste package materials testing, which includes corrosion of barrier materials and leaching of waste forms. Site-specific brine compositions have been determined, and “standard” brine compositions have been selected for testing purposes. Actual brine compositions will vary depending on origin, temperature, irradiation history, and contact with irradiated rock salt. Results of irradiating rock salt, synthetic brines, rock salt/brine mixtures, and reactions of irradiated rock salt with brine solutions are reported.


2006 ◽  
Vol 985 ◽  
Author(s):  
Darrell Dunn ◽  
Yi-Ming Pan ◽  
Xihua He ◽  
Lietai Yang ◽  
Roberto Pabalan

ABSTRACTThe evolution of environmental conditions within the emplacement drifts of a potential high-level waste repository at Yucca Mountain, Nevada, may be influenced by several factors, including the temperature and relative humidity within the emplacement drifts and the composition of seepage water. The performance of the waste package and the drip shield may be affected by the evolution of the environmental conditions within the emplacement drifts. In this study, tests evaluated the evolution of environmental conditions on the waste package surfaces and in the surrounding host rock. The tests were designed to (i) simulate the conditions expected within the emplacement drifts; (ii) measure the changes in near-field chemistry; and (iii) determine environmental influence on the performance of the engineered barrier materials. Results of tests conducted in this study indicate the composition of salt deposits was consistent with the initial dilute water chemistry. Salts and possibly concentrated calcium chloride brines may be more aggressive than either neutral or alkaline brines.


1988 ◽  
Vol 127 ◽  
Author(s):  
Martin A. Molecke ◽  
N. Rob Sorensen

ABSTRACTIn situ waste package performance experiments involving simulated (non-radioactive) defense high-level waste (DHLW) containers have been in progress since late 1984 at the Waste Isolation Pilot Plant (WIPP) facility. These experiments involve full-size, simulated DHLW containers of several metals and designs emplaced in the WIPP bedded rock salt. These test containers are surrounded by granular backfill (packing) materials, have in many cases been intentionally injected with brines, and are heavily instrumented. A majority of the test packages also contain nonradioactive DHLW borosilicate glass waste form, either within the container and/or outside of it. The primary purpose of these WIPP simulated DHLW experiments is to evaluate the in situ durability and performance of all waste package engineered barrier materials, and to perform package concept validation testing.Twelve of the test DHLW containers, emplaced in WIPP test Room B, have been in heated operation since 1985 and had a maximum surface temperature of about 190°C. These containers were recently retrieved, after about 3 years of heated exposure, for detailed posttest laboratory analyses of: general corrosion and metallurgical degradation, waste form and backfill materials alterations, and other rock salt-brine-barrier materials near-field interactions with the “repository” geochemical environment. Test canisters and overpacks made of ASTM Grade-12 titanium showed essentially no visible degradation in either the base metal or welds; cast mild steel A216/WCA over-packs have suffered some uniform corrosion. Significant degradation of the removed instruments and associated test apparatus has been found: pieces of stainless steel (both 304L and 316) apparatus have undergone extensive stress-corrosion cracking failure and non-uniform attack; Inconel 600-sheathed instruments have undergone both extensive uniform and localized (pitting) attack. Granular backfill materials have been significantly compacted by creep closure to about a density of 2 kg/m. Laboratory analyses are still in progress. Further details on these materials results plus instrumentation data and other in situ WIPP waste package test observations are discussed.


Geophysics ◽  
2019 ◽  
Vol 84 (6) ◽  
pp. D231-D248 ◽  
Author(s):  
Nicholas B. Harris ◽  
Al Moghadam ◽  
Tian Dong

We have derived relationships between organic carbon and acoustic properties in the Woodford Shale, an Upper Devonian organic-rich shale in the Permian Basin, Texas. Extensive core data enable us to relate measured total organic carbon (TOC) on core samples to gamma log response; in turn, gamma log-calculated TOC is compared with P-wave [Formula: see text] and S-wave [Formula: see text] velocities, density, and derivative properties including [Formula: see text], Young’s modulus, Poisson’s ratio, [Formula: see text], and [Formula: see text]. Because we sampled two wells at very different thermal maturity (early oil window and wet gas window), we can examine the effect of thermal maturity on these parameters. In both wells, [Formula: see text] and [Formula: see text] decrease with increasing TOC, exhibiting a rapid decrease from 0% to approximately 1.5% TOC, and a slower decrease above 1.5% TOC, similar to results from ultrasonic experiments on core samples, that we attribute to a shift from a mineral grain load-bearing to an organic matter load-bearing fabric. The [Formula: see text] decreases by 28% and [Formula: see text] by 20% over the range of 0.5%–12% TOC. [Formula: see text] and [Formula: see text] correlate more strongly to neutron porosity than to TOC in the less mature well, related to the development of a bitumen phase that is relatively soft and less dense and has greater impact on rock physical properties than kerogen; this effect disappears in the high-maturity well in which bitumen was further cracked to petroleum and physical properties of bitumen changed with increased aromatization. The effect of increased thermal maturity is to increase [Formula: see text] by approximately 12%, [Formula: see text] by 25%, and P-wave impedance by 12%. [Formula: see text] ratios decrease with increasing TOC, contrary to the behavior expected for the incorporation of a soft material into a rock. We suggest that the rock develops a horizontal planar fabric at lower TOC values that absorbs S-wave energy, counteracting the effect of the organic matter.


1990 ◽  
Vol 212 ◽  
Author(s):  
Donald T. Reed ◽  
Richard A. Van Konynenburg

ABSTRACTThe atmospheric corrosion of oxygen-free copper (CDA-102), 70/30 copper-nickel (CDA-715), and 7% aluminum bronze (CDA-613) in an irradiated moist air environment was investigated. Experiments were performed in both dry and 40% RH (@90°C) air at temperatures of 90 and 150°C. Initial corrosion rates were determined based on a combination of weight gain and weight loss measurements. Corrosion products observed were identified. These experiments support efforts by the Yucca Mountain Project (YMP) to evaluate possible metallic barrier materials for nuclear waste containers.


1987 ◽  
Vol 112 ◽  
Author(s):  
J. H. Haberman ◽  
D. J. Frydrych

AbstractThe U.S. Department of Energy's Salt Repository Project (SRP) is investigating the general corrosion resistance of cast mild steel as a candidate material for waste package containers. Evaluation of this material is being performed at the Pacific Northwest Laboratory in environments simulating expected repository conditions.General corrosion studies of mild steel (ASTM A216 grade WCA) in the as-cast and normalized conditions were conducted in hydrothermal halitesaturated (saturated at ambient temperature) brine environments simulating a “dissolution” and an “inclusion” brine. Corrosion tests were also performed in brines similar to the inclusion brine but containing magnesium concentrations ranging from 1000 to 30,000 ppm to investigate the effect of magnesium on the corrosion behavior.Corrosion rates of the cast mild steel were found to increase with increasing temperature and with increasing magnesium concentration. Some possible mechanisms that explain the observed behavior are presented.


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