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Raul B. Rebak 《JOM Journal of the Minerals, Metals and Materials Society》2014,66(3):455-460
Commercial nuclear energy has been used for over 6 decades; however, to date, none of the 30+ countries with nuclear power has opened a repository for high-level waste (HLW). All countries with nuclear waste plan to dispose of it in metallic containers located in underground geologically stable repositories. Some countries also have liquid nuclear waste that needs to be reduced and vitrified before disposition. The five articles included in this topic offer a cross section of the importance of alloy selection to handle nuclear waste at the different stages of waste processing and disposal. 相似文献
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Joseph Farmer Jor-Shan Choi Cheng Saw Jeffrey Haslam Dan Day Phillip Hailey Tiangan Lian Raul Rebak John Perepezko Joe Payer Daniel Branagan Brad Beardsley Andy D’amato Lou Aprigliano 《Metallurgical and Materials Transactions A》2009,40(6):1289-1305
An overview of the High-Performance Corrosion-Resistant Materials (HPCRM) Program, which was cosponsored by the Defense Advanced Research Projects Agency (DARPA) Defense Sciences Office (DSO) and the U.S. Department of Energy (DOE) Office of Civilian and Radioactive Waste Management (OCRWM), is discussed. Programmatic investigations have included a broad range of topics: alloy design and composition, materials synthesis, thermal stability, corrosion resistance, environmental cracking, mechanical properties, damage tolerance, radiation effects, and important potential applications. Amorphous alloys identified as SAM2X5 (Fe49.7Cr17.7Mn1.9Mo7.4W1.6B15.2C3.8Si2.4) and SAM1651 (Fe48Mo14Cr15Y2C15B6) have been produced as meltspun ribbons (MSRs), dropcast ingots, and thermal-spray coatings. Chromium (Cr), molybdenum (Mo), and tungsten (W) additions provided corrosion resistance, while boron (B) enabled glass formation. Earlier electrochemical studies of MSRs and ingots of these amorphous alloys demonstrated outstanding passive film stability. More recently, thermal-spray coatings of these amorphous alloys have been made and subjected to long-term salt-fog and immersion tests; good corrosion resistance has been observed during salt-fog testing. Corrosion rates were measured in situ with linear polarization, while the open-circuit corrosion potentials (OCPs) were simultaneously monitored; reasonably good performance was observed. The sensitivity of these measurements to electrolyte composition and temperature was determined. The high boron content of this particular amorphous metal makes this amorphous alloy an effective neutron absorber and suitable for criticality-control applications. In general, the corrosion resistance of such iron-based amorphous metals is maintained at operating temperatures up to the glass transition temperature. These materials are much harder than conventional stainless steel and Ni-based materials, and are proving to have excellent wear properties, sufficient to warrant their use in earth excavation, drilling, and tunnel-boring applications. Large areas have been successfully coated with these materials, with thicknesses of approximately 1 cm. The observed corrosion resistance may enable applications of importance in industries such as oil and gas production, refining, nuclear power generation, shipping, etc. 相似文献
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Peter L. Andresen Peter H. Chou Martin M. Morra J. Lawrence Nelson Raul B. Rebak 《Metallurgical and Materials Transactions A》2009,40(12):2824-2836
Austenitic stainless steels (SSs) core internal components in nuclear light water reactors (LWRs) are susceptible to irradiation-assisted
stress corrosion cracking (IASCC). One of the effects of irradiation is the hardening of the SS and a change in the dislocation
distribution in the alloy. Irradiation may also alter the local chemistry of the austenitic alloys; for example, silicon may
segregate and chromium may deplete at the grain boundaries. The segregation or depletion phenomena at near-grain boundaries
may enhance the susceptibility of these alloys to environmentally assisted cracking (EAC). The objective of the present work
was to perform laboratory tests in order to better understand the role of Si in the microstructure, properties, electrochemical
behavior, and susceptibility to EAC of austenitic SSs. Type 304 SS can dissolve up to 2 pct Si in the bulk while maintaining
a single austenite microstructure. Stainless steels containing 12 pct Cr can dissolve up to 5 pct bulk Si while maintaining
an austenite structure. The crack growth rate (CGR) results are not conclusive about the effect of the bulk concentration
of Si on the EAC behavior of SSs. 相似文献
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For more than two decades, an extensive scientific effort has been underway to determine whether Yucca Mountain, Nevada, is
a suitable site for a deep underground repository for spent nuclear fuel and high-level radioactive waste. Even though the
geologic site is stable, additional engineered barriers are planned, including waste packages, drip shields, and tunnel inverts
that will be within the emplacement tunnels. Research is under way into the best materials for corrosion prevention in those
engineered barriers to ensure their long-term mechanical integrity. 相似文献
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Kenneth J. Evans Ahmet Yilmaz S. Daniel Day Lana L. Wong John C. Estill Raúl B. Rebak 《JOM Journal of the Minerals, Metals and Materials Society》2005,57(1):56-61
Alloy 22 (N06022) is a nickel-based alloy highly resistant to corrosion. In aggressive conditions of high chloride concentration,
temperature, and applied potential, alloy 22 may suffer crevice corrosion, a form of localized corrosion. Several electrochemical
methods can be used to detect localized corrosion in metallic alloys. One of the most popular for rapid screening is cyclic
potentiodynamic polarization (CPP). This work compares the repassivation potentials obtained using CPP to repassivation potentials
obtained using the Tsujikawa-Hisamatsu Electrochemical method and the potentiostatic method.
For more information, contact Raúl B. Rebak, Lawrence Livermore National Laboratory, 7000 East Ave., L-631, Livermore, CA
94550; (925) 422-1854; fax (925) 422-2105; e-mail rebak1@llnl.gov. 相似文献
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Michael E. Mohorich Joshua Lamb Dhanesh Chandra Jaak Daemen Raul B. Rebak 《Metallurgical and Materials Transactions A》2010,41(10):2563-2574
Several types of carbon and high-strength low-alloy (HSLA) steels are being considered for use in the underground reinforcement
of the Yucca Mountain Nuclear Waste Repository. In this study, potentiodynamic polarization under reducing conditions was
used to determine the corrosion rates (CRs) and passivity behavior of AISI 4340 steel using different combinations of sodium
silicate (Na2SiO3) and sodium bicarbonate (NaHCO3), in both pure water (PW) and simulated seawater (SW, 3.5 pct NaCl). These experiments were carried out to examine the potential
inhibiting properties of the silicate or bicarbonate ions on the surface of the steel. The addition of sodium silicate to
solution reduced the observed CR at room temperature to 19 μm/y at 0.005 M concentration and 7 μm/y at 0.025 M concentration in PW. The addition of sodium bicarbonate increased the CR from 84 μm/y (C = 0.1 M) to 455 μm/y (C = 1 M). These same behaviors were also observed at higher temperatures. 相似文献