The long-term behaviors of passivation and hydride layer of commercial grade pure titanium in TRU waste disposal environments

Nakayama, Gen; Sakakibara, Yohei; Taniyama, Yoshihiro; Cho, Hideo; Jintoku, Takashi; Kawakami, Susumu; Takemoto, Mikio

doi:10.1016/j.jnucmat.2008.06.029

Cited by 15 publications

(18 citation statements)

References 14 publications

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“…TiH 2 is an absolutely brittle compound in fcc (face-centered cubic) structure [33,34], and its thickness will keep growing with the increase of hydrogen concentration in it. Once the thickness exceeds a critical value, cracks always in brittle mode are brought about [32], i.e. the HE [35], which was distinctly observed in Fig.…”

Section: Macroscopic Morphologiesmentioning

confidence: 79%

“…Besides the HB induced by hydrogen gases, the other degradation as HE was also aroused by the presence of TiH x on the titanium tubes in this event. The value of x usually ranges from 1.5 to 2.0 with respect to the thickness of the titanium hydride, and the surface is commonly TiH 2 [32]. TiH 2 is an absolutely brittle compound in fcc (face-centered cubic) structure [33,34], and its thickness will keep growing with the increase of hydrogen concentration in it.…”

Section: Macroscopic Morphologiesmentioning

confidence: 99%

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Failure analysis of leakage on titanium tubes within heat exchangers in a nuclear power plant. Part I: Electrochemical corrosion

Yang

Gong

Yuan

2011

Materials & Corrosion

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Titanium tubes generally exhibit superior resistance against electrochemical corrosions amid seawater for their passive films TiO 2 . However, hydrogenassisted corrosion (HAC) is actually the Achilles' heel to titanium materials when the temperature exceeds near 70 8C. In this event, severe degradations like quick thinning and leakage were frequently detected on a large number of titanium tubes exposed to natural seawater environment within heat exchangers in a nuclear power plant, which caused serious safety problems. This paper is the Part I of totally two parts conducted for the whole failure analysis study, mainly focusing on electrochemical aspect of failure causes and their behaviors. By means of over ten kinds of characterization methods, the analysis results identified that the HAC induced by the interaction effects between galvanic corrosion and crevice corrosion led to local bulges of the inner walls of some titanium tubes, and then the bulges were quickly thinned and eventually ruptured under the eddy erosion from the seawater containing sediment particles. Finally, relevant mechanisms were addressed in detail and prevention methods were proposed as well.

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Section: Macroscopic Morphologiesmentioning

confidence: 79%

Section: Macroscopic Morphologiesmentioning

confidence: 99%

Failure analysis of leakage on titanium tubes within heat exchangers in a nuclear power plant. Part I: Electrochemical corrosion

Yang

Gong

Yuan

2011

Materials & Corrosion

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“…20 The HIC of Ti has been predicted based on the concept of a threshold H ABS concentration 25 or a threshold hydride layer thickness. 106 Of all the different corrosion processes, the least attention is often paid to MIC. This is unfortunate, since MIC can be one of the most difficult corrosion processes to predict.…”

Section: Lifetime Prediction Of Hlw/sf Disposal Containersmentioning

confidence: 99%

Container Materials for the Storage and Disposal of Nuclear Waste

King¹

2013

CORROSION

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A wide range of alloys have been considered as candidate container materials for the storage and disposal of nuclear waste. The goal of the majority of national nuclear waste management programs is the ultimate disposal of the waste, although, depending upon the strategy being followed, disposal may come only after an extended period of storage. The management strategy depends on the nature of the waste, with intermediate level waste (ILW) generally being stored for a longer period before disposal than is the case for higher activity wastes, such as high-level waste (HLW) from reprocessing activities or spent fuel (SF). This review describes the corrosion issues associated with the storage and disposal of both ILW and HLW/SF. Various factors enter into the decision of which material to select for the container, of which the corrosion behavior in the expected service environment is only one. The corrosion behavior of the container material(s) is closely tied to the nature of the environment to which the containers will be exposed and how that environment changes with time. A general discussion of the corrosion behavior of the materials selected or proposed as container materials is provided, and the specific corrosion issues associated with each class of material highlighted. The classes of material considered for the storage and/or disposal of ILW and HLW/SF include copper, carbon steel and cast iron, stainless steels, titanium alloys, and nickel-based alloys.

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“…2 In the scratch test, the Ti-Gr.1 specimens are mounted on a slide stage along with a corrosion cell filled with a test solution of ambient 0?6 mol L 21…”

Section: Passive Oxide Film Stabilitymentioning

confidence: 99%

“…Findings for a welded structure were compared with those for corrosion resistance of the base material. 2…”

Section: Introductionmentioning

confidence: 99%

Long term integrity against corrosion of titanium used for TRU waste container

Nakayama

Sakakibara

Kawakami

2011

Corrosion Engineering, Science and Technology

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Commercial grade pure titanium containing palladium (Ti-Grade 17) may be used for transuranic waste containers. The long term integrity of Ti-Grade 17 against corrosion was studied in the concrete permeated alkaline sodium water environment of 0?6 mol [Cl 2 ]z0?223 mol [OH 2 ] at various temperatures up to 80uC. The study focused on the stability of the passive oxide film, the susceptibility to crevice corrosion and cracks in the titanium hydride (TiH 2 ) layer. General corrosion depth for sustained passivation may be determined as i pass times the evaluation period of 10 4 years, with addition of the electric quantity for the destruction and repair of passivation film. Crevice corrosion sensitivity is not affected by processes such as welding, cold work and heat treatment. Cathodic reactions essential for maintaining the passive state produce hydrogen that, to some extent, is adsorbed to form a hydride layer. This layer subsequently undergoes cracking to cause reduction in the critical hydride layer thickness d c of 10 mm. The crack depth becomes as much as 100 mm at 2000 years.

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The long-term behaviors of passivation and hydride layer of commercial grade pure titanium in TRU waste disposal environments

Cited by 15 publications

References 14 publications

Failure analysis of leakage on titanium tubes within heat exchangers in a nuclear power plant. Part I: Electrochemical corrosion

Failure analysis of leakage on titanium tubes within heat exchangers in a nuclear power plant. Part I: Electrochemical corrosion

Container Materials for the Storage and Disposal of Nuclear Waste

Long term integrity against corrosion of titanium used for TRU waste container

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