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Title: Investigation of environmentally assisted fracture of metallic nuclear waste package barrier materials in simulated basalt repository environments

Abstract

Statically loaded corrosion tests, slow strain rate (SSR) tests, and fatigue crack growth rate (FCGR) tests were conducted to evaluate the relative susceptibility of two titanium-base nuclear waste package candidate structural barrier materials Ti-grade 2 and Ti-grade 12-to environmentally enhanced cracking in a simulated repository environment. Statically loaded corrosion tests were done in oxic basalt ground water at 250/sup 0/C; SSR tests were done in oxic basalt ground water at 150, 250, and 300/sup 0/C and in air at 20 and 250/sup 0/C; and FCGR tests were done in basalt ground water, fluoride-ion-enhanced basalt ground water, high-purity water, and air at 90/sup 0/C. The following conclusions can be drawn: the general corrosion rate of statically loaded corrosion coupons was very low in a 3-mo test, and no pitting or cracking of the specimens was observed. Ti-grade 2 and Ti-grade 12 exhibited strain rate dependent ductility diminution in SSR tests. The ductility diminution was most severe in Ti-grade 2 at 300/sup 0/C and in Ti-grade 12 at 250/sup 0/C. For of Ti-grade 12 it was found to be highly orientation dependent. The ductility diminution was also found in tests conducted in air as well as in those conducted in the basaltmore » ground water environment; however, the extent of the degradation was less in air. The ductility diminution cannot be attributed to stress corrosion cracking because the fracture mode was microvoid coalescence in all tests. Evidence obtained in the current study and correlation of the present results with results obtained by other researchers indicate that dynamic strain aging is responsible for the loss of ductility. The FCGR of Ti-grade 2 and Ti-grade 12 was not affected by any of the environmental conditions used in this study, which indicates that no environmental cracking mechanism is operative under the conditions tested (90/sup 0/C, oxic ground water, and frequencies from 0.01 to 5 Hz).« less

Authors:
Publication Date:
Research Org.:
Pacific Northwest Lab., Richland, WA (USA)
OSTI Identifier:
6601741
Alternate Identifier(s):
OSTI ID: 6601741; Legacy ID: DE83005126
Report Number(s):
PNL-4379
ON: DE83005126
DOE Contract Number:
AC06-76RL01830
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; GROUND WATER; CORROSIVE EFFECTS; RADIOACTIVE WASTE DISPOSAL; GEOLOGIC DEPOSITS; HIGH-LEVEL RADIOACTIVE WASTES; TITANIUM BASE ALLOYS; CORROSION; CRACK PROPAGATION; FATIGUE; STRAIN RATE; BASALT; ENGINEERED SAFETY SYSTEMS; EXPERIMENTAL DATA; MATERIALS TESTING; PACKAGING; ALLOYS; CHEMICAL REACTIONS; DATA; HYDROGEN COMPOUNDS; IGNEOUS ROCKS; INFORMATION; MANAGEMENT; MATERIALS; MECHANICAL PROPERTIES; NUMERICAL DATA; OXYGEN COMPOUNDS; RADIOACTIVE MATERIALS; RADIOACTIVE WASTES; ROCKS; TESTING; TITANIUM ALLOYS; VOLCANIC ROCKS; WASTE DISPOSAL; WASTE MANAGEMENT; WASTES; WATER 360103* -- Metals & Alloys-- Mechanical Properties; 360105 -- Metals & Alloys-- Corrosion & Erosion; 052002 -- Nuclear Fuels-- Waste Disposal & Storage

Citation Formats

Pitman, S.G. Investigation of environmentally assisted fracture of metallic nuclear waste package barrier materials in simulated basalt repository environments. United States: N. p., 1982. Web. doi:10.2172/6601741.
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Pitman, S.G. Investigation of environmentally assisted fracture of metallic nuclear waste package barrier materials in simulated basalt repository environments. United States. doi:10.2172/6601741.
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Pitman, S.G. Mon . "Investigation of environmentally assisted fracture of metallic nuclear waste package barrier materials in simulated basalt repository environments". United States. doi:10.2172/6601741. https://www.osti.gov/servlets/purl/6601741.
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@article{osti_6601741,
title = {Investigation of environmentally assisted fracture of metallic nuclear waste package barrier materials in simulated basalt repository environments},
author = {Pitman, S.G.},
abstractNote = {Statically loaded corrosion tests, slow strain rate (SSR) tests, and fatigue crack growth rate (FCGR) tests were conducted to evaluate the relative susceptibility of two titanium-base nuclear waste package candidate structural barrier materials Ti-grade 2 and Ti-grade 12-to environmentally enhanced cracking in a simulated repository environment. Statically loaded corrosion tests were done in oxic basalt ground water at 250/sup 0/C; SSR tests were done in oxic basalt ground water at 150, 250, and 300/sup 0/C and in air at 20 and 250/sup 0/C; and FCGR tests were done in basalt ground water, fluoride-ion-enhanced basalt ground water, high-purity water, and air at 90/sup 0/C. The following conclusions can be drawn: the general corrosion rate of statically loaded corrosion coupons was very low in a 3-mo test, and no pitting or cracking of the specimens was observed. Ti-grade 2 and Ti-grade 12 exhibited strain rate dependent ductility diminution in SSR tests. The ductility diminution was most severe in Ti-grade 2 at 300/sup 0/C and in Ti-grade 12 at 250/sup 0/C. For of Ti-grade 12 it was found to be highly orientation dependent. The ductility diminution was also found in tests conducted in air as well as in those conducted in the basalt ground water environment; however, the extent of the degradation was less in air. The ductility diminution cannot be attributed to stress corrosion cracking because the fracture mode was microvoid coalescence in all tests. Evidence obtained in the current study and correlation of the present results with results obtained by other researchers indicate that dynamic strain aging is responsible for the loss of ductility. The FCGR of Ti-grade 2 and Ti-grade 12 was not affected by any of the environmental conditions used in this study, which indicates that no environmental cracking mechanism is operative under the conditions tested (90/sup 0/C, oxic ground water, and frequencies from 0.01 to 5 Hz).},
doi = {10.2172/6601741},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Nov 01 00:00:00 EST 1982},
month = {Mon Nov 01 00:00:00 EST 1982}
}
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Technical Report:
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DOI:  10.2172/6601741
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