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Title: Materials for high-level waste canister/overpacks in salt formations

Abstract

Studies on the corrosion and mechanical behavior of TiCode-12 and other titanium alloys, for use as candidate canister or overpack barriers in a high-level waste repository or test facility in salt, are reported. The corrosion behavior of TiCode-12 was evaluated as a function of: brine composition, temperature, time, pH, oxygen concentration, and gamma radiolysis. Uniform corrosion rates are in the range of 0.1 to 10 ..mu..m/yr; pitting or crevice corrosion has not yet been observed. The highly adherent, passivating titanium oxide film that provides the corrosion protection is being evaluated via electrochemical polarization and surface analytical techniques to enable modeling of the corrosion mechanism(s). An increase in the corrosion rate by a factor of about 2 was observed for sensitized TiCode-12; changes in the alloy microstructure are being analyzed in order to model this phenomenon. Alterations in the chemistry and processing procedure of TiCode-12 are being evaluated to optimize corrosion, mecahnical, and mill-producibility properties for high-level waste package applications. Slow strain rate testing of TiCode-12 revealed no apparent susceptibility to stress corrosion cracking; no significant changes in tensile properties were observed, but alterations in fracture mode were determined to be caused by internal hydrogen content. Hydrogen effects on titanium alloymore » mechanical properties and crack susceptibility are being studied. Some hydrogen embrittlement occurs at hydrogen concentrations in the range of 200 to 300 ppM by weight, but the strength of TiCode-12 is not affected at concentrations up to 1100 wppM. A TiCode-12 HLW canister-package is proposed that could provide long-term containment integrity and significantly minimize total HLW isolation system costs when compared to other waste package design concepts.« less

Authors:
; ;
Publication Date:
Research Org.:
Sandia National Labs., Albuquerque, NM (USA)
OSTI Identifier:
6793805
Report Number(s):
SAND-82-0429
ON: DE83006438
DOE Contract Number:  
AC04-76DP00789
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; 36 MATERIALS SCIENCE; RADIOACTIVE WASTE DISPOSAL; HIGH-LEVEL RADIOACTIVE WASTES; PACKAGING; SALT DEPOSITS; TITANIUM BASE ALLOYS; CORROSION; ELONGATION; MICROSTRUCTURE; PHYSICAL RADIATION EFFECTS; TENSILE PROPERTIES; YIELD STRENGTH; ANNEALING; BRINES; CONTAINERS; COST; GAMMA RADIATION; MATERIALS TESTING; PH VALUE; TEMPERATURE EFFECTS; ALLOYS; CHEMICAL REACTIONS; CRYSTAL STRUCTURE; ELECTROMAGNETIC RADIATION; GEOLOGIC DEPOSITS; HEAT TREATMENTS; IONIZING RADIATIONS; MANAGEMENT; MATERIALS; MECHANICAL PROPERTIES; RADIATION EFFECTS; RADIATIONS; RADIOACTIVE MATERIALS; RADIOACTIVE WASTES; TESTING; TITANIUM ALLOYS; WASTE DISPOSAL; WASTE MANAGEMENT; WASTES; 052002* - Nuclear Fuels- Waste Disposal & Storage; 360105 - Metals & Alloys- Corrosion & Erosion; 360103 - Metals & Alloys- Mechanical Properties; 360106 - Metals & Alloys- Radiation Effects; 360102 - Metals & Alloys- Structure & Phase Studies

Citation Formats

Molecke, M A, Ruppen, J A, and Diegle, R B. Materials for high-level waste canister/overpacks in salt formations. United States: N. p., 1982. Web.
Molecke, M A, Ruppen, J A, & Diegle, R B. Materials for high-level waste canister/overpacks in salt formations. United States.
Molecke, M A, Ruppen, J A, and Diegle, R B. Wed . "Materials for high-level waste canister/overpacks in salt formations". United States.
@article{osti_6793805,
title = {Materials for high-level waste canister/overpacks in salt formations},
author = {Molecke, M A and Ruppen, J A and Diegle, R B},
abstractNote = {Studies on the corrosion and mechanical behavior of TiCode-12 and other titanium alloys, for use as candidate canister or overpack barriers in a high-level waste repository or test facility in salt, are reported. The corrosion behavior of TiCode-12 was evaluated as a function of: brine composition, temperature, time, pH, oxygen concentration, and gamma radiolysis. Uniform corrosion rates are in the range of 0.1 to 10 ..mu..m/yr; pitting or crevice corrosion has not yet been observed. The highly adherent, passivating titanium oxide film that provides the corrosion protection is being evaluated via electrochemical polarization and surface analytical techniques to enable modeling of the corrosion mechanism(s). An increase in the corrosion rate by a factor of about 2 was observed for sensitized TiCode-12; changes in the alloy microstructure are being analyzed in order to model this phenomenon. Alterations in the chemistry and processing procedure of TiCode-12 are being evaluated to optimize corrosion, mecahnical, and mill-producibility properties for high-level waste package applications. Slow strain rate testing of TiCode-12 revealed no apparent susceptibility to stress corrosion cracking; no significant changes in tensile properties were observed, but alterations in fracture mode were determined to be caused by internal hydrogen content. Hydrogen effects on titanium alloy mechanical properties and crack susceptibility are being studied. Some hydrogen embrittlement occurs at hydrogen concentrations in the range of 200 to 300 ppM by weight, but the strength of TiCode-12 is not affected at concentrations up to 1100 wppM. A TiCode-12 HLW canister-package is proposed that could provide long-term containment integrity and significantly minimize total HLW isolation system costs when compared to other waste package design concepts.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1982},
month = {12}
}

Technical Report:
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