The Expected Environment for Waste Packages in a Salt Repository

1983 ◽  
Vol 26 ◽  
Author(s):  
L. R. Pederson ◽  
D. E. Clark ◽  
F. N. Hodges ◽  
G. L. Mcvpy ◽  
D. Rai
Keyword(s):  
Rock Salt ◽  
Near Field ◽  
Materials Testing ◽  
Site Specific ◽  
Waste Package ◽  
Barrier Materials ◽  
Waste Forms ◽  
Temperature Irradiation ◽  
Salt Brine ◽  
Package Materials

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.

scholarly journals Results from Simulated Remote-Handled Transuranic Waste Experiments at the Waste Isolation Pilot Plant (WIPP)

1992 ◽  
Vol 294 ◽  
Author(s):  
Martin A. Molecke
Keyword(s):  
Rock Salt ◽  
Pilot Plant ◽  
Near Field ◽  
Laboratory Data ◽  
Silica Sand ◽  
Waste Isolation Pilot Plant ◽  
Waste Package ◽  
Test Operation ◽  
Transuranic Waste ◽  
Package Materials

ABSTRACTMulti-year, simulated remote-handled transuranic waste (RH TRU, nonradioactive) experiments are being conducted underground in the Waste Isolation Pilot Plant (WIPP) facility. These experiments involve the near-reference (thermal and geometrical) testing of eight full-size RH TRU test containers emplaced into horizontal, unlined rock salt boreholes. Half of the test emplacements are partially filled with bentonite/silica-sand backfill material. All test containers were electrically heated at about 115 W/each for three years, then raised to about 300 W/each for the remaining time. Each test borehole was instrumented with a selection of remote-reading thermocouples, pressure gages, borehole vertical-closure gages, and vertical and horizontal borehole-diameter closure gages. Each test emplacements was also periodically opened for visual inspections of brine intrusions and any interactions with waste package materials, materials sampling, manual closure measurements, and observations of borehole changes. Effects of heat on borehole closure rates and near-field materials (metals, backfill, rock salt, and intruding brine) interactions were closely monitored as a function of time. This paper summarizes results for the first five years of in situ test operation with supporting instrumentation and laboratory data and interpretations. Some details of RH TRU waste package materials, designs, and assorted underground test observations are also discussed. Based on the results, the tested RH TRU waste packages, materials, and emplacement geometry in unlined salt boreholes appear to be quite adequate for initial WIPP repository-phase operations.

Evolution of Chemistry and Its Effects on the Corrosion of Engineered Barrier Materials

2006 ◽  
Vol 985 ◽  
Author(s):  
Darrell Dunn ◽  
Yi-Ming Pan ◽  
Xihua He ◽  
Lietai Yang ◽  
Roberto Pabalan
Keyword(s):  
Environmental Conditions ◽  
Environmental Influence ◽  
Near Field ◽  
Yucca Mountain ◽  
High Level Waste ◽  
Seepage Water ◽  
Waste Package ◽  
Barrier Materials ◽  
Engineered Barrier ◽  
High Level

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.

Modeling of Near Field Actinide Concentrations in Radioactive Waste Repositories in Salt Formations: Effect of Buffer Materials

2000 ◽  
Vol 663 ◽  
Author(s):  
W. Schuessler ◽  
B. Kienzler ◽  
S. Wilhelm ◽  
V. Neck ◽  
J.I. Kim
Keyword(s):  
Reaction Path ◽  
Near Field ◽  
Solution Chemistry ◽  
Salt Formation ◽  
Path Modeling ◽  
Water Penetration ◽  
Waste Forms ◽  
Radioactive Waste Repositories ◽  
Salt Brine ◽  
Waste Repositories

ABSTRACTEngineered barrier systems are designed to reduce the near field actinide concentrations in case of water penetration into a repository. In this paper, the influence of buffer materials, such as MgO/CaO and clays, on the solubilities of Am, Np, Pu, and U is studied. The analysis is performed for low level cemented waste forms in a rock salt formation in contact with MgCl2 saturated salt brine (Q-brine).The evolution of the geochemical milieu by cement corrosion is calculated using reaction path modeling supported by the code EQ3/6. The influence of different buffer materials is analyzed with respect to their impact on the solution chemistry and corresponding actinide concentrations.

Retrieval and Analysis of Simulated Defense HLW Package Experiments at the WIPP

1988 ◽  
Vol 127 ◽  
Author(s):  
Martin A. Molecke ◽  
N. Rob Sorensen
Keyword(s):  
Rock Salt ◽  
Waste Form ◽  
High Level Waste ◽  
General Corrosion ◽  
Uniform Corrosion ◽  
Geochemical Environment ◽  
Waste Package ◽  
Barrier Materials ◽  
Backfill Materials

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.

Development, Application and Validation Of Models for Waste Package Long-Term Performance; Current Trends

1986 ◽  
Vol 84 ◽  
Author(s):  
Lars O. Werme ◽  
Bernd Grambow
Keyword(s):  
Spent Nuclear Fuel ◽  
Near Field ◽  
Relative Importance ◽  
Waste Package ◽  
Current Trends ◽  
Waste Forms ◽  
Long Term Performance ◽  
Term Performance ◽  
Development Application

AbstractCurrent trends in modelling waste package performance are reviewed mainly from the perspective of the Swedish SKB studies. Examples are given, which illustrate the approaches for modelling different waste forms, i.e. HLW glass and spent nuclear fuel, and candidate canister materials, such as copper and steel. The relative importance of thermodynamics, reaction kinetics and near-field transport are discussed.

The Influence of Environmental Conditions and Passive Film Properties on the MIC of Engineered Barriers in the Yucca Mountain Repository

2004 ◽  
Vol 824 ◽  
Author(s):  
A.C. Lloyd ◽  
R.J. Schuler ◽  
J.J. Noël ◽  
D.W. Shoesmith ◽  
F. King
Keyword(s):  
Microbial Activity ◽  
Yucca Mountain ◽  
Film Properties ◽  
Waste Package ◽  
Barrier Materials ◽  
Radiation Fields ◽  
Microbially Induced Corrosion ◽  
Alloy 22 ◽  
Engineered Barriers ◽  
Package Materials

AbstractA combination of gamma radiation fields, the absence of moisture, and the high temperatures on the drip shield (DS) and waste package (WP) should combine to suspend microbial activity on the DS/WP surfaces for many tens of thousands of years. This lack of microbial activity, coupled with the corrosion resistance of the titanium Grade7 (Ti-7 drip shield) and the Alloy-22 (waste package) materials make microbially induced corrosion (MIC) of these engineered barrier materials extremely unlikely.

scholarly journals Nuclear waste package materials testing report: basaltic and tuffaceous environments

10.2172/60288 ◽  
1983 ◽  
Author(s):  
D.J. Bradley ◽  
D.G. Coles ◽  
F.N. Hodges ◽  
G.L. McVay ◽  
R.E. Westerman
Keyword(s):  
Nuclear Waste ◽  
Materials Testing ◽  
Waste Package ◽  
Package Materials

Leaching Scale Effect for Cement-Waste Forms

1988 ◽  
Vol 127 ◽  
Author(s):  
J. C. Nomine ◽  
A. Billon ◽  
G. Courtois
Keyword(s):  
Scale Effect ◽  
Practical Method ◽  
Full Scale ◽  
Time Limit ◽  
Waste Form ◽  
Leaching Tests ◽  
Local Policy ◽  
Waste Package ◽  
Waste Forms

The confinement ability of a waste package is one of the major safety characteristics to consider in shallow land burial. In order to determine if the confinement is acceptable, in accordance with local policy, one way is to proceed to leaching tests. The practical method, for sake of simplicity, cost and time limit, is to carry out the leaching tests on laboratory samples which are easier to prepare than full-scale blocks, but the representativity of which needs to be treated with caution; it is in this context, that one of the aspect of our work concerns what is known as the “scale effect”.This study has been conducted using blocks the volumes of which are respectively of 200, 20, 2 and 0, 2 1, and made with the same cement-waste form (13 Cs) system.

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
Keyword(s):  
Permian Basin ◽  
Waste Package ◽  
Barrier Materials ◽  
Iron Base ◽  
Corrosion Rates ◽  
Core Samples ◽  
Structural Barrier

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.

Determination of the Corrosion Mechanisms of High-Level Waste Containing Glass

1981 ◽  
Vol 11 ◽  
Author(s):  
Horst Scholze ◽  
Reinhard Conradt ◽  
Heinrich Engelke ◽  
Hans Roggendorf
Keyword(s):  
Rock Salt ◽  
High Level Waste ◽  
Extreme Conditions ◽  
Safety Standard ◽  
Waste Forms ◽  
Corrosion Mechanisms ◽  
High Level

The German concept of high level waste final storage provides the use of certain glasses containing radioelement oxides as glass components. These waste forms are to be stored in rock salt formations in order to isolate the waste from the biosphere. The efficiency of this isolation is a most important question. The aim is to achieve a high safety standard that remains valid under extreme conditions such as the uncontrolled water entrance to the deposit.

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