Permeability Measurements on Cementitious Materials for Nuclear Waste Isolation

1979 ◽  
pp. 471-478 ◽  
Author(s):  
E. L. White ◽  
B. E. Scheetz ◽  
D. M. Roy ◽  
K. G. Zimmerman ◽  
M. W. Grutzeck
Keyword(s):  
Nuclear Waste ◽  
Cementitious Materials

scholarly journals The dissolution of simulant vitrified intermediate level nuclear waste in young cement water

MRS Advances ◽  
2020 ◽  
Vol 5 (3-4) ◽  
pp. 131-140
Author(s):  
Colleen Mann ◽  
Jeremy R. Eskelsen ◽  
Donovan N. Leonard ◽  
Eric Pierce ◽  
Claire L Corkhill
Keyword(s):  
Nuclear Waste ◽  
Alkaline Earth ◽  
Water Solution ◽  
Cementitious Materials ◽  
Intermediate Level ◽  
Short Term ◽  
Alkaline Earth Elements ◽  
Altered Layer ◽  
Safety Case ◽  
The Uk

AbstractIt is pertinent to the safety case for geological disposal in the UK that the behaviour of vitrified wastes in proximity to cementitious materials is understood. In this study, vitrified simulant intermediate level nuclear waste (ILW) was subject to dissolution in a synthetic cement water solution to simulate disposal conditions. Results show that the presence of alkali / alkaline earth elements in the cementitious solution can be favourable, at least in the short-term, leading to lower dissolution rates associated with incorporation of these elements into the altered layer of the glass.

scholarly journals Cement as a component of the multi-barrier system: radionuclide retention in cementitious environments

2021 ◽  
Vol 1 ◽  
pp. 151-152
Author(s):  
Xavier Gaona ◽  
Marcus Altmaier ◽  
Iuliia Androniuk ◽  
Nese Çevirim-Papaioannou ◽  
Michel Herm ◽  
...  
Keyword(s):  
Nuclear Waste ◽  
Host Rock ◽  
Near Field ◽  
Quantitative Description ◽  
Cementitious Materials ◽  
Assessment Process ◽  
High Level Waste ◽  
Hardened Cement ◽  
Spectroscopic Techniques ◽  
Research Activities

Abstract. Safety concepts regarding nuclear waste disposal in underground repositories generally rely on a combination of engineered and geological barriers, which minimize the potential release of radionuclides from the containment-providing rock zone or even their transport into the biosphere. Cementitious materials are used for conditioning of certain nuclear waste types, as components of waste containers and overpacks, as well as being constituents of structural materials at the interface between backfilling and host rock in some repository concepts. For instance, the preferred option for the disposal of high-level waste (HLW) in Belgium is based on the supercontainer design, which consists of a carbon steel overpack surrounded by a thick concrete buffer (Bel et al., 2006). In the event of formation water interacting with cementitious materials, pore water solutions characterized by (highly) alkaline pH conditions will form. These boundary conditions define the chemical response of the radionuclides, but also influence the behaviour of neighbouring components of the multi-barrier system, e.g. bentonitic or argillaceous backfilling and host rock. Hardened cement paste or Sorel cement are considered to be main sorbing materials present in the near field of repositories for low- and intermediate-level waste (L/ILW). Hence, interactions of radionuclides with cementitious materials represent a very important mechanism retarding their mobility and potential migration from the near field (Wieland, 2014; Ochs et al., 2016). While the quantitative description of the sorption processes (usually in terms of sorption coefficients, i.e. Kd values) is a key input in the safety analysis of nuclear waste repositories, detailed mechanistic analysis and understanding of sorption phenomena provide additional scientific arguments and important process understanding, and thus enhance both the quality of safety arguments and the overall confidence in the safety assessment process. Research at KIT-INE dedicated to the interaction of cementitious materials with radionuclides is conducted in the context of different repository concepts, including clay (low- and high-ionic strength conditions), crystalline rock or rock salt. Experimental and theoretical studies are performed within the framework of national (GRAZ, BMWi) and international (CEBAMA and EURAD-CORI, EU Horizon 2020 Programme) projects, extending to third-party projects with several waste management organizations in Europe, e.g. SKB (Sweden), ONDRAF-NIRAS (Belgium) or BGE (Germany). The combination of classical experimental (wet chemistry) methods, advanced spectroscopic techniques and theoretical calculations provides both an accurate quantitative evaluation and a fundamental understanding of the sorption processes. Examples of recent studies at KIT-INE on radionuclide behaviour in cementitious systems in the context of both L/ILW and HLW will be presented in this contribution to explain methodologies, scientific approaches and results. The present state of knowledge as well as main remaining uncertainties affecting the retention processes of radionuclides in cementitious environments under different conditions will be critically discussed, also in view of current international research activities and repository projects.

scholarly journals Technetium-99m Transport and Immobilisation in Porous Media: Development of a Novel Nuclear Imaging Technique

2013 ◽  
Vol 1518 ◽  
pp. 123-129 ◽  
Author(s):  
Claire L. Corkhill ◽  
Jonathan W. Bridge ◽  
Philip Hillel ◽  
Laura J. Gardner ◽  
Steven A. Banwart ◽  
...  
Keyword(s):  
Nuclear Waste ◽  
Waste Disposal ◽  
Quartz Sand ◽  
Gamma Camera ◽  
Nuclear Imaging ◽  
Nuclear Waste Disposal ◽  
Cementitious Materials ◽  
Near Surface ◽  
Spatial Moments ◽  
Technetium 99M

ABSTRACTTechnetium-99, a β-emitting radioactive fission product of 235U, formed in nuclear reactors, presents a major challenge to nuclear waste disposal strategies. Its long half-life (2.1 x 105 years) and high solubility under oxic conditions as the pertechnetate anion [Tc(VII)O4] is particularly problematic for long-term disposal of radioactive waste in geological repositories. In this study, we demonstrate a novel technique for quantifying the transport and immobilisation of technetium-99m, a γ-emitting metastable isomer of technetium-99 commonly used in medical imaging. A standard medical gamma camera was used for non-invasive quantitative imaging of technetium-99m during co-advection through quartz sand and various cementitious materials commonly used in nuclear waste disposal strategies. Spatial moments analysis of the resulting 99mTc plume provided information about the relative changes in mass distribution of the radionuclide in the various test materials. 99mTc advected through quartz sand demonstrated typical conservative behaviour, while transport through the cementitious materials produced a significant reduction in radionuclide centre of mass transport velocity over time. Gamma camera imaging has proven an effective tool for helping to understand the factors which control the migration of radionuclides for surface, near-surface and deep geological disposal of nuclear waste.

scholarly journals Dissolution of simplified nuclear waste glass and formation of secondary phases

2021 ◽  
Vol 1 ◽  
pp. 143-144
Author(s):  
Felix Brandt ◽  
Martina Klinkenberg ◽  
Sébastien Caes ◽  
Jenna Poonoosamy ◽  
Wouter Van Renterghem ◽  
...  
Keyword(s):  
Dissolution Rate ◽  
Nuclear Waste ◽  
Borosilicate Glass ◽  
Glass Surface ◽  
Cementitious Materials ◽  
Solution Chemistry ◽  
Secondary Phases ◽  
Release Rates ◽  
Glass Dissolution ◽  
Safety Assessments

Abstract. Immobilization of high-level and intermediate-level nuclear wastes by vitrification in borosilicate glass is a well-established process. There is a consensus between the waste management agencies of many countries and many experts that vitrified nuclear waste should be disposed of in a deep geological waste repository and therefore its long-term behavior needs to be taken into account in safety assessments. In contact with water, borosilicate glass is metastable and dissolves. In static dissolution experiments, often a surface alteration layer (SAL) forms on the dissolving glass, and later sometimes secondary phases form. Based on boron or lithium release rates, commonly three stages of glass dissolution are defined as a function of the reaction progress: (I) initial dissolution, described by a congruent glass dissolution at the highest rate, (II) residual dissolution, characterized by a glass dissolution rate several orders of magnitude lower than the initial one, and (III) resumption of glass alteration with initial rates. Microscopically, the formation of a complex SAL has been identified as a prerequisite for the slower dissolution kinetics of stage II. Stage III is typically observed under specific conditions, i.e., high temperature and/or high pH driven by the uptake of Si and Al into secondary phases. Different glass dissolution models explaining the mechanisms of the SAL formation and rate-limiting steps have been proposed and are still under debate. In this article different aspects of glass dissolution from recent studies in the literature and our own work are discussed with a focus on the microscopic aspects of SAL formation, secondary phase formation and the resumption of glass dissolution. Most of the experiments in the literature were performed under near-neutral pH conditions and at 90 ∘C, following standard procedures, to understand the fundamental mechanisms of glass dissolution. The example of interaction of glass and cementitious materials as discussed here is relevant for safety assessments because most international concepts include cement e.g., as lining, for plugs, or as part of the general construction of the repository. The aim of the investigations presented in this paper was to study the combined effect of hyperalkaline conditions and very high surface area/volume ratios (SA/V=264000m-1) on the dissolution of international simplified glass (ISG) and the formation of secondary phases at 70 ∘C in a synthetic young cement water containing Ca (YCWCa). The new results show that the SA/V ratio is a key parameter for the dissolution rate and for the formation of the altered glass surface and secondary phases. A comparison with similar studies in the literature shows that especially on the microscopic and nanoscale, different SA/V ratios lead to different features on the dissolving glass surface, even though the SA-normalized element release rates appear similar. Zeolite and Ca-silicate-hydrate phases (CSH) were identified and play a key role for the evolution of the solution chemistry. A kinetic dissolution model coupled with precipitation of secondary phases can be applied to relate the amount of dissolved glass to the evolution of the solution's pH.

scholarly journals Alteration of vitrified intermediate level nuclear waste in alkaline media: effects of cementitious materials, pH and temperature

RSC Advances ◽  
2018 ◽  
Vol 8 (66) ◽  
pp. 37665-37680 ◽  
Author(s):  
Tomo Suzuki-Muresan ◽  
A. Abdelouas ◽  
C. Landesman ◽  
A. Ait-Chaou ◽  
Y. El Mendili ◽  
...  
Keyword(s):  
Cement Paste ◽  
Nuclear Waste ◽  
Media Effects ◽  
Cementitious Materials ◽  
Intermediate Level ◽  
Alkaline Media ◽  
Hardened Cement ◽  
Hardened Cement Paste

Alteration experiments involving intermediate level nuclear waste (ILW) glass in contact with hardened cement paste (HCP) were performed to assess its behavior under simulated repository conditions.

Ancient Analogues Concerning Stability and Durability of Cementitious Wasteform

1993 ◽  
Vol 333 ◽  
Author(s):  
W. Jiang ◽  
D.M. Roy
Keyword(s):  
Portland Cement ◽  
Nuclear Waste ◽  
Building Materials ◽  
Cementitious Materials ◽  
Acceptable Solution ◽  
Great Pyramid ◽  
History Of ◽  
Ancient Times ◽  
Pozzolanic Cement ◽  
The Ancient Chinese

ABSTRACTThe history of cemenütious materials goes back to ancient times. The Greeks and Romans used calcined limestone and later developed pozzolanic cement by grinding together lime and volcanic ash called “pozzolan” which was first found near Port Pozzuoli, Italy. The ancient Chinese used lime-pozzolanic mixes to build the Great Wall. The ancient Egyptians used calcined impure gypsum to build the Great Pyramid of Cheops. The extraordinary stability and durability of these materials has impressed us, when so much dramatically damaged infrastructure restored by using modern portland cement now requires rebuilding. Stability and durability of cementitious materials have attracted intensive research interest and contractors’ concerns, as does immobilization of radioactive and hazardous industrial waste in cementitious materials. Nuclear waste pollution of the environment and an acceptable solution for waste management and disposal constitute among the most important public concerns. The analogy of ancient cementitious materials to modern Portland cement could give us some clues to study their stability and durability. This present study examines selected results of studies of ancient building materials from France, Italy, China, and Egypt, combined with knowledge obtained from the behavior of modern portland cement to evaluate the potential for stability and durability of such materials in nuclear waste forms.

scholarly journals Special Issue: Materials for Nuclear Waste Immobilization

Materials ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 3611 ◽  
Author(s):  
Hyatt ◽  
Ojovan
Keyword(s):  
Power Generation ◽  
Nuclear Waste ◽  
Nuclear Energy ◽  
Fossil Fuels ◽  
Spent Nuclear Fuel ◽  
Cementitious Materials ◽  
Special Issue ◽  
Waste Immobilization ◽  
Nuclear Waste Immobilization

Nuclear energy is clean, reliable, and competitive with many useful applications, among which power generation is the most important as it can gradually replace fossil fuels and avoid massive pollution of environment. A by-product resulting from utilization of nuclear energy in both power generation and other applications, such as in medicine, industry, agriculture, and research, is nuclear waste. Safe and effective management of nuclear waste is crucial to ensure sustainable utilization of nuclear energy. Nuclear waste must be processed to make it safe for storage, transportation, and final disposal, which includes its conditioning, so it is immobilized and packaged before storage and disposal. Immobilization of waste radionuclides in durable wasteform materials provides the most important barrier to contribute to the overall performance of any storage and/or disposal system. Materials for nuclear waste immobilization are thus at the core of multibarrier systems of isolation of radioactive waste from environment aimed to ensure long term safety of storage and disposal. This Special Issue analyzes the materials currently used as well as novel materials for nuclear waste immobilization, including technological approaches utilized in nuclear waste conditioning pursuing to ensure efficiency and long-term safety of storage and disposal systems. It focuses on advanced cementitious materials, geopolymers, glasses, glass composite materials, and ceramics developed and used in nuclear waste immobilization, with the performance of such materials of utmost importance. The book outlines recent advances in nuclear wasteform materials including glasses, ceramics, cements, and spent nuclear fuel. It focuses on durability aspects and contains data on performance of nuclear wasteforms as well as expected behavior in a disposal environment.

Cementitious Materials for Nuclear Waste Immobilization

2014 ◽  
Author(s):  
Rehab O. Abdel Rahman ◽  
Ravil Z. Rakhimov ◽  
Nailia R. Rakhimova ◽  
Michael I. Ojovan
Keyword(s):  
Nuclear Waste ◽  
Cementitious Materials ◽  
Waste Immobilization ◽  
Nuclear Waste Immobilization

Modeling Geochemical Stability of Cement Formulations for use as Shaft Liner and Sealing Components at Yucca Mountain(1)

1990 ◽  
Vol 212 ◽  
Author(s):  
Mark A. Gardiner ◽  
Thomas E. Hinkebein ◽  
Jonathan Myers
Keyword(s):  
Ground Water ◽  
Nuclear Waste ◽  
Geochemical Modeling ◽  
Cementitious Materials ◽  
Yucca Mountain ◽  
Nuclear Waste Repository ◽  
Preliminary Estimate ◽  
Mountain Site ◽  
Compositional Changes ◽  
Waste Repository

ABSTRACTThe geochemical modeling codes EQ3NR/EQ6 were used to model the interaction of cementitious materials with ground water from the Yucca Mountain proposed nuclear waste repository site in Nevada. This paper presents a preliminary estimate of the compositional changes caused by these interactions in the ground water and in the cement-based compounds proposed for use as sealing and shaft liner materials at the Yucca Mountain site.

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