scholarly journals The Assessment of Barrier Characteristic for Cementitious Materials in the Disposal of Radioactive Waste

1997 ◽  
Vol 4 (1) ◽  
pp. 29-38
Author(s):  
Michihiro Hironaga
Keyword(s):  
Radioactive Waste ◽  
Cementitious Materials ◽  
Barrier Characteristic

Development of Superfine Spherical Silica Grout as an Alternative Grouting Material for the Geological Disposal of Long-Lived Radioactive Waste

2010 ◽  
Author(s):  
Morimasa Naito ◽  
Hirokazu Kishi ◽  
Naomi Fukuoka ◽  
Tsutomu Yamada ◽  
Hideaki Ishida
Keyword(s):  
Radioactive Waste ◽  
Calcium Hydroxide ◽  
Cementitious Materials ◽  
Geological Disposal ◽  
Grouting Material ◽  
Spherical Silica ◽  
Geological Repository ◽  
Binder Ratio ◽  
Grouting Materials ◽  
Term Performance

As an alternative grouting material for the geological repository of long-lived radioactive waste, the “Superfine Spherical silica Grout” (SFSG) material is developed using a fine spherical silica and a fine calcium hydroxide. The developed SFSG material takes an advantage of its smaller particle size distribution (max. ∼1 micron or less) than those of the cementitious materials, and also provides a low alkaline environment so as to reduce unfavorable effects on the long-term performance of geological disposal system. The SFSG is a mixture of the “super fine silica powder”, the superfine calcium hydroxide and additives such as superplasticizer. Presently, the mixture being investigated for grouting materials is focused on water/binder ratio (W/B) of 1.2. Some preliminary laboratory experiments were carried out to characterize its fundamental properties from the viewpoint of practical use for geological disposal, which is required to be equivalent with the conventional cementitious materials in terms of penetrability, strength, pH performance and workability. From a series of experiments, it was concluded that SFSG is expected to become an alternative grouting material for a geological repository.

An overview of research activities on cementitious materials for radioactive waste management

2012 ◽  
Vol 1475 ◽  
Author(s):  
Zoran Drace ◽  
Irena Mele ◽  
Michael I. Ojovan ◽  
R. O. Abdel Rahman
Keyword(s):  
Radioactive Waste ◽  
Waste Management ◽  
Nuclear Power ◽  
Power Plants ◽  
Management Practices ◽  
Fuel Cycle ◽  
Large Body ◽  
Cementitious Materials ◽  
Radioactive Waste Management ◽  
Research Activities

ABSTRACTAn overview is given on research activities on cementitious materials for radioactive waste management systems based on the IAEA Coordinated Research Project (CRP) held in 2007-2010. It has been joined by 26 research organizations from 22 countries which shared their research and practical activities on use of cementitious materials for various barrier purposes. The CRP has initially formulated the research topics considered within four specific streams: A) Conventional cementitious systems; B) Novel cementitious materials and technologies; C) Testing and waste acceptance criteria; and D) Modelling long term behaviour.The CRP has analysed both barrier functions and interactions envisaged between various components with focus on predisposal stage of waste management. Cementation processes have achieved a high degree of acceptance and many processes are now regarded as technically mature. A large body of information is currently available on proven waste conditioning technologies although novel approaches are continuing to be devised.Most of the existing technologies have been developed for conditioning of large amounts of operational radioactive waste from nuclear power plants and other nuclear fuel cycle facilities. However new waste streams including those resulting from legacy and decommissioning activities required improved material performance and technologies.The most important outcome of CRP was the exchange of information and research co-operation between different institutions and has contributed towards general enhancement of safety by improving waste management practices and their efficiency. The paper presents the most important results and trends revealed by CRP participants. The research contributions of participating organizations will be published as country contributions in a forthcoming IAEA technical publication.

Cementitious Materials for Radioactive Waste Management Within IAEA Coordinated Research Project

2011 ◽  
Author(s):  
Zoran Drace ◽  
Michael I. Ojovan
Keyword(s):  
Radioactive Waste ◽  
Waste Management ◽  
Cementitious Materials ◽  
Radioactive Waste Management ◽  
Long Term Storage ◽  
Waste Immobilization ◽  
Materials Used ◽  
Cementitious Systems ◽  
Term Storage

The IAEA Coordinated Research Project (CRP) on cementitious materials for radioactive waste management was launched in 2007 [1, 2]. The objective of CRP was to investigate the behaviour and performance of cementitious materials used in radioactive waste management system with various purposes and included waste packages, wasteforms and backfills as well as investigation of interactions and interdependencies of these individual elements during long term storage and disposal. The specific research topics considered were: (i) cementitious materials for radioactive waste packaging: including radioactive waste immobilization into a solid waste form, (ii) waste backfilling and containers; (iii) emerging and alternative cementitious systems; (iv) physical-chemical processes occurring during the hydration and ageing of cement matrices and their influence on the cement matrix quality; (v) methods of production of cementitious materials for: immobilization into wasteform, backfills and containers; (vi) conditions envisaged in the disposal environment for packages (physical and chemical conditions, temperature variations, groundwater, radiation fields); (vii) testing and nondestructive monitoring techniques for quality assurance of cementitious materials; (viii) waste acceptance criteria for waste packages, waste forms and backfills; transport, long term storage and disposal requirements; and finally (ix) modelling or simulation of long term behaviours of cementations materials used for packaging, waste immobilization and backfilling, especially in the post-closure phase. The CRP has gathered overall 26 research organizations from 22 Member States aiming to share their research and practices on the use of cementitious materials [2]. The main research outcomes of the CRP were summarized in a summary report currently under preparation to be published by IAEA. The generic topical sections covered by report are: a) conventional cementitious systems; b) novel cementitious materials and technologies; c) testing and waste acceptance criteria; and d) modelling long term behaviour. These themes as well as all contributions of participating organizations were further developed in the individual reports to be presented in the IAEA publication. The CRP facilitated the exchange of information and research co-operation in resolving similar problems between different institutions and contributed towards improving waste management practices, their efficiency and general enhancement of safety.

Towards a scientific-based assessment of long-term durability and performance of cementitious materials for radioactive waste conditioning and disposal

2021 ◽  
Vol 557 ◽  
pp. 153201
Author(s):  
Diederik Jacques ◽  
Quoc Tri Phung ◽  
Janez Perko ◽  
Suresh C. Seetharam ◽  
Norbert Maes ◽  
...  
Keyword(s):  
Radioactive Waste ◽  
Cementitious Materials ◽  
And Performance

Key Issues Identified From Project TRU-2 on the Generic Co-Location Concept of Transuranic (TRU) Waste and High-Level Radioactive Waste (HLW) Repositories in Japan

2007 ◽  
Author(s):  
Andrew J. Martin ◽  
Shigeki Kuroda ◽  
Keiji Morimoto ◽  
Gento Kamei ◽  
Masao Shiotsuki
Keyword(s):  
Radioactive Waste ◽  
Cementitious Materials ◽  
Separation Distance ◽  
Energy Agency ◽  
High Level Radioactive Waste ◽  
Key Issues ◽  
Single Complex ◽  
Materials Used ◽  
High Level ◽  
Reciprocal Influences

The Federation of the Electric Power Companies of Japan (FEPC) and the Japan Atomic Energy Agency (JAEA) have been collaborating with relevant organisations to promote the safe geological disposal of transuranic (TRU) waste following the already established disposal policy for high-level radioactive waste (HLW) in Japan. A result of this intensive collaborative effort was the production of a recent progress report (TRU-2) which describes the generic R&D for TRU-waste disposal in Japan. In order to improve feasibility and reduce costs and the burden on siting, the concept of co-locating TRU-waste and HLW repositories in a single complex was assessed in detail and compared with the results from several other countries that have also looked at co-location disposal. Heat from HLW, high pH plume(s) from the large amounts of cementitious materials used in the engineered barrier system (EBS) of TRU waste, and nitrates and organic materials in certain types of TRU waste were identified as critical reciprocal influences that might degrade the performance of the TRU/HLW co-location disposal system over the long-term. It was shown that these reciprocal influences could be avoided by establishing a separation distance between the two repositories of approximately 300 meters.

scholarly journals Spectroscopic evaluation of UVI–cement mineral interactions: ettringite and hydrotalcite

2022 ◽  
Vol 29 (1) ◽  
Author(s):  
Antonia S. Yorkshire ◽  
Martin C. Stennett ◽  
Brant Walkley ◽  
Sarah E. O'Sullivan ◽  
Lucy M. Mottram ◽  
...  
Keyword(s):  
Radioactive Waste ◽  
Secondary Phase ◽  
Cementitious Materials ◽  
Magic Angle Spinning ◽  
Supplementary Cementitious Materials ◽  
Magic Angle ◽  
Coordination Environment ◽  
X Ray ◽  
Uranyl Carbonate ◽  
Angle Spinning

Portland cement based grouts used for radioactive waste immobilization contain high replacement levels of supplementary cementitious materials, including blast-furnace slag and fly ash. The minerals formed upon hydration of these cements may have capacity for binding actinide elements present in radioactive waste. In this work, the minerals ettringite (Ca6Al2(SO4)3(OH)12·26H2O) and hydrotalcite (Mg6Al2(OH)16CO3·4H2O) were selected to investigate the importance of minor cement hydrate phases in sequestering and immobilizing UVI from radioactive waste streams. U L III-edge X-ray absorption spectroscopy (XAS) was used to probe the UVI coordination environment in contact with these minerals. For the first time, solid-state 27Al magic angle spinning nuclear magnetic resonance (MAS-NMR) spectroscopy was applied to probe the Al coordination environment in these UVI-contacted minerals and make inferences on the UVI coordination, in conjunction with the X-ray spectroscopy analyses. The U L III-edge XAS analysis of the UVI-contacted ettringite phases found them to be similar (>∼70%) to the uranyl oxyhydroxides present in a mixed becquerelite/metaschoepite mineral. Fitting of the EXAFS region, in combination with 27Al NMR analysis, indicated that a disordered Ca- or Al-bearing UVI secondary phase also formed. For the UVI-contacted hydrotalcite phases, the XAS and 27Al NMR data were interpreted as being similar to uranyl carbonate, that was likely Mg-containing.

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