Understanding Radionuclide Interactions with Cementitious Materials for Radioactive Waste Management - 18298
- NucleUS Immobilisation Science Laboratory, Department of Materials Science and Engineering, University of Sheffield (United Kingdom)
In the UK, ILW is currently managed using cementitious encapsulation in Portland cement (PC)-based grouts. The long-term behaviour of radionuclides in ILW cementitious waste-forms under varying local conditions of extended interim storage and geological disposal is not well understood and the behaviour of cement minerals in the retention of various radionuclides is poorly constrained. This work focuses on the Ca-Si-[Al,Mg,S] mineral system and how this may evolve with the introduction of radionuclides into the system. Here, we discuss the experimental program aimed at underpinning the uptake and retention mechanisms of a range of key radionuclides (U, Tc, Ce/Pu), with selected cement phases: calcium-silicate-hydrate (C-S-H), hydrotalcite (Mg{sub 6}Al{sub 2}CO{sub 3}(OH)16.4H{sub 2}O) and ettringite (Ca{sub 6}(Al{sub 2}O{sub 6})(SO{sub 4}){sub 3}.32H{sub 2}O). Described here is the syntheses of C-S-H and radionuclide incorporation experiments performed on this phase. Further to this, thermodynamic geochemical modelling has been adopted to explore the Ca-Si-U mineral system, aimed at identifying the mineral phases likely to form on contact of C-S-H phases with aqueous uranium, as a function of pH. (authors)
- Research Organization:
- WM Symposia, Inc., PO Box 27646, 85285-7646 Tempe, AZ (United States)
- OSTI ID:
- 22975442
- Report Number(s):
- INIS-US-20-WM-18298; TRN: US21V0256015484
- Resource Relation:
- Conference: WM2018: 44. Annual Waste Management Conference, Phoenix, AZ (United States), 18-22 Mar 2018; Other Information: Country of input: France; 6 refs.; Available online at: https://www.xcdsystem.com/wmsym/2018/index.html
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
38 RADIATION CHEMISTRY
RADIOCHEMISTRY AND NUCLEAR CHEMISTRY
AQUEOUS SOLUTIONS
CALCITE
CALCIUM SILICATES
CEMENTITE
CESIUM
ENCAPSULATION
GEOCHEMISTRY
GROUTING
INTERACTIONS
INTERMEDIATE-LEVEL RADIOACTIVE WASTES
PH VALUE
PLUTONIUM
PORTLAND CEMENT
RADIOACTIVE WASTE DISPOSAL
RADIOACTIVE WASTE STORAGE
RADIOISOTOPES
TECHNETIUM
UNDERGROUND DISPOSAL
UNITED KINGDOM
URANIUM