Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Experiment Videos

Evolution of technetium speciation in reducing grout.

Wayne W Lukens1, Jerome I Bucher, David K Shuh

  • 1Actinide Chemistry Group, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA. wwlukens@lbl.gov

Environmental Science & Technology
|November 22, 2005
PubMed
Summary
This summary is machine-generated.

Related Concept Videos

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Spectroscopic Characterization of Tetravalent Berkelium.

Angewandte Chemie (International ed. in English)·2026
Same author

Direct identification of Ac and No molecules with an atom-at-a-time technique.

Nature·2025
Same author

Atom-at-a-Time Radioactive Molecule Identification: Looking toward Studies of Superheavy Elements.

The journal of physical chemistry. A·2025
Same author

Berkelium-carbon bonding in a tetravalent berkelocene.

Science (New York, N.Y.)·2025
Same author

A fully contained sample holder capable of electron-yield detection at soft X-ray energies.

Journal of synchrotron radiation·2024
Same author

Revisiting the Optical Spectrum of the Plutonyl Ion (PuO<sub>2</sub>)<sup>2+</sup> in 1 M HClO<sub>4</sub>.

The journal of physical chemistry. A·2024
Same journal

Occurrence, Sources, and Export Rates of Ti-Bearing and Ce-Bearing (Nano)particles in the Seine River Where Engineered Nanoparticles Reach Natural Background Levels.

Environmental science & technology·2026
Same journal

Simulation-Guided Optimization of NH<sub>3</sub>/H<sub>2</sub> Cocombustion over a CuO Catalyst: Achieving High-Efficiency and near-Zero NO<sub><i>x</i></sub> Emissions.

Environmental science & technology·2026
Same journal

Heating-Induced Redistribution and Isotopic Fractionation of Soil Organic Carbon Among Density Fractions.

Environmental science & technology·2026
Same journal

High-Resolution Molecular Analyses Reveal Non-additive Impacts of Chronic Warming and Nitrogen Addition on Soil-Derived Dissolved Organic Matter.

Environmental science & technology·2026
Same journal

Distinct Source-Sink Patterns and Vertical Consumption of Alkyl and Aryl Organophosphate Esters in the Remote Ocean and Its Marginal Sea.

Environmental science & technology·2026
Same journal

Self-Regenerating PFOA Defluorination in Groundwater via Endogenous Electron Feedback in Biomimetic Molecular Trap.

Environmental science & technology·2026
See all related articles

Cementitious waste forms (CWFs) stabilize nuclear waste by reducing mobile technetium (TcO4-) to immobile Tc(IV). However, Tc(IV) can oxidize back to TcO4-, especially in the presence of nitrate, impacting long-term waste stability.

Area of Science:

  • Nuclear Waste Management
  • Materials Science
  • Environmental Chemistry

Background:

  • Cementitious waste forms (CWFs) are crucial for stabilizing U.S. Department of Energy nuclear waste.
  • Technetium-99 (99Tc) as pertechnetate (TcO4-) is mobile and soluble in aerobic environments.
  • Reducing TcO4- to immobile Tc(IV) species enhances 99Tc stabilization in CWFs.

Purpose of the Study:

  • To investigate the oxidation of Tc(IV) species in reducing grout samples.
  • To determine if nitrate (NO3-) or atmospheric oxygen (O2) is the primary oxidizer of Tc(IV).
  • To assess the long-term stability of reduced technetium in simulated CWFs.

Main Methods:

  • Preparation of two series of reducing grouts with and without NO3- in TcO4- containing waste simulants.

Related Experiment Videos

  • Characterization of technetium species using extended X-ray absorption fine structure (EXAFS) spectroscopy.
  • Long-term monitoring of technetium oxidation in permeable (polystyrene) and impermeable (poly-(methyl methacrylate)) sample cuvettes.

    • Main Results:

    • In permeable samples, Tc(IV) sulfide (TcSx) was steadily oxidized over 4 years.
    • In impermeable samples, TcO4- continued to be reduced, but lower-valent technetium rapidly oxidized to TcO4- upon exposure to atmosphere.
    • Nitrate presence was found to be a significant factor in Tc(IV) oxidation.

    Conclusions:

    • Nitrate in waste simulants can accelerate the oxidation of immobilized Tc(IV) in CWFs.
    • Atmospheric oxygen poses a lesser concern for Tc(IV) oxidation in reducing CWFs due to slow diffusion.
    • Understanding these oxidation pathways is critical for ensuring the long-term efficacy of CWFs in nuclear waste stabilization.