https://faculty.uml.edu/david_ryan/84.653/Course%20Material/lecture20/MarineSnowGels.pdf

The oceanic gel phase: a bridge in the DOM-POM continuum

Sorption of actinides, particularly plutonium, onto submicrometer-sized colloids increases their mobility, but these plutonium colloids are difficult to detect in the far-field. We identified actinides on colloids in the groundwater from the Mayak Production Association, Urals, Russia; at the source, the plutonium activity is ∼1000 becquerels per liter. Plutonium activities are still 0.16 becquerels per liter at a distance of 3 kilometers, where 70 to 90 mole percent of the plutonium is sorbed onto colloids, confirming that colloids are responsible for the long-distance transport of plutonium. Nano–secondary ion mass spectrometry elemental maps reveal that amorphous iron oxide colloids adsorb Pu(IV) hydroxides or carbonates along with uranium carbonates.

https://science.sciencemag.org/content/sci/314/5799/638.full.pdf

Colloid transport of plutonium in the far-field of the Mayak Production Association, Russia.

Colloid analysis by single particle inductively coupled plasma-mass spectroscopy: a feasibility study

Gold colloid analysis by inductively coupled plasma-mass spectrometry in a single particle mode

The disposal of fission products and actinides generated by the nuclear-fuel cycle is one of the major challenges in Environmental Sciences of the 21 st Century. Because some fission products (e.g., 99 Tc, 129 I, 79 Se and 135 Cs) and actinides (e.g., 239 Pu and 237 Np) are long-lived, they have a major impact on the risk assessment of geological repositories. Thus, demonstrable long-term chemical and mechanical durability are essential properties of waste forms for the immobilization and disposal of radionuclides. Mineralogical and geological studies provide excellent candidate phases for immobilization and a unique database that cannot be duplicated by a purely Materials Science approach. The “mineralogical approach” is illustrated by a discussion of zircon as a phase for the immobilization of plutonium from dismantled nuclear weapons. Other minerals, e.g., monazite, apatite, pyrochlore, zirconolite and zeolites, also are important candidates for the immobilization of actinides.

The design and evaluation of nuclear-waste forms: clues from mineralogy

Groundwater colloid properties: a global approach

Laser-induced Photoacoustic Spectroscopy (LPAS) is a new elegant instrumentation for the chemical speciation of aquatic transuranium (TRU) ions in very dilute concentrations (> 10−8 mol L−1). The aim of this paper is to review the application of LPAS to the study of the chemical behaviour of TRU ions in natural aquatic systems, the knowledge of which has become increasingly in demand in connection with the safety analysis of nuclear waste disposal in the geosphere. The first part of the paper describes the principle, instrumentation and characteristics of LPAS in aqueous solution, taking particular examples from our own experience. The theoretical estimation of the speciation sensitivity is demonstrated and the result is compared with experiment. The second part deals with the spectral work in aqueous solution and then with the application of LPAS for the speciation of TRU ions in groundwater. Some examples demonstrated are hydrolysis reaction, complexation and colloid generation of the Am3+ ion. Speciation sensitivities of U, Np, Pu and Am of different oxidation states in a variety of aqueous solutions are summarized. The present review is so oriented that the expected readers will appreciate the introductory understanding of the LPAS method and its potential applicability in the aquatic chemistry of TRU ions. The application is of course open to a broad field of microchemistry in which the conventional spectrophotometric method has difficulty with sensitivity.

Laser-induced Photoacoustic Spectroscopy for the Speciation of Transuranic Elements in Natural Aquatic Systems

Laser-Induced Photoacoustic Spectroscopy for the Speciation of Transuranic Elements in Natural Aquatic Systems

Laser-induced Photoacoustic Spectroscopy (LPAS) is developed for the direct speciation of actinides in aquatic solutions. The speciation sensitivity is attained in the submicromol range, e.g. Ami3+ (e = 400 L mol−1cm−1 down to 10−8 mol L−1, or ppb. The method provides spectroscopic information of chemical states of actinides and hence facilitates the study of their hydrolysis-reaction, complexation, redox-reaction and colloid generation. The application of LPAS is demonstrated for the speciation of Am and Pu ions in different solutions.

Jae-Il Kim

Papers

Groundwater colloid properties: a global approach

Laser-induced Photoacoustic Spectroscopy for the Speciation of Transuranic Elements in Natural Aquatic Systems

Laser-Induced Photoacoustic Spectroscopy for the Speciation of Transuranic Elements in Natural Aquatic Systems

Laser-Induced Photoacoustic Spectroscopy for the Speciation of Actinides in Submicromol Concentrations