Identifying and Quantifying Actinide Radiation Damage in Ceramics with Radiological Magic-Angle Spinning Nuclear Magnetic Resonance

Conference · Sun Jul 01 00:00:00 EDT 2007

OSTI ID:21083715

Farnan, Ian ^[1]; Cho, Herman; Weber, William J ^[2]

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1. Earth Sciences, Cambridge University, Cambridge (United Kingdom)
2. EMSL, Pacific Northwest National Laboratory, Mail Stop, P.O. Box 999, Richland, WA 99352 (United States)

In the characterisation of amorphization or local disordering due to actinide radiation damage, nuclear magnetic resonance (NMR) spectroscopy is attractive because it is element specific and equally sensitive to local structure in crystalline and amorphous materials. Here, we have applied high-resolution solid-state NMR spectroscopy (magic-angle spinning) to radiation damaged natural minerals containing {sup 238}U/{sup 232}Th to determine the 'number fraction' of amorphous material (fa) through spin-counting techniques. In samples with a known alpha dose, the number of atoms displaced per alpha decay may be determined from an integration of the spectrum. A protocol for performing similar radiological magic-angle spinning experiments on plutonium containing ceramic samples with an activity of > 5 GBq is described. Results obtained have allowed data from ancient, radiation damaged mineral samples of ZrSiO{sub 4} ({sup 238}U/{sup 232}Th) to be compared with modern {sup 238}/{sup 239}Pu doped ceramic ZrSiO{sub 4} samples. The number of atomic displacements per alpha particle from {sup 239}Pu is similar to that for {sup 238}U/{sup 232}Th (4980 {+-} 300/{alpha}). At lower {alpha}-doses there are significant differences in the amorphous volume fraction (observed by density and X-ray diffraction) and the number fraction of displaced atoms (as measured by NMR) as a function of cumulative dose. These differences arise from local density considerations that manifest themselves in the local structure of the amorphous and crystalline phases. Using ab initio simulations of the damaged crystalline and amorphous regions, the magnetic response of these structures and hence the NMR shifts can be compared with experiment to reveal the nature of radiation induced changes occurring at the local scale. (authors)

• Research Organization: Materials Research Society, 506 Keystone Drive, Warrendale, PA, 15086-7573 (United States)
• OSTI ID: 21083715
• Resource Relation: Conference: Symposium Actinides 2006 - Basic Science, Applications and Technology, Boston, MA (United States), 26-30 Nov 2006; Other Information: Country of input: France; Related Information: In: Proceedings of the symposium Actinides 2006 - Basic Science, Applications and Technology, by Blobaum, Kerri J.M. [ed. CMS, Lawrence Livermore National Laboratory, Livermore, California (United States)]; Chandler, Elaine A. [ed. Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)]; Havela, Ladislav [ed. Faculty of Mathematics and Physics, Charles University, Prague (Czech Republic)]; Maple, M. Brian [ed. University of California, San Diego, La Jolla, California (United States)]; Neu, Mary P. [ed. Los Alamos National Laboratory, Los Alamos NM (United States)], v. 986, 209 pages.
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALPHA DECAY
ALPHA PARTICLES
AMORPHOUS STATE
ATOMIC DISPLACEMENTS
CERAMICS
COUNTING TECHNIQUES
DOPED MATERIALS
NUCLEAR MAGNETIC RESONANCE
PLUTONIUM 238
PLUTONIUM 239
RADIATION DOSES
SIMULATION
SPECTRA
SPECTROSCOPY
SPIN
THORIUM 232
URANIUM 238
X-RAY DIFFRACTION
ZIRCONIUM SILICATES