IDENTIFYING AND QUANTIFYING ACTINIDE RADIATION DAMAGE IN ZrSiO4 MINERALS AND CERAMICS WITH NUCLEAR MAGNETIC RESONANCE
This paper discusses how high-resolution solid-state nuclear magnetic resonance (NMR) can be used to characterise and quantify radiation damage in natural minerals and ceramic nuclear waste forms that contain actinides. The scientific goal is to identify the nature of the amorphous component of the radiation damaged material through similar approaches to those where NMR has been used to study glasses and amorphous materials1. NMR also allows the amount of amorphous material to be quantified as an atomic number fraction of the total. This is in contrast to traditional methods that express the damaged amorphous component as volume fractions of the total. Very old mineral samples of ZrSiO4 (zircon) containing 238U and 232Th with varying alpha radiation doses can be used to provide samples with differing levels of radiation damage2,3. Radiation damage due to the emission of an alpha particle by an actinide nucleus is believed to occur through two distinct processes4. The alpha particle itself (4.5 – 5.5 MeV), will mainly cause ionisations during its flight through a material, it is also thought to cause a few hundred atomic displacements (Frenkel defects) as it is stopped by collision with atomic nuclei. The recoil of the heavy actinide nucleus (70 -100 keV) is believed to cause the majority of the localised structural damage (amorphisation) as it creates a cascade of collisions with surrounding ions. The extent and nature of this ‘displacement cascade’ is the subject of extensive modelling by both ballistic5,6 and increasingly molecular dynamics7-15 methods. There is a profound need for experimental data to distinguish between these models.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 896075
- Report Number(s):
- PNNL-SA-45788; 1864; KP1301020; TRN: US0700861
- Resource Relation:
- Conference: Proceedings of the Eighth Actinides Conference, Actinides 2005, 4-8 July 2005, University of Manchester, UK. Published in Recent Advances in Actinide Science, 305-310
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ACTINIDES
ALPHA PARTICLES
ATOMIC DISPLACEMENTS
ATOMIC NUMBER
CERAMICS
DEFECTS
MOLECULAR DYNAMICS METHOD
NUCLEAR MAGNETIC RESONANCE
NUCLEI
RADIATION DOSES
RADIATIONS
RADIOACTIVE WASTES
SIMULATION
ZIRCON
Environmental Molecular Sciences Laboratory