Self-Irradiation of Ceramics and Single Crystals Doped With Pu-238: Summary of 5 Years of Research of the V. G. Khlopin Radium Institute

2008 ◽  
Vol 1107 ◽  
Author(s):  
Boris E. Burakov ◽  
Maria A. Yagovkina ◽  
Maria V. Zamoryanskaya ◽  
Vladimir M. Garbuzov ◽  
Vladimir A. Zirlin ◽  
...  
Keyword(s):  
Single Crystal ◽  
Radiation Damage ◽  
Single Crystals ◽  
Cumulative Dose ◽  
Crack Formation ◽  
Tetragonal Zirconia ◽  
Alpha Decay ◽  
Chemical Durability ◽  
Radium Institute ◽  
Cubic Zirconia

AbstractTo investigate the resistance of actinide host phases to accelerated radiation damage, which simulates radiation induced effects of long term storage, the following samples doped with plutonium-238 (from 2 to 10 wt. %) have been repeatedly studied using XRD and other methods: cubic zirconia, Zr0.79Gd0.14Pu0.07O1.99; monazite, (La,Pu)PO4; ceramic based on Pu-phosphate of monazite structure, PuPO4; ceramic based on zircon, (Zr,Pu)SiO4, and minor phase tetragonal zirconia, (Zr,Pu)O2; single crystal zircon, (Zr,Pu)SiO4; single crystal monazite, (Eu,Pu)PO4; ceramic based on Ti-pyrochlore, (Ca,Gd,Hf,Pu,U)2Ti2O7. No change of phase composition, matrix swelling, or cracking in cubic zirconia were observed after cumulative dose 2.77×1025 alpha decay/m3. The La-monazite remained crystalline at cumulative dose 1.19×1025 alpha decay/m3, although Pu-phosphate of monazite structure became nearly amorphous at relatively low dose 4.2×1024 alpha decay/m3. Zircon has lost crystalline structures under self-irradiation at dose (1.3-1.5)×1025 alpha decay/m3, however, amorphous zircon characterized with high chemical durability. The Ti-pyrochlore after cumulative dose (1.1-1.3)×1025 alpha decay/m3 became amorphous and lost chemical durability. Radiation damage caused crack formation in zircon single crystals but not in the matrix of polycrystalline zircon. Essential swelling and crack formation as a result of radiation damage were observed in ceramics based on Ti-pyrochlore and Pu-phosphate of monazite structure, but not so far in La-monazite doped with 238Pu.

Self-Irradiation of Monazite Ceramics: Contrasting Behavior of PuPO4 and (La,Pu)PO4 Doped with Pu-238

2004 ◽  
Vol 824 ◽  
Author(s):  
Boris E. Burakov ◽  
Maria A. Yagovkina ◽  
Vladimir M. Garbuzov ◽  
Alexander A. Kitsay ◽  
Vladimir A. Zirlin
Keyword(s):  
Radiation Damage ◽  
Crack Formation ◽  
Alpha Decay ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
Deep Blue ◽  
Long Term Storage ◽  
First Time ◽  
Term Storage

AbstractTo investigate the behavior of monazite during accelerated radiation damage, which simulates effects of long term storage, 238Pu-doped polycrystalline samples of (La,Pu)PO4 and PuPO4 were synthesized for the first time ever and studied using powder X-ray diffraction (XRD) analysis and optical microscopy. The starting precursor materials were obtained by precipitation of La and (or) Pu from their aqueous nitrate solutions followed by calcination in air at 700°C for 1 hour, cold pressing, and sintering in air at 1200-1250°C for 2 hours. The 238Pu contents in ceramic samples measured using gamma spectrometry were (in wt.% el.): 8.1 for (La,Pu)PO4 and 7.2 for PuPO4. The (La,Pu)PO4 monazite remained crystalline at ambient temperature up to a cumulative dose of 1.19 × 1025 alpha decays/m3. In contrast, the PuPO4 monazite became nearly completely amorphous at a relatively low dose of 4.2 × 1024 alpha decays/m3. Swelling and crack formation due to the alpha decay damage was observed in the PuPO4 ceramic. Also, under self-irradiation this sample completely changed color from initial deep blue to black. The (La,Pu)PO4 monazite was characterized by a similar change in color from initial light blue to gray, however, no swelling or crack formation have so far been observed. The results of this study allow us to conclude that the radiation damage behavior of monazite strictly depends on the chemical composition. The justification of monazite-based ceramics as actinide waste forms requires additional investigation.

Performance Assessment of Zircon as a Waste Form for Excess Weapons Plutonium Under Deep Borehole Burial Conditions

1995 ◽  
Vol 412 ◽  
Author(s):  
W. J. Weber ◽  
R. C. Ewing ◽  
W. Lutze
Keyword(s):  
Performance Assessment ◽  
Radiation Damage ◽  
Alpha Decay ◽  
Chemical Durability ◽  
Waste Form ◽  
Accessory Mineral ◽  
Deep Borehole ◽  
Waste Forms ◽  
Weapons Grade Plutonium ◽  
Precambrian Terranes

AbstractZircon (ZrSiO4) is proposed as a waste form for excess weapons-grade plutonium. Zircon is an extremely durable ceramic that is often found as an accessory mineral in Precambrian terranes with ages up to 4 billion years. The chemical durability of zircon in groundwater far exceeds that of other waste forms, as modeled leach rates may be as low as 10-11g/m2d. At least 10 wt% Pu can substitute for Zr in zircon. Self-radiation damage from alpha decay leads to a crystalline-to-amorphous transformation that is modeled as a function of time and temperature for deep borehole conditions. Based on the results of this assessment, zircon could meet all necessary durability and criticality criteria required for a Pu waste form. The types of data used in this analysis are generally not available for other crystalline ceramics or glasses.

Radiation damage in ion-irradiated yttria-stabilized cubic zirconia single crystals

2003 ◽  
Vol 24 (1) ◽  
pp. 37-48 ◽  
Author(s):  
L. Thomé ◽  
J. Fradin ◽  
J. Jagielski ◽  
A. Gentils ◽  
S. E. Enescu ◽  
...  
Keyword(s):  
Radiation Damage ◽  
Single Crystals ◽  
Cubic Zirconia

Characterisation of Thin Film and Single-Crystal CVD Diamond by Absorption and Luminescence Spectroscopy

1989 ◽  
Vol 162 ◽  
Author(s):  
A. T. Collins ◽  
M. Kamo ◽  
Y. Sato
Keyword(s):  
Thin Film ◽  
Single Crystal ◽  
Radiation Damage ◽  
Single Crystals ◽  
Chemical Vapour Deposition ◽  
Vapour Deposition ◽  
Chemical Vapour ◽  
Cvd Diamond ◽  
Luminescence Spectroscopy ◽  
Cathodoluminescence Spectroscopy

ABSTRACTPolycrystalline films and single crystals of diamond produced by microwaveassisted chemical vapour deposition (CVD) have been examined using absorption and cathodoluminescence spectroscopy. Measurements have been carried out on material as-grown, and after radiation damage by 2 MeV electrons.

Synthesis of Actinide-Doped Ceramics: from Laboratory Experiments to Industrial Scale Technology

2003 ◽  
Vol 807 ◽  
Author(s):  
Alexander A. Kitsay ◽  
Vladimir M. Garbuzov ◽  
Boris E. Burakov
Keyword(s):  
Single Crystals ◽  
Laboratory Experiments ◽  
Industrial Scale ◽  
Synthesis Methods ◽  
Special Equipment ◽  
Radium Institute ◽  
Cubic Zirconia ◽  
Ceramic Pellet ◽  
Ceramic Synthesis ◽  
No Release

ABSTRACTThe experience of the Laboratory of Applied Mineralogy and Radiogeochemistry of the V.G.Khlopin Radium Institute on synthesis of Pu-Am-doped ceramics is summarized. During the last 5 years, dozens of actinide doped polycrystalline samples and single crystals have been successfully synthesized such as zircon, hafnon, cubic zirconia, monazite, Ti-pyrochlore, perovskite and garnet. Actinide loading has been varied as follows:-239Pu - from 5–6 wt.% in zircon (polycrystalline and single crystals), hafnon, garnet and perovskite to 10 wt.% in Ti-pyrochlore and up to 37 wt.% in zirconia;- 238Pu - from 2.5 wt.% in zircon single crystals to 5 wt. % in polycrystalline zircon and 10 wt.% in monazite and cubic zirconia;- 243Am - 20–23 wt.% in cubic zirconia and monazite.The weight of each single ceramic pellet varied from 0.2 to 2.0 grams. Special furnaces developed in KRI for ceramic synthesis allowed obtaining up to 7 ceramic pellets simultaneously during the same experiment. The highest amounts of actinides used under glove-box conditions in the same experiment were: 1.5–2.0 g for 239Pu, 0.6 g for 238Pu and 0.3 g for 243Am. Most experiments on synthesis of ceramics and single crystals doped with 239Pu, 238Pu and 243Am carried out at the KRI did not lead to contamination of internal walls of glove boxes. No release of Pu-Am-aerosols was observed as a result of sintering or melting at 1300–1600°C. These results allowed us to conclude that at the present the KRI has developed the experimental basis for transferring laboratory innovations to the industry of actinide immobilization. It is important that adopting ceramic synthesis methods at industrial scale does not require development of new special equipment.

The observation of defects on (100) CdTe surfaces by chemical etching

1992 ◽  
Vol 50 (2) ◽  
pp. 1424-1425
Author(s):  
M.E. Lee
Keyword(s):  
Single Crystal ◽  
Grain Boundaries ◽  
Single Crystals ◽  
Chemical Etching ◽  
Crystalline Perfection ◽  
Crystalline Defects ◽  
High Incidence ◽  
Crystallographic Defects ◽  
Cdznte Substrates ◽  
Device Technology

The crystalline perfection of bulk CdTe substrates plays an important role in their use in infrared device technology. The application of chemical etchants to determine crystal polarity or the density and distribution of crystallographic defects in (100) CdTe is not well understood. The lack of data on (100) CdTe surfaces is a result of the apparent difficulty in growing (100) CdTe single crystal substrates which is caused by a high incidence of twinning. Many etchants have been reported to predict polarity on one or both (111) CdTe planes but are considered to be unsuitable as defect etchants. An etchant reported recently has been considered to be a true defect etchant for CdTe, MCT and CdZnTe substrates. This etchant has been reported to reveal crystalline defects such as dislocations, grain boundaries and inclusions in (110) and (111) CdTe. In this study the effect of this new etchant on (100) CdTe surfaces is investigated.The single crystals used in this study were (100) CdTe as-cut slices (1mm thickness) from Bridgman-grown ingots.

Mounting an individual submicrometer sized single crystal

1996 ◽  
Vol 211 (6) ◽  
Author(s):  
R. B. Neder ◽  
M. Burghammer ◽  
Th. Grasl ◽  
H. Schulz
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Single Crystal ◽  
Single Crystals ◽  
High Vacuum ◽  
Nanometer Resolution ◽  
Micro Manipulator ◽  
Scanning Electron

AbstractWe developed a new micro manipulator for mounting individual sub-micrometer sized single crystals within a scanning electron microscope. The translations are realized via a commercially available piezomicroscope, adapted for high vacuum usage and realize nanometer resolution. With this novel instrument it is routinely possible to mount individual single crystals with sizes down to 0.1

Study of potential oscillations during reaction of an aluminium single crystal with an aqueous KOH solution

1990 ◽  
Vol 55 (2) ◽  
pp. 345-353 ◽  
Author(s):  
Ivan Halaša ◽  
Milica Miadoková
Keyword(s):  
Aqueous Solutions ◽  
Single Crystal ◽  
Single Crystals ◽  
Periodic Potential ◽  
Optimum Conditions ◽  
Potential Oscillations ◽  
Dilute Aqueous Solutions ◽  
Experimental Findings ◽  
Kinetics Of

The authors investigated periodic potential changes measured on oriented sections of Al single crystals during spontaneous dissolution in dilute aqueous solutions of KOH, with the aim to find optimum conditions for the formation of potential oscillations. It was found that this phenomenon is related with the kinetics of the reaction investigated, whose rate also changed periodically. The mechanism of the oscillations is discussed in view of the experimental findings.

Measurement of growth rates for single crystals and pressed tablets of CuSO4.5 H2O on a rotating disc

1989 ◽  
Vol 54 (11) ◽  
pp. 2951-2961 ◽  
Author(s):  
Miloslav Karel ◽  
Jaroslav Nývlt
Keyword(s):  
Growth Rate ◽  
Single Crystal ◽  
Single Crystals ◽  
Growth Rates ◽  
Diffusion Coefficients ◽  
Preferred Orientation ◽  
Rotating Disc ◽  
Dissolution Rates ◽  
Rates Of Growth ◽  
Good Agreement

Measured growth and dissolution rates of single crystals and tablets were used to calculate the overall linear rates of growth and dissolution of CuSO4.5 H2O crystals. The growth rate for the tablet is by 20% higher than that calculated for the single crystal. It has been concluded that this difference is due to a preferred orientation of crystal faces on the tablet surface. Calculated diffusion coefficients and thicknesses of the diffusion and hydrodynamic layers in the vicinity of the growing or dissolving crystal are in good agreement with published values.

Sign in / Sign up

Export Citation Format

Share Document