View More View Less
  • 1 Nagoya University Department of Nuclear Engineering, Faculty of Engineering Furo-cho, Chikusa-ku 464-01 Nagoya (Japan)
Restricted access

Abstract  

Heat capacities of U1–yLayO2 were measured by means of direct heating pulse calorimetry in the temperature range from 300 to 1500 K. An anomalous increase in the heat capacity curve of each sample was observed similarly to the case of U1–yGdyO2, found recently in our laboratory. As the lanthanum content of U1–yLayO2 increased, the onset temperature of an anomalous increase in the heat capacity decreased and the excess heat capacity increased. The enthalpy of activation (Hf) and the entropy of activation (Sf) of the thermally excited process, which cause the excess heat capacity were obtained to be 2.14, 1.63 and 1.50 eV and 39.4, 34.2 and 31.8 J·K–1·mol–1 for U0.956La0.044O2, U0.910La0.090O2 and U0.858La0.142O2, respectively. The values at zero La content extrapolated by using the data of Hf and Sf for U1–yLayO2 were in good agreement with the experimental values of undoped UO2 so far reported, similarly to the case of Gddoped UO2. The electrical conductivities of U1–yLayO2 (y=0.044 and 0.142) were also measured as a function temperature. No anomaly was seen in the electrical conductivity curve. It may be concluded that the excess heat capacity originates from the predominant contribution of the formation of oxygen clusters and from the small contribution of the formation of electron-hole pairs.

Manuscript Submission: HERE

  • Impact Factor (2019): 1.137
  • Scimago Journal Rank (2019): 0.360
  • SJR Hirsch-Index (2019): 65
  • SJR Quartile Score (2019): Q3 Analytical Chemistry
  • SJR Quartile Score (2019): Q3 Health, Toxicology and Mutagenesis
  • SJR Quartile Score (2019): Q2 Nuclear Energy and Engineering
  • SJR Quartile Score (2019): Q3 Pollution
  • SJR Quartile Score (2019): Q3 Public Health, Environmental and Occupational Health
  • SJR Quartile Score (2019): Q3 Radiology, Nuclear Medicine and Imaging
  • SJR Quartile Score (2019): Q3 Spectroscopy
  • Impact Factor (2018): 1.186
  • Scimago Journal Rank (2018): 0.408
  • SJR Hirsch-Index (2018): 60
  • SJR Quartile Score (2018): Q2 Nuclear Energy and Engineering
  • SJR Quartile Score (2018): Q2 Pollution

For subscription options, please visit the website of Springer Nature.

Journal of Radionalytical and Nuclear Chemistry
Language English
Size A4
Year of
Foundation
1968
Volumes
per Year
4
Issues
per Year
12
Founder Akadémiai Kiadó
Founder's
Address
H-1117 Budapest, Hungary 1516 Budapest, PO Box 245.
Publisher Akadémiai Kiadó
Springer Nature Switzerland AG
Publisher's
Address
H-1117 Budapest, Hungary 1516 Budapest, PO Box 245.
CH-6330 Cham, Switzerland Gewerbestrasse 11.
Responsible
Publisher
Chief Executive Officer, Akadémiai Kiadó
ISSN 0236-5731 (Print)
ISSN 1588-2780 (Online)