Characterisation of radioactive particles in the environment†

(Note: The full text of this document is currently only available in the PDF Version )

Brit Salbu and Trygve Krekling


Abstract

When radioactive particles are released into the environment, information on the size distribution pattern, radionuclide and matrix composition, morphology and structure is essential for assessing weathering and the subsequent mobilisation and biological uptake of associated radionuclides. The particle characteristics will depend on the source in question in addition to the release scenario, dispersion processes and deposition conditions. Following high temperature accident scenarios associated with nuclear installations (e.g., Chernobyl accident) a range of different uranium fuel particles and condensed particles were observed, varying in composition, morphology and structure (e.g., crystalline and amorphous phases). Following low temperature releases (e.g., prefire Winscale releases), flake-like uranium fuel particles significantly different from those collected at Chernobyl were identified. Furthermore, a major fraction of radionuclides in effluents from reactors and reprocessing plant during normal operations are associated with particles and colloids. Hence the presence of radioactive particles or colloids in releases from nuclear sources occurs more frequently than usually expected. After deposition, weathering of particles occurs and associated radionuclides are mobilised with time. Hence the transfer of mobilised radionuclides within the ecosystem will be delayed until weathering takes place, and the assessment of short term consequences of releases may be overestimated if particles are present. The weathering rate will depend on the particle composition (e.g., UO2 fuel), structural changes occurring during the event (e.g., transformation from UO2 to U3O8) and chemical conditions after deposition (e.g., pH, redox). Unless the impact of particle weathering is taken into account, assessment of mobilisation, transfer and long-term consequences of radionuclide releases may be underestimated. In order to improve the predicting power of transport models, ecosystem transfer models and dose assessment models, experimental information is required with respect to source term radionuclide speciation and in particular the association of radionuclides with particles and colloids, influencing mobility and biological uptake. This work was therefore focused on analytical techniques applicable to the fractionation, identification and characterisation of radioactive particles and colloids (e.g., hollow fibre fractionation, electron microscopic techniques and reactivity studies) released from a source and deposited in the environment. Results from research carried out during several years at the authors’ laboratory are presented to illustrate the usefulness of the techniques.


References

  1. B. Salbu and D. H. Oughton, in Trace Elements in Natural Waters, ed. Salbu, B., and Steinnes, E., CRC Press, Boca Raton, FL, 1994, pp. 41–69 Search PubMed.
  2. L. Arnold, The Winscale Fire 1957. Anatomy of a Nuclear Accident, Macmillan, London, 1992 Search PubMed.
  3. J. N. Smith, K. M. Ellis, A. Aarkrog, H. Dahlgaard and E. Holm, J. Environ. Radioact., 1994, 25, 134 CrossRef.
  4. UNSCEAR, Sources and Effects of Ionizing Radiation, United Nations Scientific Committee on the Effects of Atomic Radiation, New York, 1993 Search PubMed.
  5. N. A. Loschilov, V. A. Kasparov, Ye. B. Yudin, V. P. Protsak, M. A. Zurba and A. E. Parshakov, in The Radiobiological Impact of Hot Beta-Particles from the Chernobyl Fallout. Risk Assessment, IAEA, Vienna, 1992, Part I, pp. 34–39 Search PubMed.
  6. L. Devell, M. Tovedal, U. Bergstrøm, A. Applegren, J. Chussler and L. Andersson, Nature (London), 1986, 321, 817 CrossRef.
  7. R. Raunemaa, H. Saari, S. Loukkanen and S. Lehtinen, in Hot Particles from the Chernobyl Fallout, ed. von Philipsborn, H., and Steinhäuser, F., Bergbau und Industrimuseum, Theuern, 1988, p. 77 Search PubMed.
  8. D. Jakeman, Notes of the Level of Radioactive Contamination in the Sellafield Area Arising from Discharges in the Early 1950s, UKAEA, AEEW Report 2104, Atomic Energy Establishment, Winfrith, 1986 Search PubMed.
  9. B. Salbu, H. E. Bjørnstad, I. Sværen, S. L. Prosser, R. A. Bulman, B. R. Harvey and M. B. Lovett, Sci. Total Environ., 1993, 130/131, 51 CrossRef.
  10. Joint Norwegian–Russian Expert Group for Investigation of Radioactive Contamination in the Northern Areas, Sources Contributing to Radioactive Contamination of the Techa River and Areas Surrounding the ‘Mayak’ Production Association, Urals, Russia, Østerås, Norway, 1997 Search PubMed.
  11. B. Salbu and H. E. Bjørnstad, J. Radioanal. Nucl. Chem. Articles, 1990, 138, 337 Search PubMed.
  12. C. Degueldre, G. Longworth, V. Moulin, P. Vilks, C. Ross, G. Bidoglio, A. Cremers, J. Kim, J. Pieri, J. Ramsay, B. Salbu and U. Vuorinen, PSI-Ber., 1989, No. 39 Search PubMed.
  13. H. E. Lydersen, Bjørnstad, B. Salbu and A. C. Pappas, in Speciation of Metals in Water, Sediments and Soil Systems, ed. Landner, L., Lecture Notes in Earth Sciences, vol. 11, Springer, Berlin, 1987, pp. 85–97 Search PubMed.
  14. B. Salbu, H. E. Bjørnstad and J. E. Brittain, J. Radioanal. Nucl. Chem., 1989, 156, 7.
  15. A. F. Nisbet, B. Salbu and S. Shaw, J. Environ. Radioact., 1993, 18, 71 CrossRef CAS.
  16. B. Salbu, A. I. Nikitin, P. Strand, G. C. Christensen, V. B. Chumichev, B. Lind, H. Fjelldal, T. D. S. Bergan, A. L. Rudjord, M. Sickel, N. K. Valetova and L. Føyn, Sci. Total Environ., 1997, 202, 185 CrossRef CAS.
  17. D. H. Oughton, B. Salbu, T. L. Brand, J. P. Day and A. Aarkrog, Analyst, 1993, 118, 1101 RSC.
  18. B. Salbu, T. Krekling, D. H. Oughton, G. Østby, V. A. Kashparov, T. L. Brand and J. P. Day, Analyst, 1994, 119, 125 RSC.
  19. T. T. Bobovnikova, Y. P. Virchenko, A. V. Konoplev, A. Siverina and I. Shkuratova, Sov. Soil. Sci., 1991, 23, 5 Search PubMed.
  20. B. Salbu, D. H. Oughton, A. V. Ratnikov, T. L. Zhigarev, S. V. Kruglov, K. V. Petrov, N. V. Grebenshakiova, S. K. Firsakova, N. P. Astasheva, N. A. Loschilov, K. Hove and P. Strand, Health Phys., 1994, 67, 518 Search PubMed.
  21. G. Riise, H. E. Bjørnstad, H. N. Lien, D. H. Oughton and B. Salbu, J. Radioanal. Nucl. Chem., 1990, 142, 531 CAS.
  22. D. H. Oughton and B. Salbu, in Nordic Radioecology: the Transfer of Radionuclides Through Nordic Ecosystems to Man, ed. Dahlgaard, H., Elsevier, Amsterdam, 1994, pp. 165–184 Search PubMed.
  23. V. A. Kashparov, D. H. Oughton, S. I. Zvarich, V. P. Protsak and S. E. Levchuk, Health Phys., in the press Search PubMed.
  24. D. H. Oughton, B. Salbu, G. Riise, H. Lien, G. Østby and A. Nøren, Analyst, 1992, 117, 481 RSC.
  25. D. H. Oughton, P. Børretzen, B. Salbu and E. Tronstad, Sci. Tot. Environ., 1997, 202, 155 Search PubMed.
  26. P. Børretzen, H. Fjelldal, H. Lien, D. H. Oughton and B. Salbu, in Environmental Radioactivity in Arctic, ed. Strand, P., and Cooke, A., Norwegian Radiation Protection Authority, Østerås, 1995, pp. 168–172 Search PubMed.
  27. P. F. Bondar, Ivanov, A. Yu and A. G. Ozornov, in The Radiobiological Impact of Hot Beta-Particles from the Chernobyl Fallout. Risk Assessment, IAEA, Vienna, Part I, 1997, pp. 58–67 Search PubMed.
  28. B. Salbu, T. Krekling, K. Hove, D. H. Oughton, V. A. Kashparov and N. Astasheva, Proceedings of International Symposium on Environmental Impact of Radioactive Releases, IAEA, Vienna, 1995, pp. 312–313 Search PubMed.
Click here to see how this site uses Cookies. View our privacy policy here.