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Ulrika Nygren and Daniela Stricklin

Determination of actinides in emergency preparedness using Diphonix or Actinide resin in combination with gamma spectrometry. Ulrika Nygren and Daniela Stricklin. Emergency Preparedness.

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Ulrika Nygren and Daniela Stricklin

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  1. Determination of actinides in emergency preparedness using Diphonix or Actinide resin in combination with gamma spectrometry Ulrika Nygren and Daniela Stricklin Ulrika Nygren, June 2002

  2. Emergency Preparedness • To protect the Swedish population from exposure to ionising radiation produced in the decay of radioactive nuclides • Fallout from nuclear power plant accidents • Fallout from nuclear weapons explosions • Terrorism • Designated laboratory for the Swedish Radiation Protection Authority (SSI) Ulrika Nygren, June 2002

  3. Transfer of radioactive debris to the environment radioactive cloud Radioactive Cloud inhalation inhalation dry deposition dry deposition reindeer wet deposition wet deposition plant production reindeer plant production animal production animal production transfer: vegetation to forest floor fish transfer: vegetation to forest floor fish external radiation external radiation root uptake root uptake migration migration Fast determination of fall-out composition critical Ulrika Nygren, June 2002

  4. Mobile Measurement Techniques Primarily determination of deposited gamma emitting fission products – actinides and pure beta emitters not determined Measurement Vehicle HPGe, NaI for thyroid measurements Backpack NaI-detector, GPS Fieldgamma Spectrometry HPGe Ulrika Nygren, June 2002

  5. Standard radioanalytical procedure for actinide determination at FOI - identification of time consuming procedures Dry, homogenise LiB-fusion Soil Wet ashing Vegetation Water Si-removal Oxalate precipitation UTEVA U Electrodep. and α-spectrometry TRU Pu Am (Cm) Ulrika Nygren, June 2002

  6. Determination of actinides by the use of actinide specific resins and low-energy gamma spectrometry • fast preconcentration and partial separation of the actinides • good spectral resolution provides qualitative and quantitative information • geometry well suited for gamma spectrometry, facilitates calibration Issues? • sensitivity • retention of actinides on resin Ulrika Nygren, June 2002

  7. Analytical procedure – emergency preparedness LiB-fusion 1100°C, 10 min 5% HNO3, 20 min Microwave digestion HNO3 and H2O2, 15 min soil vegetation water Adjustment of acid concentration Surry with resin 0.7 g, 1 h. Low-energy γ-spectrometry Digestion of extractant Extraction chromatography Elektrodep. and α-spectrometry Ulrika Nygren, June 2002

  8. Retention of nuclides from rainwater on Actinide resin Ulrika Nygren, June 2002

  9. Retention of nuclides from rainwater on Diphonix Ulrika Nygren, June 2002

  10. Retention of nuclides from vegetation on Actinide resin 5% Nitric Acid Ulrika Nygren, June 2002

  11. Separation of 241Am from soil The sample-solutions were adjusted to 1M HF and 0.125M AA prior to the addition of the resins Ulrika Nygren, June 2002

  12. Detection limits for 241Am 1 Based on 100 min counting time and 95% conf. interval according to L. A. Currie, Anal. Chem., 40 (1968) 2 N. Green, ”An evaluation of rapid methods of radionuclide analysis for use in the aftermath of an accident”, Sci. Total Environ., 130/131 (1993) Ulrika Nygren, June 2002

  13. Time of analysis The analysis times are based on a counting time of 100 min 1N. Green, G. Ham, S. Shaw, Rapid Radioactivity Measurements in Emergency and Routine Situations, Proceedings, NPL, Teddington, UK, (1997) Ulrika Nygren, June 2002

  14. Theoretical detection limits for other actinides- complete retention on resin assumed Based on 100 min counting time and 95% conf. interval according to L. A. Currie, Anal. Chem., 40 (1968) Ulrika Nygren, June 2002

  15. Actinide resin Removal of extractant with actinides from resin by isopropanol Evaporation till dryness in Ni-crucible Fusion with Na2O2 (550ºC, 10 min) Leaching of melt by H2O followed by dilute HNO3 Diphonix 30 ml HNO3 (conc.) added to resin and evaporated to near dryness at 200ºC 10 ml H2O2, ev. to near dryness 15 ml H2O2 and 0.35 g FeSO4*7H2O, ev. to near dryness 6 ml H2O2, ev. to dryness Destruction of resin/extractant for further separation and analysis Ulrika Nygren, June 2002

  16. Chemical yields in alpha spectrometric analysis • Destruction of extractant: • Fentons reagent for Diphonix • Na2O2 fusion for Actinide resin Ulrika Nygren, June 2002

  17. Determination of actinides by the use of actinide-specific resins and low-energy gamma spectrometry-Conclusions • The method shows good capacity for the separation and determination of 241Am in water, vegetation and soil • Analysis time is dramatically reduced compared to conventional methods • The method provides sufficient sensitivity for the determination of several actinide-nuclides in emergency preparedness • The retention of 241Am is good on both resins, although the Actinide resin is somewhat more selective and provides higher retention at higher acid concentrations • Possible to process resins for further analysis based on e.g. alpha spectrometry D. L. Stricklin, Å. Tjärnhage, U. Nygren, J. Radioanal. Nucl. Chem., 251 (2002) 69 Ulrika Nygren, June 2002

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