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

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Presentation on theme: "Ulrika Nygren, June 2002 Determination of actinides in emergency preparedness using Diphonix or Actinide resin in combination with gamma spectrometry Ulrika."— Presentation transcript:

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

2 Ulrika Nygren, June 2002 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)

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

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

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

6 Ulrika Nygren, June 2002 –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 Determination of actinides by the use of actinide specific resins and low-energy gamma spectrometry

7 Ulrika Nygren, June 2002 LiB-fusion 1100°C, 10 min 5% HNO 3, 20 min Microwave digestion HNO 3 and H 2 O 2, 15 min Surry with resin 0.7 g, 1 h. vegetationsoil Low-energy γ-spectrometry water Adjustment of acid concentration Elektrodep. and α-spectrometry Digestion of extractant Extraction chromatography Analytical procedure – emergency preparedness

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

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

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

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

12 Ulrika Nygren, June 2002 Detection limits for 241 Am 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)

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

14 Ulrika Nygren, June 2002 NuclideEnergyIntensityTheoretical Detection Limits (keV)%Water (Bq/l)Grass (Bq/kg)Soil (Bq/kg) 234 U53.110.41.5150300 235 U185.7540.444488 238 U48.00.0752102100043000 239 Np103.7240.770140 237 Np86.513.11.5150290 241 Am59.536.30.6565130 238 Pu43.50.0384104100083000 239 Pu51.60.02182082000160000 240 Pu45.20.0453503500071000 241 Pu98.40.002275007500001500000 242 Cm44.00.0334904900099000 244 Cm42.80.02561061000120000 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)

15 Ulrika Nygren, June 2002 Destruction of resin/extractant for further separation and analysis Actinide resin Removal of extractant with actinides from resin by isopropanol Evaporation till dryness in Ni-crucible Fusion with Na 2 O 2 (550ºC, 10 min) Leaching of melt by H 2 O followed by dilute HNO 3 Diphonix 30 ml HNO 3 (conc.) added to resin and evaporated to near dryness at 200ºC 10 ml H 2 O 2, ev. to near dryness 15 ml H 2 O 2 and 0.35 g FeSO 4 *7H 2 O, ev. to near dryness 6 ml H 2 O 2, ev. to dryness

16 Ulrika Nygren, June 2002 Chemical yields in alpha spectrometric analysis Destruction of extractant: Fentons reagent for Diphonix Na 2 O 2 fusion for Actinide resin

17 Ulrika Nygren, June 2002 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 241 Am 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 241 Am 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


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