Workshop on Understanding and Evaluating Radioanalytical Measurement Uncertainty November 2007

Transcription

1 Workshop on Understanding and Evaluating Radioanalytical Measurement Uncertainty 5-16 November 2007 Rapid methods for ALMERA Network in an Emergency situation analysis methods for radionuclides Sandor TARJAN Hungarian Agricultural Authority Food & Feed Safety Directorate Central Radioanalytical Laboratory P.O. Box 1740, H-1465 Budapest HUNGARY

2 Rapid Methods for ALMERA Network in Emergency Situation (The first report of the rapid method group) S. Tarjan, C. K. Kim, B. Varga, 4 th ALMERA Co-ordination meeting, Trieste 5-7 November 2007

3 ALMERA => environmental monitoring Harmonisation for Nuclear or Radiation Emergency Methods Reporting of analytical results If it is possible the facilities

4 WHO recommendation for public dose: 1 msv / year from man made radionuclides

5 Current Guideline Levels by WHO for Food (in Bq/kg or litre) CAC/GL Conditions fraction of contaminated food is not higher than 0.1 total food consumption is 550 kg/year for adult total food consumption is 200 kg/year for children the activity concentrations of each radionuclide should be added together (within the same group)

6 Radionuclides in Food Guideline Level (Bq/kg) Infant Foods Other Foods 238 Pu, 239 Pu, 240 Pu, 241 Am 90 Sr, 106 Ru, 129 I, 131 I, 235 U 35 S, 60 Co, 89 Sr, 103 Ru, 134 Cs, 137 Cs, 144 Ce, 192 Ir 3 H, 14 C, 99 Tc

7 CAC/GL , WHO

8 Food consumption by age groups, kg/year (World wide averages) Food 1 year 10 years adult Milk and milk products Meat Cereals Leafy vegetables Other vegetables and fruits Fish Total food Drinking water and beverages UNSCEAR 2000

9 Type of radiation Gamma-emitters Betaemitters Alphaemitters Nuclide Proposed detection limits and methods for milk Half life Sample weight, g Sample preparation MDA, Bq/kg Co y 0.20 Ru d 0.20 Ru d 0.80 Cs y 0.15 Cs y n.a I d 3.00 I d 0.50 I h 0.40 Ce d 0.50 H y C y Sr d IAEA TECDOC 50 ml Sr y Pu y Pu y 0.10 Pu y IAEA TECDOC ml Pu y Am y Method HPGe-gsp, 450ccm Marinellibeaker, 30% rel. eff. detector, 10 cm lead shielding, 10000s IAEA TECDOC 1092 IAEA TECDOC 1092 (183) Duration 4 hours 10 hours 12 hours???

10 Type of radiation Gamma-emitters Betaemitters Alphaemitters Proposed detection limits and methods for vegetation samples Nuclide Half life Sample weight, g Sample preparation MDA, Bq/kg fresh Co y 1.00 Ru d 0.80 Ru d 5.80 Cs y 0.74 Cs y n.a I d I d 0.78 I h 0.96 Ce d 5.00 H y 40.0 combustion 0.50 LSC counting 32 hours C y 40.0 combustion LSC counting 32 hours Sr d radiochemical IAEA TECDOC 13 hours Sr y separation 1092 (183)??? Pu y Pu y Pu y radiochemical IAEA TECDOC 19 hours Pu y separation 1092 (183)??? Am y * It was calculated from the real spectrum of fresh grass by WINNER GAMMA software Method Duration HPGe-gsp, 450ccm Marinellibeaker, 30% rel. eff. detector, 10 4 hours cm lead shielding, 10000s

11 Drinking water Type of radiation Gamma-emitters Betaemitters Alphaemitters Nuclide Half life Sample Sample MDA, Method Duration weight, ml preparation Bq/l adult* Co y HPGe-gsp, Ru d ccm 228 Ru d 0.80 Marinellibeaker, 24 Cs y % 9 Cs y n.a rel. eff. 4 hours 13 I d 3.00 detector, I d 0.50 cm lead 8 shielding, I h s Ce d H y destillation 4-10 IAEA TECDOC 2-3 hours 9259 C y Sr d radiochemical IAEA TECDOC separation hours Sr y 6 Pu y 35 Pu y radiochemical 0.72 IAEA Pu y separation 10 hours TECDOC Pu y??? 1092 (183) 0.67 Am y 0.83 Guideline levels*, Bq/kg * Calculated for 0.1 msv/year without gut transfer factor using 1.6 l/day drinking water intake rate(ibss 115)

12 Aerosol WHO recommendation for internal dose by inhalation pathway is 0.1 msv the breath rate (IBSS 115) for children is 1400 m 3 /year for adult is 8400 m 3 /year there are no any guideline levels expressed in Bq/m 3

13 Derived "guideline levels" from 0.1 msv internal dose through inhalation pathway and radioanalytical methods for aerosol samples (IBSS 115) Type of radiation Gamma-emitters Beta-emitters Alphaemitters Nuclide Half life Sample weight, m 3 Sample preparation MDA, Bq/m 3 Method Duration Guideline levels, Bq/m 3 adult children Co y Ru d Ru d 0.15 HPGe-gsp, 30% rel Cs y 0.02 eff Cs y 10.0 n.a detector, 4 hours I d cm lead shielding, I d s I h Ce d H y It is required a special sampling and desorber tools (molecular sieve system) C y IAEA Sr d radiochemical TECDOC separation 32 hours Sr y Pu y Pu y IAEA Pu y radiochemical TECDOC 36 hours separation Pu y Am y

14 Gamma-spectrometry

15 Efficiency (%) of different geometries Geometry Nuclid E, kev Cylindrical, 50 ccm Cylindrical, 100 ccm Marinelli 450 ccm Well-type Det.(8 ccm) 241 Am I Cs Co n-type 30% HPGe detector

16 Relative sensitivity of different geometries Nuclide E, kev Geometry, sample density= 1kg/dm 3 Cylindrical, 50 ccm Cylindrical, 100 ccm Marinelli 450 ccm Well-type Det.(8 ccm) 241 Am I Cs Co

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20 Special applications of gammaspectrometry as a rapid method Well-type detector 131 I measurement after enrichment on anion exchange resin from water samples Journal of Radioanalytical and Nuclear Chemistry, Vol. 256, No. 2 (2003) P. Parekh,* A. Bari, P. Harris 241 Am analysis after enrichment and chemical separation Journal of Radioanalytical and Nuclear Chemistry, Vol. 274, No.1 (2007) R. J. Lagomarsino, N. Latner Compton-subtraction spectrometer 90 Sr measurement without any sample preparation using bremstrahlung detection Journal of Radioanalytical and Nuclear Chemistry, Vol. 223, Nos 1-2 (1997) C. F. Wang, *+ M. C. Yuan,** J. H. Lee**

21 Radiostrontium

22 Basic steps of radiochemical analysis sample ashing, digestion enrichment of Sr co-precipitation extraction ion exchange separation of Sr and preparatum making classical way (HNO 3 procedure) Sr-spec low level counting gas ionising detectors (proportional counter) LSC or LSS ULB plastic (pulse shape discrimination technique)

23 Special rapid methods Sr-separation from milk 1 extraction of Sr by Dowex 50 WX8 in slightly acidic condition (ph 5.5) Sr separation by Sr-spec (chemical yield is 45-60%) Sr-separation from milk 2 extraction of Sr by Dowex 50 prepared with cryptand 222 (cryptand is a bicyclic polyether): hexaoxa-1.10-dizabicyclo[8.8.8]hexacosan Merck, product name: Kirptofix 222 C-222 improve the affinity for Sr (Ca, Ba) of the D50WX8 85% chemical yield was reached at ph 5.2 time requirements 15-16h Journal of Radioanalytical and Nuclear Chemistry, Vol. 226, Nos 1-2 (1997) D. Tait, G. Haase, A. Wiechen Journal of Radioanalytical and Nuclear Chemistry, Vol. 253, No. 2 (2002) S. Brun,* S. Bessac, D. Uridat, B. Boursier

24 Special rapid methods (cont.) Solid Phase Extraction method with 3M disk (Sr, Cs and Tc available) mainly for water samples Journal of Radioanalytical and Nuclear Chemistry, Vol. 243, No. 2 (2000) D. M. Beals,1 B. S. Crandall,2 P. D. Fledderman2 Journal of Radioanalytical and Nuclear Chemistry, Vol. 274, No.1 (2007) Y. Kameo,* A. Katayama, A. Fujiwara, T. Haraga, M. Nakashima Selective scintillators: the scintillator contains the crown ether (dicyclohexyl-18-crown-6) In-sulphide new material, no any analytical application yet [In 10.5 S 14.5 ].[(H 2 NCH 2 CH 2 NHCH 2 ) 2 ] 2.5 Journal of Radioanalytical and Nuclear Chemistry, Vol. 273, No.1 (2007) Ying Lan, Zhe Su, Xingliang Li, Zhaoqun Jiang, Jun Jin, Jiali Xie, Shoujian Li*

25 Pu-isotopes HR ICP-MS intensive sampling digestion separation from the isobars questions: sample homogeneity down to g short life radionuclides ( 241 Pu) detection limit

26 Thank you for attention!