Wir schaffen Wissen – heute für morgen

11. Dezember 2014PSI, 11. Dezember 2014PSI,

Paul Scherrer Institut

Radioisotopes in Biomass and their Combustion Products

Jost Eikenberg (PSI, CH), Gina Kraft (University of Freiburg, D)

Activities of the radioanalytical laboratory at PSIIntroduction to measurement techniquesSample types and resultsDiscussion and Outlook

Overview

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Activities of the radioanalytical laboratory

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Sample measurements in the frame of radionuclide emission, immission and incorporation surveillanceDevelopment of radioanalytical separation techniques

(fast methods, low-level analysis etc.)Research work (e.g. in-situ measurements in Swiss

underground field laboratories) Collaboration with universities (dissertation, master

and bachelor theses)Quality assurance work as the accredited laboratory

(Swiss Accreditation Service)

Aerosol filters,analysed weekly

Tritium elution system,analysed weekly

-spectroscopie, online

air probe

Measured activity

• comparison with interaction limits • comparison with SDV• reports to the autorithy

Conversionto environmental-dose

Radioanalytics: routine work – emission surveillance

Vent stack

parent isotope

half-life parent

ingrowing daughter

half-life daughter

210Pb () 22.3 years 210Bi () 6.02 days

226Ra () 1602 years 222Rn () 3.82 days

228Ra () 5.76 years 228Ac () 6.13 hours

Determination of 210Pb, 226Ra and 228Ra in drinking water

Typical environmetal applications: one example

long lived mother – short lived daughter relationships

A t A e e A ey xy

y x

xt yty

yt( ) ( ) ( ) ( )

0 0

A t A e ey xy

y x

xt yt( ) ( ) ( )

0

x yy

y x

1

)1()0()( txy

yeAtA

Ingrowth of 226Ra progeny isotopes

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0 5 10 15 20 25 300.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

222Rn+218Po+214Po: measured data

226Ra decay curve

226Ra: measured data

222Rn+218Po+214Po ingrowth curve

rela

tive

activ

ity

time after separation [d]

Spectrometric methods used at PSI

Mesurement technique Radioisotope

Gamma-Spectrometry (only Photons)

7Be, 40K, 131I, 134Cs, 137Cs, 210Pb, 226Ra, 228Ra, 241Am

Liquid Scintillation-Spectrometry (LSC) (beta- and alpha-emitters)

All pure -emitter: e.g. 3H, 14C, 63Ni, 87Rb, 90Sr, 228Ra, 241Pu,

Alpha-Spectrometry (only alpha-emitters)

210Pb (via 210Po), 226Ra, 234U, 235U, 238U, 238Pu, 239+240Pu, 241Am, 244Cm

HP-Ge-Spectrometer with lead shielding and liquid N2-cooling

Detector calibration and intercomparison exercises

nuclide results

IRA [kBq] PSI [kBq] PSI/IRA109Cd 17.5 + 0.2 19.1 + 0.8 1.0957Co 0.780 + 0.006 0.78 + 0.03 1.00139Ce 0.952 + 0.006 0.94 + 0.02 0.99137Cs 7.77 + 0.03 7.58 + 0.15 0.98

88Y 4.14 + 0.03 3.96 + 0.10 0.9660Co 4.27 + 0.02 4.31 + 0.10 1.01

-Spectrum of a soil sample taking from southern Switzerland

1

10

100

1000

10000

100000

0 500 1000 1500 2000Energy [keV]

Cou

nts/

Cha

nnel

Cs-137

K-40

Bi-214Ac-228

Ac-228

Pb-212

Pb-214

Bi-214

Tl-208

Liquid scintillation spectrometry (LSC)

5 LS-Spectrometerequipped with double and triple coincidencephoto multipliers and automatic-discrimination

-continuum spectra of 3H and 14C

1 10 1000

200

400

600

800

1000

1200

LSC: spectrum of 14C und 3H

E max

=18

.6 k

eV

E max

= 1

56 k

eV

3H 14C

inte

nsity

(not

to s

cale

)

energy (keV)

classical separation with LSC measurement technique

100 110 120 130 140 1500

2

4

6

8

10

12

14

in in sp

illove

r [%

]

discriminator setting [ns]

-Spectrometer Analyst (Canberra Instruments)

-Spectrum of Uranium extracted from a soil sample

4.0 4.5 5.0 5.5 6.00

20

40

60

80

100

238U

234U

235U

232U-Tracer

-energy [MeV]

coun

ts/c

hann

el (n

ot to

sca

le)

Radioisotopes in biomass and their combustion products

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isotope half live origin Plant uptake7Be 53 days cosmic ray

spallation reactionatmosphericdeposition

210Pb 22 years 222Rn emanation atmospheric depos.40K 1.3*109 years primordial terrestric soil uptake226Ra 1600 years primordial terrestric soil uptake228Ra 5.7 years primordial terrestric soil uptake137Cs 31 years anthropogenic soil uptake

238U 234U

230Th

234Pa

234Th

226Ra

222Rn

218Po 214Po 210Po

210Bi

210Pb 206Pb

235U

231Pa

231Th 227Th

227Ac

223Ra

219Rn

232Th 228Th

228Ac

224Ra228Ra

220Rn

215Po

211Pb 207Pb

211Bi 212Bi

216Po 212Po

212Pb 208Pb

207Tl 208Tl

214Bi

214Pb

4.47x109y 2.45x105y

24.1d 7.54x104y

1.17min

4.196MeV

4.776MeV

4.688MeV

4.784MeV

5.490MeV

6.003MeV

1600y

3.825d

3.11min

19.9min

26.8min 22.3y

7.04x108y

6.038MeV

4.395MeV

5.013MeV

3.28x104y

18.7d

21.8y

11.4d

4.010MeV

1.41x1010y 1.91y

5.75y

5.423MeV6.13h

3.66d

5.686MeV

55.6s

6.288MeV

1.6x10-4s

5.01d

7.687MeV

5.304MeV

stable

138.4d

1.06d

5.716MeV

6.819MeV

3.96s

1.8x10-3s

2.14min

36.1min stable

7.386MeV

6.623MeV

4.77min

66.3%

0.15s

6.779MeV 1.01h

33.7%

6.051MeV10.6h

3.05min

stable

8.784MeV

3x10-7s

238U-Series 235U-Series 232Th-Series

UPaThAcRaFrRnAtPoBiPbTl

The U- and Th-decay series

Atmosphere – Plant – Soil Transfer System

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Uptake of radionuclides (1) atmospheric: 7Be, 210Pb and (2) via transfer from soil, 40K, 210Pb 7Be, 210Pb

11. Dezember 2014PSI,

222Rn emanation and atmospheric deposition of 210Pb

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210Pbsupp.: geogenic210Pbunsupp.: atmospheric

Sample location, sample type and reference date

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BA = Bottom AshFA = Fly Ash

Fuel = Wood Pellets (dried biomass)

Photographic pictures of the samples

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Gamma energies and emission probabilities for theradionuclides detected

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gamma spectrum from sample # 2 bottom and fly ash

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BA

FA

Bar charts of the measured activity concentrations

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Enrichment factors for the radionuclides in FA / BA

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Radium – lead correlation plots

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226Ra / 228Ra

210Pb / 226Ra vs.226Ra / 228Ra

X/ZY/Z

Comparison of the radionuclide concentrations withexemption limits in Germany and Switzerland

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isotope Exemptionlimit D [Bq/kg]

Exemptionlimit CH [Bq/kg]

Sample # 1 Fly Ash [Bq/kg]

average soil at PSI [Bq/kg]

40K 100000 2000 7700 300137Cs 1000 800 500 50210Pb 10000 10 2000 200226Ra 10000 40 100 25

6 radioisotopes were detected in bottom and fly ash from three components: (i) cosmic rays, (ii) primordial terrestrial and, (iii) anthropogenic (man-made) origin

A significant pre-concentraton of all isotopes in bottom and fly ash sample was measured

Large enrichment of natural 210Pb, 40K as well as anthropogenic 137Cs were detected particularly in fly ash samples

Conclusions: radionuclides in biomass + combustion products

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11. Dezember 2014PSI, 11. Dezember 2014PSI, Seite 30

Thank you for your attention