Radiotracer inRadiotracer inProzess Investigation

Fraunhofer Institute forFraunhofer Institute for Nondestructive Testing Dresden

D t h bil Alb t Z

Fraunhofer IZFP-D

Dr. rer. nat. habil. Albert Zeuner

Maria-Reiche-Straße 2D-01109 Dresden

+49(0)351 / 888 15-611 (Laboratory)

1

( ) ( y)Albert.Zeuner@izfp-d.fraunhofer.dewww.izfp-d.fraunhofer. deand(0351) 268 7784 / (0172) 372 8894 1( ) ( )Albert.Zeuner@web.de

VeranstaltungOrt, Termin

Function and Purposes of IzfP-D

• The Fraunhofer Institute for Nondestructive Testing (IZFP) was founded in 1972 and is situated in Saarbrücken.

• The Dresden branch (IZFP-D) was founded in 1992.

Purposes of the IZFP-D:

• Improvement of the product quality• Lowering of the Quality costsIZFP D:• Confirmation of the technical safety for devices, machines and plants as

condition of their use

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ContentContent

1 I t d ti 4 E l ti f d l1. Introduction 4. Evaluation of measured values

2. Labelling2 1 G l P bl

4.1. General4.2. Residence time investigations4 2 1 Mean residence time2.1. General Problems

2.2. Addition of labelled material2.3. Radionuclides as labelling agent2 4 Labelling possibilities

4.2.1. Mean residence time4.2.2. Mixing behaviour4.2.3. Vessel number4 3 Mixing investigations

3 Measuring technique

2.4. Labelling possibilities2.5. Amount of labelling agent

4.3. Mixing investigations4.3.1. Batch processing4.3.2. Continuous operation4 3 3 Other homogeneity terms3. Measuring technique5. Investigated subjects3.1. General

3.2. Sample measurement3 3 Outside (probe) measurement

4.3.3. Other homogeneity terms

5.1. Residence time

6. Radiation protection aspects

3.3. Outside (probe) measurement 5.2. Mixing investigations5.3. Other activities

3

p p

7. Summary

3

some basics of radionuclides1.1. IntroductionIntroduction

sealedsources

solidmaterial

openradionuclides = „radiotracer“

use of ionizing radiation itselfwhere is the radioacti e material?wherein what concentration

is the radioactive material?the actual (radio-)tracer technique- RNT -

• potassium content in the potash industry

• estimation of radionuclides in human body („Body counter“)

ions

:

• soil analysis (gamma spectrometry)

chemical investigations (equilibria)

• investigation of residence time and mixing processes

appl

icat

i

4

• chemical investigations (equilibria)

• nuclear medicine

4

• residence time and mixing investigations2.2. LabellingLabelling

The radioactve material has the function of „labelled atoms“ and allows conclusions with regard to the origin of the radiation

application:nuclear medicine

t h i

in nuclear medicine - scintigraphyin continuously working technical devices• residence time analysis

technique• mixing investigations

principle: • addition of a (radioactive) indicator what indicator?how much?

measuring technique• measurement of the indicator

concentration

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justified?• conclusion about the behaviour of the

interesting material

5

some remarks to labelling of material (with radionuclides):

2.2. LabellingLabellingro

blem

1:

but the properties of labelled material must not differ from those of the original

to label something (by an indicator)means to change its properties

pr material.

m 2

: well detectibilitybut large change of propertiesmuch labelling agent

prob

lem

small change of propertiesbut bad detectibility

little labelling agent

labelling paradox“

99mTc : 0.1 GBq108 Bq

3 x 1012 atomsexample for calculation:

Let‘s ass me a„labelling paradox“

nsw

er:

use ofradionuclides !

• extremely little material = practicallyno change of the properties

t l ll d t tibilit

Let‘s assume a100-fold spillover:

10-9 molesca. 10-13 g

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an radionuclides ! • extremely well detectibilityin addition: • decay of the radioactivity

gless than each other imputity

6

process analysis versus radionuclide technique

connections between

2.2. LabellingLabelling

connections between

result(product)

process parameters

pressurestemperatures

of materials

use of radionuclides allows to estimate:(p )

qualityamount

cs yield p

amounts andconcentrations

and energies

depending ontime and placehn

ical

onom

icar

acte

risti yield

conversion degreecosts of material

energyi flow rates

balances

p

this results in:investigation possibilities:

tech

eco

cha equipment

• singular investigation at constant

residence timereaction time

elapsed timevelocity

• singular investigation at constant parameters actual state

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mixinghomogeneity

yfilling degree• repeated investigation with parameter

variation correlations

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scheme of radiotracer application3.3. MeasuringMeasuring techniquetechnique

process section in investigationradionuclides

propertiesnuclear physicalphysical

economicresults

yield

technicalphysical conditionsh i lphysical

chemicalavailabilitycosts

yieldconversion

energy inputcosts

chemicalradioactive contamination

of the environment

control

outs

ide

prob

es

ampl

es

ctio

nev

icechoise of a

radionuclide

processinterpretation

o p sa

inje

c dedi ti

activityestimation

transition-function

measuringvalues (incl.correction)in

put

sign

alradioactivelabelling of

a sample of the material

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labelling measurement evaluation

material

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outside (probe) measurement3.3. MeasuringMeasuring techniquetechnique

scintillation detector

…inserted into a cooling jacket

20 O2

120O

61… and in an collimator (lead, tungsten)

920160 9160

3.3. MeasuringMeasuring techniquetechnique sample measurement

samplebeaker h3

h4

beakerabove thedetector h1

h2

theoretical

th l d itthe pulse densitydepends on the sample mass(sample high)

realmeasurement

(sample high)

for this reason a calibration is necessary,due to the self-absorption of

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measurementdue to the self absorption ofradiation inside the sample

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material transport4.4. EvaluationEvaluation

uni

ts

different shapesof residence timedistributions,d di

rel.depending on n

l e n0 t 0 t

t sig

nal

c pu

lse

wer

sig

naen

ce ti

me

strib

utio

n0 t 0 t

11

normalized mean residence timeinpu

tD

irac

answ

resi

de dis

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4.4. EvaluationEvaluation material transport

than: mean residence time first step: density function1. initial moment

most important parametermost important parametermean residence time :

derived: elapsed time between 2 (detector) positions, 1 und 2

• material velocity between 2 (detector) positions

• material amount between 2 (detector) positions( ) p

• filling degree

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• filling degree

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4.4. EvaluationEvaluation material transport

third step: plug flow or mixer?

∞

( )∫∞

⋅−=0

22 )()()( dttwtEttZ2. central momentthe variance around the mean value characterizes the uniformity of the material transport vessel ( ))( 2tEnp vessel

number( )

)()(2tZ

n =n

1→n - mixer behaviour

∞→n - plug flow

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batch mixer

4.4. EvaluationEvaluation mixing investigation

batch mixer • labelled substance is added at one point of the mixer volume

• samples are taken at different moments (after stopping the mixer)

• mean value standard deviation and variance are calculatedmean value, standard deviation, and variance are calculated

• the variance is plottet against time

• the optimal mixing time is at the minimum of the variance

continuously working mixers

• labelled substance is continuously added at the mixer inlet

• one or more detectors

• puls rate is plotted as function of time

• in case of homogeneous mixing, the pulse rate at each detector is

t t

14

constant

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4.4. EvaluationEvaluation mixing investigation

xx x

xσσ ,,

al tim

eop

tima

mix

ing

decomposition practice

theory

batch operation:At different moments, the mixer is stopped samples are taken;

y

stopped, samples are taken;

mean value, standard deviation, and variance are calculated

i i t i i ti

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variance against mixing time(mixing of two sorts of sand)

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4.4. EvaluationEvaluation mixing investigation, other homogeneity terms

1. homogeneity degree H: H=1-ν...only usable when the measured values are near to a Gauss or Poisson distribution.In practice, the variance may be greater than 1, so a negative homogeneity degree would arise.

B h d h d d d i i f h P i

2. relative inhomogeneity I

In practical investigations, the condition that the particles do not influence each other

Between the mean µ and the standard deviation σ of the Poissondistribution exists the relationship

is not fulfilled, this equation may be not valid.For these cases the connection between mean and standard deviation is assembled by the definition of the relative inhomogeneity I: I (relative inhomogeneity)g y

If I > 1 - the mixture is classified assubstochastic (inefficient mixing)

( g y)• allows to compare different

mixing investigations and• shows the difference of the

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If I < 1 - the mixture is hyperstochastic found homogeneity to the ideal value I = 1

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5.5. InvestigatedInvestigated subjectssubjects ((extractextract))

5 15 1 residenceresidence timetimeSolid:• material transport in a lot of drum dryers and rotary kilns in coal processing and in

cement and potash industry

5.1.5.1. residenceresidence timetime

cement and potash industry.radiotracer: 140La, eluated from a 140Ba/140La generator.

• transport of a single particle through a screw conveyor by the CARPT method.a small glass ball was activated The built radionuclide was 24Naa small glass ball was activated. The built radionuclide was 24Na.

Liquid:• In a pilot plant (two-phase system, 20 bar pressure) a benzene derivative was p p ( p y , p )

labelled with 82Br.7 detectors at different points along the plant.

GGaseous:• In a gas reactor the transport of the gaseous phase was investigated by addition of

41Ar.This work was referred already in the 4 IGCC&XtL in 2010

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This work was referred already in the 4. IGCC&XtL in 2010.• The air exchange in cabs of trucks was investigated by using 85Kr.

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5.5. InvestigatedInvestigated subjectssubjects ((extractextract))

5 25 2 mixingmixing5.2.5.2. mixingmixingsolid:• Optimization of mixing time for batch mixers by using 99mTc.

Th bi d di t ib ti i i l l l t i ti t d b diff t• The binder distribution in mineral wool plates was investigated by different radionuclides (140La, 99mTc, 32P) to study the influence of radiation from outside volume elements.

• In the same way the distribution of one reaction partner in polyurethane foam was• In the same way the distribution of one reaction partner in polyurethane foam was investigated (99mTc).

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5.5. InvestigatedInvestigated subjectssubjects ((extractextract))

5 35 3 otherother activitiesactivities5.3.5.3. otherother activitiesactivities• Isotope generators: Because radionuclides from isotope generators are very useful

also for technical application, a lot of investigations were done by these generator 113 99nuclides (113mIn, 99mTc).

As these radionuclides are not usable for investigation of processes at higher temperatures, a 140La generator was developed. 140La was used for a lot of i ti ti i t ti d i ll t hi h t tinvestigations in rotating drums, especially at higher temperatures.

• By labelling with 99mTc the grain growth in a fluid bed was investigated.I ti ith th l b lli f h d b i k th l bilit f L O• In connection with the labelling of crushed brick, the solubility of La2O3 was estimated.

i l i ti ti ith l dsome special investigations with sealed sources• very exact density estimation• determination of steam content in streaming hot water.

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6.6. Radiation Radiation protectionprotection aspectsaspects

• The IZFP (Institute for non-destructive testing) Dresden has a legal permission to apply radionuclides for investigations also outside the laboratory.

• The radioactively contaminated material is to collect and to store until its activity lies below the maximum permissible value, accordingly to the annex XVI of the German radiation protection ordinance.German radiation protection ordinance.

• Being compliant with these limitations is not an issue, especially in pilot plants.

• The radiation exposure for the involved personnel of the industrial partner can be neglegted.

• The radiation exposure of the staff of the institute is controlled by dosimeters and in no p ycase exceeded the limiting values.

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Radiotracers

7.7. SummarySummary

Radiotracers• offer some advantages in investigation of laboratory and technical processes:

- The amount of radiotracers is in the order of 10-6 moles/use. This is normally below the concentration of other impurities and does practically not influence the quality of the product,

- By using short lived radionuclides, the time until the activity is below the permitted limit is short. So, a temporary storage causes no issues, especially in investigation in laboratory or pilot plant scalepilot plant scale,

- By using short lived gamma radiation emitting radionuclides, the necessity of taking samples is omitted and probes can be positioned outside the walls of the plant.

- Results of the measurement are available shortly after the end of the experiment.

• can be used in investigation of material transport and mixing processes.

Results of the measurement are available shortly after the end of the experiment.

- vessel number n can be calculated only from the measured values

- Mixing investigations have been explained, as well as another interpretation of homogeneity.

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