r. gellermann, nov. 2009 prognosis of radioactivity in tenorm rainer gellermann, fugro-hgn gmbh,...
DESCRIPTION
R. Gellermann, Nov Industrial process Industrial process Industrial process NORM industries Scales and sludges of oil or gas production Water treatment Filter dust of the hot metal production Extraction of Rare Earth Minerals Bauxite processing Phosphate processing Cement production Waste incineration Examples Dilution by mixing Enrichment by separation “Case A” and / or “Case B” Background radioactivity Enhanced natural radioactivity Raw materials Products, Wastes Case A Case B Case CTRANSCRIPT
Prognosis of radioactivity in
TENORM
Rainer Gellermann, FUGRO-HGN GmbH, BraunschweigMail: [email protected]
R. Gellermann, Nov. 2009
Industries and materials
TENORM
Technologically enhanced NORM
R. Gellermann, Nov. 2009
Industrial process
Industrial process
Industrial process
NORM industries
Scales and sludges of oil or gas productionWater treatmentFilter dust of the hot metal production
Extraction of Rare Earth Minerals Bauxite processingPhosphate processing
Cement productionWaste incineration
Examples
Dilution by mixing
Enrichment by separation
“Case A” and / or “Case B”
Backgroundradioactivity
Enhanced naturalradioactivity
Raw materials
Products, Wastes
Case A Case B Case C
R. Gellermann, Nov. 2009
The questions from the undertakings
OK, we know we have to deal with radioactivity.But: • What happens, if our technology is changed?• How much NORM-wastes will arise in a
certain facility?• How can the exposure of the employees
from NORM-waste be influenced?
R. Gellermann, Nov. 2009
The expected changes
NORM shall be considered as planned exposure situation
are we able to “plan” NORM amounts arising in a certain facility in advance?
How we can make prognosis on NORM wastes? (activity concentrations and masses!!)
R. Gellermann, Nov. 2009
There is a lot of experience
We know waste masses and activities of TENORM in industries.We know, that radioactivity may be enriched by technical processes
0,1
1
10
100
1000
1 10 100 1000 10000 100000 1000000
Mass in t
Spec
ific
activ
ity in
Bq/
g
Scales
Sludges
Bauxite
Filter dust
Mineral sands
Phosphate
R. Gellermann, Nov. 2009
But …
we tell us stories about radioactivity
We have examples and explanations on a qualitative level – no theory, no quantifying models, no established terms for characterising the processes of RN enrichment.
What we need is a helpful tool for analysing the processes which may result in TENORM + to communicate about these processes in an easy comparable way.
R. Gellermann, Nov. 2009
The general approach
TENORM consists of two components:
• Several radionuclides • A non-radioactive carrier
The non-radioactive carrier is an inherent part of any TENORM!
Molten silicates + RN slag
BaSO4 + Ra scale
Sand/clay + RN red mud
….
Conclusion:We have to deal with both: radioactivity AND masses!
R. Gellermann, Nov. 2009
The problem: complex systems
Real processes: pig-iron plant / steel mill
R. Gellermann, Nov. 2009
Phenomenological model of TENORM formation
Raw Material (A)
Additive (Z)uschlagstoff Product / depleted fraction
Residue / enriched fraction
Process
Balance equations
Mass balance: MMAA + + MMZZ = = MMRR + + MMPP Activity balance: : AAAA + + AAZZ = = AARR + + AAPP
ZA
R
MMM
MTF
ZA
R
AAAATF
ZFiMTFiATF
iaia
iEFA
RRA
)()(
)()(
)(
)(/)(1)(/)(1iMiMiAiA
ZFAZ
AZ
Process parameters 1: Transfer factors Process parameter 2: Enrichment factor
Additive factor
For every RN
R. Gellermann, Nov. 2009
Elementary processes
Processes Type of residue Parameters and processes affecting the radionuclide enrichment
Physical processes Thermal volatilisation Filter dust (from mineral
sintering, blast furnace smelting or other thermal processes)
Temperature (above 1000°C); total mass fraction of dust (!); content of other volatile components
Solubility of chemical elements in the molten metal
Slag Grade of ore; volatilisation (Pb-210, Po-210)
Sorption of dissolved radionuclides on oxide hydrate surfaces
Filter sands in water treatment Ra-concentration of raw water; chemical composition of raw water; duration of filter use
Chemical processes (Chemical reactions) Incineration; combustion of carbon
Ashes Carbon content of fuel
Precipitation of Ba-Sr-sulfates from water or brines
Scales, sludges (oil or gas production; geothermal plants, etc.)
Concentration of Ba-Sr-Ca in the water or brine
NaOH treatment of bauxite Red mud Grade of ore Sulphuric acid treatment of phosphate ore
Phosphogypsum Grade of ore
R. Gellermann, Nov. 2009
Iron smelting
R. Gellermann, Nov. 2009
0,01
0,10
1,00
10,00
100,00
1000,00
10000,00
100000,00
1E-05 1E-04 1E-03 1E-02 1E-01 1E+00
Massentrennfaktor MTF
Anr
eich
erun
gsfa
ktor
EF
Result: large enrichments occur only in processes with small MTF
ZFiMTFiATF
iaia
iEFA
RRA
)()(
)()(
)(
ATF = 1 (borderline)
ATF = MTF
A
R
Theory
R. Gellermann, Nov. 2009
Conclusion
· The radioactivity of wastes is only partially determined from the radioactivity of raw materials. The transfer of radionuclides into waste may result in an increase of activity concentrations which cannot be disregarded from the radiation protection point of view.
· Because high radionuclide enrichments are attributed to (very) low mass transfer factors, wastes with high activity concentrations occur usually in mass streams of technological processes, which constitute a small fraction of the total mass streams.
· Processes with mass amounts of products and wastes in the same order of magnitude are less sensitive in regard to changes of activity concentrations in the waste. Here the EF are low and the activity of wastes can be well estimated from the activity concentration of raw materials. (e.g. aluminia production from bauxite).
· Activity concentrations in wastes arising from processes with high enrichment factors are very sensitive in regard to any changes of masses in the process. That’s why the activity concentrations of scales in oil and gas production vary in different facilities in a poorly predictable degree.
R. Gellermann, Nov. 2009
Real processes
Pb-210
0,01
0,10
1,00
10,00
100,00
1000,00
10000,00
100000,00
1E-06 1E-05 1E-04 1E-03 1E-02 1E-01 1E+00
Massentrennfaktor MTF
Anr
eich
erun
gsfa
ktor
EF
Pb-2
10
Scales, ErdgasScales, ErdölScales, GeothermieSchlämme, SteinkohlenbergbauSchlämme, WasserwerkStäube, Schlämme GranitbearbeitungSchlämme, Kohleaufarbeit.PhosphogipsRotschlammAufschlussrückstand TitanerzP-SchlackeFe-SchlackeFilterstaub (Fe, P)Steinkohlen AbsetzbeckenschlammKraftwerk-FilterstaubKraftwerk-Filterpressen schlammREA-GipsHolzkraftwerk, FeuerraumascheHolzkraftwerk, FilterascheGrenzlinie
Ra-226
0,01
0,10
1,00
10,00
100,00
1000,00
10000,00
100000,00
1E-06 1E-05 1E-04 1E-03 1E-02 1E-01 1E+00
Massentrennfaktor MTF
Anr
eich
erun
gsfa
ktor
EF
Ra-
226
Scales, ErdgasScales, ErdölScales, GeothermieSchlämme, SteinkohlenbergbauSchlämme, WasserwerkStäube, Schlämme GranitbearbeitungSchlämme, Kohleaufarbeit.PhosphogipsRotschlammAufschlussrückstand TitanerzP-SchlackeFe-SchlackeFe-FilterstaubSteinkohlen AbsetzbeckenschlammKraftwerk-FilterstaubKraftwerk-Filterpressen schlammREA-GipsHolzkraftwerk, FeuerraumascheHolzkraftwerk, FilterascheGrenzlinie
Precipitation, sorption from water
High temperature processes (without combustion)
Metal smelting – Slag
R. Gellermann, Nov. 2009
Model parameters
Physical or chemical elementary process
MTF Radioelements (-nuclides) r
ATF (r) ZF (r) EF (r)
Thermal volatilisation (blast furnace, pig iron production)
0.005 Pb-210 0.9 1.4 250
U, Ra, Th 1 3 – 10 Solubility of chemical elements in the molten metal
0.1-0.3 Pb-210 0.1(b)
0.3 - 1
Sorption of dissolved radionuclides on oxide hydrate surfaces
< 1E-5 Ra 0.8-0.99 1 >1E+5
Incineration; combustion of carbon
0.1 – 0.01 U, Ra, Th 1 1 10 - 100
Precipitation of Ba-Sr-sulfates from water or brines
1E-5 Ra 0.1 1 1E+4
NaOH treatment of bauxite 0.3 U, Th, Ra, Pb-210 1 0.8 2.7 Th, Ra, Pb-210 0,9 0.55 Sulphuric acid treatment of
phosphate ore 0.72
U 0.1(a) 0.44
0.06
R. Gellermann, Nov. 2009
Application 1: Combustion of peat
U-238 Ra-226 Pb-210 Th-232 K-40Peat Bq/kg 8 4 26 1 7fly ash Bq/kg 102 26 414 12 71bottom ash Bq/kg 122 30 129 5 109
EF(Fly ash) EF 12,8 6,5 15,9 12,0 10,1EF(Bott. Ash) EF 15,3 7,5 5,0 5 15,6
R. Gellermann, Nov. 2009
Application 2: Mass-activity balance of a sinter facility
Sample Mass
(t) Mass Pb
(t)Pb-210Bq/kg
Pb 210 MBq
Ra226 MBq
Ore-coal-mix 1 1.388 1,82 133 185 5,3Ore-coal-mix 2 847 0,02 14 12 24,6F-Mix 581 1,34 3.300 1.917 4,6F-Mix 184 0,58 175 32 2,6F-Mix 188 0,53 153 29 1,5F-Mix 183 0,99 400 73 1,6Coke 99 0,01 90 9 2,1Mix V 506 0,96 20 10 2,0Input W 1.095 0,02 11 12 0,0input C 521 0,01 19 10 6,8Input V 330 1,09 25 8 0,6Dust C 339 3,84 14.600 4.956 16,6Sum Input SF 6.260 11,20 7 0,07
Sinter A 6.937 4,37 110 763 90,2Sinter B 28 6,37 158.000 4.471 0,1Residue 68 0,24 3.200 216 0,4Sum Output SF 7.033 10,97 5.449.932 90.728
R. Gellermann, Nov. 2009
The next step
• Calculate EF from chemical data!
R. Gellermann, Nov. 2009
Final remark
This approach was published in
Journal “Kerntechnik” 2008
R. Gellermann, Nov. 2009
Nuclide compositions: 6 basic types of NORM
ai,Normalized = ai/(aU-238,max + aTh-232,max)
NORM: decay series usually in equilibrium
TENORM: processes including /applying water
Products: radionuclides technically isolated
Type M2 (Precipitates from water or aqueous solutions)
0
0,2
0,4
0,6
0,8
1
Th-232 Ra-228 Th-228 U-238 Th-230 Ra-226 Pb-210 Pa-231* Ac-227*
Nor
mal
ised
act
ivity
M2-Ra,old M2-Ra, young M2-Pb
Typ M3 (Residues of chemical extractions)
0
0,2
0,4
0,6
0,8
1
Th-232 Ra-228 Th-228 U-238 Th-230 Ra-226 Pb-210 Pa-231* Ac-227*
Nor
mal
ised
act
ivity
Tailings (U-mill, carbonate leaching)Chemical processing residue (Th-230 dominated)
Type M5 (Thermo-dust)
00,20,40,60,8
1
Th-232 Ra-228 Th-228 U-238 Th-230 Ra-226 Pb-210 Pa-231* Ac-227*Nor
mal
ised
act
ivity
Filter dust from blast furnace Silicate dust from Zr-TemperingFly ash from TPP
Type M1 (Raw materials)
0
0,2
0,4
0,6
0,8
1
Th-232 Ra-228 Th-228 U-238 Th-230 Ra-226 Pb-210 Pa-231* Ac-227*
Norm
alis
ed a
ctiv
ity
M1-U (U-dominated) M1-Th (Th-dominated)
Type M6 (Product)
0
0,2
0,4
0,6
0,8
1
Th-232 Ra-228 Th-228 U-238 Th-230 Ra-226 Pb-210 Pa-231* Ac-227*
Nor
mal
ised
act
ivity
U-metal Th-alloy,old Th-alloy,young Ra-paint,old
Type M4 (Slag, ash)
0
0,2
0,4
0,6
0,8
1
Th-232 Ra-228 Th-228 U-238 Th-230 Ra-226 Pb-210 Pa-231* Ac-227*N
orm
alis
ed a
ctiv
ity
Iron Slag Slag, ash from TPP
TENORM: processes applying fire
R. Gellermann, Nov. 2009
Conclusions
• Processes of TENORM formation can be used as guidance for classification of industries regarding NORM identification of materials which have to be investigated as residue.
• Processes result in specific nuclide compositions knowledge of the processes allows conclusions regarding radiological properties optimisation of measurements.