– EMRAS II, WG7, January 2010 – Page 1 TRANSFER STUDY OF 14 C and 3 H BETWEEN AIR, GRASS AND COWS : VALIDATION OF TOCATTA MODEL (VATO) IRSN / DEI / SECRE (France) Denis MARO 1 Séverine Le Dizès 2 & Didier Hébert 1 1 IRSN/Laboratory of Continental Radioecology/Cherbourg-Octeville 2 IRSN/DEI/Environmental Modelling Laboratory/Cadarache, St-Paul-lez Durance
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TRANSFER STUDY OF C and H BETWEEN AIR, GRASS AND COWS ...€¦ · – EMRAS II, WG7, January 2010 – Page 3 Estimate fluxes of 14 C and 3H in a grassland ecosystem ( Raygrass ),
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– EMRAS II, WG7, January 2010 – Page 1
TRANSFER STUDY OF 14C and 3H BETWEEN AIR, GRASS AND COWS : VALIDATION OF
TOCATTA MODEL (VATO)
IRSN / DEI / SECRE (France)
Denis MARO 1
Séverine Le Dizès 2 & Didier Hébert 1
1IRSN/Laboratory of Continental Radioecology/Cherbou rg-Octeville2IRSN/DEI/Environmental Modelling Laboratory/Cadarac he, St-Paul-lez
Durance
– EMRAS II, WG7, January 2010 – Page 2
Context and objectives | Methodology | Results | Conclusion
� Uncertainties in transfer models of 14C and 3H in rural environment in case of accidental release due to a lack of global experimental data
� In general transfer models are based on constant isotopic ratio and this concept is not very appropriate with accidental releases
Necessary to acquire well-documented new data of concentrations of 14C and 3H in different compartments of the rural environment
Context
– EMRAS II, WG7, January 2010 – Page 3
� Estimate fluxes of 14C and 3H in a grassland ecosystem (Raygrass), in relation with : - 14C and 3H concentrations in air,- Climate conditions,- Land use (grazing, silage maize and hay).
� Study transfers of 14C and 3H to cows and milk in function of the alimentary diet.
In order to improve the TOCATTA model or another model
Objectives
Context and objectives | Methodology | Results | Conclusion
– EMRAS II, WG7, January 2010 – Page 4
� Originality : Using the atmospheric release of radionuclidesof AREVA NC La Hague reprocessing plant to quantify the transfers of 14C and 3H in rural environment
Two chimneys
Context and objectives | Methodology | Results | Conclusion
– EMRAS II, WG7, January 2010 – Page 5
14C and 3H atmospheric releases
0,0E+00
1,0E+13
2,0E+13
3,0E+13
2003 2004 2005 2006 2007
Time (years)
3H (Bq.an-1)
0,0E+00
1,0E+12
2,0E+12
3,0E+12
14C (Bq.an-1)
Tritium
Carbon 14
Lead to greater concentration than the background level in the environment
Context and objectives | Methodology | Results | Conclusion
– EMRAS II, WG7, January 2010 – Page 6
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#BEAUMONT-HAGUE
SAINT-GERMAIN-DES-VAUX
AUDERVILLE
DIGULLEVILLE
OMONVILLE-LA-ROGUE
OMONVILLE-LA-PETITE
JOBOURG
ECULLEVILLE
GREVILLE-HAGUE
HERQUEVILLE
6.3
5.5
5.4
4.8
5.5
5.2
7.9
6.6
6.1
5.2
6.9
8.7
8.5
7.7
4.3 8.0
5.2
5.9
9.1
9.0
9.2
3.1
4.4
5.9
9.4
8.0
9.2
9.9
8.3
3.9
7.5
5.1
6.0
7.9
7.0
5.5
6.9
10.3
13.2
15.2
54.6
10.9
14.0
12.5
12.9
11.4
12.8
13.1
14.4
12.5
10.7
13.2
14.4
12.3
11.1
10.2
COGEMA-ANDRA
N
EO
S
500 0 500 1000 M
Example of OBT concentration measured in furze
AREVA NC
0
5
10
15
20
25
30
35
40
1975 1980 1985 1990 1995 2000 2005
Date (year)
concentration (Bq.L
-1)
Background noise
Context and objectives | Methodology | Results | Conclusion
– EMRAS II, WG7, January 2010 – Page 7
Wind conditions 2008 - "Omonville La Petite". Wind speed (m.s-1) and Direction (°)
« Atelier Nord » : a well located experimental site, considering the most frequent wind direction
EXPERIMENTAL SITE« Ateli er Nord »
AREVA LA HAGUE
Site location
0
2
4
6
8
10
12
360
20
40
60
80
100
120
140
160
180
200
220
240
260
280
300
320
340
Context and objectives | Methodology | Results | Conclusion
Context and objectives | Methodology | Results | Conclusion
Example of CO2 atmospheric concentrations
– EMRAS II, WG7, January 2010 – Page 10
Context and objectives | Methodology | Results | Conclusion
Example of 14C concentrations
Does the model give a good representation of 14CO2 between air and grass? No, as it uses constant isotopic ratio (no photosynthetic process)To get a better model-measures comparison : need to rebuild 14Catmospheric concentrations on an hourly basis and use a dynamic model
Context and objectives | Methodology | Results | Conclusion
To obtain more precise 14C atmospheric concentrations for calculations
– EMRAS II, WG7, January 2010 – Page 13
Conclusion
� The results analysis needs dynamic modelling of 14C and 3H in plants, it’s necessary to take into account the modelling of photosynthesis
� Concerning 3H modelling in case of accidental release, it is also necessary to consider water transfer processes with a dynamic approach based on a short time step
� Ongoing discussions with INRA (Clermont-Ferrand) to use the PASIM* model
� PASIM* is a biogeochemical grassland ecosystem model that simulates fluxes of C, N, water and energy at the soil-plant atmosphere interface with hourly step time
*Riédo et a., 1998. A Pasture Simulation Model for dry matter production, and fluxed of carbon, nitrogen, water and energy. Ecol. Model. 105, 141-183.
Context and objectives | Methodology | Results | Conclusion
– EMRAS II, WG7, January 2010 – Page 14
Agenda
Carbon 14
2007-2009 : Transfers between air, grass and soil
Tritium
2010 : Measurement (speciation of 3H releases in air)
2009-2010 : Transfers to cow
2009-2010 : Model-measures comparisons
2010/2011 : Publication
2010-2011 : Transfers between air, rain water, grass and soil…dry and wet deposition
2012 : Transfers to cow
2012 : Publication
2011-2012 : Model-measures comparison
Context and objectives | Methodology | Results | Conclusion