low-background environmentalactivitiesat irsn
TRANSCRIPT
Low-background environmental activities atIRSN
SurveillanceRadioecologyDosimetryand other things
R. GurriaranIRSN/DEI/STEME/LMRE
- - 2/37
1.The IRSN
2.The need for low background measurements
3.Actual use of LSM measurementsSome examples
- 3/ 37 LMRE @ LSM 10/2009
ASN
French Authority
French Nuclear Establishment
IRSN
Independent Expert body
EDF, CEA, AREVA…
Nuclear facilities
Decisions (opening, closure…)
Expertise
- 4/ 37 LMRE @ LSM 10/2009
General director
Reactor Safety Division
Plants, Laboratories, Transports and Waste Safety Division
Nuclear defence Expertise Division
Major Accident Prevention Division
Radiological Protection and Human Health Division
Environment and Emergency
Operations Division
Institute for Radiological Protection and Nuclear Safety
~1600 persons involved in all the aspects of nuclear safety
~70 PhD students
Quantification, monitoring and interpretationof radioactivity in the environment ;
- 5/ 37
Environmental levels
…or the continuous need for improvement
- 6/ 37 LMRE @ LSM 10/2009
Russian and american tests1960 to 1963
17 juin 1967 à 14 octobre 1970
17 juin 1974
17 novembre 1976
16 octobre 1980
Chinese tests
Algesiras
Saclay
137Cs in the atmosphere
- 7/ 37 LMRE @ LSM 10/2009
Other radionuclides in the atmosphere(Orsay)
- 8/ 37 LMRE @ LSM 10/2009
Environmental levelsFucus serratus -seaweed- English Channel
0,1
1
10
100
1000
10000
02/01/1983 01/01/1985 02/01/1987 01/01/1989 02/01/1991 01/01/1993 02/01/1995 01/01/1997 02/01/1999 01/01/2001 02/01/2003 01/01/2005 02/01/2007
Sampling date
Act
ivity
[Bq.
kg-1
dry
wei
ght]
60Co 40K 137Cs 241Am 154Eu 106Rh 60Co 40K 137Cs 106Rh 241Am
- 9/ 37 LMRE @ LSM 10/2009
• Aims : Radioecological studies, understand and forecast the behaviour of released radionuclides in normal or incidental operation
• Detection limits are not good enough to validate the models
• Need to continuously improve the measurementmethods
- 10/ 37 LMRE @ LSM 10/2009
Standard detectors @ Orsay
•Shielded room, 50% relative efficiency•3 m concrete overhead (~ 10mwe)
- 11/ 37 LMRE @ LSM 10/2009
Special and low background detectors @ Orsay
- 12/ 37 LMRE @ LSM 10/2009
Ultra low background detectors @ LSM
Le laboratoire est situé à 1700 m sous la pointe du Fréjus au milieu du tunnel routier
- 50% coaxial N-type
-Well type 860 cm3
-Well type 450 cm3
- 13/ 37 LMRE @ LSM 10/2009
Detector Backgrounds
1
10
100
1000
10000
30 230 430 630 830 1030 1230
E [keV]
Cou
ps/c
anal
a)
b)
c)
d)
210Pb
214 BiPb214
511 keV
228 214BiAc
Standard
Low background
Low background+ Anti-cosmic
Ultra lowbackground
- 14/ 37 LMRE @ LSM 10/2009
Background count rates[cpm 30 keV-2700 keV]
Detector backgrounds
PPT
XXL
51C n
52E
64O n
64O a
51C a
56I (1 PM)
56I
50E61C
46C
59C47O55O54O
50C
68O63O61O60O
0,10
1,00
10,00
100,00
1000,00
events/m
in [20-2700 keV]
Coaxial N type BEGe
anti
cosm
ic d
evi
ce
Standard detectors under 3 m concrete -
shielded room (10 cm Lead - 1 cm Cu)
~10 mwe
Low background at
~10 mwe
3 m concrete
ultra low
background
LSM ~4800 m we
anti
-com
pto
n d
evi
ce
Replacement of detectors by a new
generation - better adapted, better
backround
Replacement of detectors by a
new generation - better
adapted, better backround
- 15/ 37
Understand and forecast…
•Regulatory surveillance
•Aerodynamics particle sizes
•Dosimetry impact
•Chronic doses
- 16/ 37 LMRE @ LSM 10/2009
Knowing the radioactive backgroundpart of French regulatory surveillance
Far from nuclear facilities :
• Air • Aerosol• Rain
• Ocean and Terrestrialcompartment
• Soil• flora• fauna
• Fluvial compartment• Water
+ Papeete (Tahiti)+ La Réunion
- 17/ 37 LMRE @ LSM 10/2009
Evolution du césium-137 et du béryllium-7 dans les aérosols prélevés à Papeete de 1970 à juin 2000 (données décadaires)
0,01
0,1
1
10
100
1000
10000
100000
70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 00
Année
Act
ivité
[µB
q.m
-3]
Césium-137
Béryllium-7
LMRE
Standard detectors
anti-cosmic Orsay, 40% of detections
Ultra low level @ LSM, ≈100% of detections
Atmospheric 137Cs and 7Be at Papeete
- 18/ 37 LMRE @ LSM 10/2009
Understanding the sources of radioactivity
Understand and forecast the behaviour of released radionuclidesin normal or incidental operation
•Atmospheric discharges
•Aerosol Aerodynamic sizes
Aerosol aerodynamic sizes @ AREVA La Hague
- 19/ 37 LMRE @ LSM 10/2009
Aerodynamic sizes @ AREVA La Hague
13 Disks from 0.059 to >10.08 µm
0.040.90.45Total
137Cs106Rh125Sb129IBq
- 20/ 37 LMRE @ LSM 10/2009
Environmental expertise
Camargue sand beaches
• Ambiant dose rates reaching a few µSv/h
• Natural origin (U and Th) up to 5000 Bq/kg at secular equilibrium
• Zyrcons
• Internal dosimetry questions : - i.e. inhalation
DRPH/SRBE/Laboratoire de RadioTOXicologie Expérimentale
- 21/ 37 LMRE @ LSM 10/2009
• Solubility of the sand in a pulmonar fluid
• Difficulty : • - extremely small samples/low radioactive
• - measurements at LSM
• Children : 1 mSv reached with 40 kg of sand
0
20
40
60
80
100
120
140
234Th 214Pb 214Bi 210Pb
Descendants de l’Uranium
% Solubilisé
0102030405060708090
228Ac 212Bi 212Pb 208Tl
% Solubilisé
Descendants du Thorium
Camargue sand beaches
- 22/ 37 LMRE @ LSM 10/2009
Evaluation of the 137Cs distribution in rats after chronical consumption of contaminated water (6500 Bq.l-1)
Measurement of 137Cs in the thyroid of contaminated rats, Need of LSM measuremenst
Not expected on the biokinetics models
* Activités obtenues en utilisant un détecteur Ge ultra pur, coaxial, Φ= 58.8mm ; efficacité à 1.33 Mev = 42.1%
Chronic doses
- 23/ 37 LMRE @ LSM 10/2009
Understanding transport phenomena
- 24/ 37 LMRE @ LSM 10/2009
Conclusions
• Globally, artificial radioactivity in the environment is decreasing
• Hence, need of improving the detection limits for radioecologystudies and Regulatory surveillance
• The use of underground gamma spectrometry opens a window of oportunity in several fields :
• Environment
• Biology
• Dosimetry
• Our future studies :- Measuring the radioactivty of clouds
- Understanding the accumulation of radioactivity in the first few drops of rain
- …