Transcript スライド 1 - International Atomic Energy Agency

D2O release experiments
Prof N. Momoshima, Kyushu University, Japan
• From a view point of health physics, studies on
tritium behavior in the environment are necessary
for an accurate dose assessment ; such as actual
HT oxidation in the local environment, transfer of
HTO to soil, plants and animals, and OBT
formation and tritium elimination in them.
• However, field experiments on environmental
behavior of tritium are quite difficult to do because
of the public acceptance problem in Japan.
• Thus heavy water (D2O) vapor release
experiments was planed and carried out.
Grants-in-Aid for Scientific Research from the
Ministry of Education, Science and Culture,
Japan
• Environmental Behavior and Biological
Conversion of Tritium -Preliminary Release
Experiment of Heavy water in a Greenhouse1995～1996
• Transfer of tritium to crops, animals and
fishes during an accidental release of tritium
and its retention
1997-1999
Prof. M. Ichimasa, Ibaraki Univ. Japan
Members of the program and joined to the D2O experiments (red)
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M. Ichimasa (Ibaraki Univ.)
Y. Ichimasa (Ibaraki Univ.)
H. Takeda (NIRS)
S. Hisamatsu (Akita Univ.)
H. Amano (JAERI), M. Atarashi
H. Noguchi (JAERI), S. Yokoyama
N. Momoshima (Kyushu Univ.), H. Kakiuchi
T. Okai (Kyushu Univ.)
Y. Sakuma (NIFS)
M. Saito (Kyoto Univ.)
A. Ito (Hiroshima Univ.)
K. Komatsu (Hiroshima Univ.)
K. Okuno (Shizuoka Univ.)
Transfer of D2O to soil, plants and animals, and OBD formation
and tritium elimination
A greenhouse was constructed in the field of the Ibaraki
University. Closed type and top open type.
Closed type
(1995-97 and 1999)
D2O
Top open type
(1998)
1995
1996
1997
1998
1999
Size
12.8m3
23.3m3
(3.6mLx3.6mWx1.8mH)
23.3m3(3.6x3.6x1.8m)
62m3 (two cylinders)
5.74mDx2.4mH
23.3m3 (two houses)
(3.6x3.6x1.8m)
Date
3-4 Nov.
24-26 Aug.
23-25 Aug.
22-24 Aug
22-24 Aug
Release
24h
48h
48h
9h (daytime)
11h (nighttime)
8h (daytime)
8h (nighttime)
17.9L (20% D2O)
19.5L daytime
14.9L nighttime
20% D2O
20% D2O and 13CO2
3300 ppm (daytime)
10600 ppm
(nighttime)
29.6-34.1 (daytime)
19.6-23.6 (nighttime)
Air conditioner (4)
1.3L (20%D2O)
4.5L (20%D2O)
3.6x104 ppm
2.2x104 ppm
1.2x104 ppm
8500 ppm (daytime)
8100 ppm (nighttime)
Temp
(℃)
13.1-27.9
heater
17-30
Air conditioner (2)
20.6-27.9
Air conditioner (4)
22-27 (daytime)
20.5-22(nighttime)
No control
Relative
Humidity
61% (48-69)
daytime
71% (67-73)
nighttime
8/24 81% '72-88)
daytime
8/25 75% (60-80)
daytime
8/24 88% nighttime
65% (37-70) daytime
66% (62-69)
nighttime
42% (32-56) daytime
94% (84-97)
nighttime
Light
11/4 13:00-15:00
103 umol/s/m2
(20-690)
8/25 13:00-15:00
222 umol/s/m2
(79-460)
8/24 13:00-15:00
283 umol/s/m2
(41-620)
189 umol/s/m2
(33-671)
158 umol/s/m2
(23-370)
Atmospheric D2O concentrations in the close type greenhouse (1997).
End
D2O
Different
points
48h release
Time (h)
Atmospheric D2O concentrations in the
top open type greenhouse(1998).
The D2O concentrations
changed with time due to
wind and did not reach to a
steady state.
A large difference in
concentration with height
near the D2O humidifies
but not so much apart
points.
Topic of research
• Uptake and release of D2O by plants
– rice, radish, tomato, komatsuna, cabbage,
orange, soybean, (maze, potato・・）
• Uptake and reemission by soil
– Sandy soil
• OBD formation
– rice
List of publications related to D2O experiments
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Deposition of D2O from air to plant and soil during an experiment of D2O vapor release into a vinyl house,
Mariko Atarashi, Hikaru Amano, Michiko Ichimasa, Yusuke Ichimasa, Fusion Engineering and Design 42
(1998) 133–140
Formation and retention of organically bound deuterium in rice in deuterium water release experiment, M.
Atarashi-Andoh, H. Amano, H. Kakiuchi, M. Ichimasa and Y. Ichimasa, Heaoth Physics, 82, 863-868 (2002).
Uptake of heavy water vapor from atmosphere by plant leaves as a function of stomatal resistance, M.
Atarashi, H. Amano, M. Ichimasa, M. Kaneko and Y. Ichimasa, Proceedings of International Meeting on
Influence of Climatic Characteristics upon Behavior of Radioactive Elements, Rokkasho, Aomori, Japan,
October 14-16, 1997, Edited by Y. Ohmomo and N. Sakurai, IES, 236-242 (1997).
Conversion rate of HTO to OBT in plants, M. Atarashi-Andoh, H. Amano, M. Ichimasa and Y. Ichimasa,
Fusion Science and Technology, 41, 427-431 (2002).
Uptake kinetics of deuteriated water vapor by plants: Experiments of D20 release in a greenhouse as a
substitute for tritiated water, N. Momoshima, H. Kakiuchi, T. Okai, S. Yokoyama, H. Noguchi, M. Atarashi, H.
Amano, S. Hisamatsu, M. Ichimasa, Y. Ichimasa, Y. Maeda, Journal of Radioanalytical and Nuclear
Chemistry, Vol. 239, No. 3 (1999) 459-464
Uptake of deuterium by dead leaves exposed to deuteriated water vapor in a greenhouse at daytime and
nighttime, N. Momoshima, R. Matsushita, Y. Nagao and T. Okai, J. Environ. Radioactivity,88, 90-100 (2006).
Organically bound deuterium in soybean exposed to atmospheric D2O vapor as a substitute for HTO under
different growth phase, M. Ichimasa, T. Maejima, N. Seino, T. Ara, A. Masukura, S. Nishihiro, H. Tauchi and Y.
Ichimasa, Proceedings of the International Symposium: Transfer of Radionuclides in Biosphere –
Prediction and Assessment-, Mito, December 18-19, 2002, JAERI-Conf 2003-010, 226-232 (2003).
Heavy water vapor release experiment in a green house –Transfer of Heavy water to tomato and dishcloth
gourd—, M. Ichimasa, T. Hakamada, A. Li, Y. Ichimasa, H. Noguchi, S. Yokoyama, H. Amano and M. Atarashi,
Proceedings of International Meeting on Influence of Climatic Characteristics upon Behavior of
Radioactive Elements, Rokkasho, Aomori, Japan, October 14-16, 1997, Edited by Y. Ohmomo and N.
Sakurai, IES, 243-248 (1997).
Organically bound deuterium in rice and soybean after exposure to heavy water vapor as a substitute for
tritiated water, M. Ichimasa, C. Weng, T. Ara and Y. Ichimasa , Fusion Science and Technology, 41, 393-398
(2002).
Deposition of heavy water on soil and reemission to the atmosphere, Sumi Yokoyama, Hiroshi Noguchi,
Michiko Ichimasa, Yusuke Ichimasa, Satoshi Fukutani, Fusion Engineering and Design 42 (1998) 141–148
Re-emission of heavy water vapor from soil to the atmosphere, S. Yokoyama, H. Noguchi, Y. Ichimasa and
M. Ichimasa, Journal of Environmental Radioactivity, 71, 201-213 (2004).
Rate constants and mostly cases Cmax/Cair
were obtained for various kind of plants
Uptake
Cp=Cmax (1-e-kt)
Release
Cp=Co e-k’t
•Deposition of D2O from air to plant and soil during an experiment
of D2O vapor release into a vinyl house, Mariko Atarashi, Hikaru
Amano, Michiko Ichimasa, Yusuke Ichimasa, Fusion Engineering
and Design 42 (1998) 133–140
OBD formation at daytime and nighttime
Formation and retention of organically bound deuterium in rice in
deuterium water release experiment, M. Atarashi-Andoh, H. Amano, H.
Kakiuchi, M. Ichimasa and Y. Ichimasa, Health Physics, 82, 863-868 (2002).
OBD formation at daytime and nighttime
1998/8/22/8:00
17:00
5000
D 2 O Concentration (ppm)
dead (daytime)
fresh (daytime)
4000
Daytime exposure
3000
2000
1000
0
0
5
1998/8/23/20:00
10
15
Time (h)
20
25
30
8/24/7:00
D 2 O Concentration (ppm)
5000
dead (nighttime)
fresh (nighttime)
4000
The dead cedar needles
taken up more D2O than
fresh ones both in daytime
and nighttime exposures.
Nighttime exposure
3000
2000
The release rate was faster in
dead cedar needles.
1000
0
0
5
10
15
Time (h)
20
25
30
Four kinds of leaves
were exposed to D2O
at daytime and
nighttime in 1999.
Fresh leaves dried at
80 °C were rewetted
for 3 days and the
biaxial leaf surface
was exposed.
D 2O Concentration in air (ppm)
25000
20000
Nighttime
15000
Daytime-１
Daytime-２
Nighttime
0
Exp.
1h
1h
2h
茨城大学測定
Exposure
5000
0
Run
Daytime
10000
1
2
3
4
5
Time (h)
Temp
（℃）
32.3〜33.3
34.2〜36.0
23.2
6
RH
（%）
58〜61
57〜59
99
7
8
D2O conc.
（ppm）
13700
12200
16300
1
Prunus
mume
Run-1 daytime
Concentration ratio leaf to air
Run-2 daytime
0.8
Acer
palmatum
Run-3 nighttime
Nighttime
0.6
0.4
Cinnamomum
camphora
Camellia
sasanqua
Daytime
0.2
0
4
1 10
2 10
4
3 10
4
4 10
4
5 10
4
6 10
4
7 10
4
Number of stama (cm-2)
Uptake of deuterium by dead leaves exposed to deuteriated water vapor in a
greenhouse at daytime and nighttime, N. Momoshima, R. Matsushita, Y.
Nagao and T. Okai, J. Environ. Radioactivity,88, 90-100 (2006).
F = Vex ･ (Ca - r ･ h･Cs)
Cinnamomum camphora
10kV（top）と30kV（below）、
magnification 3500
Stoma size 20-30μm
Re-wetted
Dry
Vex：exchange rate （m/s）
Ca：HTO conc. in air （Bq/m3）
r：HTO & H2Ovapor saturation ratio （0.92）
h：Water content at leaf surface
（kg-H2O/m3-air）
Cs：HTO conc. in leaf （Bq/kg）
Air
H2O
D2O
1996