JAEA-Conf 2011-002 - 日本原子力研究開発機構

components, the 0.56Wt% for hydrogen concentration adopted
in ITER design is employed, and the concrete density of
2.1g/cm 3 (instead of 2.3 for ITER) is used to consider a safety
margin for required environmental assessment.
3.3 Calculations
Fig.3 shows the neutron number in void at the angle of 60º
with respect to beam direction and the position of the
3.1m-radius. The gamma-ray and neutron are generated in
central Cu with 0.005m radius. For the neutron number, the
maximum of 5x10 8 [n] is obtained and the energy range extends
to 15MeV. For photon, the maximum number is 5x10 7 [n] and the maximum energy is 14MeV.
In Fig.4, neutron and photon numbers at the same detector position with additional 0.75m radius water
layer is indicated. This geometry corresponds to Material0 (Copper) radius r0=0.005, Material1 (water)
layer r1=0.755m (0.005m+0.75m) and no Material2 and Material3 layer, in Fig.2. The neutron number is
reduced to the 10 4 -order level.
Fig.5 indicates neutron and photons
throughout the combined geometry with water
layer of 0.75m and the concrete layer of 2.0m
(local concrete: 0.5m + concrete wall: 1.5m) at the
same detector position. The numbers of neutron
and photon is reduced to 10 2 detector position
(3.1m)
0 0 Center (Cu)
(r0 :0.005m)
60 60
90 90
r2
Material2
Material1
r1
r3
Material3
Figure 2: Analysis model
no. = 5, reg =10
-order level, and it is
found that these energy ranges extend to 6MeV
(neutron) and 8MeV (photon).
As shown in Fig.6, for geometry with the
water layer of 0.75m and the iron layer of 0.25m
the maximum neutron number is the same level as Figure 3: No shield (Vacuum status)
(M1, M2 and M3 are in vacuum)
-5
10
neutron
photon
0 5 10 15 20
Energy [MeV]
5
10 2
10 4
10 3
10 9
10 6
10 8
10 7
Flux [1/cm 2 /MeV/source]
10 5
10 2
10 4
10 3
10 9
10 6
10 8
10 7
10 1 05
no. = 5, reg =10 -5
10 15 20
Energy [MeV]
neutron
photon
Figure 4: Water
(M1 is water, r1=0.755m without M2 and M3)
JAEA-Conf 2011-002
Flux [1/cm 2 /MeV/source]
Flux [1/cm 2 /MeV/source]
10 2
10 1
no. = 5, reg =10 -5
0 5 10 15 20
Energy [MeV]
neutron
photon
Figure 5: Water & Concrete
(M1 is water, r1=0.755m and M2 is concrete,
r2=2.755m, without M3)