4. Conclusions
In the current study the effect of adding colemanite minerals to
barite concretes and some its radiation shielding and engineering
outcomes were studied. The photoneutrons production from two
new barite–colemanite concretes was calculated by MC simulations.
Additionally, the photon attenuation properties of new concretes
were measured against available photon beams in radiation therapy.
Adding colemanite to barite concrete caused lower photoneutron
production at the maze door for new concretes. On the other hand,
the engineering tests on our barite–colemanite concretes revealed
significant reduction in compressive strength compared to the barite concrete. According to our results, it can be concluded that adding
colemanite to barite concrete can reduce neutron production inside
radiation bunkers, but its main disadvantages including reduced
0 1020304050
0.01
0.1
1
Transmitted radiation fraction
Thickness (cm)
Barite
Barite-Colemanite 5%
Barite-Colemanite 10%
Fig. 5.The measured attenuation curves for studied concretes in 18 MV photon
beam of Varian 2100 linac.
Table 2
Measured linear attenuation coefficients and half value layers for three concretes
against
60
Co gammas, 9 MeV and 18 MeV photon beams.
Concrete
type
60
Co 9 MeV 18 MeV
HVL
(cm)
l
(cm
1
)
HVL
(cm)
l
(cm
1
)
HVL
(cm)
l
(cm
1
)
Barite 3.3 0.21 4.47 0.155 5.68 0.122
B–C5% 3.55 0.195 4.68 0.148 5.92 0.117
B–C10% 3.85 0.18 4.95 0.140 6.18 0.112
Table 3
The results of compressive strength study on constructed concrete blocks 14 and
28 days after production.
Concrete type Mass density of fresh concrete (g/
cm
3
)
Compressive
strength (MPa)
14 days 28 days
Barite 3400 35 45
Barite–colemanite
5%
3235 25 30
Barite–colemanite
10%
3060 18 24
110 A. Mesbahi et al. / Annals of Nuclear Energy 51 (2013) 107–111
photon attenuation coefficient and lower compressive strength remains unsolved and should be considered in shielding and engineering planning.