62
C. H. Pyeon
Table 3.5 Comparison of
C/E values in measured and
calculated neutron decay
constants (Ref. [2])
Case
Fiber #1
Fiber #2
Fiber #3
10
1.02 ± 0.02
1.12 ± 0.03
1.07 ± 0.02
11
1.16 ± 0.02
1.11 ± 0.03
1.18 ± 0.03
12
1.05 ± 0.02
1.07 ± 0.03
1.09 ± 0.02
13
1.04 ± 0.03
1.07 ± 0.04
1.12 ± 0.04
14
1.07 ± 0.03
1.04 ± 0.04
1.14 ± 0.04
15
1.16 ± 0.03
1.18 ± 0.05
1.21 ± 0.04
16
1.11 ± 0.04
1.03 ± 0.05
1.06 ± 0.04
17
0.88 ± 0.03
0.96 ± 0.05
0.83 ± 0.03
18
1.13 ± 0.03
1.06 ± 0.03
1.12 ± 0.03
Fig. 3.7 Measured and
calculated results of neutron
decay constants in KUCA
kinetic experiments (Ref.
[2])
500.0
1000.0
1500.0
2000.0
500.0
1000.0
1500.0
2000.0
Calculated neutron decay constant α (1/sec)
Measured neutron decay constant
α (1/sec)
Fiber #1
Fiber #2
Fiber #3
#2 showed a good evaluation of the prompt neutron decay constant, considering the
detector position dependency of prompt neutron decay constant measurements.
3.2 Pulsed-Neutron Source Method
3.2.1 Experimental Settings
3.2.1.1 Core Configurations
The ADS experiments with 100 MeV protons (Pb–Bi target) were carried out in the Acore (Fig. A2.11) [10] comprising a highly-enriched uranium (HEU) fuel, a polyethylene moderator, and Pb–Bi reflector rods. The fuel assembly “F” (3/8
p36EU) is
composed of 36 unit cells, and upper and lower polyethylene blocks are about 25
and 20
long, respectively, in an aluminum (Al) sheath 2.1
× 2.1
× 60
, as shown
in Fig. A2.12. A special fuel assembly “f” (1/8
p5EUEU <1/8
Pb-Bi30EUEU>