4 Effective Delayed Neutron Fraction
109
Fig. 4.9 Comparison
between measured and
calculated (MCNP6.1 with
ENDF/B-VII.1 and
PARTISN) prompt neutron
decay constants in 14 MeV
neutrons (Ref. [15])
500
1000
1500
2000
500
1000
1500
2000
2500
0
Calculated by MCNP6.1 [1/s]
Measured
[1/s]
BF 3 #1
BF 3 #2
BF 3 #3
BF 3 #4
PARTISN
Fig. 4.10 Comparison
between measured and
calculated (MCNP6.1 with
ENDF/B-VII.1 and
PARTISN) prompt neutron
decay constants in spallation
neutrons (Ref. [15])
500
1000
1500
2000
500
1000
1500
2000
2500
0
Calculated by MCNP6.1 [1/s]
Measured
[1/s]
BF 3 #1
BF 3 #2
BF 3 #3
BF 3 #4
LiFCAF
PARTISN
4.3.3 Results and Discussion
4.3.3.1 Evaluation of β eff /
β eff / as representative of the cores were experimentally deduced by combining α
and ρ $ at BF 3 #2 detector as follows:
β eff
Λ
EXP
=
α
EXP
1 + ρ
EXP
$
.
(4.46)
Also, calculated β eff / values were obtained by combining adjoint-weighted
effective delayed neutron fraction β
PARTISN
eff
by PARTISN, and the adjoint-weighted
generation time
PARTISN was defined as follows: