184
5 Miscellaneous Calculations
U-235
neutron
capture
U-238
fission
U-236
fission
products
# 1
Pu-239
fission
Pu-240
Pu-241
Pu-242
neutron
capture and
beta-decay
neutron
capture
neutron
capture
neutron
capture
fission
products
# 2
neutron
capture
fission
Fig. 5.3 Flowchart for species tracked in reactor simulation. The relevant cross-sections appear in
Table 5.1
per fission, then the rate R of fissions must be R = P t /E f . Converting to power in
megawatts, E f in MeV, and a time unit of one day, the daily rate of fissions must be
f issions/day = R =
(86400)
10
6
P t
1.6022 × 10 −13 E f
.
(5.12)
The unit of time in the simulation is taken to be one day, but the user can set the
timestep in days or fractions thereof as desired. Over such a timestep, we will
have
5 Miscellaneous Calculations
U-235
neutron
capture
U-238
fission
U-236
fission
products
# 1
Pu-239
fission
Pu-240
Pu-241
Pu-242
neutron
capture and
beta-decay
neutron
capture
neutron
capture
neutron
capture
fission
products
# 2
neutron
capture
fission
Fig. 5.3 Flowchart for species tracked in reactor simulation. The relevant cross-sections appear in
Table 5.1
per fission, then the rate R of fissions must be R = P t /E f . Converting to power in
megawatts, E f in MeV, and a time unit of one day, the daily rate of fissions must be
f issions/day = R =
(86400)
10
6
P t
1.6022 × 10 −13 E f
.
(5.12)
The unit of time in the simulation is taken to be one day, but the user can set the
timestep in days or fractions thereof as desired. Over such a timestep, we will
have